BHO Extraction Booth Design

With legalization, comes regulation, and one regulation facing local extractors, is the requirement that they have a certified extraction facility.

To obtain that certification, requires a panoply of steps and maneuvers, including certified extraction equipment, but a subject that comes up regularly, is what is required for a legal extraction booth itself???

More at:  https://skunkpharmresearch.com/bho-extraction-booth-design/

18 responses to this post.

  1. Going through the post ( https://skunkpharmresearch.com/bho-extraction-booth-design/ ) I found the following mistakes (most of which fall into the non-obvious category, so they are reasonable for an non-expert chemical to make). While the tables in the post are correct for their intended use, their intended use was not for butane/propane extraction systems or other chemical processes that generate large amounts of flammable vapor which may suddenly be released. Spray booths generally fall well below the range I’m referring to. I finish with recommendations for chemical fumehoods with links to examples. I also include my version on the dangers of blasting.

    First mistake: There are no intrinsically safe extractor designs, butane or otherwise, just degrees of risk.

    Mistake #2: Risk analysis has two parts, frequency of accidents and inherent danger. Well designed and maintained equipment along with well trained people following well thought out procedures reduces the frequency of accidents, but sooner or later an accident will happen. Butane (and propane) are inherently extremely dangerous because they are gases at room temperature and pressure, so can not be contained in the event of a spill. On top of that they are flammable and the rate of ignition is largely determined by the amount of vapor (gas)… which is why the SDS for butane lists it as an explosive hazard, but an SDS for hexane (a liquid) does not. That said, any process which creates a large amount of organic vapor (such as distillation) poses an explosive risk.

    Mistake #3: A sudden release of gas will swamp any ventilation system, and in the worse case butane extractors rupture (fast and large release) not leak (slow and small release). Risk analysis dictates one plans according to worst reasonable case accident: in the case of butane that is an explosion. On a pound per pound basis the heat of combustion (energy released by burning) a kilo of butane is more than 9 times the work energy of detonation of TNT (figuring out how destructive a butane explosion could be relative to a TNT explosion is not as simple as comparing these energies but it is a starting point). Therefore professionally (and I mean chemical engineers) designed facilities doing butane or propane extraction are designed as stand alone buildings remote from other buildings (this is largely true of alcohol distilleries, and always true of petroleum refineries, as well). For a facility doing low ton scale butane extractions, figure a 1/2 mile (~1 km) of empty field between the extraction facility and the next closest, well, anything. This is to account for both direct blast damage and flying debris. Oh, by empty field I mean empty field – no crops, no storage, no livestock, no nothing that would require people in that area while the facility was in use. A 1/2 mile safety perimeter works out to be about 500 acres, making large scale butane extraction uneconomical for all but large businesses. For those using a 10 kg tank of butane, a 50 meter safety perimeter might be on the low side, considering probably less than 2 kg of natural gas did this ( http://www.nbcnews.com/news/us-news/oregon-natural-gas-explosion-injures-eight-destroys-building-n669156 http://www.oregonlive.com/portland/index.ssf/2016/10/portland_gas_explosion_2016_bu.html ). Note: the distances between storage tanks and buildings is less than those I’ve outlined above, largely due to the fact that storage tanks tend to leak when they fail while with extractors one must plan for ruptures (blow seals, etc) releasing a lot of gas at once. OSHA regulations set the distances between storage tanks and the size limit on storage within a building. Those regulations can be found here: http://www.ecfr.gov/cgi-bin/text-idx?SID=a8ce610c9aa63d9b9e50651823779ee1&mc=true&node=se29.5.1910_1110&rgn=div8

    In general, the OSHA regulations (including ventilation) can be found here: http://www.ecfr.gov/cgi-bin/text-idx?SID=a8ce610c9aa63d9b9e50651823779ee1&mc=true&tpl=/ecfrbrowse/Title29/29cfr1910_main_02.tpl

    Mistake #4: the designs in the post are more appropriate for particulate matter not chemical hazards. Again the closest standard from the tables in the post are spray booths, which fall far short of the potential vapor release from a ruptured extractor. Chemical fumehoods, which are required to be ANSI (or equivalent) certified, thus are not DIY projects, and are heavily engineered to ensure proper air flow at all times around anything that has been properly placed within (meaning things are not over crowded and have airflow under as well as around and above). I have a PhD in chemistry and I can’t do it; one really needs a certified aeronautical engineer to do it – there are significant issues of turbulent airflow involved which do not appear to be accounted for in designs in the post (BTW the first design is much better than the second, but still needs to draw air in from all levels not just the floor). Since you are reading this, that probably means you don’t have the correct training either. Like all things done by experts, experts make hard things look simple, fumehoods and distillation equipment are no different.

    Mistake #5: Nearly all regulations/standards regarding butane and propane systems, assumes the butane and propane will be intentionally burned (in a furnace, boiler, oven, stove, etc. ) or just stored. Hand in hand with that goes the assumption that any other use or process involving butane or propane will be designed by highly trained and expert engineers/chemists, i.e. not you the reader. In short most of the regulations are not appropriate for butane extractors (one hopes that will change).

    All that said, what should a safe enclosure look like for butane extractors look like? Well, if the unit is benchtop scale, then you’ll want something like this ( https://us.vwr.com/store/product/9875274/rediship-protector-premier-laboratory-hoods-and-rediship-spillstopper-work-surfaces-labconco ) which is built into a work bench. A floor mounted unit will need a walk-in like this ( https://us.vwr.com/store/product/4832618/supreme-air-general-purpose-walk-in-fume-hood-kewaunee ) . If the unit is to large for a standard walk-in hood then you’ll need to hire an architectural firm that specializes in designing labs and chemical plants. All of this equipment needs to be professionally installed (i.e. licensed contractors) and should be equipped with scrubbers (activated charcoal filters should be sufficient if the filters are regularly replaced, in general this reduces/eliminates VOCs and not all of your neighbors like the smell of cannabis). The other feature of explosion proof fumehoods/rooms that is they contain not electrical outlets or switches and all electronics used within them are designed such they do not create sparks. Again, none of these systems will provide much protection from a rupture (sudden large vapor/gas release) but they will provide adequate protection during the event of a leak.

    Finally on blasting: butane and propane are heavy gases which do not dissipate as quickly as one might think. They also tend to pool on the ground and in depressions. Both of those factors means ignition sources are still a risk even if they are quite far from where the butane was released. For example 100lbs of butane released in a 15 degree wide jet does not reach its lower explosion limit (LEL) until past the 700-750 meter point, wind will change the direct but not likely the distance (look at clouds of smoke to understand why I say this). So if one is blasting then one needs to control all ignition sources in a pretty large area. Since that is not easy, it is much safer to use a closed loop system and if the butane must be released, do a controlled burn.

    Reply

    • First mistake: There are no intrinsically safe extractor designs, butane or otherwise, just degrees of risk.
      ***********************

      Define intrinsically safe in manufacturing. An intrinsically safe design isn’t without risk, but those risks are contained at 3X or greater safety factor and the process doesn’t include any steps that directly expose the operator to undue hazards.

      Closer to layman language, your automobile fuel tank and your butane lighter are a bomb, but automobiles and lighters are considered intrinsically safe to operate in a safe and sane manner.
      *************************************

      Mistake #2: Risk analysis has two parts, frequency of accidents and inherent danger. Well designed and maintained equipment along with well trained people following well thought out procedures reduces the frequency of accidents, but sooner or later an accident will happen. Butane (and propane) are inherently extremely dangerous because they are gases at room temperature and pressure, so can not be contained in the event of a spill. On top of that they are flammable and the rate of ignition is largely determined by the amount of vapor (gas)… which is why the SDS for butane lists it as an explosive hazard, but an SDS for hexane (a liquid) does not. That said, any process which creates a large amount of organic vapor (such as distillation) poses an explosive risk.
      *************************

      As a retired manufacturing engineering professional who designed hazardous material handling and ventilation equipment/systems for aerospace application, I’m aware of how to access risk management, but a good exercise for those readers whom lack professional training in that arena.

      I’m also aware of what the professionals writing the International Fire Code, NFPA 58, UL-21 and ASME Section VIII say about how to deal with the hazards, and question whether you’re similarly aware.

      They spell out under what circumstances you can operate the equipment of which we speak in a commercial environment. OSHA relies on them as standards when accessing compliance in matters related to employee safety.

      It is a matter of record that WolfWurx Mk IVC/Vs are certified to all of those standards in OR, WA, CO, NV, and MD, and that not only the equipment, but the installation and the extraction booth are included in the actual PE sign offs.
      *******************************

      Mistake #3: A sudden release of gas will swamp any ventilation system, and in the worse case butane extractors rupture (fast and large release) not leak (slow and small release). Risk analysis dictates one plans according to worst reasonable case accident: in the case of butane that is an explosion. On a pound per pound basis the heat of combustion (energy released by burning) a kilo of butane is more than 9 times the work energy of detonation of TNT (figuring out how destructive a butane explosion could be relative to a TNT explosion is not as simple as comparing these energies but it is a starting point). Therefore professionally (and I mean chemical engineers) designed facilities doing butane or propane extraction are designed as stand alone buildings remote from other buildings (this is largely true of alcohol distilleries, and always true of petroleum refineries, as well). For a facility doing low ton scale butane extractions, figure a 1/2 mile (~1 km) of empty field between the extraction facility and the next closest, well, anything. This is to account for both direct blast damage and flying debris. Oh, by empty field I mean empty field – no crops, no storage, no livestock, no nothing that would require people in that area while the facility was in use. A 1/2 mile safety perimeter works out to be about 500 acres, making large scale butane extraction uneconomical for all but large businesses. For those using a 10 kg tank of butane, a 50 meter safety perimeter might be on the low side, considering probably less than 2 kg of natural gas did this ( http://www.nbcnews.com/news/us-news/oregon-natural-gas-explosion-injures-eight-destroys-building-n669156 http://www.oregonlive.com/portland/index.ssf/2016/10/portland_gas_explosion_2016_bu.html ). Note: the distances between storage tanks and buildings is less than those I’ve outlined above, largely due to the fact that storage tanks tend to leak when they fail while with extractors one must plan for ruptures (blow seals, etc) releasing a lot of gas at once. OSHA regulations set the distances between storage tanks and the size limit on storage within a building. Those regulations can be found here: http://www.ecfr.gov/cgi-bin/text-idx?SID=a8ce610c9aa63d9b9e50651823779ee1&mc=true&node=se29.5.1910_1110&rgn=div8
      In general, the OSHA regulations (including ventilation) can be found here: http://www.ecfr.gov/cgi-bin/text-idx?SID=a8ce610c9aa63d9b9e50651823779ee1&mc=true&tpl=/ecfrbrowse/Title29/29cfr1910_main_02.tpl
      ****************************************

      You build a good argument for a LPG tank farm, but LPG tanks are on the ubiqtious fork lifts, and some folks are carrying butane lighters in their pockets.

      An extraction booth isn’t a tank farm, and the quantities that may be in the booth are spelled out in the certification of compliance, as is the location.

      ***********************************

      Mistake #4: the designs in the post are more appropriate for particulate matter not chemical hazards. Again the closest standard from the tables in the post are spray booths, which fall far short of the potential vapor release from a ruptured extractor. Chemical fumehoods, which are required to be ANSI (or equivalent) certified, thus are not DIY projects, and are heavily engineered to ensure proper air flow at all times around anything that has been properly placed within (meaning things are not over crowded and have airflow under as well as around and above). I have a PhD in chemistry and I can’t do it; one really needs a certified aeronautical engineer to do it – there are significant issues of turbulent airflow involved which do not appear to be accounted for in designs in the post (BTW the first design is much better than the second, but still needs to draw air in from all levels not just the floor). Since you are reading this, that probably means you don’t have the correct training either. Like all things done by experts, experts make hard things look simple, fumehoods and distillation equipment are no different.
      *********************************

      I’m more than aware a PhD in chemistry doesn’t remotely qualify a person to design ventilation systems, but thank you for pointing that out to the readership.

      It is however one of the things that I did professionally for everything from fumes to particulate, and had to meet all applicable codes, including OSHA. It would have never occurred to our PhD Chemists to even try, because that isn’t what they were trained for, and we were.

      By the references you are grabbing for, I infer you still haven’t read the ventilation design bible aka Industrial Ventilation.

      It may have escaped your attention that you are dealing with vapors 1.5 to 2.5X the weight of air, and that 100 sf air flow directs the vapors to the slot operating at 1000 sf.

      While it clearly doesn’t meet your standards, it does those Registered Professional Engineers actually certifying installations, so I am simply passing on my actual experiences.
      *****************************

      Mistake #5: Nearly all regulations/standards regarding butane and propane systems, assumes the butane and propane will be intentionally burned (in a furnace, boiler, oven, stove, etc. ) or just stored. Hand in hand with that goes the assumption that any other use or process involving butane or propane will be designed by highly trained and expert engineers/chemists, i.e. not you the reader. In short most of the regulations are not appropriate for butane extractors (one hopes that will change).
      All that said, what should a safe enclosure look like for butane extractors look like? Well, if the unit is benchtop scale, then you’ll want something like this ( https://us.vwr.com/store/product/9875274/rediship-protector-premier-laboratory-hoods-and-rediship-spillstopper-work-surfaces-labconco ) which is built into a work bench. A floor mounted unit will need a walk-in like this ( https://us.vwr.com/store/product/4832618/supreme-air-general-purpose-walk-in-fume-hood-kewaunee ) . If the unit is to large for a standard walk-in hood then you’ll need to hire an architectural firm that specializes in designing labs and chemical plants. All of this equipment needs to be professionally installed (i.e. licensed contractors) and should be equipped with scrubbers (activated charcoal filters should be sufficient if the filters are regularly replaced, in general this reduces/eliminates VOCs and not all of your neighbors like the smell of cannabis). The other feature of explosion proof fumehoods/rooms that is they contain not electrical outlets or switches and all electronics used within them are designed such they do not create sparks. Again, none of these systems will provide much protection from a rupture (sudden large vapor/gas release) but they will provide adequate protection during the event of a leak.
      Finally on blasting: butane and propane are heavy gases which do not dissipate as quickly as one might think. They also tend to pool on the ground and in depressions. Both of those factors means ignition sources are still a risk even if they are quite far from where the butane was released. For example 100lbs of butane released in a 15 degree wide jet does not reach its lower explosion limit (LEL) until past the 700-750 meter point, wind will change the direct but not likely the distance (look at clouds of smoke to understand why I say this). So if one is blasting then one needs to control all ignition sources in a pretty large area. Since that is not easy, it is much safer to use a closed loop system and if the butane must be released, do a controlled burn.
      ****************************************************

      While I admire your enthusiasm and the effort you put into your posts, it is off- putting for you to declare as facts, things you are not professionally trained to give advice on. It would be much better received if you acknowledge them as personal concerns vis a vis facts.

      Perspective, perspective, and then perspective appears where you may have gone astray.

      This article was not to a home DIY operator, because you can’t legally install an extraction booth in a residential zone. The regulations in the legal states are clear on that point, and the Fire Marshal is one of the professionals that has to sign off on the installation.

      It, and much of what I’ve offered of late, is support to those extractors who are looking to install a legal certifiable extraction booth. That may have been more clear if I had mentioned that the Mk IVC I used in the example, retailed for $65,000, putting the volume required to process for a reasonable Return On Investment beyond most home operators.

      GW

      Reply

      • GW,

        My comments weren’t directed to you, but your readers. Every area I talk about in I’ve personally seen problems with in businesses operating legally.

        Let me deal with your last reply first: “This article was not to a home DIY operator…” The problem is that many businesses are DIYing their fumehoods because they look at professionally designed ones and think they are simple. Worse they are getting signed off by fire marshals (I’ve seen “explosion proof rooms” lined with electrical outlets that a fire marshal signed off on – clearly either money was involved or the fire marshal didn’t really understand the requirements). This is an issue of training of both fire marshals and building inspectors, and is tied to the fact that most cannabis processors are operating in areas that do not have a history of chemical industries. So right now it is far safer for everyone if businesses where directed to professional designers and installers ( more professionals involved, the less likely something will slip through).

        “Define intrinsically safe in manufacturing…” We actually agree on this to the extent it is limited to equipment. From the point of view of safety training, it is important to get people to think that there is always risk in what they are doing, and talking about “inherently safe” does the opposite. Too many operators are currently dismissing any safety concerns, or worse automatically dismiss accidents as the result of “poor equipment” or “poor training” implying that they believe it “could never happen to me.” That is the very type of thinking that increases the chances of an accident. I do have experience doing EH&S…

        “I’m also aware of what the professionals writing the International Fire Code, NFPA 58, UL-21 and ASME Section VIII say about how to deal with the hazards, and question whether you’re similarly aware.
        They spell out under what circumstances you can operate the equipment of which we speak in a commercial environment. OSHA relies on them as standards when accessing compliance in matters related to employee safety.”

        I am aware of both of these points, though not as fully as I like. That is part of the problem, that (outside what is directly listed in OSHA) is not easily accessible and as you mentioned elsewhere is very expensive. At least both of us know what to go looking, but most of your readers don’t. I’m also aware that they are not very good at dealing with the issue of chemical fumehoods (and here it maybe more a problem of communication than of fact) at addressing the needs of chemical manufacturing and laboratories. The closest I’ve found in the OSHA regulations are spray booths, which deal with lower vapor loads per unit of volume then what one can reasonably expect in a chemical fumehood (chemical fumehood airflow = minimum of 100 CFM per open face area (there is an absolute minimum open face area for these), which if I’m not mistaken is quite a bit higher than that of a spray booth).

        “It is a matter of record that WolfWurx Mk IVC/Vs are certified to all of those standards in OR, WA, CO, NV, and MD, and that not only the equipment, but the installation and the extraction booth are included in the actual PE sign offs.”

        I’m not concerned with the certified equipment used in fumehoods and larger enclosures. Instead I’m concerned that equipment is used in the right enclosure and that is where problems begin.

        “You build a good argument for a LPG tank farm, but LPG tanks are on the ubiqtious fork lifts, and some folks are carrying butane lighters in their pockets.
        An extraction booth isn’t a tank farm, and the quantities that may be in the booth are spelled out in the certification of compliance, as is the location.”

        First, the distance between fork lifts and the size of their tanks, plus the fact they they are designed to burn their fuel puts them well within the regulations, so your comparison is a red herring. Use plays a significant part in determining hazardous conditions, and butane extractors are not designed to burn their butane and have more failure points than a forklift (or at least ones that get adjusted regularly).

        Unfortunately I’ve seen as many as five extractors packed into an enclosure totaling about 200 pounds of butane in the enclosure. That is just at the limit for an entire fire zone before one has to be in a high hazard building. I’ve also seen six 100 pound unsecured butane cylinders stored within a 1 yard radius and not within an enclosure… There is a disconnect between what you and I know needs to be done for safe operations and what is actually happening. Worse, many operators will comply with the regulations to pass their initial inspection then disregard those regulations afterwards. Until a safety culture is ingrained in the industry, these problems will continue. Most of the people I deal with have little to no experience with chemical manufacturing (which is what the cannabis extraction business really is), so the only way we are going to ingrain a safety culture in them is to tell them that they need to seek and follow professional advice.

        “It would have never occurred to our PhD Chemists to even try, because that isn’t what they were trained for, and we were.” While this maybe true of the PhD chemists you have worked with, it is certainly not true of all of them. I actually know of one who tried to build a perchlorate hood… talk about a bad idea if you don’t really understand all the design issues.

        “By the references you are grabbing for, I infer you still haven’t read the ventilation design bible aka Industrial Ventilation.” I can’t afford it. Again, I know to go looking for it but most of your readers don’t.

        “It may have escaped your attention that you are dealing with vapors 1.5 to 2.5X the weight of air, and that 100 sf air flow directs the vapors to the slot operating at 1000 sf.” This tells me you are at the end of your expertise. While dense gases do settle, the rate they settle is dependent on several factors including turbulence and the velocity of the gases relative to the airflow. In particular gases escaping a pressurized vessel can do so against the prevailing airflow. Given sufficient distance between the gas source and the vent, you are right, it is not an issue. Nor is it an issue in a spray booth where vapors are coming off a large surface area at atmospheric pressure and the airflow is gentle and smooth.

        The dynamics in a chemical fumehood are different though. The distances between equipment and the vents tend to be short (for a typical chemical fumehood, benchtop or walk-in, they are commonly in the 100-200 mm range). To compensate one needs a full height baffled vent (best), or a top and bottom vent (acceptable in a benchtop fumehood). Also turbulence is a major issue which can greatly increase the residence time of the vapors (cross currents in front of fumehoods significantly reduces their performance, as can turbulence around equipment). Things get very complicated when dealing with room sized enclosures for pressurized chemical manufacturing, for one has to find the right balance between the size of the enclosure, the equipment in it, and the distance from the equipment to the vent. It is for these types of issues where the standards fail: the range of situations one encounters in chemical manufacturing are wide enough that one can’t write rules that work for all them. At a certain point, and with what we are talking about here we are there, the regulations become guide posts where engineers have to do a through analysis of the situation before settling on a design. To be clear GW, I think everything you are saying is spot on if we were discussing unpressurized liquid extractors (i.e. one using ethanol, hexane, etc.) but we aren’t.

        One other serious issue one has to consider when design enclosures for pressurized systems using organic compounds (read flammable and insulating) is that when they escape (spray) out of their vessels they tend to develop static charges – with enough static charge you’ll get a spark. Grounded metal vessels don’t actually help this situation because it is the spray that carries the charge not the vessels. This is one reason one does not hear much about large scale normal phase (using solvents other than mixtures water or low mass alcohols) HPLC. This issue of static is one of the reasons industrial chemists greatly dislike working with propane or butane as a solvent.

        GW, we are both experts at what we do (and I do have chemical manufacturing experience with EH&S training). Right here our areas of expertise are bumping up against each other, and I believe we can learn a lot from each other.

        Reply

        • GW,
          My comments weren’t directed to you, but your readers. Every area I talk about in I’ve personally seen problems with in businesses operating legally.
          Let me deal with your last reply first: “This article was not to a home DIY operator…” The problem is that many businesses are DIYing their fumehoods because they look at professionally designed ones and think they are simple.
          Worse they are getting signed off by fire marshals (I’ve seen “explosion proof rooms” lined with electrical outlets that a fire marshal signed off on – clearly either money was involved or the fire marshal didn’t really understand the requirements).
          This is an issue of training of both fire marshals and building inspectors, and is tied to the fact that most cannabis processors are operating in areas that do not have a history of chemical industries. So right now it is far safer for everyone if businesses where directed to professional designers and installers ( more professionals involved, the less likely something will slip through).
          ************************************************************************************************

          A good point that the cannabis industry is just now joining the fold as a legal enterprise, so many fire safety professionals lack training and direction.

          About five years ago we started getting calls from Fire Marshals scattered around the US, looking for insight.

          We’ve provided information to all that called, worked with a forensic team in New Mexico investigating an accident with injury, helped train NIOSH Industrial Hygienists who are writing the OSHA standards for our industry, and have provided support to the UFCW representing the employees injured in NM, and was last in contact with fire professionals in CA, whom are striving to get their arms around the issue.

          I also met with a Senator in NV when they were writing their regulations, and personally demonstrated how fuel, oxygen, and ignition are addressed in the design and operation, because he was seriously concerned about operator safety.

          I have faith that both the fire safety and the governmental industrial hygienists at NIOSH will sort it out, because none I talked to came across as idiots. In point of fact, much to the contrary.

          The reason that I published the article, was to make the target clearer for those whose intent is to operate legally, which means professional signoff.

          Certification of a BHO extraction booth also requires the signoff of a Registered Professional Engineer qualified by training and experience, as well as certified in the state they operate.

          You didn’t mention if your errant fire marshal signed it off as NEMA 7, Class I, or Class II, nor did you specify what type of electrical outlets, so more information needed to comment, but I’ve never met a fire marshal or electrical inspector that ignorant or stupid.

          Bringing us to the point that the electrical inspector had to sign off to IEC before the fire marshal would sign off, so ignorance and conspiracy would also have to be involved there as well.

          Their specialty seems to be to remember every minute detail chapter and verse, for the most part. The one’s contacting us weren’t woefully ignorant of NFPA-58, and they were making their best efforts to learn as much as possible about BHO extraction, so as to understand what to look for when inspecting or responding.

          Precisely what we ask those professionals to do.
          ************************************************************************************************

          “Define intrinsically safe in manufacturing…” We actually agree on this to the extent it is limited to equipment. From the point of view of safety training, it is important to get people to think that there is always risk in what they are doing, and talking about “inherently safe” does the opposite. Too many operators are currently dismissing any safety concerns, or worse automatically dismiss accidents as the result of “poor equipment” or “poor training” implying that they believe it “could never happen to me.” That is the very type of thinking that increases the chances of an accident. I do have experience doing EH&S…
          **************************************************************************

          On the other hand, NIOSH and the United Food & Commercial Workers union are keen on equipment that is “intrinsically safe” to operate per the operating manual, so operator error is their biggest worry.

          Not only did I have to certify the equipment, I had to certify the manuals, which spell out chapter and verse how the system is to be operated.

          We also trained the operators once the equipment and facility was certified and the permits all signed off, so we don’t see them as poorly trained. In fact we’re impressed with how savvy they are and how quickly they absorbed the information.

          That does leave us with abnormal thinking and actions, and Abraham Maslow did note that it was a mistake to forget pathology in the populous.
          **********************************************************************************

          “I’m also aware of what the professionals writing the International Fire Code, NFPA 58, UL-21 and ASME Section VIII say about how to deal with the hazards, and question whether you’re similarly aware.
          They spell out under what circumstances you can operate the equipment of which we speak in a commercial environment. OSHA relies on them as standards when accessing compliance in matters related to employee safety.”
          I am aware of both of these points, though not as fully as I like. That is part of the problem, that (outside what is directly listed in OSHA) is not easily accessible and as you mentioned elsewhere is very expensive. At least both of us know what to go looking, but most of your readers don’t. I’m also aware that they are not very good at dealing with the issue of chemical fumehoods (and here it maybe more a problem of communication than of fact) at addressing the needs of chemical manufacturing and laboratories. The closest I’ve found in the OSHA regulations are spray booths, which deal with lower vapor loads per unit of volume then what one can reasonably expect in a chemical fumehood (chemical fumehood airflow = minimum of 100 CFM per open face area (there is an absolute minimum open face area for these), which if I’m not mistaken is quite a bit higher than that of a spray booth).
          *********************************************************************************************

          100 cfm per square foot of face area, and 100 surface feet per square foot of face area are the same thing, and is what I used in my booth design.

          You will note Table 1 gives a range of up to 200 surface feet, and I saw one commercial design operating at 150 surface feet.

          I picked 100 sf, because the vapors have little mass or velocity, and a 34” deep Terpenator leaking a foot from the plenum would take between .6 and 2.2 seconds to reach the plenum and HC detector.

          That is how fast the column of air that contains the LPG is traveling on its way out.

          A good point that most readers don’t know what to look for in a fume hood, or how to calculate how much air flow is required, as well as how to achieve it with static losses, etc!

          One size definitely doesn’t fit all, and systems designed for lighter than air contaminants like VOC’s and smoke, operate differently than ones designed to extract heavier than air fumes like LPG and acids.

          That is one of the reasons I shared with them what to look for and how to figure out how much air is required, to put things in perspective.
          **********************************************************************************

          “It is a matter of record that WolfWurx Mk IVC/Vs are certified to all of those standards in OR, WA, CO, NV, and MD, and that not only the equipment, but the installation and the extraction booth are included in the actual PE sign offs.”
          I’m not concerned with the certified equipment used in fumehoods and larger enclosures. Instead I’m concerned that equipment is used in the right enclosure and that is where problems begin.
          “You build a good argument for a LPG tank farm, but LPG tanks are on the ubiqtious fork lifts, and some folks are carrying butane lighters in their pockets.
          An extraction booth isn’t a tank farm, and the quantities that may be in the booth are spelled out in the certification of compliance, as is the location.”
          First, the distance between fork lifts and the size of their tanks, plus the fact they they are designed to burn their fuel puts them well within the regulations, so your comparison is a red herring. Use plays a significant part in determining hazardous conditions, and butane extractors are not designed to burn their butane and have more failure points than a forklift (or at least ones that get adjusted regularly).
          **************************************************

          I don’t use red herrings. A forklift also has an LPG ASME pressure vessel strapped to it, actually moving around as opposed to being at a protected fixed location.

          The point missed is that they are allowed to do so because of the low risk of a catastrophic failure.

          The same as a properly engineered and professional third party certified extraction equipment built to the same standards.
          ********************************************

          Unfortunately I’ve seen as many as five extractors packed into an enclosure totaling about 200 pounds of butane in the enclosure. That is just at the limit for an entire fire zone before one has to be in a high hazard building. I’ve also seen six 100 pound unsecured butane cylinders stored within a 1 yard radius and not within an enclosure… There is a disconnect between what you and I know needs to be done for safe operations and what is actually happening.
          *******************************

          I’ve seen some ghastly setups as well, but they weren’t certified and I didn’t stick around or return. Especially now that it is a Class B felony locally, and me being just too too pretty to go to jail at age 73 and change.

          There is no disconnect between what I know needs to be done and what I’m observing, only a question regarding the proper response.

          Skunk Pharm Research’s approach has always centered around education, as opposed to hidden knowledge and secret handshakes.

          Sometimes what is learned by the educated, is not so much the details of how to do it right, but what all is involved doing it right, so that non-professionals seek professionals for the task.
          **********************************************

          Worse, many operators will comply with the regulations to pass their initial inspection then disregard those regulations afterwards. Until a safety culture is ingrained in the industry, these problems will continue. Most of the people I deal with have little to no experience with chemical manufacturing (which is what the cannabis extraction business really is), so the only way we are going to ingrain a safety culture in them is to tell them that they need to seek and follow professional advice.
          *************************

          Tis true that there are always those who agree to one thing and then do another. Part of Maslow’s pathology in the populous……..

          Statistically half the population is below average intelligence, and even in the upper quartile there are those whom think they know more than the professionals in other fields, not to mention the sociopaths that don’t really care about anything but themselves.

          Not much new there, as all industries have to deal with it. What is new is the cannabis industry entering the fold and struggling to come up to speed
          ******************************************

          “It would have never occurred to our PhD Chemists to even try, because that isn’t what they were trained for, and we were.” While this maybe true of the PhD chemists you have worked with, it is certainly not true of all of them. I actually know of one who tried to build a perchlorate hood… talk about a bad idea if you don’t really understand all the design issues.
          *******************************************

          We kept our expensive PhD’s busy up to their hocks, working in their areas of expertise. In our case it included doctorates in chemistry, metallurgy, and ceramics and we couldn’t afford to have them mucking about in highly regulated areas that they were untrained in, like HVAC, and industrial ventilation
          *********************************

          “By the references you are grabbing for, I infer you still haven’t read the ventilation design bible aka Industrial Ventilation.” I can’t afford it. Again, I know to go looking for it but most of your readers don’t.
          ******************************************************

          Given that I told them where to go looking for it and used copies are cheap, I’m missing your points.

          “It may have escaped your attention that you are dealing with vapors 1.5 to 2.5X the weight of air, and that 100 sf air flow directs the vapors to the slot operating at 1000 sf.” This tells me you are at the end of your expertise. While dense gases do settle, the rate they settle is dependent on several factors including turbulence and the velocity of the gases relative to the airflow. In particular gases escaping a pressurized vessel can do so against the prevailing airflow. Given sufficient distance between the gas source and the vent, you are right, it is not an issue. Nor is it an issue in a spray booth where vapors are coming off a large surface area at atmospheric pressure and the airflow is gentle and smooth.
          The dynamics in a chemical fumehood are different though. The distances between equipment and the vents tend to be short (for a typical chemical fumehood, benchtop or walk-in, they are commonly in the 100-200 mm range). To compensate one needs a full height baffled vent (best), or a top and bottom vent (acceptable in a benchtop fumehood). Also turbulence is a major issue which can greatly increase the residence time of the vapors (cross currents in front of fumehoods significantly reduces their performance, as can turbulence around equipment). Things get very complicated when dealing with room sized enclosures for pressurized chemical manufacturing, for one has to find the right balance between the size of the enclosure, the equipment in it, and the distance from the equipment to the vent. It is for these types of issues where the standards fail: the range of situations one encounters in chemical manufacturing are wide enough that one can’t write rules that work for all them. At a certain point, and with what we are talking about here we are there, the regulations become guide posts where engineers have to do a through analysis of the situation before settling on a design.
          **********************************************

          One point we are missing each other on, is that a fume hood is an extremely poor selection for heavier than air contaminants, because of the extreme air flows it takes to reach capture velocity.

          It could be improved by blocking three sides to minimize open area, but you are still fighting the direction the vapors are doing their level best to go.
          I’ve used air knives on open sides to minimize that issue, but a extraction booth, not an exhaust hood is required.

          *************************************

          To be clear GW, I think everything you are saying is spot on if we were discussing unpressurized liquid extractors (i.e. one using ethanol, hexane, etc.) but we aren’t.
          One other serious issue one has to consider when design enclosures for pressurized systems using organic compounds (read flammable and insulating) is that when they escape (spray) out of their vessels they tend to develop static charges – with enough static charge you’ll get a spark. Grounded metal vessels don’t actually help this situation because it is the spray that carries the charge not the vessels. This is one reason one does not hear much about large scale normal phase (using solvents other than mixtures water or low mass alcohols) HPLC. This issue of static is one of the reasons industrial chemists greatly dislike working with propane or butane as a solvent.
          *******************************

          Static charges are a reality, which NFPA-58 considers. Just flow through the piping and hoses can build static charge, which is why the systems are bonded and the hoses have to meet UL-21.

          GW, we are both experts at what we do (and I do have chemical manufacturing experience with EH&S training). Right here our areas of expertise are bumping up against each other, and I believe we can learn a lot from each other.
          *******************************

          I’m pretty sure there is absolutely nothing that I’m an expert on, including what makes young Jimmy tick, but I think where we are bumping into one another is we are approaching the issue from different directions.

          I am trying to provide the education and means to address problems in the industry, for everyone from ma and pa, to serious commercial extractors.

          Not remotely close to everyone that I showed how to build a Terpenator did so, most bought one from someone else, because they lacked the training and equipment required.

          I predict that most people who read my articles on ventilation will hire a professional to do it as well, because they will have to have it signed off by a professional.
          If I were to post an article that said, “BHO Booth Ventilation Design”, and then said that the reader should bother, but instead just call a professional, how much impact do you imagine it would have?

          We can beat this to death, but it is my perception that I am the one with training and experience in industrial ventilation, as opposed to your focus on chemistry.
          I understand your concern that the great unwashed will learn just enough to get into trouble, and it is a valid one, but not one that I believe justifies keeping the rest in ignorance.

          We would probably be more productive debating that difference, than fencing in a technical area where I am the one with extensive experience and training.

          GW

          Reply

        • Leave us keep the apples and oranges in their respective baskets! Laboratory standards were never the debate, but we will return to that in a moment.

          Reality check:

          We are discussing commercial extraction at industrial volume, not a laboratory scale.

          These machines are about three foot square and eight foot tall, and you have to get intimate with them during operation.

          The WW Terpenators are actually highly compact compared to some of the competitive systems

          They all require an extraction booth, not a “hood”, and a booth is in fact what the registered professional engineers have certified in our applications.

          Industrial standards apply, not laboratory standards, but getting back to laboratory standards, despite no mention of the highly applicable NFPA-58 in that standard, I draw your attention to the fact that they twice listed Industrial Ventilation, Editions 1 and 27, the industrial standard I keep drawing your attention to?

          GW

          Reply

          • Reality check is right. You are not talking industrial scale (>1000L), you aren’t even talking large pilot plant scale (250L-1000L). The equipment in question is small (10L-100L) to medium pilot plant scale (100L-250L) and most of them will fit into walk-in hoods (it is possible to a these that are deeper than 3 feet and with 10 ceilings).

          • You have seriously missed the point, which is that regardless of how you think things should go, the standards that have been applied by the Professional Engineers certifying our installations are not the standards you propound.

            You also continue to miss the point that the standard you propound are based on standards from the same Industrial Ventilation “bible” that I propound and that all of us designers use to achieve what is written in various standards based on it.

            That and ASRAE covered most of our ventilation needs, with an occasional trip to other handbooks.

            You say that you aren’t qualified to design ventilation systems yourself, yet are somehow qualified to critique my design and deny the validity of my resources, which include registered professional engineers in their specific field of expertise.

            If you have an alternate design you would like to offer, feel free to do so and we will use all of our professional design insight to critique it for you chapter and verse.

            GW

          • GW,

            You are missing my point, all of these issues have been solved by professional chemists/chemical engineers for decades. Just because neither you nor the majority of the cannabis industry know about them is besides the point. Unless one is dealing with engineers who regularly work with chemical industry (i.e. ones who don’t already know what is available off-the-shelf) one is likely to end up applying the wrong set of standards, just re-invent the wheel, or miss non-obvious but critical details of the problem.

            While some producers may need to re-configure their extractors, I assure you one can get a 250L extractor into a walk-in fumehood. Remember that columns and receivers do not need to be in a an enclosure while they are being loaded and unloaded (well if there are a lot of terpenes in the receiver, then it would be wise).

            You’ve asked for an alternative design, yet I’ve repeatedly said “walk-in fumehoods” for large units and “benchtop fumehoods” for small ones. The fumehoods are commercially available off-the-shelf units that meet all the requirements, and when installed by licensed professionals and annually inspected (required by law) are a pretty-damn fool-proof solution for this problem (and chemists do work with pressurized systems in them).

            Let’s talk about my concerns about your designs. I have been in an enclosure similar to your second design (it had two exhaust fans instead of one). My problem with that one was that it created turbulence in the room, meaning the rate of clearance from the enclosure was not uniform throughout, which can create pockets of gas that build up/slow to be removed. Also because of how make-up air entered the enclosure, the air above about 2 off the floor was nearly static. That maybe the result of the wrong size of exhaust fans, yet the space was designed by an engineer.

            Your first design appears to assume that the leaking butane will rapidly descend to the floor exhaust vent which is not a valid assumption when dealing with leaks from pressurized systems. The solution for that issue is a full height baffled exhaust vent. My next concern deals with the fact that on your drawing you have a lot of space around the extractor with overhead make-up air begging the questions: 1) does that create a vortex between the floor and wall opposite the vent, and 2) is the airflow across the floor uniform/adequate? Guaranteed fix, move the make-up air outside the enclosure, though leave it overhead, with a vertical sash or horizontal sliding doors with grates across the bottom in front of the enclosure. Guess what, with those two “fixes” to your first design it becomes the design of a walk-in fumehood. One could also deal with my second concern by simply having some of the make-up air come in a floor level opposite the exhaust vent if the enclosure is more than say 6 feet deep.

          • GW,
            You are missing my point, all of these issues have been solved by professional chemists/chemical engineers for decades. Just because neither you nor the majority of the cannabis industry know about them is besides the point.
            ***********************************************************************
            I think I’m starting to see the disconnect in perspective. You believe the professional chemist/chemical engineers engineered ventilation systems, and I’m aware that it was the mechanical engineers. That projects at the very least arrogant ignorance from this perspective.

            I also believe that the American Conference of Governmental Industrial Hygienists are the professionals who set the standards that we engineers designed to. I always designed to those standards, because that is what the various other standards are based on.

            The cannabis industry is not who is writing the rules, the fire safety professionals are applying existing ASME, IBC, IEC, and NFPA codes.

            In your arrogance equating chemist and chemical engineers with having solved chemical industry ventilation problems, as well as your ASSumption of my personal ignorance, you yourself ignore that my profession before retirement included designing ventilation systems for chemical systems for a Fortune 500 aerospace company.
            ***********************************************************************
            Unless one is dealing with engineers who regularly work with chemical industry (i.e. ones who don’t already know what is available off-the-shelf) one is likely to end up applying the wrong set of standards, just re-invent the wheel, or miss non-obvious but critical details of the problem.
            **************************************************************
            I certainly purchased and installed simple off the shelf fume hoods and enclosed hoods for the chemists in our laboratories at the Fortune 500 aerospace company I designed equipment, processes, and facilities for.

            Because we were the leaders in our industry, most of what we needed was not available to manufacture parts, so the manufacturing engineers had to mostly design our own equipment. Those processes including the chemical milling departments using heavier than air Nitric/Hydrofluoric acids among other things, and where air quality was strictly monitored.

            It also included the treatment plants for our waste water, including radioactivity in some locations, as well as our various air emissions.
            **************************************************************
            While some producers may need to re-configure their extractors, I assure you one can get a 250L extractor into a walk-in fumehood. Remember that columns and receivers do not need to be in a an enclosure while they are being loaded and unloaded (well if there are a lot of terpenes in the receiver, then it would be wise).
            ***************************************************************
            Your assurance are eliciting nothing but peals of laughter from those of whom have operated this equipment, because you are obviously ignorant of how intimate you get with it.

            You continue to push your solution in the face of the decision already having been made, as evidenced by the standards that have already been applied when I certified our equipment to operate in five different states.

            Even if I accepted your position, those writing the regulations don’t really care what either of us think, because they are the professionals here.
            **************************************************************
            You’ve asked for an alternative design, yet I’ve repeatedly said “walk-in fumehoods” for large units and “benchtop fumehoods” for small ones. The fumehoods are commercially available off-the-shelf units that meet all the requirements, and when installed by licensed professionals and annually inspected (required by law) are a pretty-damn fool-proof solution for this problem (and chemists do work with pressurized systems in them).
            ****************************************************************
            See above.
            *********************************************************************
            Let’s talk about my concerns about your designs. I have been in an enclosure similar to your second design (it had two exhaust fans instead of one). My problem with that one was that it created turbulence in the room, meaning the rate of clearance from the enclosure was not uniform throughout, which can create pockets of gas that build up/slow to be removed. Also because of how make-up air entered the enclosure, the air above about 2 off the floor was nearly static. That maybe the result of the wrong size of exhaust fans, yet the space was designed by an engineer.
            ************************************************************
            Let’s put things in perspective. The first design is mine.

            The second two are existing certified designs by others, that have been tested by the certifying PE.

            Valid point that they aren’t the design made in heaven, but they don’t have to be if the can actually be shown to work, which these were, or I wouldn’t have including them.

            They are what the PE’s at those locations designed after I had shown them my design made in heaven, and they priced it out.
            **********************************************************************
            Your first design appears to assume that the leaking butane will rapidly descend to the floor exhaust vent which is not a valid assumption when dealing with leaks from pressurized systems.
            ************************************************************
            Now here is where your lack of actual education, training, and personal hands on experience on the subject, causes you to start making ASSumptions above your pay grade.

            Have you done the math on the flow through the live ceiling to the 1000 sf intake slot?

            What do you think is going to happen to that air column moving downward at 100 surface feet, regardless of what is being stirred around in it?
            ************************************************************
            The solution for that issue is a full height baffled exhaust vent.
            **************************************************************
            That is certainly what a shade tree designer would do, having no clue on the effects on air flow requirements for all your extra slots, or the effects of additional slots on the orderly 100 sf advancement of the exhaust column.

            Professionals on the other hand would have quickly been fired, because the whole purpose of following the design parameters set forth by the American Conference of Governmental Hygienists in Industrial Ventilation is to achieve results that are safe, at reasonable operating costs.
            **********************************************************************
            My next concern deals with the fact that on your drawing you have a lot of space around the extractor with overhead make-up air begging the questions: 1) does that create a vortex between the floor and wall opposite the vent, and 2) is the airflow across the floor uniform/adequate? Guaranteed fix, move the make-up air outside the enclosure, though leave it overhead, with a vertical sash or horizontal sliding doors with grates across the bottom in front of the enclosure. Guess what, with those two “fixes” to your first design it becomes the design of a walk-in fumehood. One could also deal with my second concern by simply having some of the make-up air come in a floor level opposite the exhaust vent if the enclosure is more than say 6 feet deep.
            ********************************************************
            The spaces around the extractor is actually so the operator can operate it. Clearly you’ve never done so or we wouldn’t be having this conversation.

            With the make up air advancing at 100 sf feet through a live ceiling on my design, where is the vortex coming from?

            Why do you think I carefully calculated how much airflow and the velocity using that ceiling plate with that many holes of that size?

            On the other designs by others, that have already been proven and certified, a good academic question?

            Passive vents in a 2 hour firewall? How big are they to keep static pressure within the room legal for occupancy and where do they lead? You are aware of those requirements, are you not?

            So here is the deal! You’ve made it clear that you think chemist and chemical engineers are responsible for everything that has been accomplished, and that your pile it higher and deeper credentials in chemistry qualifies you in subjects you clearly lack in depth training and experience in.

            I have no objection to your asking clarification questions, and making suggestions, but you’re barging in as the voice from the mountain, telling me that I don’t know what I’m talking about in an area that I do have enough training and experience to realize that you just looked at the pictures and haven’t done any in depth study of the engineering.

            I on the other hand, not only had to design and install the systems for a Fortune 500 aerospace company, they without fail had to work, and it is a matter of record that they did.

            I’m not going to debate it with you any further. Feel free to submit an actual design instead of waving your arms and offering sage platitudes.

            Don’t forget to do your math. The formulas are in Industrial Ventilation.

            Until then, please no more responses on this subject, because of the time it takes responding and its negative effect on my sense of humor.

            GW

          • GW,

            This is fundamentally a a chemistry environment issue, which is why I said chemist and chemical engineers solved this problem, but of course we work with others.

            Accessibility is an issue of layout/ergonomics. I assure you, for the extractor scales we are talking about, one can design an extractor with all routine access points accessible from one side. It does take more planning and may require more modularity than what is currently being done, but it can be done. If you are talking about the need to rebuild a pump or something similar then yes that would have to be pulled out. Industrial chemists put skids the size we are talking about in hoods all the time, so I know this can be done.

            Your drawings don’t have a scale, so if your intent was that there was say at least 10 ft between the extractor and walls/vent (about car spray booth size) then I’m sure you are right (which I’ve said before). However there is a distance where jets of leaking gas aren’t quickly forced down by the downward airflow. The distance those jets travel before being forced down depends on things like angular width of the jet, the angle between the jet and the airflow, quantity of escaping gases, and velocity of the jet. Now remember I’m talking about putting extractors into hoods, which means minimal space (1-1.75m deep) and the issues I’m concerned with do matter. Seriously, a concentrated 1 m/s jet of gas, which is on the slow side, can travel a fair ways against a 0.5 m/s (~100 ft/min) airflow (before you say it, yes a “fair ways” depends on what one means by “concentrated”). Nor am I concerned about small leaks, I’m concerned with things like failed seals while one is boiling off the butane, or heaven forbid a hose becomes disconnected for some stupid reason. We are both right for the scales we have in mind, but clearly we are not talking about the same scales.

            Again, given the right scale I don’t have much of a problem with your first design. The second one less so, because I’ve seen something similar botched. Also, while we may butt heads and get mad as hell at each other while we do it, I’m absolutely certain we can work out an acceptable design for our intended installations, but we both know the things that cause us concerns. But what about the engineers who simply look at the standards and go “I need X cfm air in to balance X cfm air out, so I need a fan Y big, done” and don’t give the problem anymore thought (that is what I assume lead to the botched enclosure I’ve referred to)? Or the would be processor who has no experience with chemical systems (we both know there are a lot of them) and doesn’t know what to ask? Better to tell people go talk to a professional who is experienced designing chemical labs/plants, then to say here are some generic plans.

            Frustrating as it may have been, it has been a useful discussion.

            Peace and have a good new year.

          • GW,
            This is fundamentally a a chemistry environment issue, which is why I said chemist and chemical engineers solved this problem, but of course we work with others.
            ********************************
            I understand that you believe that it is a chemistry problem, but suggest that when the only tool in your tool box is a hammer, everything begins to look like a nail.

            Not only did the chemical engineer work with the mechanical engineers on ventilation, the mechanical engineers were the ones with the training and experience who did the work, regardless of whom may be taking credit for it.

            Their work depended heavily on the numbers arrived at by the American Conference of Governmental Hygienist, so they don’t get full credit either.
            I have to believe the electrical engineers made it in there, when I look at the fan laws, sooo at best I’m ready to concede that the chemists said which chemicals they wanted to use and how, but left the rest of to the professionals in their respective fields.

            As manufacturing engineering program manager, I worked with various other disciplines as well. Those other disciplines fell under my aegis as project leader, but I relied on their professional input in their areas of expertise.

            IE: I did the PID, and told the EE-PE precisely what I was going to do and wanted to accomplish, but he was my same job grade, did not directly report to me, and did what he was professionally trained to do, using me as a technical resource on the overall design only.
            *********************************************
            Accessibility is an issue of layout/ergonomics. I assure you, for the extractor scales we are talking about, one can design an extractor with all routine access points accessible from one side. It does take more planning and may require more modularity than what is currently being done, but it can be done. If you are talking about the need to rebuild a pump or something similar then yes that would have to be pulled out. Industrial chemists put skids the size we are talking about in hoods all the time, so I know this can be done.
            ******************************************
            You continue to assure me, and I continue to laugh, having designed and operated systems myself.

            I’m not calling it a stupid idea, because it is a matter of record that I also designed an early system in a cabinet flooded with nitrogen, but the access issues became immediately apparent, so I moved on.

            I could have started over and redesigned the equipment, but having actually operated the stuff, I realized that there were a number of things that I needed to access to operate or maintain, that would require that I either be able to be in the cabinet with it, or leave the cabinet open at times, which seriously defeats the purpose.

            A WW Terpenator system wraps around itself to conserve space, and you could indeed stretch it out to more than twice its current footprint, but who would be gullible enough to buy anything requiring that much real estate, requiring ventilation levels/costs based on that footprint?

            The fish trap exists only because of the fish. The fish is high quality concentrate at the least cost, while maintaining all official safety standards established by the professionals in that that field.

            As a concept, consider what a competent designer would come up with if his direction was to come up with the best solution, as opposed to figure out a way to do it “your way?”

            Consider for a moment, that while you believe yourself proficient enough in the subject of ventilation and extractor design, to challenge the direction the professional in that field have already gone, both fall outside of chemical engineering, as well as your areas of expertise by virtue of training and experience.
            ***********************************************
            Your drawings don’t have a scale, so if your intent was that there was say at least 10 ft between the extractor and walls/vent (about car spray booth size) then I’m sure you are right (which I’ve said before).
            ****************************************************
            The CAD drawings are to scale, and I’ve noted above that there is one foot (not 10 ft) between the extractor and the intake plenum.

            If you look at the calculations I provided regarding evacuation rates, you should have all the numbers that you need. It is a 7’ wide, 8’ tall, 8’ deep booth in the example.

            The volume of the booth is replenished every 4.8 seconds, which is 12.5 turns per minute.

            The velocities and flows are called out in the print.
            *******************************************
            However there is a distance where jets of leaking gas aren’t quickly forced down by the downward airflow. The distance those jets travel before being forced down depends on things like angular width of the jet, the angle between the jet and the airflow, quantity of escaping gases, and velocity of the jet.
            *****************************************************************
            Can you really believe that something that obvious was not only overlooked by MOI, but the American Conference of Governmental Industrial Hygienist when they published the designs, engineering formulas, and standards for industrial ventilation?

            If you had actual hands on design experience, you would know that their numbers are not academic and that they work.

            They are also not up for discussion, because they are also the basis for most of the regulations and standards on the subject.

            Consider the velocity of the air mass the leak is entering and how long it takes to exit.
            *******************************************************************
            Now remember I’m talking about putting extractors into hoods, which means minimal space (1-1.75m deep) and the issues I’m concerned with do matter. Seriously, a concentrated 1 m/s jet of gas, which is on the slow side, can travel a fair ways against a 0.5 m/s (~100 ft/min) airflow (before you say it, yes a “fair ways” depends on what one means by “concentrated”). Nor am I concerned about small leaks, I’m concerned with things like failed seals while one is boiling off the butane, or heaven forbid a hose becomes disconnected for some stupid reason. We are both right for the scales we have in mind, but clearly we are not talking about the same scales.
            ***********************************************************
            See above. The fish is not a perfect containment, without addressing the operational barriers that it produces.

            All of the WW Terpenators hold 48# of LPG, in a 100# ASME DOT refrigerant tank, so that much gas suddenly released would be the worst case.

            It doesn’t take a math genius to figure out that there is no way to accommodate that much gas spontaneously without exceeding LEL.

            That is exactly the same condition you regularly have in a paint spray booth containing things too big to fit on a table top, and too intricate to throw paint at through glove ports, while using highly flammable solvents.

            Does that mean they are banned or regularly blow up? No, it means that they are highly regulated, because they have that potential, and enough safety factors added to make ignition during the brief period it is in residence between its upper and lower explosive limits improbable, if protocols are followed.

            It would matter little if you were standing beside the machine or in front of the hood glass if an explosion occurred, so clearly either relies on explosions not occurring.
            *******************************************************************
            Again, given the right scale I don’t have much of a problem with your first design. The second one less so, because I’ve seen something similar botched. Also, while we may butt heads and get mad as hell at each other while we do it, I’m absolutely certain we can work out an acceptable design for our intended installations, but we both know the things that cause us concerns. But what about the engineers who simply look at the standards and go “I need X cfm air in to balance X cfm air out, so I need a fan Y big, done” and don’t give the problem anymore thought (that is what I assume lead to the botched enclosure I’ve referred to)?
            ************************************************
            Do I infer the engineer was not a professional, or was operating outside is areas of expertise by virtue of training and experience?

            Engineering is different than designing. Engineering suggest the proper engineering principles were followed, while designing is an art form. A professional does both.

            Let’s stick to what I’m presenting, because I’m not going to debate that there is pathology in the populous, in addition to ignorance and greed.
            **************************************************
            Or the would be processor who has no experience with chemical systems (we both know there are a lot of them) and doesn’t know what to ask? Better to tell people go talk to a professional who is experienced designing chemical labs/plants, then to say here are some generic plans.
            Frustrating as it may have been, it has been a useful discussion.
            Peace and have a good new year.
            *************************************************

            I doubt that you would get much of an argument from anyone that perfect is best, but then we have to define perfect.

            My definition of perfect as a manufacturing engineer, is one that provides the highest utility at the margin, while sending all of the employee’s home safe to their families every night, protecting the other assets, and maintaining environmental standards.

            The items in the “while” part, aren’t up for negotiation, only the utility at the margin part, which leads us to the part about being profitable enough to stay in business against the competition.

            If we define the fish as a quality concentrate, without anyone getting hurt, any property damaged, or any laws bent/broken, then ostensibly the only open issue on fish trap design, is utility at the margin.

            I continue to return to suggesting that you design something that you think is made in heaven and submit it for critique.

            If you see one on the shelf you believe will work, provide the cut sheets and we will critique it for you as well.

            If you have a complete extraction system design that you believe solves the issues I’ve brought up about accessibility, by all means share it.

            As I noted earlier, only the first extraction booth design is mine, and the other two are examples of how others have built systems that were tested to verify that they worked and certified.

            They didn’t use my design, even though I offered it, because their design worked and was more cost effective. When I say they worked, I mean they released butane and used instrumentation to measure rates and effect, not some academic exercise.

            And speaking of that design that you’ve casually brushed aside as almost/barely/maybe acceptable, and I infer that means that you haven’t read (verified) the flow numbers, or appreciate what they mean.

            The live ceiling brings the make-up air in with minimal turbulence at 154 surface feet, without leaving any blind spots.

            The baffled back wall plenum gives maximum distance to split and spread the intake stream the full width of the booth, so that the extremities don’t starve, while the center section intakes most of the air. They do so at a long enough distance to minimizes static pressure losses.

            There are no slots at the top of the plenum, because slots require cfm to accommodate and everything is traveling downward at 154 feet per minute, and besides wasting cfm, the slots would create eddies and vortices along that surface that disrupt the orderly flow of the advancing column of air.

            Once you start an air column moving in a given direction, you don’t want to speed it up, slow it down, bend it, or stir it up. Anything sprayed in it, comes along for the ride. That’s what capture velocity means.

            For any not aware, fan laws are such that increases in static pressure require the square of that increase in increased horsepower.

            Every extra cfm required to accomplish the task, is directly proportional to the fan rpm, but every increase in rpm requires the cube of the increase in horsepower.

            A professional tries to design for minimal air flow that works, because not only does horsepower go up exponentially, all that exhausted air has to be replaced in many cases with tempered air for both operator comfort and to maintain process standards.

            GW

          • “Not only did the chemical engineer work with the mechanical engineers on ventilation, …”

            I know, nor did I mean to suggest otherwise. The point I was trying to make is that the solution to this problem has been known for a long time by the community of chemists/chemical engineers.

            “I could have started over and redesigned the equipment, but having actually operated the stuff, I realized that there were a number of things that I needed to access to operate or maintain,…”

            I’ve seen your design there are ways to space things out, though it would still require some reach through, so that all the things that had to be accessed could be reached in the first 18″ all without increasing the footprint. From a UI stand-point, all the controls need to be on one side so the operator can see all of them at the same time (this can be a safety issue), most of yours are but you’ve just said not all. More to the point though is, how could you modify the design to reduce the maintenance issue? Doing so will make your customers happy and allow them to produce an even more consistent product. What those modifications would have to be I can’t say because you’re right I don’t use butane/propane systems since there are inherently safer methods of extraction plus other reasons… For this discussion, that is besides the point; people choose to take the risks of working with butane/propane, so the question is how to make the process as safe as possible. BTW all of these discussion points also apply to large scale hydrogenations using high pressure hydrogen gas, something that industrial chemists try to avoid (can’t always be done, for several reasons) because of the high inherent risk.

            Oh, on the issue of system height, you can reduce the column height (which is the tallest component in every butane and CO2 extractor I’ve seen used by the cannabis industry) by switching to a larger ID pipe (obviously). If the reason you are using a tall and narrow column is due to concerns about uniform solvent distribution, there are designs for high efficiency diffuser plates to deal with that issue. I can help you find those designs if you’d like, or you can look through chromatography patents. Beside space issues, there are also other advantages to short columns, but that is not for a public discussion. If you are going with the tall & narrow column due to cost and availability issues, such is life.

            “… to challenge the direction the professional in that field…”
            An expert must be able to answer all concerns when the answers to those concerns are known. So it doesn’t matter what my level of expertise is, if I or someone else sees a potential problem the experts need to be able to address them. Sometimes it is the least experienced that find the problems (though rarer, sometimes the solutions too). The “I’m an expert and you are not, so how dare you question me” attitude is where a shit load of problems, in all fields, begin.

            “The CAD drawings are to scale, and I’ve noted above that there is one foot (not 10 ft) between the extractor and the intake plenum.” I said 10 ft, because even without seeing any additional numbers or thought I know there would be no problems with the gases reaching the floor. I do also know that depending on the numbers, that can be much shorter.

            “If you look at the calculations I provided regarding evacuation rates, you should have all the numbers that you need. It is a 7’ wide, 8’ tall, 8’ deep booth in the example.
            The volume of the booth is replenished every 4.8 seconds, which is 12.5 turns per minute.”

            Seeing these makes me much more comfortable, and for whatever reason I did not see them before (I’m both dyslexic and AHDH, so I literally may not have seen them…). At 8′ deep, the vortex I was concerned about between the floor and wall opposite the vent should be so small and weak as to be insignificant, at half or less of that distance I’d want to see a fluid dynamics model before I wrote it off (because a vortex there can create a containment problems around sashes and doors).

            “Can you really believe that something that obvious was not only overlooked by…”
            Actually no but like you, I say things to communicate that I know the issues that need to be considered, and not because I think the people I’m talking to don’t know them.

            “Consider the velocity of the air mass the leak is entering and how long it takes to exit.”
            Which is exactly what I’ve been thinking about all along…

            “All of the WW Terpenators hold 48# of LPG, in a 100# ASME DOT refrigerant tank, so that much gas suddenly released would be the worst case.
            It doesn’t take a math genius to figure out that there is no way to accommodate that much gas spontaneously without exceeding LEL.”

            A point I made in my first post. And as you say later, being above LEL is not a barrier in itself so long as the residence time is short. A lot of my concerns, have centered around major but not catastrophic leaks (ie LEL level leaks where the enclosure still maintains a balance between the leak rate and the removal rate), that due to directionality and velocity have longer than usual residence times (not a problem one would/should encounter spraying paint, but a potential one for pressurized extractors, hydrogenators, HPLC, etc.). It is those types of leaks I want to see modeled instead of relying on “simple textbook formula.” Sometimes the solution is easier than the calculation, how hard/expensive would it be to design a system where the airflow could be increased (say doubled) while the leak was dealt with? Admittedly not an ideal solution, but we are talking about a far from ideal situation.

            “Do I infer the engineer was not a professional, or was operating outside is areas of expertise by virtue of training and experience?
            Engineering is different than designing. Engineering suggest the proper engineering principles were followed, while designing is an art form. A professional does both.”

            We both not know all “professionals” are cut from the same cloth…

            “I doubt that you would get much of an argument from anyone that perfect is best, but then we have to define perfect.” Unfortunately, I’ve had to remind a few academics that “prefect is the enemy of good,” but that is a different story.

            “My definition of perfect as a manufacturing engineer, is one that provides the highest utility at the margin, while sending all of the employee’s home safe to their families every night, protecting the other assets, and maintaining environmental standards.
            The items in the “while” part, aren’t up for negotiation, only the utility at the margin part, which leads us to the part about being profitable enough to stay in business against the competition.”

            I’ve met very few professional chemists who will disagree with you, but I’ve met too many in the cannabis world who put profit over safety (their employees’ and the public’s) and I want them gone as quickly as possible…

            “As I noted earlier, only the first extraction booth design is mine, and the other two are examples of how others have built systems that were tested to verify that they worked and certified.”

            With this additional information I’m pretty happy with your design. I say “pretty happy” because I’m always asking can it be done better. I’m also less than perfectly happy with it due to the fact that operators have to share the air with contaminates which would not be the case if an extractor was in a walk-in fume hood. Admittedly in the case of butane that is a minor issue, but does show a chemist’s preference to maximize the separation between people and hazardous materials. BTW do you have a dB for the floor vent? I ask because I’ve seen a lot of places that overlook audio safety. My reluctance to embrace the other designs, is tied to seeing the botched version (15+ ft ceiling, a pair of fans ~1 ft off the floor with passive make-up air vents at the same level: when the fans were on there was a fast and visibly turbulent air flow below knee level (you could see dust being picked-up a swirled in eddies) and very little air flow above that (at head level dust just floated around as if the fans weren’t even on)) which honestly could have been fixed with an overhead make-up air source and adjusting the fan speed.

            When I set-up my own lab, I’ll come talk to you about the engineering. In the meantime I’ll continue to suggest that people use hoods (plenty of stuff should be done in them, even one isn’t using them for extraction) and consult licensed architects experienced in designing labs who will subcontract the engineering.

            —-
            My other gripe about the standards/building codes in OR for science spaces is that there is not one clear and concise summary of the standards for wet lab spaces that the public can easily access for free. That is no longer a significant issue for the cannabis industry due to the new regulations and multitude of inspections but other “non-regulated” science start-ups are still being told to convert warehouses into labs. So the entrepreneurs DIYing labs without understanding the full requirements or seeking professional advice. What makes things worse is that the only obvious requirement in the OR building code for labs is that either one meets the high hazard standards, or one meet the requirements for a B class (business) and a start-up lab can easily come under the thresholds for a high hazard occupancy. The OSHA standards are a bit better as are OR firecode, but again one has to know to go looking. At least the CA building code specifically defines the requirements for wets labs (class L) which operate below the high hazard occupancy threshold…


            Final questions:
            1) Do you have any experience designing tangent flow filtration systems?
            2) Do you know chemical engineers who could answer the following question: “what is the minimum economically viable fluidized reactor bed for converting paraffin into gasoline?” Hey, someone has to figure out what to do with all that wax by-product from the cannabis industry… 🙂

          • “Not only did the chemical engineer work with the mechanical engineers on ventilation, …”
            I know, nor did I mean to suggest otherwise. The point I was trying to make is that the solution to this problem has been known for a long time by the community of chemists/chemical engineers.

            **************************************************
            And since it was designed for them by the other disciplines, ostensibly it was known to us that designed those systems as well, so I miss your point.
            *************
            ****************************************
            “I could have started over and redesigned the equipment, but having actually operated the stuff, I realized that there were a number of things that I needed to access to operate or maintain,…”
            I’ve seen your design there are ways to space things out, though it would still require some reach through, so that all the things that had to be accessed could be reached in the first 18″ all without increasing the footprint. From a UI stand-point, all the controls need to be on one side so the operator can see all of them at the same time (this can be a safety issue), most of yours are but you’ve just said not all. More to the point though is, how could you modify the design to reduce the maintenance issue?
            *****************************************
            Easy for you to say, which brings us to one of the key points of contention, which is that you continue to speak from the mountain, without demonstrating your design abilities with actual lines on paper.

            I doubt that you would disagree that proficiency in chemistry does not mean competency in equipment and ventilation design, which brings to a fundamental law of nature.

            The problem with ignorance and incompetence in a subject, is that it is impossible to perceive your level of incompetence.
            It also causes you to not understand or appreciate the fine points, even when they are paraded before you.

            Professionals do make things look simple and easy, and I think we can agree that it’s easier to offer sage advice that to actually engineer a design.

            To that point, I already said I could spread my design out, but you seem to have missed or are ignoring my point about size of the foot print and what that does to the ventilation requirements, which are based on area.

            If we can also agree that a primary object is to never expose anything outside the booth to the dangers within, then consider that with a booth, that exposure to the adjoining space is only when you enter and exit, and you could put in an interlock if the risk was high.

            Since the risk is very low, no professional PE, or fire safety professional has thus far ever required an interlock.

            Consider what happens to a cabinet? The adjoining space, any anyone in it, is exposed the whole time the cabinet is open for any reason. Loading, unloading, periodic cleaning of the food/pharma grade equipment as regularly required, etc.

            Food/pharma grade equipment have design parameters regarding ease of cleaning and frequency?

            For instance, how do you even load the machine, or do any significant work on it without having the doors door open?
            Chemical hoods do that by spooling up the ventilation so that the open door space is 100 to 200 surface feet, or 100/200 cfm per square foot open???

            Have you considered that the make-up air would be coming directly out of the room during those operations?
            How about if there was ignition, the room and those in it would not be protected from it?

            ***********************************************
            Doing so will make your customers happy and allow them to produce an even more consistent product.
            ***************************************
            I don’t have any unhappy WolfWurx customers that I’m aware of, are you?

            I’m left to wonder how can you hope to speak for what makes my customers happy without knowing or talking to them?
            They bought my design because it provided them with a certified system that provided a higher utility at the margin and ROI than any competitive systems that they found .

            Space is also at a premium, and not one of them would have been happy with me spreading the system out into twice as much real estate or significantly increasing their HVAC costs.

            I also think it is a far stretch stating that redesigning my whole system so that it fits into a long skinny cabinet, would improve product quality. How exactly does that part work?
            **************************************************
            What those modifications would have to be I can’t say because you’re right I don’t use butane/propane systems since there are inherently safer methods of extraction plus other reasons… For this discussion, that is besides the point; people choose to take the risks of working with butane/propane, so the question is how to make the process as safe as possible. BTW all of these discussion points also apply to large scale hydrogenations using high pressure hydrogen gas, something that industrial chemists try to avoid (can’t always be done, for several reasons) because of the high inherent risk.
            Oh, on the issue of system height, you can reduce the column height (which is the tallest component in every butane and CO2 extractor I’ve seen used by the cannabis industry) by switching to a larger ID pipe (obviously). If the reason you are using a tall and narrow column is due to concerns about uniform solvent distribution, there are designs for high efficiency diffuser plates to deal with that issue.
            *********************************************
            Spoken like a designer, not an engineer. WolfWurx supplies diffuser heads for 4” columns, but you seem to be ignoring flow on the larger ones.

            Not only do you have to dissolve the oleoresins, to remove them efficiently you have to keep the boundary layers replenished, so that fresh solvent and undiluted oleoresin are in contact.

            Otherwise the solvent in contact with the material becomes highly saturated, so less of a solvent, and the oleoresin becomes partially dissolved, therefore not as concentrated.

            With unlimited flow you might feed short fat columns, but these systems do not have unlimited flow, so engineers go a step beyond brain farts, and balance the system using actual numbers.

            We also have to recover the LPG before opening a column, which we do by heating to 150F under vacuum. Large diameter columns under vacuum do not heat as fast or uniformly as smaller diameter columns.
            ********************************************************
            I can help you find those designs if you’d like, or you can look through chromatography patents. Beside space issues, there are also other advantages to short columns, but that is not for a public discussion. If you are going with the tall & narrow column due to cost and availability issues, such is life.
            ******************************************************
            I’ve not had any problem finding columns, or building my own, which is what we ended up doing at WolfWurx when things weren’t readily available.
            *******************************************************
            “… to challenge the direction the professional in that field…”
            An expert must be able to answer all concerns when the answers to those concerns are known. So it doesn’t matter what my level of expertise is, if I or someone else sees a potential problem the experts need to be able to address them. Sometimes it is the least experienced that find the problems (though rarer, sometimes the solutions too). The “I’m an expert and you are not, so how dare you question me” attitude is where a shit load of problems, in all fields, begin.
            ****************************************
            Consider the difference between questioning the direction, and professing to be the voice from the mountain.

            Consider the difference between pages of ventilation 101 sage platitudes “educating” those already trained and experienced, instead of just asking why things are done one way, instead of the way you think they should.

            It isn’t the challenge, it is what you say and how you say it.
            ******************************************
            “The CAD drawings are to scale, and I’ve noted above that there is one foot (not 10 ft) between the extractor and the intake plenum.” I said 10 ft, because even without seeing any additional numbers or thought I know there would be no problems with the gases reaching the floor. I do also know that depending on the numbers, that can be much shorter.
            “If you look at the calculations I provided regarding evacuation rates, you should have all the numbers that you need. It is a 7’ wide, 8’ tall, 8’ deep booth in the example.
            The volume of the booth is replenished every 4.8 seconds, which is 12.5 turns per minute.”
            Seeing these makes me much more comfortable, and for whatever reason I did not see them before (I’m both dyslexic and AHDH, so I literally may not have seen them…). At 8′ deep, the vortex I was concerned about between the floor and wall opposite the vent should be so small and weak as to be insignificant, at half or less of that distance I’d want to see a fluid dynamics model before I wrote it off (because a vortex there can create a containment problems around sashes and doors).

            “Can you really believe that something that obvious was not only overlooked by…”
            Actually no but like you, I say things to communicate that I know the issues that need to be considered, and not because I think the people I’m talking to don’t know them.
            “Consider the velocity of the air mass the leak is entering and how long it takes to exit.”
            Which is exactly what I’ve been thinking about all along…
            “All of the WW Terpenators hold 48# of LPG, in a 100# ASME DOT refrigerant tank, so that much gas suddenly released would be the worst case.
            It doesn’t take a math genius to figure out that there is no way to accommodate that much gas spontaneously without exceeding LEL.”
            A point I made in my first post. And as you say later, being above LEL is not a barrier in itself so long as the residence time is short. A lot of my concerns, have centered around major but not catastrophic leaks (ie LEL level leaks where the enclosure still maintains a balance between the leak rate and the removal rate), that due to directionality and velocity have longer than usual residence times (not a problem one would/should encounter spraying paint, but a potential one for pressurized extractors, hydrogenators, HPLC, etc.). It is those types of leaks I want to see modeled instead of relying on “simple textbook formula.” Sometimes the solution is easier than the calculation, how hard/expensive would it be to design a system where the airflow could be increased (say doubled) while the leak was dealt with? Admittedly not an ideal solution, but we are talking about a far from ideal situation.
            *********************************************
            Not hard at all, and not a unique thought. If you read my post there is a discussion of the difference between Class I, Div I, and Div II airflows, as well as sizing the system to pull any leaks by the HC sensor, and spooling up to Div I requirements in alarm state.

            In fact you will note that is what I recommend for both operator comfort and safety.

            As far as the air velocities and principles to achieve that, I continue to rely on the numbers the US government professionals with almost unlimited resources, who were paid to determine those values, have published in Industrial Ventilation.

            I do so for two reasons. The first is that over a professional lifetime, I found that they work. The second is that they are what the legislators used to establish regulations.
            ************************************************************
            “Do I infer the engineer was not a professional, or was operating outside is areas of expertise by virtue of training and experience?
            Engineering is different than designing. Engineering suggest the proper engineering principles were followed, while designing is an art form. A professional does both.”
            We both not know all “professionals” are cut from the same cloth…
            **************************
            Or all who design professionals. Do you know if he was or was not a PE?

            While they aren’t cut from the same cloth, they do have a certification and license to maintain.
            ****************
            “I doubt that you would get much of an argument from anyone that perfect is best, but then we have to define perfect.” Unfortunately, I’ve had to remind a few academics that “prefect is the enemy of good,” but that is a different story.
            “My definition of perfect as a manufacturing engineer, is one that provides the highest utility at the margin, while sending all of the employee’s home safe to their families every night, protecting the other assets, and maintaining environmental standards.
            The items in the “while” part, aren’t up for negotiation, only the utility at the margin part, which leads us to the part about being profitable enough to stay in business against the competition.”
            I’ve met very few professional chemists who will disagree with you, but I’ve met too many in the cannabis world who put profit over safety (their employees’ and the public’s) and I want them gone as quickly as possible…
            ************************************************
            We’ve all met them, and most of us want them gone as well, which is why I favor legalization and regulation.

            The “fish” for me is for quality cannabis products to be available to us all, the same as any other pharmaceutical or herbal medicine falling under the aegis of the FDA.
            *******************************************
            “As I noted earlier, only the first extraction booth design is mine, and the other two are examples of how others have built systems that were tested to verify that they worked and certified.”
            With this additional information I’m pretty happy with your design. I say “pretty happy” because I’m always asking can it be done better. I’m also less than perfectly happy with it due to the fact that operators have to share the air with contaminates which would not be the case if an extractor was in a walk-in fume hood.
            *****************************************************
            And yet we come back to the point that there ostensibly are no contaminates to breath, because they normally don’t leak.
            *************************************************
            Admittedly in the case of butane that is a minor issue, but does show a chemist’s preference to maximize the separation between people and hazardous materials.
            *****************************************************
            A preference that manufacturing engineers share, but we have to meet the whole list of requirements, not just the one, and it has to reliably work. Not only did we monitor our systems to verify their working, so did OSHA.
            ********************************************
            BTW do you have a dB for the floor vent? I ask because I’ve seen a lot of places that overlook audio safety.
            *************************************************************
            Hearing protection and chemical goggles are required, as are non static coveralls. The only time sound exceeded 75dB was when the Vaccon venturi vacuums are engaged, at which time hearing protection is needed.
            **************************************************
            My reluctance to embrace the other designs, is tied to seeing the botched version (15+ ft ceiling, a pair of fans ~1 ft off the floor with passive make-up air vents at the same level: when the fans were on there was a fast and visibly turbulent air flow below knee level (you could see dust being picked-up a swirled in eddies) and very little air flow above that (at head level dust just floated around as if the fans weren’t even on)) which honestly could have been fixed with an overhead make-up air source and adjusting the fan speed.
            When I set-up my own lab, I’ll come talk to you about the engineering. In the meantime I’ll continue to suggest that people use hoods (plenty of stuff should be done in them, even one isn’t using them for extraction) and consult licensed architects experienced in designing labs who will subcontract the engineering.
            —-
            My other gripe about the standards/building codes in OR for science spaces is that there is not one clear and concise summary of the standards for wet lab spaces that the public can easily access for free. That is no longer a significant issue for the cannabis industry due to the new regulations and multitude of inspections but other “non-regulated” science start-ups are still being told to convert warehouses into labs. So the entrepreneurs DIYing labs without understanding the full requirements or seeking professional advice. What makes things worse is that the only obvious requirement in the OR building code for labs is that either one meets the high hazard standards, or one meet the requirements for a B class (business) and a start-up lab can easily come under the thresholds for a high hazard occupancy. The OSHA standards are a bit better as are OR firecode, but again one has to know to go looking. At least the CA building code specifically defines the requirements for wets labs (class L) which operate below the high hazard occupancy threshold…

            Final questions:
            1) Do you have any experience designing tangent flow filtration systems?
            2) Do you know chemical engineers who could answer the following question: “what is the minimum economically viable fluidized reactor bed for converting paraffin into gasoline?” Hey, someone has to figure out what to do with all that wax by-product from the cannabis industry…
            ***************************************************************
            I have experience with cross flow micro filtration to 0.2 micron and 100gpm, removing radioactive LSA Thorium Oxide to below background radiation.

            I used polysulphone plate and frame, but you can also use ceramic tubes, which will take more cleaning abuse.

            I retired a decade ago, so have lost track of most personnel, including the labs and R&D. The last A Team retirement luncheon, only three of us made it. The rest are either dead or moved away.

            Do I infer you’re talking about a fluidized platinum reactor bed, similar to the ones used in a petroleum refinery cat cracker tower?

          • “To that point, I already said I could spread my design out, but you seem to have missed or are ignoring my point about size of the foot print and what that does to the ventilation requirements, which are based on area.”

            No I did not miss it, but you do have some vertical space to work with if you so choose.

            “Consider what happens to a cabinet? The adjoining space, any anyone in it, is exposed the whole time the cabinet is open for any reason. Loading, unloading, periodic cleaning of the food/pharma grade equipment as regularly required, etc.”

            This is false with fumehoods, which are designed to keep containments within them even when open (assuming proper installation and the source of the containment is not pressurized). A 3 ft deep fumehood can be cleaned without entering it, as can almost anything put in it. Your point is fair for deeper fumehoods. Are there other types of cabinets, that don’t function that way, yes. The closest chemists regularly work with are chemical storage cabinets which are suppose to be connected to the ventilation system if they are used to store volatile compounds.

            I don’t work with food equipment, but will assume that it is like pharmaceutical equipment which can be cleaned without entering it under normal circumstances. In the case of large reactors and many other types of equipment, they are designed to also contain solvent vapors while being cleaned. In the rare instances when one must enter large pharmaceutical equipment, one does so wearing a respirator, a self-contained breathing apparatus, or very rarely a breathing apparatus connected to a remote air source via hose.

            “Food/pharma grade equipment have design parameters regarding ease of cleaning and frequency?”

            The GMP regulations do stipulate the frequency of cleaning (after each and every batch on the pharmaceutical side, and I believe it is the same on the food side but would have to double check). As for ease of cleaning, we want it easy to clean but if it isn’t too bad, clean it anyway (which is why one sometimes sees strange looking cleaning tools).

            “Have you considered that the make-up air would be coming directly out of the room during those operations?”

            In a properly designed lab with chemical fumehoods, the make-up air is supplied to the room in addition to regular ventilation, with a preference for an overhead make-up air vent directly in front of fumehood (which is why chemists often take jackets and sweaters to work even during the hottest days of summer). BTW not a fumehoods have variable speed blowers, though that is the preference these days (energy conservation), and the make-up air systems are matched accordingly.

            “Spoken like a designer, not an engineer. WolfWurx supplies diffuser heads for 4” columns, but you seem to be ignoring flow on the larger ones.”
            Not at all. Diffuser head designs are engineered for diameters from < 1mm to 2m, with flows ranging from 100L/min and every practical combination of the two parameters you can imagine.

            “Not only do you have to dissolve the oleoresins, to remove them efficiently you have to keep the boundary layers replenished, so that fresh solvent and undiluted oleoresin are in contact.”
            Same issue in chromatography – there are reasons we choose diameter over length when processing large amounts of material…

            “With unlimited flow you might feed short fat columns, but these systems do not have unlimited flow, so engineers go a step beyond brain farts, and balance the system using actual numbers.”

            High flow does not necessarily improve the performance – actually it often makes it worse. Chemists optimize systems based on experimental data, not theoretical numbers. Again, there are reasons we choose diameter over length. Of course, we also prefer to stir instead of rely solely on diffusion (which you aren’t).

            “We also have to recover the LPG before opening a column, which we do by heating to 150F under vacuum. Large diameter columns under vacuum do not heat as fast or uniformly as smaller diameter columns.”

            While it wouldn’t work here, one would normally purge a column with air/nitrogen/vacuum. The heating issue is, so far, your best justification for the narrow and tall column. There are ways around that issue, but they could easily create more problems than they solve. In a bit of the reverse situation, I had to solve the heat equation to show some people that their design would not be practical if they solely relied on external cooling to cool a column from RT to -40C; for the column size, material and thermal contact it would have taken over 25hrs. Yes, I’m that rare chemist who does pure & applied mathematics, physics (love GR and QFT, been known to do fluid dynamics, EM, theoretical optics, heat transfer, etc.), physical chemistry, organic synthesis and drug discovery.

            As you are alluding to, there are also other considerations to consider – it was just an idea that I mentioned because not everyone is aware about the diffuser plates.

            “It isn’t the challenge, it is what you say and how you say it.”
            Fair enough. Like most with ADHD, I tend to speak first then realize I should have chosen different wording. Also, again the first post was not directed at you. It was also written with the expectation that many of your readers would simply try to implement your plans without seeking further professional advice to tailor the plans to the space being used (less an issue in heavily regulated states like OR, much more of an issue in places like CA (though that is in the process of changing for the cannabis industry) and AZ, and a definite issue for those operating illegally).

            “Not hard at all, and not a unique thought. If you read my post there is a discussion of the difference between Class I, Div I, and Div II airflows, as well as sizing the system to pull any leaks by the HC sensor, and spooling up to Div I requirements in alarm state.

            In fact you will note that is what I recommend for both operator comfort and safety.”

            Cool, I did see the discussion but I missed the recommendation.

            “As far as the air velocities and principles to achieve that, I continue to rely on the numbers the US government professionals with almost unlimited resources, who were paid to determine those values, have published in Industrial Ventilation.”

            I trust these sources but don’t know where the assumptions behind them break down. In the case of spraying paint (or similar mists) or diffuse “low velocity” gas leaks, no worries. Even a 1 micron diameter droplet of paint has a cross-sectional area about 25,000,000 times larger than a molecule of nitrogen, so the droplet has an effective mean-free-path of zero and it’s movement will quickly be determined by the surrounding airflow (unless the droplet was ejected under high pressure like a leak from HPLC operating at 400-1200 Bar (1 Bar ~ 0.987 atm)). What worries me, is how well do those values deal with focused “high velocity” gas leaks (i.e. jets)? The physics of slowing down/deflecting a jet of gas are different than those of a jet of mist (same principles, different results). Again, I’m showing my thinking here… Butane, with a cross-sectional area about twice that of nitrogen, has a mean-free-path comparable to nitrogen which means, on a microscopic level, one needs to consider statistical scattering distributions (instead of the average momentum effects when dealing with droplets) resulting in longer distances travelled before a jet of gas is broken up and the gas’ movement is determined by the surrounding airflow. For those reading this that didn’t follow the technical jargon: mists interact more strongly with an airflow then do jets of gas.

            I also saw that you included the tables and liked that a lot. Again, I’ve always preferred your design over the others precisely because it clearly was designed to sweep the full room. For me, the other designs raise concerns about mixing efficiency and actual airflow patterns in the room.

            “Do you know if he was or was not a PE?”
            No, it was the business supervisor (he was not responsible for contracting any part of the construction work/design) who first pointed out that his “explosion proof” enclosure was not designed to work properly, neither the explosion proof (a room full of electrical outlets, which passed both building and fire inspection) nor the ventilation (which was “engineered”), so I didn’t ask.

            “And yet we come back to the point that there ostensibly are no contaminates to breath, because they normally don’t leak.”

            This is the opposite thought partner of an EH&S officer. For them (including myself) it is: “when a leak happens, what is the operators exposure and how do we minimize it?” The good news for those working with butane is that below LEL it poses very few health risks. And for a room above LEL, well, one should be calling emergency response (from outside the room) and seriously considering evacuating the neighborhood. <- Not directed at GW.

            "Hearing protection and chemical goggles are required, as are non static coveralls. The only time sound exceeded 75dB was when the Vaccon venturi vacuums are engaged, at which time hearing protection is needed."

            Good. I've been in businesses doing extractions where I had to point out that they needed hearing protection. In one case, they had to be over 100 dB constantly. Admittedly a guess but we had to shout to be heard 3 ft away – in a separate room.

            "I have experience with cross flow micro filtration to 0.2 micron and 100gpm, removing radioactive LSA Thorium Oxide to below background radiation.
            I used polysulphone plate and frame, but you can also use ceramic tubes, which will take more cleaning abuse."

            Cool. Ok, I have a design choice to make: I can treat my filters (sintered SS or glass, ceramics are unlikely to be sufficiently chemically stable for my application) to make them solvent selective and use them to filter a stirred abrasive reaction mixture. My concern is damaging the treated filters and the choice is either to do a two stage filtration (remove the abrasive material completely then selectively filter the solvents with each stage done in a separate piece of equipment) or I can have one piece of equipment that has a very fine screen that separates most of the abrasive material from the treated filters with the down side being increased wear on the filters and the need for more solvent. Which way would you lean and why?

            "I retired a decade ago, so have lost track of most personnel, including the labs and R&D. The last A Team retirement luncheon, only three of us made it. The rest are either dead or moved away."
            Fair enough. I don't know any CE types right now either…

            "Do I infer you’re talking about a fluidized platinum reactor bed, similar to the ones used in a petroleum refinery cat cracker tower?"

            Yes, except the petroleum industry has mostly switched to zeolites. I can't remember that last time I heard anyone talk about using Pt for cracking (BTW I mostly make C-C bonds, not break them, so this isn't my normal chemistry turf). I know Pt is still sometimes used to desaturate hydrocarbons though. Anyway, what is completely out of my depth on this one is figuring out what the smallest reactor one can make, and how much product must be produced in it for it to be profitable?

          • To that point, I already said I could spread my design out, but you seem to have missed or are ignoring my point about size of the foot print and what that does to the ventilation requirements, which are based on area.”
            No I did not miss it, but you do have some vertical space to work with if you so choose.
            *************************************
            “Some” does not define “enough”. You have some elevations you have to maintain, and limits to reach if you consider ergonomics. That is why I said only double, and if you look at similar rack mounted designs, they are typically double or greater.

            Did your chemical engineering degree include the industrial engineering studies of motion and flow, as well as ergonomics, which is always a part of a manufacturing engineering design?

            In that case, the standard bible is Motion and Time Study, the design and measurement of work, by Barnes.
            *********************************************
            “Consider what happens to a cabinet? The adjoining space, any anyone in it, is exposed the whole time the cabinet is open for any reason. Loading, unloading, periodic cleaning of the food/pharma grade equipment as regularly required, etc.”
            This is false with fumehoods, which are designed to keep containments within them even when open (assuming proper installation and the source of the containment is not pressurized).
            **********************************************
            False??? And there is where your lack of understanding of how they work, leads you to your aberrant thinking.

            The way a hood contains what is going on inside, is move the same amount of air through that opening, that we are moving per square foot through a booth to obtain capture velocity.

            Are you ignoring the question of where the make-up air comes from?

            Even those designs minimizing make up air from the room, can’t provide 100% air makeup from the push blower, and while it begins to sound like a broken record, if you had at least read the Industrial Ventilation book I keep directing your attention to, you would know why.

            Are you also ignoring the issue of what happens to the adjoining room when you have a catastrophic release while the hood is open?

            How about the significance of a catastrophic release exceeding LEL for a period of time? What happens if the hood is open?
            *******************************************
            A 3 ft deep fumehood can be cleaned without entering it, as can almost anything put in it. Your point is fair for deeper fumehoods. Are there other types of cabinets, that don’t function that way, yes. The closest chemists regularly work with are chemical storage cabinets which are suppose to be connected to the ventilation system if they are used to store volatile compounds.
            I don’t work with food equipment, but will assume that it is like pharmaceutical equipment which can be cleaned without entering it under normal circumstances. In the case of large reactors and many other types of equipment, they are designed to also contain solvent vapors while being cleaned. In the rare instances when one must enter large pharmaceutical equipment, one does so wearing a respirator, a self-contained breathing apparatus, or very rarely a breathing apparatus connected to a remote air source via hose.
            “Food/pharma grade equipment have design parameters regarding ease of cleaning and frequency?”
            The GMP regulations do stipulate the frequency of cleaning (after each and every batch on the pharmaceutical side, and I believe it is the same on the food side but would have to double check). As for ease of cleaning, we want it easy to clean but if it isn’t too bad, clean it anyway (which is why one sometimes sees strange looking cleaning tools).
            ***********************************************
            Clearly you haven’t designed any of that equipment either, or read the specifications, so suggest that you do so, before waving it aside. It requires a design without traps, that can either be easily taken apart and cleaned, or cleaned in place.

            Cleaned in place is typically how they do large or difficult to clean portions, and how we do our LPG piping, but it would require a somewhat elaborate system to clean the rest in place, not to mention that the zeolite filter driers can’t be serviced in place.

            Cleaning aside, the cabinet is open just to load and un load it with raw material and product.
            ******************************************
            “Have you considered that the make-up air would be coming directly out of the room during those operations?”
            In a properly designed lab with chemical fumehoods, the make-up air is supplied to the room in addition to regular ventilation, with a preference for an overhead make-up air vent directly in front of fumehood (which is why chemists often take jackets and sweaters to work even during the hottest days of summer). BTW not a fumehoods have variable speed blowers, though that is the preference these days (energy conservation), and the make-up air systems are matched accordingly.
            ***************************************
            Consider what you just said? What happens to HVAC air balance in the room when you open or close the hood? With the kind of air flow required for a large opening, even a variable speed drive would be hard pressed to keep up without hysteresis, which means besides popping ears, you are now violating OSHA rules on room static pressure imbalance leading to injuries opening doors.

            You also still don’t address what happens with a release driving the system above LEL with the hood open. Is the rest of the room NEMA 7, Class I, Div I or II?
            *******************************************
            “Spoken like a designer, not an engineer. WolfWurx supplies diffuser heads for 4” columns, but you seem to be ignoring flow on the larger ones.”
            Not at all. Diffuser head designs are engineered for diameters from < 1mm to 2m, with flows ranging from 100L/min and every practical combination of the two parameters you can imagine.
            ****************************************
            We built diffuser plates 72” in diameter for air treatment, which aren’t as large as they get, but you appear to place no significance on the issue of flow, which isn’t unlimited in our designs, though it appears to be in yours.
            ***************************************************
            “Not only do you have to dissolve the oleoresins, to remove them efficiently you have to keep the boundary layers replenished, so that fresh solvent and undiluted oleoresin are in contact.”
            Same issue in chromatography – there are reasons we choose diameter over length when processing large amounts of material…
            “With unlimited flow you might feed short fat columns, but these systems do not have unlimited flow, so engineers go a step beyond brain farts, and balance the system using actual numbers.”
            High flow does not necessarily improve the performance – actually it often makes it worse. Chemists optimize systems based on experimental data, not theoretical numbers. Again, there are reasons we choose diameter over length. Of course, we also prefer to stir instead of rely solely on diffusion (which you aren’t).
            ************************
            Absolutely true. The column ID and flow need balance. That is the difference between a design and an engineered system.
            What column diameters and lengths did you have in mind and how much flow does your system have? Engineering is after all about numbers, as applied to brain farts, not the epiphany themselves.

            **************
            “We also have to recover the LPG before opening a column, which we do by heating to 150F under vacuum. Large diameter columns under vacuum do not heat as fast or uniformly as smaller diameter columns.”
            While it wouldn’t work here, one would normally purge a column with air/nitrogen/vacuum. The heating issue is, so far, your best justification for the narrow and tall column. There are ways around that issue, but they could easily create more problems than they solve.
            ******************************************
            No air/nitrogen/vacuum didn’t work here, which is why we took the extra steps to add the hot water jackets and put in a PID controlled system.

            Remember me telling you that a manufacturing engineer’s designs are measured by whether they meet the design performance parameters or not, and his employment is based on the same?

            The parameters that I had to meet, were the process had to be completed in a period of time considered reasonable to the buyer.

            I also had to end up with an end product that wasn’t considered hazardous by the fire safety professionals who required show and tells, regardless of what the PE certifying the system thought.

            You can literally hold a lighter to the spent product as it’s removed, and it is no more flammable than raw material, with the added bonus that they can run more cycles per day, at the same labor cost, as well as give them more time to clean at the end of the day.

            My point is, that what I’m demonstrating, is an appropriate use, meeting the job requirements, not philosophical beliefs on utopia.
            ************************************************
            In a bit of the reverse situation, I had to solve the heat equation to show some people that their design would not be practical if they solely relied on external cooling to cool a column from RT to -40C; for the column size, material and thermal contact it would have taken over 25hrs. Yes, I’m that rare chemist who does pure & applied mathematics, physics (love GR and QFT, been known to do fluid dynamics, EM, theoretical optics, heat transfer, etc.), physical chemistry, organic synthesis and drug discovery.
            As you are alluding to, there are also other considerations to consider – it was just an idea that I mentioned because not everyone is aware about the diffuser plates.
            “It isn’t the challenge, it is what you say and how you say it.”
            Fair enough. Like most with ADHD, I tend to speak first then realize I should have chosen different wording. Also, again the first post was not directed at you. It was also written with the expectation that many of your readers would simply try to implement your plans without seeking further professional advice to tailor the plans to the space being used (less an issue in heavily regulated states like OR, much more of an issue in places like CA (though that is in the process of changing for the cannabis industry) and AZ, and a definite issue for those operating illegally).
            ***************************************
            Consider that your ADHD or whatever reason, may make it hard for others to see exactly who it is directed toward, when it includes challenges to the design principles I used, to whoever your intended audience was.
            After you said that, I went back and read it and still got tripped up on some of your statements.
            Using the analogy of the walk around the elephant to see it from other perspectives, consider if I did the same on your site dedicated to chemistry, and challenged the principles that you used to make you successful, throughout your professional career.
            What if I told your readers things you knew to be untrue or unreasonable under the circumstances? Not through malice, but ignorance.
            Consider how much time I’ve now spent debating it with you, and what I would rather be doing……….

            ****************************************
            “Not hard at all, and not a unique thought. If you read my post there is a discussion of the difference between Class I, Div I, and Div II airflows, as well as sizing the system to pull any leaks by the HC sensor, and spooling up to Div I requirements in alarm state.

            In fact you will note that is what I recommend for both operator comfort and safety.”

            Cool, I did see the discussion but I missed the recommendation.
            “As far as the air velocities and principles to achieve that, I continue to rely on the numbers the US government professionals with almost unlimited resources, who were paid to determine those values, have published in Industrial Ventilation.”
            I trust these sources but don’t know where the assumptions behind them break down. In the case of spraying paint (or similar mists) or diffuse “low velocity” gas leaks, no worries. Even a 1 micron diameter droplet of paint has a cross-sectional area about 25,000,000 times larger than a molecule of nitrogen, so the droplet has an effective mean-free-path of zero and it’s movement will quickly be determined by the surrounding airflow (unless the droplet was ejected under high pressure like a leak from HPLC operating at 400-1200 Bar (1 Bar ~ 0.987 atm)). What worries me, is how well do those values deal with focused “high velocity” gas leaks (i.e. jets)? The physics of slowing down/deflecting a jet of gas are different than those of a jet of mist (same principles, different results). Again, I’m showing my thinking here… Butane, with a cross-sectional area about twice that of nitrogen, has a mean-free-path comparable to nitrogen which means, on a microscopic level, one needs to consider statistical scattering distributions (instead of the average momentum effects when dealing with droplets) resulting in longer distances travelled before a jet of gas is broken up and the gas’ movement is determined by the surrounding airflow. For those reading this that didn’t follow the technical jargon: mists interact more strongly with an airflow then do jets of gas.
            **************************************
            If you read the verbiage at the bottom of Table 2, you will see what the hygienists doing the testing found, which is why they give a range of 100 to 200 for capture velocity.
            ***********************************************
            I also saw that you included the tables and liked that a lot. Again, I’ve always preferred your design over the others precisely because it clearly was designed to sweep the full room. For me, the other designs raise concerns about mixing efficiency and actual airflow patterns in the room.
            “Do you know if he was or was not a PE?”
            No, it was the business supervisor (he was not responsible for contracting any part of the construction work/design) who first pointed out that his “explosion proof” enclosure was not designed to work properly, neither the explosion proof (a room full of electrical outlets, which passed both building and fire inspection) nor the ventilation (which was “engineered”), so I didn’t ask.
            “And yet we come back to the point that there ostensibly are no contaminates to breath, because they normally don’t leak.”
            This is the opposite thought partner of an EH&S officer. For them (including myself) it is: “when a leak happens, what is the operators exposure and how do we minimize it?” The good news for those working with butane is that below LEL it poses very few health risks. And for a room above LEL, well, one should be calling emergency response (from outside the room) and seriously considering evacuating the neighborhood. <- Not directed at GW.
            *********************************************
            Not the opposite; the principles simply place limits on their exposure to hazards and say we will exhaust all reasonable engineering avenues before relying on personal protection.

            The probability of a leak of any significance is remote with a properly designed and operated system, but not zero, so that brings us to who is being protected and how.
            With your design, the probability is higher the hood will be open and the adjacent room and personnel are exposed, so that room will ostensibly need to be at least NEMA 7, Class I, Div II.

            You only have that exposure at entry and egress with a booth.
            ************************************************************
            “Hearing protection and chemical goggles are required, as are non static coveralls. The only time sound exceeded 75dB was when the Vaccon venturi vacuums are engaged, at which time hearing protection is needed.”
            Good. I’ve been in businesses doing extractions where I had to point out that they needed hearing protection. In one case, they had to be over 100 dB constantly. Admittedly a guess but we had to shout to be heard 3 ft away – in a separate room.
            “I have experience with cross flow micro filtration to 0.2 micron and 100gpm, removing radioactive LSA Thorium Oxide to below background radiation.
            I used polysulphone plate and frame, but you can also use ceramic tubes, which will take more cleaning abuse.”
            Cool. Ok, I have a design choice to make: I can treat my filters (sintered SS or glass, ceramics are unlikely to be sufficiently chemically stable for my application) to make them solvent selective and use them to filter a stirred abrasive reaction mixture. My concern is damaging the treated filters and the choice is either to do a two stage filtration (remove the abrasive material completely then selectively filter the solvents with each stage done in a separate piece of equipment) or I can have one piece of equipment that has a very fine screen that separates most of the abrasive material from the treated filters with the down side being increased wear on the filters and the need for more solvent. Which way would you lean and why?
            **********************************************
            Without knowing more about your process, I’m speaking in general, which is I removed everything I could before the micro filters, to increase the time between insitu cleaning and the wear on the membranes, which were about $10K per set two decades ago.
            I was treating wastewater, so I simply slammed the Ph to about 4.5 with H2SO4, reacted it with lime, dropped the Ph again to between 8.5 and 10.5, before sending it through two delta stack precipitators in series, and then the micro filtration plants.
            To protect from facility shutdown, I had three microfiltration plants, so I could be rebuilding one, cleaning one, and running one.
            For what it’s worth, I designed the $2.2 million plant around the process presented to me by the chemical engineer that I hired as an outside waste water treatment consultant. None of our own chemists were specialized in that field, and he made it look like duck soup.
            I also had an EE-PE covering my six on automation controls and programming, whom I would have been lost without.

            **********************************************************
            “I retired a decade ago, so have lost track of most personnel, including the labs and R&D. The last A Team retirement luncheon, only three of us made it. The rest are either dead or moved away.”
            Fair enough. I don’t know any CE types right now either…
            “Do I infer you’re talking about a fluidized platinum reactor bed, similar to the ones used in a petroleum refinery cat cracker tower?”
            Yes, except the petroleum industry has mostly switched to zeolites. I can’t remember that last time I heard anyone talk about using Pt for cracking (BTW I mostly make C-C bonds, not break them, so this isn’t my normal chemistry turf). I know Pt is still sometimes used to desaturate hydrocarbons though. Anyway, what is completely out of my depth on this one is figuring out what the smallest reactor one can make, and how much product must be produced in it for it to be profitable?
            **********************************************
            It’s out of my area of expertise as well. My petroleum industry background dates to growing up in a refinery town, where my father was refinery maintenance superintendent and I just paid attention.

            I didn’t care for the limited opportunity the town presented, or even how it smelled at times, so moved on to aerospace and haven’t looked back.

          • What you say about fumehoods was once true, and I’ve worked with a few really old hoods where you are spot on, but it is no longer – electronics/computers have changed a lot of things.

            “Without knowing more about your process, I’m speaking in general, which is I removed everything I could before the micro filters, to increase the time between insitu cleaning and the wear on the membranes, which were about $10K per set two decades ago.
            I was treating wastewater, so I simply slammed the Ph to about 4.5 with H2SO4, reacted it with lime, dropped the Ph again to between 8.5 and 10.5, before sending it through two delta stack precipitators in series, and then the micro filtration plants.
            To protect from facility shutdown, I had three microfiltration plants, so I could be rebuilding one, cleaning one, and running one.
            For what it’s worth, I designed the $2.2 million plant around the process presented to me by the chemical engineer that I hired as an outside waste water treatment consultant. None of our own chemists were specialized in that field, and he made it look like duck soup.
            I also had an EE-PE covering my six on automation controls and programming, whom I would have been lost without. ”

            Thank you, it is useful information. Fortunately, I don’t have to same type of problem to deal with so it is a little easier system to design.

          • What you say about fumehoods was once true, and I’ve worked with a few really old hoods where you are spot on, but it is no longer – electronics/computers have changed a lot of things.
            **********************************************************
            Surprisingly they had electronics and computers back in the hoary days of yore, when I was still gainfully employed and they don’t change the actual fan and ventilation laws, they just make it easier to deal with it.

            Some problems are still better solved mechanically. For instance, I had a fume collection and scrubbing system that had a 100 horse power blower on it, and I had to keep the room in balance as it went on and off line, which I did using solid links to open another damper to compensate, as the first damper is opened to ventilate.

            The issue as I see it, is that we agree that a properly designed fume hood is a good solution up to a certain size, but don’t agree about its suitability for all our applications.

            Since we’ve beaten it to death, let’s agree to disagree???

            Good luck with your project! I wait with bait on mah breath to see about ~C-30 plant waxes cracked into about C-6 gasoline.

            I recently saw a project using CO2 and electricity to make ethanol and I already drive an all electric car that I pay to charge using wind power, so look forward to more viable alternatives to fossil fuels.

            GW

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