BHO Extraction Booth Design

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

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