Hi ya'll! Have ya'll been watching the folks blowing themselves and their homes up using butane extraction techniques, thus leading you to believe that such an attempt is suicidal?
Thank Gawd (Great Spirit) that paying attention to details reduces the odds to limits that you might embrace, after being thus enlightened. May we discuss, before you give up all BHO extraction attempts in deference to your family and home?
Clearly Butane is flammable and can be explosive, if confined in a small space and supplied with about 1.86 to 8.41 percent butane to atmospheric air content and an ignition source.
In addition, ignition sources come from a number of different unexpected sources, so let's discuss that issue.
For starters, I never personally do a butane extraction indoors or any confined space! None at all, zero, zip, forget about it! It is important to keep it below explosive limits!
I do it all outdoors, with a non sparking plastic fan blowing, not sucking, the butane evaporation away! Butane loves self abuse and will clump together and pool, being that it is heavier than air.
I use three fans to keep any free butane dispersed below ignition limits of 1.86% and from it pooling and accumulating in low spots like through my basement window to my basement, chock full of ignition sources.
The central point is that concentration of the butane boiling off can be kept diluted below combustion limits, by blowing the accumulating vapors away using a fan.
Butane liquid expands 288:1 when changing from a liquid to a vapor, and Henry's law tells us that the butane vapor and the air it combines with at 1.86%, expands in direct proportion to their temperature change. Butane in open air has a flame temperature of 1970C/3578F, so for instance if the butane vapor ignited at an ambient temperature of 291 Kelvin (18C/65F), it would expand about 7.2 times.
A 300 ml can of butane occupies about 18 cubic inches, X 288 = 5184 cubic inches.
5184 cubic inches divided by .00186 mixture = 2,787,097 cubic inches
2,787,097 X 7.2 = 20,067,098 cubic inches, or 11,613 cubic feet. With 8 foot ceilings, that is a 1452 square foot house. That expansion occurs in the blink of an eye, so you can see why a room incapable of containing a 1452 square foot house would have to expand its ceiling and walls outward to accommodate it.
It also doesn't take much imagination to realize what 3578F flame temperature does to organic matter like skin and eyeballs, so except for the prestige of having been immolated, it has little to recommend it.
Secondly, let's talk about stupid ignition sources. Despite previous discussions, I have literally grabbed the hands of cigarette smokers poised to light a cigarette while extracting. What can I say about addicts whom go on automatic pilot and forget where they are? Leave your cigarettes and lighter elsewhere.
Lose the lighter and cigarettes (bong?) if you are an addict! Once the pin is pulled on a 5 second grenade, it is not your friend!
All pretty simple, but lets talk about subtleties! How about sparks?
Starting simple, dragging your feet on concrete with gravel imbedded in your shoes can create a spark.
Wearing plastic clothing, especially socks, can also build up and discharge a static electricity spark, especially on cold dry days.
Unless it is an explosion proof fan, always blow, instead of suck the vapors away, not only for efficiency reasons, but because the sparks from an electric motor slip ring can ignite the vapors.
Always use plastic or other spark proof blades, because a grain of sand can spark when hitting a steel blade, and be propelled into the concentrated vapors.
Always keep a fully charged and recently inspected fire extinguisher on hand. Shit sometimes happens and less shit is better, as I see it!
Never had to use one at home, though I have in industry, and they can't be beaten when they are called for!
If you get inadvertently sprayed with butane, stop, and go change clothes. Immolating as I sees it, is highly overrated!
Keep a blanket on hand, and if you do get unexpectedly ignited, immediately wrap yourself in it to extinguish the flames.
The good news is that none of the above has ever happened to me, or any of my friends who pay close attention and try their very best to avoid it.