end of the code pool. Remember that room that houses your hammer mill? Any concerns with that? Of course there are. Anyone that has spent time dumping corn into the hammer mill knows what it is like to pull corn boogers out of your nose for the next few days, and although those are uncomfortable, they are quite safe in comparison to the corn dust that is preventing you from seeing the other side of the milling room. According to the very knowledgeable folks at the Distilled Spirits Council of the United States, grain dust can be very explosive. Ridiculously small amounts of corn dust particles per cubic foot of air can, if ignited, produce an explosion capable of pressures greater than 100 pounds per square inch. Compare that to atmospheric pressure which is about 15 pounds per square inch, and you can quickly grasp just how bad a dust explosion can be, particularly when the six-time increase in pressure occurs in a fraction of a second! Since explosions in your distillery will be looked upon unfavorably, your milling room is required to be separated from the remainder of the distillery by “fire barriers” which have a fire-resistance rating of no less than two hours. The room must also be equipped with a dust removal system that can safely remove the dust cloud. Additionally, some codes will require explosion venting, a mechanism that allows much of the force of an explosion to move somewhat harmlessly outdoors. Once again, all of this sounds horrible but it really is not. A “fire barrier” is defined in the
International Building Code as “a fireresistant-rated wall assembly of materials designed to restrict the spread of fire in which continuity is maintained.” Simple explanation: this fire barrier is a wall that extends from the floor to the ceiling, is substantially attached thereto, and is constructed of materials that provide the necessary two-hour fire rating. The 19th edition of the Fire Resistant Design Manual published by the Gypsum Association provides seven wall assemblies constructed of wood studs and gypsum wallboard that will fulfill this requirement. The codes do allow door openings through the “fire barrier,” however the doors and door frames are required to be fire rated for oneand-one-half hours. The doors also need to be self-closing and when closed, they are required to be “positively latching,” which means they stay closed until you open them. Code compliant doors, door frames and hardware meeting all of the requirements are readily available, usually by special order from your local building supplier. Now what about that dust removal? Nothing overwhelming here either. Most startup distilleries have a small milling room, which your designer should put on an outside wall. This will make your life easier, the code people happier and save you hard-to-come-by funds. Remember, what we are looking to do is remove an extremely explosive and very fine airborne dust and send this outdoors or to a filter system of some type. Filter systems work well, but they give you yet another piece of equipment that will break down at the
worst possible moment, so sending the dust outdoors is preferable. This can be accomplished by installing an explosion proof through-wall exhaust fan, which is turned on as soon as the mill comes to life. Although “explosion proof” sounds daunting, again, it really is not. Throughwall, explosion proof electric fans are readily available. Just make sure you work with your electrical inspector to get a fan that is properly rated for this Electric Code “special occupancy,” and remember that as dusty air is removed from the milling room, it needs to be replaced with clean air from somewhere. If provisions are not made for replacement air, your exhaust fan will not exhaust for long. This takes us towards the future. What’s left? We have not completely finished the selection or installation of the exhaust fan in the milling room, nor have we talked about the requirements to separate your retail area from the distillery itself. We have not talked about the boiler installation, the sprinkler system, the fire alarm system… wow, we still have our work cut out for us. We will continue onto these and other topics in the future, and someday we will talk about the specific requirements for your new rick house, because you are definitely going to need one of those.
Shawn Bergeron is an NFPA and ICC Certified Fire Protection Specialist and Building Official with Bergeron Technical Services in North Conway, NH. For more info or assistance call (603) 356-0022 or visit www.bergerontechnical.com. They will be happy to help you with your distillery no matter how near or far.