Ventilation is an important aspect of a distillery’s function and safety. The model building codes, mechanical codes, and fire codes inform us on much of the requirements surrounding this topic. But, experience is what tells us the best way to design ventilation in distilleries. Here we will learn about the main ventilation concepts in distilleries.
Exhaust Low, Intake High
For every distillery, regardless of quantity/ still size, we advise to have exhaust routed to pull air within 12″ of the floor near potential flammable vapor sources like a still, tanks, or barrels. Exhaust in your distillery is a key to safety, as it essentially “sucks out” potential flammable vapor sources, if the still develops a pinhole leak, or something of that nature.
When we exhaust air, we must provide make up (incoming/ intake) air. We usually place this intake high as possible, on a wall, or the roof, and as opposite across the room as possible from the exhaust. The ensures that air sweeps across the room in an efficient manner and there are no dead spot / eddies of air that do not move.
Often, the exhaust is a powered fan, and the intake can be gravity dampered, meaning, the intake is designed sot that the pressure from the exhaust fan across the room automatically opens louvers and allows air to come in when it reaches a certain pressure.
Tempering Air
When air come in from the outside, in many climates, it needs to be heated or cooled to maintain comfortable temperatures inside. So, the intake may actually be a heating unit, cooling unit, both. Sometimes inside, near the intake, we can place a separate heating unit, such as a unit heater, which can be electric or gas powered.
We can also utilize ERV’s (energy recovery ventilators) for both intake and exhaust, which recover some of the lost energy (heat or cool) and reuse it.
Exhaust rates
Exhaust rates can vary based on a number of factors. Larger distilleries may need to have 1 CFM per SF of space. This is often triggered when MAQ’s (maximum allowable quantities ) are exceeded. When under the MAQ’s, less than 1 cfm per sf may be possible. We can also determine ventilation rates based on the still potential, and in doing so, electrically declassify the space as well. See another article all about electrical declassification:
https://dalkita.com/the-electric-sombrero-of-death-for-distilleries/
When we have an adjacent tasting room
When we have a tasting room adjacent to a distillery, we have an opportunity for a unique ventilation concept in the distillery. Tasting rooms have their own ventilation/ fresh air requirements. They will usually require a relatively high amount of fresh air to be introduced to the space. Then, instead of just exhausting that straight outside, we can then transfer the air to the distillery to be re-used, and then exhausted. This is efficient because it allows the energy needed to temper (heated or cooled) the air to be used twice.
Hazardous Exhaust
Hazardous exhaust is generally not required in distilleries. This type of system is one where flammable vapors are normally expected and the duct and fans must be classified electrical, and sometimes explosion proof. This is the case in an exhaust from a spray booth where flammable paints or solvents are being sprayed. But, in a distillery, the exhaust should be in place to maintain < 25 % of the lower flammable limit at all times, and the code permits this scenario to not have hazardous exhaust systems. The mechanical code still has requirements as to where exhaust must terminate on roofs or walls (setbacks from intakes, from property lines, etc).
Conclusion
Ventilation Concepts in Distilleries is a complex topic. A qualified mechanical engineer, along with a distillery specialist such as Dalkita, can help come up with the best design for your distillery, considering safety, costs (up front and operating costs), aesthetics, and function-ability.
-Article by: Matthew Taylor-Rennert
