Thoughts on smoke exhaust system for bar

[jarcrocker]

Working in a bar that has big problem with cigarette smoke accumulation.
The owner wants to put in an exhaust system to help minimize the smoke. Their thoughts are a large exhaust fan on a timer that cycles for less than 30 seconds every hour. I'm concerned about the humidity and negative building pressure problems that could occur but not sure I have a better idea. They have tried smoke eaters and air cleaners but its not really doing the job. I told her to just spray them out with a large water hose to keep it down at the source. She didn't like that idea...

Anyone had any experience with this and have any good ideas?

[jb-eng]

If you used an energy recovery ventilator you would somewhat reduce your humidity issue and eliminate your building pressurization issue. The heat exchanger in the ERV might get gummed up really quick in a smoky environment though. Just a thought.

[motoguy128]

Balanced fresh air. What type of AC equipment do they have now? Add an economizer and set a minimum position of maybe 20%. Then install an exhaust fan that ramps it's speed either in proportion to the economizer position, or set-up to keep the building slightly negative. With smoke, I think you want the building a little negative to keep it out of the walls and from blowing outward as people enter the building. The exhaust can be located near the greatest point sources (over the bar, pool tables, etc.).

I would think you want to target something like 3-5 ACH... but i don't have any scientific reason for that number. The Cooling requirements, will increase significantly.

They could also lobby the state to pass an indoor smoking ban as many states have already and make them sit outside. :)

[Jarreau]

I believe the ASHRAE guidelines are 50 CFM/person for a smoking environment. As Motoguy mentions a central exhaust fan that ramps up in relation to an economizer damper position would be the way I would control it. Your owner will realize more benefits than just eliminating the smoke odor. Furnishing, electronic equipment all benefit and will have an improved life without all of that nicotine "dust".

J