As public sentiment against cigarette smoking continues to rise, and as many communities enact anti-smoking laws for more and more types of indoor locations -- including offices and condominium complexes -- constructing a ventilated smoking room may soon be the only way you can lawfully smoke indoors.
Determine an efficient pathway for installing ventilation ductwork from the proposed smoking room to the outdoors. This ductwork must collect all the smoke-filled air at the ventilation fan and propel it out of the home or building. Cover all exterior vents with bird-, insect- and rodent-proof covers.
Install a fresh air supply duct system as well. You'll need to draw fresh air into the room from an outdoor intake vent that empties into the smoking room, usually at the floorboard level. This fresh air supply must be wholly separate from other fresh air supply ducts in the building.
Install one or more powerful ventilation fans in the ceiling. Ventilation fans must be able to forcefully pull or push smoke-filled air out of the room at a high rate of "exchange." Cigarette smoke, like smoke generated by cooking, must be removed from a location at a higher rate of speed than a bathroom ventilation fan is capable of. Fan power is rated in CFMs or "cubic feet per minute." Do research and purchase one or more fan units rated at 200 CFMs or more.
Do research on high-CFM ventilation fans that are also relatively quiet. Fan noises are rated in sones. Look for high CFM fans that are rated at six sones, or lower, for quieter operation. This problem is one of the dilemmas of constructing a smoking room: the fans that do the most good are often so noisy they make other activities, such as watching television, difficult.
Insulate the room as tightly as possible. Remove all drywall on walls and ceilings and install a plastic vapor barrier. Install a solid door with generous rubber gasket insulation strips around the edges and a good rubber "sweep" at the bottom of the door.
Test the speed of this air exchange system thoroughly before closing up any access points in the walls or ductwork. Smoke one or more cigarettes in the room. Use the nose of a nonsmoker volunteer to test whether the odor of cigarette smoke can be detected in other rooms while you are smoking.
Conduct another test: Turn on a powerful flashlight and set it in the middle of the room, pointing up, with the other lights turned off. Five minutes after you cease smoking, determine visually how much smoke may be collecting in the room by looking at the flashlight beam. If there is a still lot of smoke in the room, the smoke will be illuminated by the flashlight beam. The fan may not be removing enough air from the room at a fast enough rate of exchange. In this case, upgrade to a more powerful CFM model or add a second or third fan.
Run a final test of your system: An hour after extinguishing the last cigarette, and turning off the ventilation fan, have a new nonsmoker volunteer enter the premises without any warning as to why their help is needed. Ask him immediately upon entering the room what, if anything, he smells. If he instantly says "cigarette smoke," more work needs to be done on your system, including switching to a higher CFM fan or increasing the insulation.