• The most recent International Residential Code (2009) makes few requirements related to general ventilation, none relevant to fresh air requirements for dining rooms. In general, municipal and state codes have not addressed this area either. The 2008 Oregon Residential Specialty Code (ORSC) does include ventilation requirements for kitchen exhaust hoods. These may be relevant to residential designs that incorporate eating and cooking areas in a single room. In lieu of code requirements, recommendations do exist for general residential ventilation and for additional ventilation for a single room that combines cooking and dining functions.
  
  

EPA Recommendations

• The U.S. Environmental Protection (EPA) has returned to an earlier recommendation for residences, namely that the HVAC system should provide a minimum of 15 cubic feet per minute of outside air for each occupant. The EPA briefly lowered this recommendation, but later concluded that lower air transfer rates contributed to sick building syndrome. A 15-CFM air transfer for an 1,800-square-foot house with three occupants requires about a 2.5-ton heating, ventilating and air-conditioning (HVAC) system capable of constant air transfer. Most HVACs in newer houses will provide this. For houses with separate dining rooms, general ventilation meeting this standard will suffice.
  
  

Additonal Ventilation for Older Houses

• Older houses may not have HVAC or air-handlers that meet the 15-CFM EPA recommendation. Some houses built during the lower EPA CFM recommendation period (1973 to 1986), will almost certainly not meet it; during that period the EPA recommended five CFM for residential housing. These houses may require additional air transfer capabilities in kitchens and dining rooms. In these cases the U.S. Department of Energy recommends whole-house ventilation. Of four recommended systems, the simplest adds a secondary exhaust ventilation system that extracts indoor air from the building, often through an attic exhaust, and relies on leaks in the building shell to provide replacement fresh air. In some cases, a whole-house system may be overkill. You can simply install a low-noise fan that exhausts air from the dining room through an outside wall.
  
  

Kitchen/Dining Rooms

• Single rooms that share cooking and eating functions present a slightly different problem. The overall ventilation system may be sufficient, but cooking odors will drift from the kitchen area into the open dining area. A range hood that exhausts to the outside solves this problem. The OSRC mandates an exhaust fan in a full-size hood over the stove that vents through a through-wall duct to the outside. All hoods reviewed met or exceeded the OSRC's 150-CFM recommendation. Some exceeded the recommendation to a degree that proposed a new hazard--carbon monoxide-laden air from open fireplaces that got sucked into the room by the hood's excessive CFM exhaust rate--in some cases up to 750 CFM. The OSRC recommends a 250-CFM maximum.