New ways to ensure combustion safety have been suggested for ASHRAE’s IAQ standard.

The American Society of Heating, Refrigeration and Air-Conditioning Engineers’ standard 62.2, “Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings,” current uses exhaust limits that presume a “tight” structure. The proposed addendum would allow designers to consider the actual attributes of the house when deciding on how well it protects against combustion, said Paul Francisco, vice chairman of the standard committee.

“Combustion safety is a major issue for weatherization programs that are using standard 62.2,” Francisco said. “The majority of homes in those programs are leakier than the assumed leakage in the current 62.2 exhaust flow limit, even after retrofit. The current limit in 62.2 can prescriptively preclude them from using an exhaust option even though from a performance standpoint there would not be a problem.” 

The suggested addendum also makes clear that existing combustion appliances do not have to be brought up to current standards, although new installations must follow code guidelines.

“The issue of bringing appliances up to code is also an issue for weatherization programs,” Francisco said. “There are many appliances installed that operate satisfactorily despite not being installed to the latest code. With the limited budgets of retrofit programs, as well as rules in some programs prohibiting spending these limited dollars bringing existing appliances up to code unless there is a demonstrated active concern, making it clear that it is a not a mandatory requirement of 62.2 makes it easier for these programs to fully adopt 62.2 while still delivering a final result that is safe for the residents.”

The proposal is open for public review until Oct. 14 at