What is the maximum allowable level of ambient CO in the Combustion Appliance Zone during safety testing?

The maximum allowable level of ambient carbon monoxide (CO) in the Combustion Appliance Zone during safety testing is recognized as 35 ppm. This standard is important for ensuring safety in residential environments where combustion appliances function.

Carbon monoxide is a colorless, odorless gas that can pose serious health risks to occupants if accumulated in high concentrations. The safety limit of 35 ppm helps to minimize the risk of CO poisoning and ensures proper ventilation and appliance operation. In practice, maintaining levels at or below this threshold protects both the health of the occupants and the efficiency of the appliances.

Exceeding this level could indicate improper ventilation or appliance malfunction, necessitating further evaluation and remediation to ensure occupant safety. This threshold is part of best practices established in building performance standards, emphasizing the importance of safe indoor air quality in multifamily buildings.