Unvented combustion

ASHRAE has published a position document titled 'Unvented Combustion Devices and Indoor Air Quality', which reviews the current state of knowledge regarding unvented combustion devices and provides recommendations. The focus of this document is on liquid and gas combustion, and on modern cooking and heating appliances. Four primary products of combustion, carbon monoxide, nitrogen dioxide, moisture and particles are considered in the document. For each of the four primary products of combustion, the position document presents the current understanding of health concerns. It also describes the types of appliances of interest, including the intended use of each category and the requirements of the pertinent appliance standards. The position document also discusses research results on emissions and indoor air concentrations of combustion products from propane and natural gas-fired heating and cooking equipment.