Measurement of emission rates from gas-fired space heaters. Final report, June 1984-December 1985

Emission-factor data of nitrogen dioxide (NO/sub 2/), nitrogen oxide (NO), carbon monoxide (CO) and unburned hydrocarbons (UBH) were experimentally determined for each of 10 different unvented gas space heaters (UVGSH) by each of 3 different measurement methodologies (probe, hood, chamber). The heaters were of various designs (blue-flame with/without radiating tiles, infrared) and were fueled by natural gas or liquid propane gas (LPG) at various gas input rates (10,000 to 40,000 Btu/h). Emission factors were found to be dependent primarily on heater design (blue-flame vs. infrared) and method of measurement and secondarily on other factors. Emission obtained by the probe or hood method were almost identical but different than obtained by the chamber method, especially emission factors for NO and CO. These differences were investigated and it was concluded that they were caused by the vitiated atmosphere maintained within the chamber at the low (0.5 air changes per hour) chamber air infiltration prescribed as part of the chamber methodology.