road-runner I must apologize. It was controlled air exchanges.
I think I got that impression of sealed from this:
"The current standard for portable infrared camp heaters (ANSI Z21.63) does not address the issue of hydrocarbon emissions. However, the standard currently being proposed for portable catalytic camp heaters (ANSI Z21.62-draft) does limit the hydrocarbon emission to 500 ppm when the O2 concentration has been reduced to 19.4 percent in a room with no air changes. For both tests with no air changes, the hydrocarbon concentration was approximately 210 ppm (1 percent LEL) at an O2 concentration of 19.4 percent.
Although Heater 1 would meet the hydrocarbon emission requirement currently being proposed in the new standard for catalytic heaters, the proposed standard does not address hydrocarbon emissions at lower O2 concentrations. During the closed room tests, the hydrocarbon concentration reached 13,440ppm (64 percent LEL) prior to the test being terminated. Therefore, the proposed standard for catalytic camp heaters does not adequately protect the consumer from high emissions of hydrocarbons. The 18unreacted propane further acts to increase the degree of hypoxia experienced by an individual. To address this issue, CPSC staff recommends limiting the hydrocarbon emissions from catalytic camp heaters to 500 ppm throughout the entire test when the catalytic heater is tested in a 100 ft3 room at air exchange rates of 0.5, 1.0 and 1.5 ACH."
