Mobile home smoke detector siting study

Investigation of the effects of heating and air conditioning on the performance of smoke detectors in mobile homes

“…The slowest and least consistent were ceiling mounted detectors at the rear end of the hall. The reason for the inconsistency and slower response of the ceiling mounted detectors was not a result of thermal inversion layers at the exterior surfaces as was found in the 1976 NBS study [2] , but rather was a function of the smoke flow. Figure A3 3 shows that there was only a very small thermal gradient at the ceiling, which would not account for this effect.…”

“…This initial experimental work, sponsored and conducted by NBS [2], was reported in May of 1976. Some of the conclusions of that report were;…”

“…In order to expand upon the scope of the initial study, and to examine the effects of improved construction requirements in the HUD standard on the current smoke detector installation criteria, a follow-up study was conducted. The major emphasis of this study was to (1) incorporate actual rather than simulated ignition sources, (2) test both prevalent detector sensing modes (ionization and photoelectric) , (3) vary test conditions to include winter/ summer, heating/air conditioning, and (4) conduct tests in a mobile home which was constructed in accordance with the current HUD standard's requirements for thermal insulation.…”

“…Tests 23 and 24 were conducted using a 20.3 cm (8 inch) diameter cast iron pan on the right front burner, filled with 5-8 cm (2)(3) inches) of vegetable oil and covered with a lid.…”

“…It was further specified that the test samples be provided at a nominal 0.02 OD/m (1.5 %/ft)^obscuration sensitivity level as measured in the UL 217 type test compartment [13] . 2 While the preferred unit of smoke density is OD/m, the %/ft units are shown for the benefit of the readers who might be more familiar with these units.…”