- Author
- Lougheed, G. D.
- Title
- Duct Smoke Detectors: The Impact of Various Factors on Their Effectiveness.
- Coporate
- National Research Council of Canada, Ottawa, Ontario
- Journal
- Construction Technology Update, No. 72, 1-8, December 2008
- Keywords
- smoke detectors | ducts | effectiveness | impact | smoke movement | heating | ventilation | air conditioning | regulators | building codes | dilution | filters | tubes
- Identifiers
- detector response (analog output) relative to smoke optical density and visibility; effect of HVAC filter type on detector output; spot-type smoke detectors installed in the ducts; similar detector contained in a housing attached to the exterior of the duct
- Abstract
- This Update presents the results of research on smoke movement through HVAC systems and the effectiveness of duct smoke detectors. It provides guidance to practitioners and regulatory authorities in the context of North American code requirements for such detectors. Requirements on the use of smoke detectors in HVAC ducts are included in most building codes, including the National Building Code of Canada (NBC). The intent of the requirements, based on a recommendation made by the National Board of Fire Underwriters in 1939 2, is that the HVAC system be shut down during a fire to minimize the circulation of smoke through the building by the HVAC fan system. In most cases, the detectors must be located in the supply air duct downstream of the fresh air inlets, filters and fans. In some jurisdictions, detectors must be located in the return air duct as well. Installation requirements are provided in standards, including CAN/ULC-S524.