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Introduction to Air Sampling
An air sampling smoke detector (ASSD) is one of five ways listed in the National Fire Alarm and Signaling Code to detect smoke.
Additionally listed are: spot-type smoke detectors, projected beam-type smoke detectors, duct mounted smoke detectors, and video image smoke detectors.
Air sampling detectors use three main components: the detector, which includes the fan and detection chamber, the air sampling pipe (usually ¾” CPVC), and sampling ports, which are holes drilled in the pipe. The fan inside the detector draws air from the protected room into the sampling holes, channeling it back through the pipes and into the detector, where the detection chamber both detects for the presence of smoke and measures the quantity of smoke in the air. Sampling holes at the ceiling level are arranged just as spot-type smoke detectors would be and follow the same spacing rules (refer to NFPA 72-2013 ed., Chapter 17).
