Very Early Smoke Detection and Alarm

Very Early Smoke Detection and Alarm (VESDA)... [Pg.179]

High sensitivity sampling smoke detection systems provide the best form of rapid smoke detection for Ir hly critical equipment or in high air flow situations. The Very Early Smoke Detection and Alarm (VESDA) system is basically a suction pump with collection tubes or pipes that use an optical smoke detection device test for evidence of smoke particles. Since it gathers air samples from the protected area, it is much faster in detection than ordinary detection devices that have to wait for the smoke to arrive to it. VESDA systems may be subject to some dilution effect to the sampling mechanism since the tubes may collect air samples from several sampling ports. This may reduce its response time. [Pg.280]

The other accepted detector is the sampling t) e detector. These differ from conventional sampling duct or HVAC detectors found in office building HVAC systems. They are much more sensitive than the ordinary photoelectric or ionization type detector. These detectors have the capability of detecting smoke obscuration in the range of 0.03-0.003%. These detectors can be very successful as early warning devices when used in the return air plenum of the cleanroom air handling system. They can be set for multiple levels of sensitivity. The first level could sound a pre-alarm and a second level could shut down room recirculation and initiate exhaust. [Pg.412]

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