The Cerberus Pyrotronics of the Siemens DI-3IS Ionization Detector operates on the ionization principle. In the first place, the detectors respond to the first traces of fire in the form of visible smoke or invisible products of combustion. The Siemens DI-3IS Ionization Detector has been expand for the wide range of commercial, industrial and institutional fire detection and extinguishing applications. These are approved in environments covered by UL 268 & UL 268A. The DI-B3 must be use with a Series 3 TM air duct housing.
A series detector is a plug-in, ionization detector and is make for a two-wire system operation. The DI-3IS, DI-A3, DI-B3, DI-3H, DI-A3H, and DI-B3H ionization detectors are Underwriters Laboratories, Inc. Listed. The series is also FM, CSFM and NYMEA approved. An FM approved, intrinsically safe DI-3 is available under model DI-3IS. Also, the DI-3IS must be use with the intrinsically safe System 3 zone module, model ZS-30, or MXL zone module CZM-1.
In addition, this detector is applicable to the 30-foot center spacing (900 sq. ft.) as referred to in NFPA 72. This spacing, however, is based on ideal conditions namely, a smooth ceiling, no air movement, and no physical obstructions between the fire source and the detector.