Fire alarm installation entails more than merely placing smoke detectors in strategic areas of a building. Technicians are often required to interface fire alarm systems with other building subsystems. This includes, but is not limited to, heating, ventilation and air conditioning (HVAC); lighting controllers; roll-down door controllers; elevator controllers; access control; and CCTV. Fire code is often specific how these tasks are to be accomplished.
Fire safety functions are by far the most challenging because of the wide diversity of building systems technicians are asked to connect together.
Not only do they vary in how interconnections are made, but there are times when fire alarm technicians must go above and beyond simple fire protection by assisting other trades in programming their equipment to work in conjunction with fire alarm panels per fire code, such as roll-down fire doors under the control of special electronic controllers. At other times they are merely asked to assist in establishing the interface of complicated building management systems, or programmable logic controllers (PLCs).
This month, we’ll discuss some of the more common interfaces fire technicians have to deal with on a daily basis. We’ll also look at code requirements with regard to smoke spread and elevator recall.
Ensuring Elevator Safety
Elevators represent a tremendous risk to all concerned in a burning building. And yet in a large facility this is the fastest way for occupants to descend large high-rise buildings. Elevators are also used by firefighters to reach upper floors in a reasonable period of time, which is helpful considering all the gear they wear as well as carry with them.
In this regard, arriving firefighters must know whether an elevator can be used before they risk life and limb. All of the fire codes involving the interface of fire alarm systems and elevators are the result of unsuspecting people who were killed or injured when an elevator door opened in the middle of an inferno.
Section 21.3.9 of NFPA 72, 2010 Edition, addresses this issue by describing how to interface those initiating devices contained in areas related to elevator operations: “Actuation from the elevator hoistway, elevator machine room, elevator machinery space, elevator control space, or elevator control room smoke detectors, or other automatic fire detection as permitted by 21.3.7, shall cause separate and distinct visible annunciation at the building fire alarm control unit, or the fire alarm control unit described in 21.3.2, and at required annunciators to alert firefighters and other emergency personnel that the elevators are no longer safe to use.”
For clarification, Section 21.3.7 allows fire technicians to use other types of fire/smoke detection other than automatic smoke detection when the ambient conditions in an area prohibit their use. This can include fixed-temperature, rate-of-rise, combination rate-of-rise/fixed-temperature, rate-compensation heat detectors, and others.
As a general rule, the ordinary relay is the interface device of choice among fire alarm equipment manufacturers. It’s important for fire alarm technicians to have a thorough understanding of how these devices work, how to select the right one for each specific task and how to use them to control a variety of systems, such as elevators, door holder closers, door holders, lighting and more Interface in this regard can be accomplished using an auxiliary output on the smoke detectors that provide elevator recall. Addressable output modules can also be used to invoke recall.
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Fire/Life Safety · Fire/Life Safety 2 ·
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