Commercial smoke detectors
These are the spot smoke detectors that sit on the ceiling and initiate an alarm at the panel. The selection covers photoelectric detectors, detectors that combine photoelectric sensing with a thermal element, and multi-criteria units, in conventional two-wire and four-wire versions as well as addressable versions that report individually to the panel. Options include integral sounder bases, relay versions, isolated versions, remote test capability and ivory or white finishes for architecturally sensitive areas.
Selection starts at the panel. A two-wire detector draws its power from the initiating device circuit and has to be listed as compatible with that specific panel; a four-wire detector takes separate power and needs an end-of-line relay to supervise it. Addressable detectors have to match the protocol the loop is running. Getting this wrong is the single most common ordering mistake in fire alarm replacement work.
After compatibility, match the sensing technology to the space. Photoelectric responds well to smoldering fires and is the usual choice for most commercial occupancies. Adding a thermal element helps in areas prone to nuisance alarms. Finally, confirm the base: most plug-in detectors and their bases are ordered separately, and sounder, relay and isolator bases are not interchangeable. Spacing and placement are governed by NFPA 72 and by the approved design drawings. Compatibility and listing details are on each product page.
FSG - Fire Services Group
