Siemens OP121


Photoelectric Smoke Detector

Available with Lead Time

Brand: Siemens Part #: 004601 Categories: , , Manufacturer Part #: OP121Secondary Part #: S54372-F1-A1 Tags: , ,


Model OP121 from Siemens ─ Fire Safety is a photoelectric smoke detector with microprocessor-controlled, self-diagnostic circuitry, eliminating the need for burdensome sensitivity test equipment.

Model OP121 also comes with a new magnet-test feature. The magnet-test feature allows installers and test personnel to prove the integrity of the wiring and proper connection to the fire alarm control panel (FACP).

The auto-sensitivity feature for Model OP121 stems from the internal, self-monitoring circuitry, and provides dynamic verification of sensitivity and / or required maintenance. The auto-sensitivity feature is displayed by Siemens Fire Safety’s unique (3) three-color light-emitting diode (LED), provided locally on the detector ─ and optionally with the various remote LED indicators.


Weight 0.50 lbs
Dimensions 2.00 × 4.00 × 4.00 in

Sensing Element



  • Magnet-test feature
  • Incorporates one (1) state-of-the-art chamber for rapid, uniform response to alarm criteria (i.e. – smoke)
  • Automatic sensitivity test without the need for a special tester (per NFPA 72)
  • Available optional sounder base, providing an alert and evacuation signal
  • UL 268 Listed [for open-area protection], UL 268A Listed [for direct in-duct use], ULC 529 Listed; FM, CSFM Approved


Photoelectric Smoke Detector; Model OP121
Siemens, Data Sheet
Models OP121/OH121; Photoelectric Smoke Detector and Photo Smoke/Thermal Detector
Siemens, Installation Instructions

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