Siemens OOH941 (S54320-F7-A2) — two-wire addressable multi-criteria fire detector for Cerberus PRO, combining dual-optical (forward and backward light-scattering) smoke sensing with two thermal sensors, UL 268 7th edition Listed.
The OOH941 is a flexible, multi-purpose head that occupies a single address yet can be field programmed for simultaneous or independent functionality: multi-criteria fire detection, heat detection with field-selectable temperatures and rate-of-rise options, direct in-duct (plenum) detection, ambient temperature supervision, and NFPA 76 Very Early Warning Fire Detection. ASAtechnology (Advanced Signal Analysis) feeds the sensor signals into a neural network so the detector distinguishes real products of combustion from dust, steam and aerosols. Because it is photoelectric rather than ionization there is no radioactive source to dispose of, and the patented forward-and-backward scattering chamber responds to both small and large combustion particles — smouldering and flaming fires alike. Built-in ISOtechnology provides optional True Class X SLC operation. A tri-color status LED gives 360-degree indication.
Specifications
| Part number |
S54320-F7-A2 |
| Sensors |
Two optical transmitters (forward and backward scatter), one optical receiver, two thermal sensors |
| Input voltage range |
13 to 32 VDC |
| Alarm current |
0.65 mA |
| Operating temperature |
+32°F to +120°F (0°C to +49°C) |
| Heat detector range |
+135°F to +175°F (+57°C to +79°C) |
| Fixed temperature profiles |
135°F, 145°F, 155°F, 165°F, 175°F (57.2°C, 62.8°C, 68.3°C, 73.9°C, 79.4°C) |
| Fixed plus rate-of-rise profiles |
135°F or 175°F, each with 15°F or 20°F rate-of-rise |
| Alarm threshold profiles |
2.5% and 3.0% per foot, each also available verified |
| Detector sensitivity range |
UL Listed 0.88 to 3.35% per ft.; NFPA 76 VEWFD 0.2% per ft. pre-alarm, 1.0% per ft. alarm |
| Programmable supervisory temperature warning |
-4°F to +120°F (-20°C to +49°C), with compatible FACPs |
| Air velocity |
0 to 4,000 fpm open area; 0 to 4,000 fpm direct in-duct |
| Air pressure |
No effect |
| Application profiles |
22, field configurable |
| Relative humidity |
0 to 95%, non-condensing |
| Isolation |
Built-in ISOtechnology; True Class X SLC operation, use optional; up to 252 isolation-ready devices per loop |
| Compatible panels |
Cerberus PRO FC901, FC922, FC924 and the FV voice variants; FireFinder XLS |
| Mounting base |
DB-11 (500-094151) or DB-11E (500-094151E); ordered separately |
| Approvals and standards |
UL 268 7th edition Listed, UL 268A, UL 521; ULC-S529, ULC-S530; FM 3210, 3230; CSFM 7272-0067:0260; complies with NFPA 25, 72, 76 |
Installation notes
-
Base ordered separately: the head plugs into a DB-11 or the smaller DB-11E on a 4-inch octagonal, square or single-gang box. In Canada order the ULC DB-11C (500-095687).
-
One head, several jobs: optical and heat sensing can run together for multi-criteria detection while independent heat outputs are reported at the same time. Any combination of the sensors is possible, so a change of use often means a profile change rather than a new device.
-
Direct in-duct to 4,000 fpm: UL 268A Listed for direct in-duct use, but the duct application profile must be selected for that installation.
-
Low-temperature warning: can be set to signal at 40°F (4.4°C) to protect wet sprinkler pipework from freezing, per NFPA 25 and NFPA 72, with a compatible FACP.
-
Sensitivity self-monitoring: the detector checks its own sensitivity automatically and reports it in percent-per-foot at the panel, meeting the NFPA 72 sensitivity requirement without a field meter.
-
Standby (quiescent) current is published in a graphical table that does not survive text extraction; take it from the printed data sheet for battery calculations.
Related models
-
OOHC941 (S54320-F8-A2) — the same Cerberus PRO housing with a carbon monoxide sensor added; 26 application profiles instead of 22, plus CO supervisory reporting
-
FDOOT441 — the equivalent dual-optical and thermal multi-criteria head catalogued for the Desigo Fire Safety platform
-
OP921 (S54320-F4-A2) — photoelectric smoke detector only, on the same base and platform
-
HI921 (S54320-F5-A2) — heat detector only, where smoke sensing is unsuitable
Specifications taken from the Siemens data sheet "Cerberus® PRO Multi-Criteria Fire Detector [with ASAtechnology™], Model OOH941," document 9904 (March 2024, Rev. 12). Manufacturer specifications are subject to change without notice.
