Siemens OOHC941 (S54320-F8-A2) — two-wire addressable multi-criteria fire and CO detector combining dual optical (forward and backward light-scattering) sensing, two thermal sensors and an electrochemical carbon monoxide sensor in a single ceiling footprint on the Cerberus PRO platform.
The OOHC941 occupies one address on the signalling line circuit yet works as several devices at once: multi-criteria smoke detector, heat detector with field-selectable temperature and rate-of-rise settings, direct in-duct detector, CO supervisory sensor, and NFPA 76 Very Early Warning Fire Detector. Signals from the sensors are combined by the ASAtechnology (Advanced Signal Analysis) algorithm into a neural network, which is what lets the detector reject dust, steam and aerosols while still responding to both smouldering and flaming fire signatures. The CO sensor speeds detection of fires with incomplete combustion and carries a 10-year lifetime. Built-in ISOtechnology provides the True Class X, NFPA 72-compliant SLC isolation feature. As a photoelectric device it is an environmentally sound alternative to ionization detectors, with no radioactive source to dispose of.
Specifications
| Part number |
S54320-F8-A2 |
| Sensors |
Two optical transmitters (forward and backward scatter), one optical receiver, two thermal sensors, one CO sensor |
| 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), field selectable, with fixed-temperature and fixed-plus-rate-of-rise (15°F or 20°F) profiles |
| 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 |
| Alarm threshold profiles |
2.5% per ft. and 3.0% per ft., each also available verified |
| Programmable supervisory temperature warning |
-4°F to +120°F (-20°C to +49°C), with compatible FACPs |
| Programmable supervisory CO-gas warning |
30 to 600 ppm, with compatible FACPs |
| CO concentration response times |
70±5 ppm in 60–240 min; 150±5 ppm in 10–50 min; 400±10 ppm in 4–15 min |
| Air velocity |
0 to 4,000 fpm open area; 0 to 4,000 fpm direct in-duct |
| Air pressure |
No effect |
| Active, standby current |
0.75 mA |
| Application profiles |
26, field configurable |
| Relative humidity |
0 to 95%, non-condensing |
| Isolation |
Built-in ISOtechnology; up to 252 isolation-ready devices per loop, max. 30 non-isolated devices between isolation devices in mixed mode |
| Compatible panels |
Cerberus PRO FC901, FC922, FC924, FV922, FV924, Cerberus PRO Modular; FireFinder XLS and XLSV |
| Mounting base |
DB-11 (500-094151) or DB-11E (500-094151E); ordered separately |
| Standards |
UL 268, UL 268A, UL 521, UL 2034, UL 2075; ULC Listed; FM and CSFM Approved; complies with NFPA 25, 72 and 76 |
Installation notes
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Base ordered separately: the head plugs into a DB-11 or the smaller DB-11E, which mounts on a 4-inch octagonal, square or single-gang box. In Canada order the DB-11C (500-095687).
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One address, several functions: the optical, thermal and CO elements can be configured for simultaneous or independent operation, so a single address can report multi-criteria fire alarm plus independent heat alarm and CO supervisory signals. Configuration is per the installation manual, P/N A6V10324657.
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Mixed-mode isolation limit: where isolated and non-isolated devices share a loop, no more than 30 non-isolated devices may sit between isolation devices.
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CO sensor has a service life: the electrochemical CO cell is rated for a 10-year lifetime; the detector is replaced, not re-celled, at end of life.
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Direct in-duct use is listed to 4,000 fpm, so this head can be used in duct applications without stepping down to a separate duct-only detector — but the duct application profile must be selected.
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Low-temperature warning: can be configured to signal at 40°F (4.4°C) for sprinkler-pipe freeze protection per NFPA 25 and NFPA 72, when connected to a compatible FACP.
Related models
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FDOOTC441 (S54320-F8-A1) — the same detector with the same technical data, catalogued for the Desigo Fire Safety platform (FC2005/FC2025/FC2050, FV2025/FV2050) instead of Cerberus PRO
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OOH941 (S54320-F7-A2) — the same Cerberus PRO housing without the carbon monoxide element; dual-optical and thermal only
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OP921 (S54320-F4-A2) — photoelectric smoke detector only, where multi-criteria and CO sensing are not required
Specifications taken from the Siemens data sheet "Cerberus® PRO Multi-Criteria Fire | CO Detector [with ASAtechnology™], Model OOHC941," document 9903 (February 2022, Rev. 9). Manufacturer specifications are subject to change without notice.
