Siemens OP921 Commercial Smoke Detector P/N:100923245

The Siemens OP921 is a commercial smoke detector designed for compatible Cerberus PRO and Siemens fire alarm systems. It uses optical light-scattering technology to detect smoke while continuously monitoring its sensitivity and operating condition.

The detector features a low-profile housing, tri-color LED indication, automatic environmental compensation, and built-in ISO technology for improved signaling-line-circuit reliability. Siemens currently lists the OP921 as an active product.

Product Functions

• Optical smoke detection
• Continuous sensitivity monitoring
• Automatic environmental compensation
• Built-in short-circuit isolation
• Tri-color status indication
• Self-testing and diagnostic reporting
• Open-area and approved duct detection

Electrical & System Information

The OP921 connects to a compatible Siemens two-wire signaling line circuit and occupies one device address. It is polarity-insensitive during standard Class B installation, although installers must maintain polarity when using Class X isolation operation.

The detector communicates alarm, trouble, sensitivity, and maintenance information to the connected control panel.

Features

• Dust-resistant optical sensing chamber
• Built-in ISOtechnology
• Two selectable sensitivity profiles
• Tri-color green, yellow, and red LED
• 360-degree LED visibility
• Automatic detector self-test
• Protective dust cover included
• Remote sensitivity reporting

Mounting & Design

The OP921 installs on a compatible Siemens DB-11 or DB-11E detector base. These bases support standard 4-inch square, octagonal, or single-gang electrical boxes.

An optional LK-11 locking kit helps prevent unauthorized detector removal.

Protection & Applications

Suitable for:

• Office Buildings
• Schools
• Hospitals
• Hotels
• Government Buildings
• Retail Facilities
• Warehouses
• Commercial Properties
• Approved HVAC Duct Applications

Compatibility

The OP921 is designed for compatible Siemens systems, including selected:

• Cerberus PRO Panels
• Desigo Fire Safety Systems
• FireFinder XLS Systems
• FC922 and FC924 Panels
• FV922 and FV924 Voice Systems
• DB-11 and DB-11E Bases
• FDBZ492 Series Duct Housings

Always verify panel firmware, detector-base compatibility, and project approvals before installation.

Technical Specifications

Manufacturer: Siemens

Model: OP921

Stock Number: S54320-F4-A2

Product Type: Commercial Optical Smoke Detector

Detection Technology: Light-Scattering Optical Sensing

Wiring: Two-Wire Signaling Line Circuit

Device Addresses Required: One

Status Indicator: Tri-Color LED

Isolation: Built-In ISOtechnology

Operating Temperature: 32°F to 120°F (0°C to 49°C)

Mounting Bases: DB-11 or DB-11E

Open-Area Listing: UL 268

Duct Listing: UL 268A

Canadian Listings: ULC S529 and ULC S530

Approvals: UL, ULC, FM, and CSFM

Product Status: Active

Always verify electrical ratings and approvals using the label and documentation supplied with the specific detector.

Applications

The Siemens OP921 is commonly installed in commercial fire alarm systems requiring dependable smoke detection, individual device identification, continuous diagnostics, and built-in circuit isolation.

OP921