Alarm Check Valve for Fire Sprinkler Systems
An alarm check valve is the hydraulic heart of an automatic fire sprinkler system. Installed on the system riser between the water supply and the sprinkler pipework, it performs three critical functions simultaneously: it acts as a one-way check valve preventing backflow into the water supply main; it maintains the sprinkler system at the correct standby pressure; and when a sprinkler head opens in response to fire, it detects the resulting pressure drop and flow, automatically triggering the water motor alarm gong and pressure switch to signal the fire alarm control panel — all without any electrical power or external control signal.
CA-FIRE supplies a complete range of alarm check valves covering wet pipe, dry pipe and pre-action sprinkler system applications, in cast iron, stainless steel, flanged and grooved-end configurations from DN65 to DN300. Every CA-FIRE alarm check valve assembly is tested to GB 15931 and meets NFPA 13 requirements for alarm valve performance, with full certification documentation available for authority submission.
Alarm Check Valve — Product Range
CATEGORIES
CA-FIRE’s alarm check valve series covers five configurations to match the full range of sprinkler system types and installation environments:
Wet Alarm Valve — Flanged Cast Iron (ZSFZ Series)
The standard alarm check valve for wet pipe automatic sprinkler systems. The flanged cast iron body suits the majority of commercial, industrial and institutional building applications. When any sprinkler head opens, water flows through the alarm check valve clapper, enters the alarm port and drives the water motor alarm gong to produce a mechanical alarm signal — with no electrical supply required. Available in DN65–DN300 with flanged end connections per ANSI B16.1 or DIN 2501.
Core keyword: wet alarm valve | Best for: High-rise buildings, shopping centres, hotels, hospitals, warehouses
Wet Alarm Valve — Stainless Steel (ZSFZ-Ex Series)
A stainless steel alarm check valve for installations where the standard cast iron body is vulnerable to chemical attack, external corrosion or high-humidity environments. The SS316 body and internal components resist acid, alkali and salt-spray conditions that would rapidly degrade a cast iron valve — making it the correct specification for coastal facilities, chemical processing plants, food production facilities and outdoor or semi-outdoor sprinkler installations. Available in DN65–DN200.
Core keyword: stainless steel alarm valve | Best for: Chemical plants, coastal facilities, food processing, outdoor installations
Grooved Wet Alarm Valve (ZSXZF Series)
A grooved-end alarm check valve for sprinkler systems using Victaulic IPS-compatible grooved pipework throughout. The mechanical grooved coupling connections reduce installation time significantly compared to flanged alternatives — no gasket alignment, no bolt pattern torquing, and future disassembly for maintenance without cutting the pipeline. The alarm check valve assembly functions identically to the flanged wet type, with the same water motor alarm gong output and pressure switch signal. Available in DN65–DN250 with Victaulic-compatible grooved ends.
Core keyword: grooved alarm valve | Best for: Fast-track construction, retrofit projects, fully grooved pipeline systems
Dry Alarm Valve (ZSFC Series)
A dry pipe alarm check valve for sprinkler systems installed in spaces subject to freezing temperatures, where water-filled pipework would be damaged by frost. In a dry pipe system, the sprinkler pipework downstream of the dry alarm check valve is pressurised with compressed air or nitrogen rather than water. When a sprinkler head opens, the air pressure drops, the dry alarm check valve trips, water enters the system pipework and discharges through the open head. The CA-FIRE dry alarm valve incorporates an accelerator device that reduces the time delay between head operation and water delivery, meeting NFPA 13 trip time requirements. Available in DN100–DN200.
Core keyword: dry alarm valve | Best for: Cold stores, unheated warehouses, car parks, exposed pipework in freezing environments
Pre-Action Alarm Device (ZSFU Series)
A pre-action alarm valve assembly for sprinkler systems protecting areas where accidental water discharge would cause unacceptable damage — data centres, server rooms, museums, archives, libraries, art galleries and precision instrument laboratories. The pre-action alarm check valve assembly holds the sprinkler pipework in a dry (unpressurised or supervisory air pressure) condition until a fire detection signal from the room’s smoke or heat detectors confirms a genuine fire. Only when both the detection system signals and a sprinkler head opens does the system deliver water — providing a double-interlock protection against false discharge. Available in DN100–DN150 with flanged connections.
Core keyword: pre action alarm valve | Best for: Data centres, server rooms, museums, archives, precision instrument rooms
How an Alarm Check Valve Assembly Works
1，Standby condition: The alarm check valve clapper is held closed against its seat by the system water pressure downstream. The sprinkler pipework is maintained at the supply pressure. No water flows through the alarm port. conditions.
2，Sprinkler head activation: When a sprinkler head opens, the downstream pressure drops. The pressure differential across the alarm check valve clapper exceeds the clapper’s closing force and the clapper lifts off its seat. Water flows through the clapper opening into the downstream sprinkler pipework and simultaneously enters the alarm port.
3，Alarm signal generation: Water flowing through the alarm port passes through the retard chamber — a small pressure vessel that absorbs minor pressure fluctuations to prevent spurious alarms from supply pressure surges — and then drives the water motor alarm gong. The rotating motion of the water motor strikes the alarm gong, producing a mechanical alarm sound audible throughout the building. Simultaneously, a pressure switch in the alarm line sends an electrical signal to the fire alarm control panel.
4，Post-fire restoration: After the fire is extinguished and the sprinkler system is shut down, the alarm check valve clapper reseats under restored water supply pressure. The system is drained, any operated sprinkler heads are replaced, and the system is recharged and returned to standby.
Alarm Check Valve Technical Specifications
| Parameter | Wet Type (Cast Iron) | Wet Type (SS) | Grooved Type | Dry Type | Pre-Action |
|---|---|---|---|---|---|
| Series | ZSFZ | ZSFZ-Ex | ZSXZF | ZSFC | ZSFU |
| Size Range | DN65–DN300 | DN65–DN200 | DN65–DN250 | DN100–DN200 | DN100–DN150 |
| Working Pressure | 1.2 MPa | 1.2 MPa | 1.2 MPa | 1.2 MPa | 1.2 MPa |
| Strength Test | 6.4 MPa | 6.4 MPa | 6.4 MPa | 6.4 MPa | 6.4 MPa |
| Seal Test | 3.2 MPa | 3.2 MPa | 3.2 MPa | 3.2 MPa | 3.2 MPa |
| Body Material | Cast iron | SS316 | Cast iron | Cast iron | Cast iron |
| Connection | Flanged | Flanged | Grooved | Flanged | Flanged |
| Alarm Output | Water motor gong + pressure switch | ✓ | ✓ | ✓ | ✓ |
| Standard | GB 15931, NFPA 13 | GB 15931 | GB 15931 | GB 15931 | GB 15931 |
Alarm Check Valve Selection Guide
Selecting the correct alarm check valve for a project depends on four factors:
1. Sprinkler system type Wet pipe systems → wet alarm check valve (flanged cast iron or stainless steel, or grooved). Dry pipe systems → dry alarm check valve. Pre-action systems → pre-action alarm device.
2. Installation environment Standard indoor environments → cast iron flanged. Corrosive, coastal or outdoor environments → stainless steel. Freezing environments → dry pipe system with dry alarm check valve. High-sensitivity areas where accidental discharge is unacceptable → pre-action alarm device.
3. Pipeline connection type Flanged pipework → flanged alarm check valve. Grooved (Victaulic) pipework → grooved alarm check valve. Mixed systems → specify the connection type at the alarm valve station.
4. Nominal diameter Select the alarm check valve nominal diameter to match the sprinkler system riser diameter — typically DN65–DN150 for residential and light commercial systems, DN100–DN200 for medium commercial and industrial systems, and DN200–DN300 for large-area systems and high-rise building primary risers.
Applications
CA-FIRE alarm check valves are installed across the full range of fire protection applications worldwide:
Commercial buildings — Shopping centres, hotels, office towers and retail parks use wet alarm check valves on each sprinkler zone riser, providing automatic alarm triggering and zone isolation for large multi-tenancy buildings.
High-rise residential and mixed-use — Wet alarm check valves on every residential floor zone, with stainless steel types specified for balcony and car park sprinkler systems exposed to the external environment.
Data centres and server rooms — Pre-action alarm devices protect IT infrastructure from accidental water discharge, with double-interlock configurations providing maximum protection against false activation.
Cold stores and unheated warehouses — Dry alarm check valves allow sprinkler protection in below-zero temperature environments where wet pipe systems would freeze.
Chemical and petrochemical facilities — Stainless steel alarm check valves resist the corrosive atmospheres of chemical processing plants, providing reliable fire protection in environments that would rapidly degrade standard cast iron valves.
Airports, rail stations and public infrastructure — Wet alarm check valves on large-area wet pipe systems, with grooved types used on fast-track construction projects requiring compressed installation programmes.
Why Choose CA-FIRE Alarm Check Valves?
CA-FIRE manufactures alarm check valves exclusively for fire protection applications, bringing focused engineering experience to every product in the range. Every alarm check valve assembly leaving our facility has passed:
- Hydrostatic strength test to 6.4 MPa
- Seal test to 3.2 MPa
- Clapper opening pressure verification
- Water motor alarm gong flow test
- Pressure switch response test
With ISO 9001 certified manufacturing, GB 15931 product certification and alarm check valves installed in projects across more than 50 countries, CA-FIRE provides the technical depth, certification documentation and supply reliability that specifying engineers and fire protection contractors require. Full technical support is available from initial product selection through to commissioning and long-term maintenance — contact our engineering team to discuss your project requirements.
FAQ – Alarm Check Valves
It prevents backflow and triggers alarms when water flows into the sprinkler system during fire activation.
Standards include UL, FM, CE, CCCF, and relevant ISO manufacturing requirements (depending on product model).
DN65–DN300 (or 2.5″ to 12″), depending on the product type.
Yes. Connection types (flanged/grooved), pressure ratings, materials, and accessories can be customized.
Yes. Full datasheets, CAD drawings, and technical manuals are available for engineering teams.
Get a Quote
Contact CA-FIRE for pricing, technical drawings, project specifications or OEM supply enquiries. Our engineering team responds within one business day.
- Email: sales@ca-fire.com
- Mobile: +86 13400715622 | WhatsApp: +86 18150362095
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- Website: www.ca-fire.com
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For alarm check valve installation, testing and maintenance requirements, refer to NFPA 13 (Standard for the Installation of Sprinkler Systems) and NFPA 25 (Inspection, Testing and Maintenance of Water-Based Fire Protection Systems).