CA-FIRE Protection · Fujian, China
Water Flow Indicators
Saddle · Stainless Steel · Threaded Inline · Explosion-Proof · DN25–DN300 · 1.6 MPa · IP66
Fire Sprinkler Water Flow Indicators
The Complete Range of Water Flow Indicators — DN25 to DN300
CA-FIRE manufactures a complete range of water flow indicators for automatic sprinkler fire protection systems. Mounted on the branch line or riser downstream of the main control valve, each unit detects sprinkler activation the moment water begins to flow — a paddle vane deflects with the flow, actuates a Hall-effect micro-switch, and converts the hydraulic signal into a dual-contact electrical alarm to the fire alarm control panel.
From the standard saddle-mount ZSJZ for ductile iron sprinkler risers, to stainless steel variants for humid and coastal installations, to DN25 threaded inline units for small branch lines, to ATEX / IECEx explosion-proof models for hazardous areas — CA-FIRE covers every sprinkler water flow detection scenario in a single product family.
4
Product Variants
DN300
Max Size
1.6
MPa Rated
IP66
Enclosure
Technology Overview
What Is a Water Flow Indicator?
A water flow indicator — sometimes called a sprinkler flow switch or paddle-type flow detector — is an electro-mechanical device installed on wet-pipe sprinkler piping to detect when water begins flowing in response to a sprinkler head activation. It is one of the core monitored devices required on any automatic fire sprinkler system.
The indicator sits saddle-mounted or threaded inline on the pipe, with a flexible paddle vane projecting into the flow path. When water moves, the paddle deflects, rotates a shaft, and actuates a sealed micro-switch inside the weatherproof head. The switch closes two sets of electrical contacts that feed directly into the fire alarm control panel, identifying which sprinkler zone has activated so emergency response can target the correct area.
Working Principle — 4 Steps
- Sprinkler head opens — fire triggers the fusible element; water begins flowing toward the discharging head.
- Paddle deflects — water flow pushes the vane blade inside the pipe away from vertical.
- Micro-switch actuates — the deflection rotates the shaft and closes a Hall-effect switch after a brief retard delay to ignore pressure surges.
- Signal to FACP — two sets of NC contacts send a zone alarm to the fire alarm control panel; sirens and strobes activate.
All Products
Flagship
Saddle Mount · Paddle Vane
Saddle-Type Water Flow Indicator
Ductile iron saddle-mount ZSJZ water flow indicator — the standard paddle-type flow detector for wet-pipe sprinkler systems. Mounts directly on branch lines with U-bolt saddle and EPDM seal. Dual NC contacts, 15–37.5 L/min alarm flow sensitivity, Hall-effect micro-switch for long service life.
DN50–DN300
1.6 MPa
Dual NC Contact
DC24V / AC220V
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Coastal / Tropical
Stainless Steel Saddle · SS304
Stainless Steel Water Flow Indicator
SS304 stainless steel saddle water flow indicator for corrosive, humid and coastal fire protection installations. Ideal for GCC high-rises, tropical Southeast Asian projects and African coastal or mining environments where carbon steel saddles suffer accelerated corrosion. SS316 available on request.
DN100–DN200
1.6 MPa
SS304 / SS316
Corrosion-Resistant
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Inline / Small Pipe
Threaded Inline · Paddle Vane
Inline Water Flow Indicator DN25
DN25 threaded inline water flow indicator for small-diameter sprinkler branches, single-zone residential and light-hazard occupancies. Threaded connection (NPT or BSP) installs in line with the pipe — no pipe-cutting or saddle required. Ideal for retrofit and cost-sensitive projects.
DN25 / 1"
1.6 MPa
NPT / BSP
15 L/min Alarm
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Hazardous Area
Explosion-Proof · Ex db IIC T6 Gb
Explosion-Proof Water Flow Indicator ZSJZ Ex
ATEX / IECEx compatible explosion-proof water flow indicator for Zone 1, Zone 2, Zone 21 and Zone 22 hazardous-area fire protection. Flameproof housing rated Ex db IIC T6 Gb / Ex tb IIIC T80°C Db. Specified for oil & gas, LNG, petrochemical, and mining fire sprinkler systems.
DN50–DN300
Ex db IIC T6 Gb
IP66
DC24V / 1A
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Applications
Where Water Flow Indicators Are Installed
Commercial High-Rise
One indicator per floor on the sprinkler riser — identifies which floor has activated so building management can respond to the correct zone.
Warehouses & Factories
Installed on each branch line or per fire compartment — large high-hazard storage areas use zoned indicators to isolate activation points quickly.
Hotels & Malls
Wing-level or floor-level indicators feed the FACP for precise zone reporting across guest rooms, back-of-house and retail tenancies.
Oil & Gas / LNG
Explosion-proof ZSJZ Ex models required for tank farms, LNG terminals and process areas classified as ATEX / IECEx Zone 1 or Zone 2.
Mining Operations
Stainless steel or Ex variants for underground mining, conveyor protection and process plant fire water systems — corrosive and dust-hazard environments.
Data Centres & Utilities
Pre-action and wet-pipe system monitoring with dual-contact output — one contact to the FACP, one to the BMS for precise downtime tracking.
Shared Specifications
Common Technical Specifications
All CA-FIRE water flow indicators share the same core electrical and mechanical design, so specifying engineers can standardise wiring and FACP programming across the entire sprinkler system regardless of the model used on each pipe size.
| Parameter | Specification |
|---|---|
| Working pressure | 1.6 MPa (16 bar / ~230 psi) maximum |
| Alarm flow sensitivity | 15 L/min to 37.5 L/min (DN-dependent) |
| Switch type | Hall-effect micro-switch, sealed, with retard delay |
| Contact output | Two sets of normally closed (NC) contacts |
| Contact rating | DC24V 1A / AC220V 0.5A |
| Enclosure rating | IP66 (standard and Ex models) |
| Ex protection (Ex model) | Ex db IIC T6 Gb / Ex tb IIIC T80°C Db |
| Media temperature | 4°C to 70°C (water / foam-water mixture) |
| Connection types | Saddle (U-bolt) DN50–DN300 · Threaded (NPT/BSP) DN25 |
| Body materials | Ductile iron · SS304 / SS316 · Brass (DN25) |
Direct Manufacturer
All water flow indicators manufactured in-house at our Fujian facility. Factory pricing direct to sprinkler contractors and EPC projects — no middlemen, no trading markup.
Full DN Coverage
DN25 threaded inline through DN300 saddle-mount — one supplier covers every sprinkler branch and riser size in your project schedule.
Dual-Contact Output
Two sets of NC contacts standard, Hall-effect micro-switch, DC24V 1A / AC220V 0.5A. Direct interface with any addressable or conventional FACP.
Export Ready
ISO 9001 certified. Shipped to 60+ countries. Full submittal datasheets, wiring diagrams and compliance documentation for every product.
Product Selection Guide — 4 Water Flow Indicators at a Glance
| Product | Mount Type | Size Range | Body Material | Key Feature | Best For |
|---|---|---|---|---|---|
| Saddle-Type ZSJZ | Saddle (U-bolt) | DN50–DN300 | Ductile Iron | Retrofit-friendly, no pipe cutting | Wet-pipe sprinkler risers & mains (NFPA 13) |
| Stainless Steel Saddle | Saddle (U-bolt) | DN100–DN200 | SS304 / SS316 | Full corrosion resistance | Coastal, tropical, marine & mining sites |
| Inline DN25 Threaded | Threaded (NPT / BSP) | DN25 only | Brass / Plated Steel | Smallest footprint, lowest cost | Small branches, residential, retrofit zones |
| Explosion-Proof ZSJZ Ex | Saddle (U-bolt) | DN50–DN300 | Ductile Iron + Ex Housing | ATEX / IECEx Zone 1/2/21/22 | Oil & gas, LNG, petrochemical, mining |
FAQ
Frequently Asked Questions
What is a water flow indicator in a fire sprinkler system?
A water flow indicator (also called a sprinkler flow switch or paddle-type flow detector) is a device installed on sprinkler piping that senses the movement of water when a sprinkler head activates. A paddle vane inside the pipe deflects with the flow and triggers a micro-switch, sending an electrical signal to the fire alarm control panel (FACP). It tells the alarm system exactly when and where water is flowing so fire zones can be reported individually.
What is the difference between a water flow indicator and a flow switch?
In fire protection practice, a water flow indicator is a specific type of paddle-vane flow switch designed for wet-pipe sprinkler systems and wired to the FACP. A generic "flow switch" may refer to any device that detects flow — including pressure switches, thermal flow switches, or vane-type models used in HVAC or industrial water systems. For fire sprinklers, the correct device is always a paddle-type water flow indicator rated per NFPA 13 or equivalent local code.
Which water flow indicator do I need — saddle, threaded, stainless or explosion-proof?
Choose by pipe size and installation environment. Saddle-type ZSJZ (DN50–DN300) is the standard for wet-pipe risers and branch mains. Threaded inline DN25 is for small 1-inch branches in residential or light-hazard zones. Stainless steel is required where pipework is exposed to humidity, salt air, or corrosive atmospheres such as coastal Gulf high-rises, tropical Southeast Asian sites and African mining operations. Explosion-proof ZSJZ Ex is mandatory in ATEX / IECEx Zone 1/2/21/22 hazardous areas such as oil & gas, LNG, petrochemical and mining facilities.
What is the maximum working pressure of CA-FIRE water flow indicators?
All CA-FIRE water flow indicators are rated for 1.6 MPa (approximately 230 psi or 16 bar) maximum working pressure, which is standard for automatic fire sprinkler systems and meets typical city water main pressures in most regions.
What is the electrical output of the water flow indicator?
CA-FIRE water flow indicators provide two sets of normally closed (NC) contacts rated DC24V at 1A or AC220V at 0.5A. The dual-contact output allows connection to both a fire alarm control panel and an auxiliary monitoring system such as a BMS. A Hall-effect micro-switch is used for long service life and reliability compared to mechanical reed switches.
What is the alarm flow sensitivity?
The alarm flow rate for saddle-mount DN50 to DN300 models is 15 L/min to 37.5 L/min depending on diameter. The indicator is designed to ignore momentary pressure surges and only actuate when a sustained flow — equivalent to at least one open sprinkler head — is detected, reducing false alarms.
Does the water flow indicator meet NFPA 13 and UAE Civil Defence requirements?
CA-FIRE water flow indicators are manufactured to GB 16280 (Chinese fire standard) and are designed to be compatible with NFPA 13, UAE Civil Defence, SASO (Saudi Arabia), SIRIM (Malaysia) and SABS (South Africa) installation requirements. Full technical submittals and test certificates are available for project approval in each jurisdiction.
What is the MOQ and lead time?
Minimum order quantity starts at 20 pieces for explosion-proof models and 50 pieces for standard saddle-type models. Standard lead time is 15–20 days for saddle-type and threaded units, 25–30 days for stainless steel, and 30–45 days for explosion-proof variants (Ex certification documentation included). FOB Ningbo or CIF to your destination port available. OEM and private-label orders welcome — contact our sales team for a tailored quotation.
Request a Quote for the Full Water Flow Indicator Range
Contact CA-FIRE for pricing, MOQ, lead times, project submittals, wiring diagrams or OEM enquiries on any water flow indicator.
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