Explosion-Proof Water Flow Indicator
ZSJZ Ex · Ex db IIC T6 Gb / Ex tb IIIC T80°C Db · Zone 1/2/21/22 · DN50–DN300 · IP66
Explosion-Proof Water Flow Indicator for Hazardous Areas
The CA-FIRE ZSJZ Ex is the hazardous-area variant of our ZSJZ saddle-mount water flow indicator, engineered for fire sprinkler systems installed inside ATEX / IECEx classified zones. A flameproof housing (Ex db) encloses the switch head, containing any internal spark or arc and preventing ignition of the surrounding explosive atmosphere. Certified for Zone 1, Zone 2, Zone 21 and Zone 22 — suitable for oil and gas, LNG, petrochemical, mining and fertilizer facilities across Southeast Asia, the Middle East and Africa.
What Does "Ex db IIC T6 Gb" Actually Mean?
The Ex marking tells a safety engineer in 11 characters exactly where this device can be installed and what explosive atmospheres it can survive. Each part of the code carries a specific meaning — the decoder grid below breaks down all five segments.
The secondary dust marking "Ex tb IIIC T80°C Db" uses the same logic for dust atmospheres: tb = dust-ignition protection by enclosure, IIIC = all dust groups including conductive dust, T80°C = max 80°C surface on dust layer, Db = suitable for Zone 21.
The 4 Hazardous Zones This Unit Covers
Hazardous areas are classified by how often an explosive atmosphere is present. Gas zones (0, 1, 2) and dust zones (20, 21, 22) follow the same logic: lower number means more frequent hazard. The ZSJZ Ex covers Zone 1 and Zone 2 for gas, plus Zone 21 and Zone 22 for dust — which addresses virtually all fire sprinkler installations in classified process facilities. Note: Zone 0 and Zone 20 (continuously hazardous) typically do not house fire sprinkler equipment directly.
ATEX vs IECEx — Which Applies in Your Market?
Both schemes use the same underlying IEC 60079 technical standards, so an engineer in the UAE reads the "Ex db IIC T6 Gb" marking identically to an engineer in Germany. The difference is the issuing framework and regional acceptance. Check your project specification to confirm which scheme is mandated.
| Scheme | Jurisdiction | Typical Markets | Accepted In Target Regions |
|---|---|---|---|
| ATEX | European Union Directive 2014/34/EU | EU, UK, Russia, selected projects in ME/AF with European EPC contractors | UAE ✓ · Saudi ✓ · Malaysia ✓ · South Africa ✓ · Philippines ✓ |
| IECEx | International IEC scheme (global framework) | Most countries in the Middle East, SE Asia, Africa, Australia, LatAm | UAE ✓ · Saudi ✓ · Malaysia ✓ · South Africa ✓ · Philippines ✓ |
| Local national schemes | Country-specific (e.g. SASO-GCC in GCC, CNEx in China) | Added on top of ATEX/IECEx when required for customs clearance | Confirm with local Civil Defence or regulator on each project |
Full Technical Specifications
The ZSJZ Ex shares its hydraulic platform and sensing principle with the standard ductile iron ZSJZ — same paddle vane, same alarm flow rates, same dual NC contact output. The explosion-proof variant adds a certified flameproof housing (Ex d) around the switch head.
| Parameter | Specification |
|---|---|
| Model | ZSJZ (50–300)-M-1.6Ex |
| Size range | DN50 to DN300 (saddle-mount) |
| Gas-atmosphere marking | Ex db IIC T6 Gb |
| Dust-atmosphere marking | Ex tb IIIC T80°C Db |
| Hazardous zones | Zone 1, Zone 2, Zone 21, Zone 22 |
| Certification pathway | ATEX / IECEx compatible documentation available |
| Body material | Ductile iron with epoxy coating · SS304 Ex housing optional |
| Ex housing material | Flameproof alloy, powder-coated |
| Paddle material | Stainless steel flexible vane |
| Working pressure | 1.6 MPa (16 bar / ~230 psi) maximum |
| Alarm flow rate | 15 L/min (DN50) to 37.5 L/min (DN300) |
| Media temperature | 4°C to 70°C |
| Ambient temperature | −20°C to +55°C |
| Rated voltage / current | DC 24V, 1A maximum |
| Contact form | Two sets of normally closed (NC) contacts |
| Enclosure rating | IP66 |
| Cable entry | Ex-rated M20×1.5 flameproof cable gland |
| Max surface temp | 85°C (T6 class) |
| Mounting | Saddle (U-bolt) as per standard ZSJZ procedure |
| Documentation | Ex certificate + declaration of conformity + test report per order |
Where Ex-Rated Flow Indicators Are Mandatory
Every application below has dedicated hazardous-area classification requirements. A standard water flow indicator is non-compliant on these projects regardless of its electrical rating — only an Ex-certified unit can be installed inside the classified zone.
Factory-Direct Export Terms
Each ZSJZ Ex unit ships with signed and stamped certification documentation required for Civil Defence / project handover in the destination market. Extra lead time covers document preparation and certificate authentication. Contact our sales team for firm project pricing, Aramco / ADNOC vendor enquiries, or LC terms.
