Explosion-proof perimeter alarm
Detection and alarm inside the hazardous area, not at its edge.
- Series / models
- Ex d IIB T6 Gb / Ex ib IIC T6 detector family
- Detection
- Ex-rated IR, gas, smoke, heat, vibration
- Typical range
- IR 1–100 m; gas 5–20 m²; smoke 60–80 m²
- Control
- Relay / Ex-rated control outside the zone
Explosion-proof perimeter alarm
| Ex code | Ex d IIB T6 Gb |
|---|---|
| IR range | 1–100 m |
| Gas alarm | 8% LEL |
| Rating | IP65 / IP66 |
Detection and alarm inside the hazardous area, not at its edge.
Ex-rated enclosures
Flameproof and intrinsically safe designs cover Ex d IIB T6 Gb, Ex d IIC T6 Gb and Ex ib IIC T6, for Zone 1 and Zone 2 gas environments.
Corrosion-resistant hardware
Fasteners are 304 stainless steel and the viewing windows use explosion-proof glass with high light transmission.
Barrier, curtain and detector
Two-, three- and four-beam barriers cover 1–100 m; four- to ten-beam curtains cover 1–80 m; microwave/PIR detectors cover 1–10 m at the door or wall.
Gas, smoke and heat
Combustible gas (8% LEL ±3%), smoke, temperature/humidity and vibration detectors share the same hazardous-area mounting logic.
Audible and visual alarm
The Ex alarm sounder delivers ≥90 dB with 150 flashes per minute and is rated Ex d IIC T6 / DIP A20.
From principle to site
Values are typical manufacturer data. Site conditions, power supply and configuration can change the final specification.
Start from the zone classification
The detector you can use is decided by the area classification drawing, not by the product catalogue. Confirm whether the location is Zone 1 or Zone 2, which gas group (IIA, IIB or IIC) and which temperature class (T1–T6) applies. A detector rated Ex d IIB T6 is not interchangeable with an Ex ib IIC T6 device; they solve different problems and require different wiring.
Explosion-proof does not mean maintenance-free. Flameproof joints must not be painted, filed or opened in the hazardous area; intrinsic-safe circuits need their own isolators and cable parameters. Include the certification documents and the installation drawing in the handover pack.
Layered detection for tank farms and loading areas
Use explosion-proof infrared barriers or curtains along the perimeter wall, vibration detectors on the fence or tank shell, gas detectors at the pump and loading points, and an Ex sounder for local alarm. The control equipment sits outside the hazardous area, connected through suitable barriers or isolators.
Avoid placing the beam across a loading arm’s normal travel or a tank’s relief path. A detector that alarms during every transfer will be bypassed within a week. Mark the detection envelope on the site plan and review it with operations before installation.
Technical specifications
Values are typical manufacturer data. Site conditions, power supply and configuration can change the final specification.
| Certification codes | Ex d IIB T6 Gb; Ex d IIC T6 Gb; Ex ib IIC T6; DIP A20 Ta, T6 |
|---|---|
| IR barrier beams | 2 / 3 / 4 beams |
| IR barrier range | 1–100 m |
| IR curtain beams | 4 / 6 / 8 / 10 beams; 1–80 m |
| Microwave/PIR range | 1–10 m; 110° wide angle / 15° curtain |
| Gas detection | 8% LEL ±3%; 5–20 m²; DN15 / G1/2 thread |
| Smoke detection | 0.10–0.27 dB/m; 60–80 m² protection |
| Temperature/humidity | RS485, MODBUS RTU; 10–20 m² |
| Vibration detector | DC8–18 V; 6-level sensitivity; NO/NC |
| Alarm sounder | ≥90 dB; 150 flashes/min; DC12 V; 5 W |
| IR barrier power | DC12–24 V; 2 W |
| Operating temperature | −40 °C to +60 °C; RH < 95% |
| Protection | IP65 / IP66 |
| Output | Dry NO/NC relay; 12 V siren where applicable |
Where this system is usually specified
Buyer questions
Which certificates should be supplied?
Ask for the explosion-proof certificate for each model, the marking plate photograph showing the Ex code, the installation and maintenance manual, and the certificate for any associated isolator or barrier. The certificate must match the area classification, gas group and temperature class.
Can standard CCTV cameras be used in the same area?
Only if the camera is in an appropriate explosion-proof housing and the cable entry is rated for the area. A standard camera in a weatherproof housing is not acceptable in a Zone 1 or Zone 2 location, even if it is mounted high up.
How is the gas detector calibrated?
Calibrate with the target gas or a certified surrogate at the specified flow rate, following the manufacturer’s interval. The published alarm point is 8% LEL ±3%; record the zero and span values and keep the calibration tag on the device.
What maintenance is allowed inside the hazardous area?
Visual inspection, cleaning of the window with a damp cloth and replacement of parts explicitly permitted by the manual. Opening a flameproof enclosure or disconnecting an intrinsic-safe circuit usually requires a gas-free permit and isolation; follow the site procedure.
Systems that work alongside it
Laser barrier
Beam detection · 1–8 beam laser detectors
A narrow beam that holds its line for hundreds of metres.
Infrared barrier
Beam detection · 2 / 3 / 4-beam active infrared
The economical beam layer for short and medium spans.
Electric fence alarm & control
Electric fence alarm · K7 / K9 / K10 hosts · touch terminal · management software
Arm, map and verify every electric fence zone from one interface.
Specify this system for your perimeter
Send the perimeter length, fence or wall type and the response requirement. We will return a zone plan and a configuration.