Need Help? Call +44 (0)1235 557700

Find the right product

for your gas detection needs


Infra-red pellistor replacement flammable gas detector



IR Technology versus Pellistor

Pellistors do not fail safe Sensors can be ‘poisoned’ and rendered insensitive to gas by silicones, lead, sulphurs and chlorinated compounds.
Pellistors are high maintenance Sensors must be regularly tested with gas to ensure they are stilloperational. Sensors typically last 3-5 years, after which they must beexchanged.
Pellistors must be operated behind a sinter (flame arrestor) Sinters may become blocked, thus preventing gas from reaching thesensor.
Pellistors may burn out If exposed to gas concentrations in excess of 110% LEL.
Pellistors need oxygen Their ability to detect gas reduces significantly in oxygen deficientatmospheres.

Low power

  • IREX consumes less than 1W of power - ensures compatability with a wide range of control systems


  • Independantly tested for reliability and performance in harsh offshore conditions by Micropack Engineering Ltd - demonstrates IREX will operate dependable in any application
  • 3rd party approval to the performance standard EN60079-29-1
  • Employs sophisticated systems and algorithms - ensures reliable operation at all times
  • T90 response time of less than 4 seconds - rapid indication of hydrocarbon gas hazards
  • Optical components are treated with a STAY-CLIR coating - prevents partial obscuration in condensing atmospheres

Easy to maintain

  • No adjustments are necessary at the detectors, zero and span adjustments (if required) are performed at the control panel only - saves significant time and cost
  • Test can be applied remotely via a tube to the standard weather cover
  • Sinter-free operation - unlike a pellistor sensor, there is no risk of a sinter becoming blocked

Contact [email protected] for more information.




Size 120 x 55 x 130mm (1.7 x 5.1 x 3.3ins) (with spigot gland)
Weight 1.5kg (10.8oz)
Ingress protection IP66
Enclosure material 316 stainless steel
Power 800mW nominal
Connection Supplied either with M20 spigot gland for insallation into existing junction
boxes or with one M20 cable gland entry
Operating voltage and current 3Vdc nominal (2.9-3.2Vdc)
260mA nominal (260-280mA)
Electrical output 3-wire mV (Wheatstone) Bridge. Typically 10-20mV per % vol. methane
Operating temperature -40°C to +75°C
Humidity 0 to 100% RH non-condensing
Repeatability +/- 2% FSD
Zero drift +/- 2% FSD per year maximum
Response time T-90 <4 seconds
Performance Tested in accordance with EN60079-29-1
Functional safety Validation to IEC61508 SIL 2
Approvals II 2 G Exd IIB + H2 T6 (-40 to +50°C) T4 (-40 to +75°C)
EMC compliance EN 50270, FCC, ICES-003


For a full list of Gases see the datasheet on the downloads tab.



Below is a small selection of the accessories available for the Crowcon IREX. For a full list please call 01235 557700 or Contact Us.

Mounting bracket kit


Enables mounting to a wall or 2" (50mm) pipe. Comprises: bracket, straps/nuts/bolts for pipe-mounting. Not required if IREX is being fitted to a junction box using a spigot gland. Wall-mounting fixings must be supplied by the installer.

Stainless steel pipe mounting bracket kit


Supplied with stainless steel u-bolts to enable IREX to be rigidly mounted to a 50mm (2") pipe.

Spigot gland (M20)


Required for connecting IREX to an auxiliary junction box. 5-wire, ATEX and IECEx certified.

Calibration cap


Fits over the standard weatherproof cap to enable calibration where local air speed exceeds 2 metres per second.

Flow adaptor


Replaces standard weatherproof cap for application where gas is being sampled via a pipe or tube.

PC Communications Kit


Communications module supplied with a software CD and USB cables for PC and IREX detector connection. Enables zeroing, calibration, gas type changes etc. Not suitable for use in a hazardous area.

316 Stainless Steel Auxiliary Junction Box


Enables IREX to be connected on an RS-485 Modbus network. Two cable gland entries, five terminals suitable for 2.5mm2 cables. A Spigot Gland is required if IREX is to be connected directly. ATEX/IECEx certified for Gas and Dust hazardous areas.

GRP Auxiliary Junction Box


Provides compliance with NORSOK standards which stipulate detectors must have an Exe cable termination area. GRP Exe junction box with one cable gland entry on the left-side, fitted with a six-way terminal block suitable for 2.5mm2 cables. A Spigot Gland is required if IREX is to be connected directly.

Related Products

Sorry, you cannot add this product because...

  1. It belongs to a different category to the products you are already comparing or...
  2. You are already comparing the maximum of 3 products