Tetra 3



The Tetra 3 portable multi gas monitor can detect and monitor the four most common gases (carbon monoxide, methane, oxygen and hydrogen sulphide), but also an expanded range: ammonia, ozone, sulphur dioxide, H2 filtered CO (for steel plants) and IR carbon dioxide (for safe area use only).


  • Rugged and impact-resistant design provides extra shock and vibration protection – provides protection in the harshest environment
  • Water and dust resistant to IP65 and IP67
  • Can be submerged in water

Effective warning

  • 95dB audible alarm – ensures clear warning facilitating prompt evacuations from hazard zones
  • Vivid red/blue visual alarm
  • Vibrating alarm


  • Proven sensor technology and software operation – Provides reliability you can trust and has the power to cover you for an extended shift
  • Clear “calibration due” warning
  • Lithium-ion battery provides over 14 hours continuous operation from a single charge with no memory effects

User friendly

  • Single button operation for all functions – can be operated with gloved hands
  • Top mounted, backlit display of all gas readings, diagnostics and battery life – ‘at a glance’ operating status



Size 114 x 71 x 48mm (tapers to 20mm) (4.5 x 2.8 x 1.9ins)
Weight 295g (10.4oz)
Alarms 95dB multiple alarm sounds allow selection of distinctive tones for different alarm levels
Internal vibrating alarm
Display Graphic LCD with backlight, giving simultaneous display for all gas channels. Graphic symbols for battery (with proportional indication of remaining operation time), healthy operation or fault warning. Start up indication when calibration is due, overdue, or service required.
Normal display: Real time gas concentration levels
Display recall: Peak readings and TWA
Data logging Timed: 50 hours at 1-minute data rate (>12,000 data logs of 4 channels)
Threshold: Starts after adjustable pre-set level
Event: >5,000 events
Event logging Alarm, over range, calibration, bump, on/off, TWA, 1000 events
Battery Rechargeable Li-ion battery
Operating time Based on four-gas instrument fitted with flammable sensor: A 5-hour charge from flat provides at least 12 hours of continuous use.A 12-hour charge provides at least 14 hours of continuous use
Sampling Diffusion or hand aspirator
Operating temperature -20°C to +55°C (-4°F to +131°F)
Storage -25°C to +65°C (-13°F to +149°F)
Humidity 15-95% RH@ 40°C non-condensing
Ingress protection IP65 and IP67
Approvals ATEX II 2G Ex ia db IIC T4 Gb (-20°C ≤ Ta ≤ +55°C)
IECEx Ex db ia IIC T4 Gb (-20°C ≤ Ta ≤ +55°C) BAS05.0059
CSA Class I Division 1 Groups A, B, C and D
Safety standards EN60079-0, EN60079-11, EN60079-1
CSA22.2, 152
EN50270, EN50271, EN50104, EN45544, EN60079, IEC61508
PC Interface RS232 connection from interface module in charger
RS232/USB converter available
Calibration Can be routinely calibrated using Portables PC software or Crowcon Checkbox IMH
Accessories Integral alligator clip

Optional accessories:

Universal harness plate, shoulder strap, chest harness, aspirator assembly (flow plate, bulb and 2m/6ft tubing), fixed and telescopic sample probes, and an in-line water trap

Charging Single way drop-in charger with UK, EU or US plug or in-line 110V/220V supply
Single way drop-in charger with options as above including PC interface
5 way multi-charger with universal power supply
Vehicle adapter for in-vehicle charging
Universal charger for vehicle, wall and desk mounting with a multi-region plug (supplied with EU/UK/US/Australian inserts) and status indication
Crowcon Connect Compatible? Yes


Gases and Ranges

Ranges and alarms vary by country and application; these can be configured as required. Each channel can have two instantaneous alarms. Toxic channels also have TWA alarms. Flammable gas calibration is available for methane, propane, butane, pentane, hydrogen and ethylene as standard.

Gas Range Typical Alarms
Flammable  0-100% LEL  20% LEL
Oxygen (O2)  0-25% 19/23.5% volume
Hydrogen Sulphide (H2S)  0-100ppm  5ppm
Carbon Monoxide (CO)  1-500ppm 30ppm
Sulphur Dioxide (SO2)  0-20ppm 1ppm
Ozone (O3)  0-1ppm 0.1ppm
Ammonia (NH2)  0-100ppm 25ppm
*Carbon Dioxide (CO2)  0-5% 0.5 % volume
Carbon Monoxide (CO) H2 compensated  0-500ppm 30ppm
Hydrogen Cyanide (HCN)  0-30ppm 10ppm









* T3 is available in a safe area CO2 version offering 0-5% carbon dioxide measurement.

The CO2 sensor replaces the flammable option and can be supplied with oxygen and toxic sensors.


Below is a small selection of the accessories available for the Tetra 3.

T3 universal charger


Wall, desk or vehicle storage compartment mounting, holds T3 firmly for charging. With multiregion mains PSU (UK, EU, NA and Australian plugs included).

T3 Gas Tester


Wall mount gas test solution for CH4, O2, CO, H2S & CO2 configured T3s

Charger Interface Software and Communication Kit


Charger interface kit enables data download, calibration and instrument configuration. Includes multi-region power supply, single way charger/interface cradle, USB-RS232 adaptor and RS232 cable. Software CD available separately (C01832).

5 way multi-charger


To allow charging of five Tetra 3 units at once. Supplied with 90-260V inline power supply. Select lead option.

Harness plate


Enables detector to be worn using the shoulder strap or chest harness straps.

Shoulder strap


Shoulder strap – use with harness plate or leather carry case.

Leather Carry Case


Enables unit to be worn either on a belt or with a shoulder strap.

External Dust Filter


For use in high dust environments such as steel plants.

Tetra3 Hard Shell Carry Case


To house T3 and charger.

Gas Test Kit


Includes Crowmag, regulator, hose, flow plate.

T3 Gas Tester inlet tubing, 1m


For use with T3 Gas Tester. Includes tube insert.

T3 Gas Tester fixed flow regulator


0.5l/min fixed flow regulator with on/off switch for use with T3 Gas Tester.

T3 Gas Tester cylinder holder


Cylinder holder (wall mount) for 34l to 110l cylinders, for use with T3 Gas Tester





Additional information

Crowcon Connect Compatible



Basic Operation:

  Menu Function

Includes: Menu function. Duration: 37secs

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Includes: Explanation of Tetra 3 charging. Duration: 45secs

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Duration: 36secs

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Includes: Explanation of Tetra 3 alarm display. Duration: 42 secs

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  Peak Mode

Includes: Peak mode. Duration: 53secs

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  Field Calibration

Includes: Explanation of Tetra 3 field calibration. Duration: 53secs

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  Manual zeroing

Includes: Explanation of Tetra 3 manual zeroing. Duration: 56secs

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