Crowcon Tetra 4

Crowcon Tetra 4 is designed as a tough, everyday personal gas detector for environments where oxygen, carbon monoxide, hydrogen sulphide and flammable gas hazards are a routine concern. Dedicated sensors for each configured gas provide fast, accurate readings, while a compact, lightweight format makes continuous wear practical during confined space entry, work at height and extended site inspections.

The detector’s robust housing, including an integrated rubber boot and 4m drop test performance onto concrete, withstands rough handling, transport and accidental drops. Dual ingress protection ratings against dust and water support reliable operation in wet, dirty or washdown-prone areas. These characteristics make the instrument well suited to oil and gas, utilities, construction, wastewater, chemical processing, shipbuilding and other sectors where physical and environmental stresses are high.

Crowcon Tetra 4 is intrinsically safe and approved for use in hazardous areas, including explosive atmospheres in appropriate zones depending on configuration. This allows consistent personal monitoring across sites with classified areas, both onshore and offshore. A triple alarm system comprising a loud audible alarm, bright red/blue LEDs and a strong vibration alert ensures warnings are noticeable, even in noisy plants, low-visibility conditions or when the detector is worn on clothing or a harness.

The Positive Safety traffic-light indicator provides continuous visual confirmation of detector status and compliance with bump test and calibration policies. Green and red LEDs allow wearers, supervisors and nearby colleagues to verify at a glance that a unit is operating correctly and is safe to use before entering hazardous areas, supporting safer access control and personal gas monitoring discipline.

Tetra 4 is built around a simple, single large-button interface and an intuitive menu structure. This supports fast familiarisation, straightforward operation with gloved hands and reduced training demands for rotating crews or contractors. Quick view and information screens present key status information without complex navigation or, in some cases, without fully powering up the detector, helping users confirm readiness quickly before deployment.

The large, front-mounted backlit display is designed for clarity in low light and confined spaces. An optional 180° screen flip allows readings and status indicators to remain correctly oriented when the detector is clipped upside down to chest pockets, harnesses or belts. Combined with the front-facing Positive Safety indicators, this design improves visibility not only for the wearer but also for supervisors and colleagues monitoring team safety.

A high-capacity rechargeable lithium-ion battery provides more than 18 hours of typical runtime between charges, supporting long or double shifts without frequent interruptions. A typical recharge time of around 5.5 hours fits conveniently into overnight or between-shift charging schedules, helping keep detectors available when required.

Power and charging options are designed for fleet deployment. Versions are available with a charging cradle and multi-region power supply, or as detector-only for sites with existing infrastructure. Optional multi-way charger systems enable simultaneous charging and storage of multiple detectors from a single outlet, simplifying bench management for large user bases. Vehicle charging solutions support safe charging and storage in transit, improving readiness for mobile maintenance and inspection teams.

Crowcon Tetra 4 incorporates advanced exposure monitoring tools to support regulatory and internal policy compliance. It provides STEL and time weighted average (TWA) alarms for toxic gases, allowing supervisors to assess both short-term peaks and long-term exposure during a shift. The unique TWA Resume function continues TWA calculations across breaks and transport periods when the detector may be switched off, giving a more realistic picture of total exposure and reducing gaps in monitoring data.

Peak reading mode captures and displays the highest measured gas concentrations during a work period, helping identify subtle deteriorations in atmosphere or ventilation that may not trigger alarms but still warrant attention. Integrated data and event logging record substantial histories of readings and alarm events, which can be downloaded using optional USB communication leads and software. Compatibility with Crowcon Connect and Portables Pro software enables fleet-wide analysis, maintenance tracking and reporting, supporting auditability and evidence-based safety management.

The detector is engineered to minimise lifetime cost. Its rugged mechanics, long-life rechargeable battery and robust sensors reduce unplanned repairs and replacement cycles. Diffusion-type sampling as standard keeps the design compact and mechanically simple, avoiding the additional wear points associated with integral pumps. Where pre-entry or remote sampling is needed, optional aspirator plates, hand bulbs, hoses and telescopic probes enable gas checks in confined or hard-to-reach spaces using the same platform.

Routine maintenance is simplified by compatibility with Crowcon I-Test automated bump and calibration stations, which help standardise performance checks and record results across fleets. Manual zeroing in clean air supports sensor accuracy between scheduled calibrations. Instruments are supplied calibrated from the manufacturer, commonly with a calibration certificate, and extended or updated certificates are available as a service. Authorised service centres and available spare parts further support long-term maintenance strategies and help extend instrument life.

Crowcon Tetra 4 is available in 2, 3 or 4 gas configurations, enabling alignment of each detector with site-specific risk profiles. H2-immune CO sensor variants support accurate carbon monoxide monitoring in locations where hydrogen is present, while improved detection performance for longer-chain hydrocarbons such as pentane and hexane compared with previous versions broadens suitability for processing, storage and handling applications.

A wide range of accessories, including aspirator kits, calibration caps, telescopic probes and power/communication cables, allows the same detector platform to be adapted for routine personal monitoring, pre-entry checks and remote sampling tasks. An integrated alligator clip and tethering loop keep the detector securely attached to clothing or harnesses in tight spaces or on moving plant, reducing the risk of loss or damage.

For organisations operating across multiple regions, Tetra 4 supports standard and region-specific alarm settings and multiple language profiles, aided by multi-language datasheets, manuals and support materials. Compliance with relevant electromagnetic and marine directives in applicable configurations broadens its use into marine and offshore environments. Combined with hazardous area approvals and optional multi-way and vehicle charging systems, this enables standardisation on a single multigas platform across diverse sites, climates and working practices.

By uniting rugged construction, shift-long power, configurable gas sensing, advanced exposure monitoring and strong support for automated testing and data management, Crowcon Tetra 4 delivers a dependable, field-proven solution for personal multigas protection in demanding industrial and hazardous area applications.

For detailed technical data, consult the Specifications tab.