Bieler+Lang ExMonitor — intrinsically safe toxic gas and oxygen detector

An electrochemical detector for toxic gases and oxygen in an intrinsically safe design, approved for zones 1 and 2. Depending on the cell it measures one of eleven gases — including chlorine, which most fixed detectors do not handle.

Two hazards, one device

The ExMonitor warns of the two things that kill most often in an enclosed space: too high a concentration of a toxic gas and oxygen deficiency. Both are odourless and both develop faster than a person can react.

Once a level is exceeded, the controller starts the technical response — fan, shut-off, purge — and the organisational one: visual and audible signalling, entry blocking.

Intrinsic safety — why that is a different league

Intrinsic safety (Ex ia) limits the energy in the circuit so that even a fault cannot produce a spark able to ignite an explosive atmosphere. It is the highest level of protection, which is why the ExMonitor may be used in zone 1, not only in zone 2.

Marking II 2G Ex ia IIC T4 Gb, type examination BVS 03 ATEX E 384, measurement function certificate BAM 03 ATEX 0003 X.

Chlorine — the special case

The manufacturer lists chlorine detection separately. Cl₂ is difficult to measure: it is strongly corrosive, it clings to tubing and cells, and most general-purpose designs simply do not support it.

That makes the ExMonitor the natural choice for water treatment plants, swimming pools, sewage works and chemical plants — anywhere chlorine is stored or dosed.

Where else

Sewage works and pumping stations (H₂S), boiler rooms and garages (CO), cold stores and food processing (NH₃), battery rooms and hydrogen installations (H₂), laboratories, hazardous goods stores, tanks and confined spaces (oxygen deficiency).

If the mounting location is not a hazardous area, a cheaper and equally good answer is the GasMonitor — the same measuring technology without explosion protection.

Technical data

Parameter	Value
Measuring principle	electrochemical measuring cell
Detectable gases	CO, H₂S, SO₂, NO, NO₂, Cl₂, HCN, HCl, H₂, O₂, NH₃ — depending on the cell
Zones	zone 1 and zone 2
Protection	intrinsically safe (Ex ia), ATEX compliant
Marking	II 2G · Ex ia IIC T4 Gb · BVS 03 ATEX E 384
Type examination	EU type examination to directive 94/9/EC
Measurement function certificate	BAM 03 ATEX 0003 X
Measuring signal	linear 4–20 mA
One-man calibration	yes — adjustment on the display and at the sensor
Manufactured in	Germany

Service with us

We are an authorised Bieler+Lang trade and service partner — we hold the manufacturer's written authorisation covering commissioning, maintenance and other service work, valid until 31 December 2028. Our technicians were trained in Achern and work with original parts and factory procedures.

In practice that means we commission, calibrate and service what we sell — nothing has to be shipped back to Germany. See our service scope or send equipment in.