Breathing / Rescue Air Contamination Monitors

The dangers associated with breathing contaminated air are also well known and especially critical when using SCBA tanks in emergency situations.

Sigma Sensing has solutions for individual or multiple contaminant monitoring of breathing or rescue air.


Occupational Safety and Health regulations require procedures to ensure adequate quality of breathing air contained in breathing apparatus (SCBA).
SCBA is a device worn by rescue workers, firefighters, paramedics and others working for example on ships & oil rigs to provide breathable air in an immediately dangerous to life or health atmosphere (IDLH).


Sigma Sensing is offering for this purpose a fixed installation unit of the Sigma95H-B series with display that can monitor the correct levels of CO2 and CO (NOx optional) in the air system. The unit which is designed for industrial applications is using a long life NDIR CO 2 sensor and an electrochemical CO sensor for this purpose.. The sensors monitor the air in ambient pressure as the compressed air pressure is reduced to ambient pressure for air sampling in a low pressure measurement chamber.
Version Sigma 95H-B-A with an alarm beacon and the alarm setting freely configurable is also available.

Breathing Air Quality Monitor, Fireman CO2 protection, Scuba Diver protection 

Sigma 95H-B series Specifications


System max pressure: <15 bar
Response time ≤30 seconds (T90)
Sensor measuring range: 

CO2: 0 ~2000 ppm

CO: 0-50 ppm

Sensor operating principle:

CO2: Non-dispersive infrared (NDIR)

CO: Electrochemical -

Accuracy :  ≤±5%F.S. (higher accuracy optional)
Sensor operating humidity: 0 - 95% RH, non-condensing
Sensor operating temperature: -20.....+50C
Gas sampling method: suction pump
Sensor operating life expectancy:

CO2: 5 years in air

CO: 18-24 months in air

Recommended calibration interval: 12 months


2.4-inch color display, resolution 320*240

Display content: gas molecular formula, concentration, unit, pump status, etc.
Power supply: 12-24V DC
Current outputs (for one sensor): 4-20mA
Relay output: 1
Other outputs RS485

Alarm mode:



buzzer, alarm status prompt on the display screen, high and low alarm values can be set by end user.

Protection rating:


Other configurations:

On request