Safety Gas Detection - Using technology to safeguard life

Oxygen depletion gas detection

Oxygen depletion systems and alarms

  • Safety Gas Detection manufactures oxygen depletion systems and enrichment gas detection systems which measure oxygen levels and provide oxygen depletion alarms and oxygen enrichment alarms.
  • These systems can be supplied to measure other gases simultaneously.
Areas suitable for detection systems

Typical areas which need oxygen depletion detection systems

  • Research and teaching laboratories
  • Food
  • Manufacturing
  • Electronics
the risk of oxygen depletion

The risk of oxygen depletion

  • If liquid nitrogen (or any other inert gas) is allowed to escape into the air, the oxygen level is depleted.
  • Since liquid nitrogen expands rapidly after it is released (1 litre of LN2 can expand to 680 litres), even a small amount of liquid nitrogen can, if released, reduce the oxygen concentration by enough to cause danger.
  • Depleted oxygen levels are not just deadly but initially impair physical and mental ability.
  • This leads to an increased risk of accidents and other physical problems.
  • Common gases in use where oxygen depletion monitoring is used include nitrogen, helium (special conditions necessary – contact us for details), argon and many others.
  • Oxygen depletion monitoring should not be used where the target gas is carbon dioxide (CO2) since it is not sensitive enough to meet the effects of CO2 enrichment.
  • For CO2 monitoring, see here application example – combined oxygen depletion and CO2 enrichment Monitor in a laboratory environment.
  • Whatever the specific risks, you can safeguard personnel against the danger of asphyxiation due to depleted oxygen levels by installing an oxygen depletion alarm.
The solution to a build up

The solution

  • Utilising the basic functions of our oxygen depletion system, users of liquid nitrogen or other inert gases can monitor up to 48 points around the workplace using our O2SafeGuard system, or alternatively up to 8 using the extremely cost effective 02SafeGuardLite.
  • Oxygen depletion sensors are distributed in the areas at risk and are monitored by the central monitoring station.
  • In a normal working environment, sensors are normally situated at around 1.25 metres above floor level, but this, of course, would be tailored to suit the circumstances of the application – for example for gases significantly lighter than air they would be mounted at a high level.
  • We can advise you on the best location for the sensors during a site survey or by inspecting site drawings.
  • The oxygen depletion sensors usually have a range of 5% oxygen and are of the electro-chemical type.
  • The system is normally set to give a first stage warning alarm at 19.5% oxygen, and then a second stage full alarm at 18.0%.
  • This enables action to be taken before an evacuation is required and evacuation before danger.
  • The oxygen depletion system has a user interface, which for the O2SafeGuard is a full colour touch screen.
  • Here it is possible to view the readings from the gas sensors, an indication is made audibly and visually if the system detects an alarm condition.
  • It is advisable that the user interface is located outside of the risk area so that in the event of an alarm, the information from the system can be accessed without entry into the risk area.
  • In this example, the oxygen depletion system could be used to switch on or increase the speed of ventilation to the risk area to ensure an adequate oxygen level.
  • The system has two alarm settings.
  • The first (amber) alarm can be utilised to trigger the ventilation, and the second (red) alarm is utilised to indicate evacuation of the area.
  • The audible alarm is only triggered at the second (red) alarm stage.
  • Either alarm stage could be utilised to shut off the bulk storage supply of gas.
Options for detection system

Application specific options

  • Zoned alarm outputs – enabling the system to monitor multiple rooms, floors or even buildings, with area specific zoned alarm outputs.
  • IP66 rated oxygen depletion sensor enclosures for wet/dusty manufacturing environments.
  • Attractive sensor enclosure for laboratory and office environments.
  • Gas shutdown control module.
  • Incorporated fan control switchgear.
  • Separate interface panel and oxygen depletion monitoring station – ideal where the Interface needs to be in a corridor or central area. This can also reduce installation cost where the interface panel is located at a distance from the sensors.
  • Email and SMS upon alarm module.
F Gas technical information

Oxygen depletion technical information

Oxygen (O2)

  • Oxygen is a colourless, tasteless and odourless gas, normally found in air at 20.95%.
  • It can be toxic at elevated partial pressures, and enrichment results in increased flammability and risk of fire.
  • Another common risk is from a lack of oxygen content in breathing air resulting in the progressive physiological effects outlined below – eventually resulting in the risk of death.

CAS No. 7782-44-7

Relative Density


Physiological Effects of Oxygen Depletion

Physiological Effects

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