Oxygen Gas Detectors (O2 Detectors)

O2Accurate oxygen (O2) level measurements are essential in preventing injury or death in situations where safe levels may be compromised. Oxygen gas detection instruments will typically trigger an alarm when the oxygen level drops below 19.5% volume, the OSHA-mandated level. The most common use of oxygen gas detection is in confined spaces – totally or partially closed areas generally not designed to be permanently occupied. It is essential that an O2 gas sample is drawn prior to entering these spaces, and is continuously monitored after entry. Industrial Scientific provides a range of monitors including the GasBadge® Pro single-gas detector, the Ventis® Pro, Ventis® MX4, MX6 iBrid® multi-gas detectors, and the Radius® BZ1 Area Monitor, to monitor oxygen levels.

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Oxygen - O2

Effects of Various O2 Levels

Of Oxygen

Resulting Conditions on Humans

23.5% Volume

Maximum "Safe Level"; OSHA.


Oxygen Concentration of AIR (20.954).


Minimum "Safe Level"; OSHA, NIOSH.


Impairment of judgment starts to be evident.


First signs of anoxia appears. 


Breathing and pulse rate increases, muscular co-ordination is slightly impaired.


Consciousness continuous; emotional upsets, abnormal fatigue upon exertion, disturbed respiration.


Nausea and vomiting, inability to move freely and loss of consciousness may occur.


Convulsive movements and gasping respiration occurs; respiration stops and a few minutes
later heart action ceases.

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