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AC/OX CUTTING/WELDING/BRAZING

Rules relating to Oxygen

– Oxygen that leaks out into the air increases the danger of combustible materials igniting, i.e. body hair, clothes etc. catching fire. This can occur even with a small increas in the Oxygen content of the air, and can cause serious burns and other injuries.

– Never use Oxygen instead of air to start a diesel engine.

Never use Oxygen to blow dust from working clothes. lf clothing has been accidentally exposed to an increase in Oxygen content it may take a long time to get rid of the excess Oxygen, often several hours. – Never use Oxygen to freshen the air Oxygen Content (% by Volume)

when you are working in a confined space.

– Fittings for Oxygen must be kept free of dust and metal particles because of the danger of spontaneous combustion.

Oxygen-deficient atmospheres The normal Oxygen content of air is approximately 21%. Depletion of Oxygen content in air, either by combustion or displacement with inert gas, is a potentional hazard to personnel. A general indication of what can potentially occur relative to the percentage of Oxygen available is given in the table below.

Effects and Symptoms

(At Atmospheric Pressure)

15-19%

Decreased ability to work strenuously. May impair coordination and may induce early symptoms in persons with coronary, pulmonary, or circulatory problems.

12-14%

Respiration increases in exertion, pulse up, impaired coordination, perception, and judgment.

10-12%

Respiration further increases in rate and depth, poor judgment, lips blue.

8-10%

Mental failure, fainting, unconsciousness, ashen face, blueness of lips, nausea, and vomiting.

6-8%

8 minutes; 100% fatal, 6 minutes; 50% fatal, 4-5 minutes; recovery with treatment.

4-6%

Coma in 40 seconds, convulsions, respiration ceases, death.

Note: Exposure to atmospheres containing 12% or less Oxygen will bring about unconsciousness without warning and so quickly that the individual cannot help or protect himself. An asphyxia victim should be taken into the open air quickly and given Oxygen or artificial respiration. Medical attention should be obtained immediately. Inhalation of an Oxygen-rich atmosphere also requires medical attention.

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