Gas Testing Essentials for Work Permits

Safety first! When issuing work permits, gases like Oxygen (O2), Hydrogen Sulfide (H2S), Carbon Monoxide (CO), and Flammable Gases (LEL) are closely monitored.

Always use calibrated gas detectors before issuing work permits.

Continuous monitoring is mandatory in confined spaces.

Workers must be trained on emergency response and gas hazards......

Oxygen (O?)

Normal level: 20.9%

Below 19.5%: Breathing apparatus required (as per OSHA 29 CFR 1910.146).

Above 23.5%: No work allowed due to fire risk (as per NFPA 350).

Hydrogen Sulfide (H?S)

10 ppm: Breathing apparatus required (as per NIOSH Recommended Exposure Limit - REL).

20 ppm: Permissible Exposure Limit (PEL) ceiling (as per OSHA 29 CFR 1910.1000).

Above 100 ppm: Immediate Danger to Life and Health (IDLH); no work allowed (as per NIOSH IDLH guidelines).

Carbon Monoxide (CO)

35 ppm: Permissible Exposure Limit (PEL) over 8 hours (as per OSHA 29 CFR 1910.1000).

50 ppm: Threshold Limit Value (TLV) over 8 hours (as per ACGIH).

Above 1,200 ppm: Immediate Danger to Life and Health (IDLH); confined space entry prohibited (as per NIOSH IDLH guidelines).

Flammable Gases (LEL - Lower Explosive Limit)

Above 0% LEL: No hot work allowed (as per NFPA 51B).

5-10% LEL: Breathing apparatus required (as per OSHA 29 CFR 1910.146).

Above 10% LEL: No work allowed due to explosion risk (as per NFPA 69).

Quick Tip: LEL for Common Gases

Methane: ~5%

Propane: ~2.1%

Hydrogen: ~4%

Stay safe, stay vigilant!