Requirements for use of Confined Space Gas Detectors
Requirements for use of Confined Space Gas Detectors
Regulatory Requirements
OSHA 1910.146 "Permit-required confined spaces"
OSHA CPL 2.100 "Application of the PermitRequired Confined Spaces (PRCS) Standards, 29 CFR 1910.146"
1915 Subpart b "Confined and Enclosed Spaces
and Other Dangerous Atmospheres in Shipyard
Employment"
Requirements for use of Confined Space Gas Detectors
Use of gas detectors in hazard assessment
Use of gas detectors in non-permit spaces
Use of gas detectors in permit spaces which have been reclassified as non-permit spaces
Use of gas detectors in permit-required confined spaces (per 1910.146)
Using Confined Space Gas Detectors
"Pick-hole" sampling
Pre-ventilation
Sampling during initial (purge) ventilation
Final pre-entry
Monitor continuously while entry underway!
Sample at all vertical levels!
Atmosphere tested (at least) a distance of approximately 4 feet (1.22 m) in the direction of travel and to each side
1910.146 Appendix E: "Sewer System Entry"
Major points:
Sewer workers' usual work environment is a permit space
Because isolation not complete, always potential for atmosphere to become suddenly and unpredictably lethal
Testing instrument should be carried by the entrant while in the sewer to warn of any deterioration
Atmospheric monitoring equipment must calibrated according to the manufacturer's instructions
Broad range vs. substance specific sensors in sewer entry per Appendix E
Broad range best suited for initial use where actual or potential contaminants have not been identified
However, such sensors only indicate that a hazardous threshold of a class of chemicals has been exceeded
Therefore, substance-specific best suited for use where actual and potential contaminants have been identified.
However, sewers may change unpredictably, and substance-specific devices may not detect new potentially lethal hazards
Broad Range vs. Substance Specific Sensors in Sewer Entry
OSHA emphasizes it’s up to the employer to decide, based on knowledge and experience, what the best type of testing instrument may be for any specific entry operation.
