Confined Space Rescue
What this domain covers
Confined space rescue tests the permit-required confined space (PRCS) rule and the rescue layer on top of it: hazard recognition, atmospheric monitoring, ventilation, isolation, roles, and non-entry versus entry rescue.
Definitions and rules
A PRCS is large enough to enter, has limited entry and exit, is not designed for continuous occupancy, and contains a hazard (atmospheric, engulfment, entrapment, or energy). OSHA 1910.146 requires a permit, an entry supervisor, an attendant outside, and a rescue service that can respond. The attendant does not enter.
- Monitor in order: oxygen first, then flammables (%LEL), then toxics such as CO and H2S.
- Oxygen below 19.5% or above 23.5% is not enterable; 10% LEL is the alarm threshold for flammables.
- Ventilate and re-test; never ventilate and assume.
- Isolate energy with lockout/tagout and blank off lines - a closed valve is not isolation.
- Non-entry rescue with a tripod, winch, and full-body harness is the first choice. Entry rescue requires at least two entrants plus an attendant, supplied air, and a standby team.
Worked example
A meter reads 17.8% oxygen at the manhole with no change on re-test, and a worker is unresponsive at the bottom. The correct sequence: do not enter on that reading; ventilate and re-test from outside; then configure for entry with SCBA or supplied air plus an escape cylinder, a backup entrant, a retrieval line, and a standby team. The initial reading drives the plan - it is not a number to argue with.
Traps
Sampling only at the opening in a deep space (stratification). Reporting %LEL when the question asks ppm. Skipping lockout/tagout because the equipment is 'off'. Sending the attendant in.