Entry is planned into a sanitary sewer manhole that has been classified as a permit-required confined space. Beyond testing the atmosphere, what does the OSHA construction standard require during that entry?
- An attendant stationed outside the space for the duration of the entry, together with retrieval equipment such as a full body harness and lifeline where it would aid rescue
- BA second worker inside the space at all times so that the two can assist each other, since an entrant who is overcome can be brought out faster by somebody already down there with him
The buddy system is the right instinct from other kinds of work and the wrong one here. It removes the person watching from outside and adds a second potential victim, and most confined space deaths are would-be rescuers.
- CThe cover left off for 24 hours before the entry so that the space airs out, after which neither continued monitoring nor a person stationed outside is required
Airing out a manhole is useful preparation and does lower the first reading you take. Hydrogen sulfide and oxygen deficiency return within minutes once an entrant starts disturbing the flow, so ventilation replaces nothing.
- DA written note left at the shop stating the location entered and the expected time of return, so the crew knows where to start looking if the worker does not come back
A note is a form of communication, which is why it feels responsible. It does nothing for a worker unconscious at the bottom of a manhole, and the standard requires an attendant present and a way to summon rescue.
Why A is correct
The confined spaces in construction standard requires an attendant outside the permit space for the duration of entry operations, continuous or periodic monitoring as the permit specifies, and retrieval systems, typically a full body harness and a line attached to a mechanical device or fixed point, whenever such a system would contribute to rescue and does not create a greater hazard.
What this question is testing
The item tests knowledge of confined space entry duties that are entirely outside the plumbing code but govern real underground work, particularly the role of the attendant and the use of retrieval equipment.
On the job
Sewer manholes carry hydrogen sulfide, methane and oxygen deficiency, and the gas that kills is the one that also destroys your sense of smell at high concentration. Practical routine: test from the top down before anyone enters, ventilate, keep the meter on the entrant, harness up with the tripod and winch rigged, and agree in advance who calls rescue. Never let a helper go down after somebody who has collapsed.
Memory technique
One goes in, one stays out, the line stays on.
Exam tip
Confined space answers almost always involve someone staying outside. Any option that puts a second person in the hole is wrong.
Where to look it up
This requirement comes from the OSHA construction standard for confined spaces, not from the plumbing code. Look under the confined spaces in construction subpart rather than in any plumbing code chapter.