Permit-required confined spaces
Published 2026-09-04 · 11 min read · sources checked 2026-09-04
Construction got its own confined-space standard in Subpart AA, and it is stricter than the general-industry version in one way that matters on a jobsite: multiple employers work in the same space, so the standard spends a lot of words on who tells whom what.
The two-part test
First: is it a confined space? Large enough and so configured that an employee can bodily enter it, has limited or restricted means of entry or exit, and is not designed for continuous employee occupancy. All three, together.
Then: does it have one of the four features that make it permit-required? A hazardous atmosphere; a material with the potential to engulf; an internal configuration that could trap or asphyxiate by inwardly converging walls or a floor that slopes and tapers to a smaller cross-section; or any other recognised serious safety or health hazard.
| On a jobsite | Usually |
|---|---|
| Manhole, lift station, wet well | permit-required |
| Sewer | permit-required |
| Crawl space with no hazard | confined, not permit-required |
| Trench over 4 ft with a possible hazardous atmosphere | test before entry — 1926.651(g) |
| Attic with a hot-work permit open in it | the hot work is the “other recognised hazard” |
Classification worked from 29 CFR 1926.1203 and 1926.651, read 2026-09-04. Each space is evaluated on its own.
Danger
Four roles, and who talks to whom
Subpart AA writes three employers into the standard — the host employer who owns or manages the workplace, the controlling contractor with overall responsibility for the site, and each entry employer whose people go in. Information about known hazards flows from host to controlling contractor to entry employers, and results and near-misses flow back the other way.
Inside the space, the three named jobs are the authorised entrant, the attendant and the entry supervisor. The entry employer must designate each person with an active role, identify their duties and provide them with the training the standard requires.
The attendant is the role that gets bent on a busy site. Attendants may be assigned to more than one permit space, but only if the duties under 1926.1209 can be performed effectively for every one of them, and the permit program has to set out how the attendant answers an emergency in one space without abandoning the others.
The two narrow routes out
Alternate procedures, 1926.1203(e). Available only when the entry employer can demonstrate that the only hazard is an actual or potential hazardous atmosphere, and that continuous forced-air ventilation alone is sufficient to maintain the space safe for entry. Monitoring, documentation and the ability to demonstrate all of it are part of the route, not an alternative to it.
Reclassification, 1926.1203(g). Available only when every hazard within the space has been eliminated. Controlled is not eliminated. Ventilated is not eliminated — if you need the fan running to stay safe, you are on the alternate-procedures route, not this one.
A sign reading DANGER — PERMIT-REQUIRED CONFINED SPACE, DO NOT ENTER, or similar language, satisfies the standard’s requirement to inform exposed employees of the existence, location and danger of a permit space.
Reclassification, and how it unravels
Two clauses close the loop, and they are the reason a casual reclassification is dangerous. If a hazard arises within a space reclassified as non-permit, every employee in the space must exit; the entry employer then re-evaluates the space and reclassifies it as a permit space as appropriate.
And when the use or configuration of a non-permit confined space changes in a way that might increase the hazards to entrants — or there is any indication the initial evaluation was not adequate — a competent person must re-evaluate and, if necessary, reclassify it. That is the same competent-person definition as everywhere else in part 1926: capable of identifying the hazards and authorised to take prompt corrective measures.
The permit itself, with the atmospheric readings and the rescue arrangement, is on the confined space entry permit. Who may hold the designation is in competent person under OSHA.