Confined space entry & hot work permits
Some construction work is too dangerous to start on a verbal "looks fine" — it needs a written permit that proves the hazard was checked and controlled first. The two big ones are permit-required confined-space entry (29 CFR 1926 Subpart AA) and hot work (1926.352). This hub covers when each permit is required, the atmospheric testing, the roles, the rescue plan, and the fire watch — with the exact CFR paragraph for each.
Verified against osha.gov · July 21, 2026
At a glance
What's a permit space
A confined space (big enough to enter, limited entry/exit, not for continuous occupancy) that has or could have a hazardous atmosphere, engulfment, an entrapment configuration, or any other serious hazard
1926.1202The written permit
Identify and evaluate the space's hazards before entry, and run a system to prepare, issue, use, and cancel entry permits — no entry on a verbal OK
1926.1204(b), (j)Test the air
Test before entry and monitor continuously during entry, in the order oxygen → combustible gases → toxic gases
1926.1204(e)Three roles
An entry supervisor authorizes and can terminate entry; an attendant stays outside and never enters; authorized entrants do the work and exit on command
1926.1204(h)Rescue
Provide for summoning rescue and for rescuing entrants — a non-entry retrieval system or a rescue service; self-rescue alone is not a compliant PRCS rescue plan
1926.1204(i); 1926.1211Hot work
Welding, cutting, grinding and other heat/spark work needs a fire watch wherever more than a minor fire could develop — usually its own permit
1926.352(e)The permit essentials, verified against 29 CFR 1926 Subpart AA and the hot-work standard. A single unsafe entry rarely draws just one citation — a missing permit, un-tested air, no attendant, and no rescue plan each cite separately, up to $16,550 per serious violation.
Is the atmosphere safe to enter?
Enter the four pre-entry gas readings for a permit-required confined space. Each is checked against the acceptable range and you get the entry verdict. Runs on the same engine as our Confined Space Permit Generator.
1926.1202: 19.5-23.5%
1926.1202: <10% of LFL
4-gas alarm setpoint, below the 50 ppm construction PEL (1926.55 Table 1)
10 ppm construction PEL, 1926.55 Table 1 (NIOSH 10-min ceiling REL is the same)
Test from outside the space first, in this order — oxygen, then combustible gases, then toxics (1926.1204(e)(3)) — and monitor continuously during entry (1926.1204(e)(2)).
Enter the four pre-entry gas readings to check them against the acceptable ranges and get the entry verdict.
When a permit is required
Two kinds of construction work carry their own permit because the hazard has to be proven controlled before the work starts.
Permit-required confined space
A confined space is one big enough to enter, with limited entry/exit, not designed for continuous occupancy. It becomes permit-required when it has or could have a hazardous atmosphere, engulfment potential, an entrapment configuration, or any other serious hazard.
1926.1202 · Subpart AAHot work
Welding, cutting, grinding, brazing, and other heat- or spark-producing work needs fire prevention — a fire watch wherever more than a minor fire could develop — usually documented on its own permit.
29 CFR 1926.352The three roles
A permit-required entry needs three named people. The one detail that costs lives: the attendant stays out.
Entry supervisor
Authorizes entry, verifies the permit and acceptable conditions, and terminates entry when conditions change. Signs the permit before anyone goes in.
1926.1210Attendant
Stays OUTSIDE the space, monitors the entrants and the atmosphere, keeps continuous communication, and initiates rescue — and must never enter the space to attempt one.
1926.1209Authorized entrant
Does the work inside, knows the hazards and the symptoms of exposure, keeps in contact with the attendant, and exits immediately when told or when an alarm sounds.
1926.1208Testing the atmosphere
Test from outside the space, in a fixed order, before entry — and keep monitoring while anyone is inside (1926.1204(e)). A blank reading is not a pass: you can’t authorize entry on air you didn’t test.
| Test (in order) | Acceptable | Basis |
|---|---|---|
| 1. Oxygen (O₂) | 19.5–23.5% | 1926.1202: 19.5-23.5% |
| 2. Combustible Gas (LEL) | < 10% LEL | 1926.1202: <10% of LFL |
| 3. Carbon Monoxide (CO) | < 25 ppm | 4-gas alarm setpoint, below the 50 ppm construction PEL (1926.55 Table 1) |
| 4. Hydrogen Sulfide (H₂S) | < 10 ppm | 10 ppm construction PEL, 1926.55 Table 1 (NIOSH 10-min ceiling REL is the same) |
H₂S is shown at 10 ppm because that IS the construction limit — 29 CFR 1926.55 Table 1, and the same figure NIOSH sets as a 10-minute ceiling. The 20 ppm ceiling belongs to Table Z-2, general industry, which does not govern construction work. CO alarms at 25 ppm, below the 50 ppm construction PEL. Oxygen and combustible ranges are the 1926.1202 hazardous-atmosphere definitions.
Rescue — planned before entry, not during
The rescue duty
Before entry, you must provide for summoning rescue and for rescuing entrants — a non-entry retrieval system (tripod and winch) or a trained rescue service on call. Most confined-space deaths are would-be rescuers.
1926.1204(i); 1926.1211Self-rescue is not a plan
“The entrant will climb out” is not a compliant rescue plan for a permit-required space. And the attendant never enters to attempt a rescue — they summon it. Non-entry retrieval is the default because it protects the would-be rescuer.
1926.1211Hot work & the fire watch
Construction fire prevention for welding, cutting, grinding, and other heat/spark work is 29 CFR 1926.352. A fire watch is required wherever more than a minor fire could develop or appreciable combustibles are within reach of the sparks (1926.352(e)).
A note on the familiar numbers. The 35-foot combustible-clearance rule comes from NFPA 51B — the recognized industry practice OSHA references and inspectors expect — not from a literal number in the CFR. The fire-watch duration is where most guidance goes wrong: NFPA 51B sets a minimum of 60 minutes, and has since its 2019 edition. The 30 minutes quoted everywhere is OSHA general industry (1910.252(a)(2)(iii)(B)), which does not reach construction work — and 1926.352(e) fixes no duration at all, requiring instead a sufficient period to ensure that no possibility of fire exists.
Hot work inside a confined space needs both permits — the entry permit and the hot-work permit. HazComFast builds each, keeps the fire-watch and atmospheric records, and stores the signed permit so the job is defensible.
Key facts
- A confined space is only 'permit-required' when it carries a real hazard — a hazardous atmosphere, engulfment risk, an entrapment configuration, or another serious hazard (1926.1202).
- Test from outside first, in order — oxygen, then combustibles, then toxics — and monitor continuously during entry (1926.1204(e)(2)/(3)).
- Acceptable oxygen is 19.5–23.5%; combustible gas must be below 10% of its lower flammable limit (1926.1202).
- The attendant never enters the space to rescue — non-entry retrieval or a trained rescue service is the plan (1926.1211).
- Construction confined spaces are governed by 1926 Subpart AA — the general-industry standard 1910.146 does not apply to construction.
- Hot work needs a fire watch wherever more than a minor fire could develop (1926.352(e)). The familiar 35-ft clearance and 30–60-minute post-work watch are NFPA 51B recognized practice, not literal CFR text.
Tools, guides and the standard
Free tools
- Confined Space Permit Generator
Build the bilingual entry permit with the atmospheric readings and roles.
- Hot Work Permit Generator
Document the fire watch, clearance, and sign-offs for heat/spark work.
- Toolbox Talk Generator
Brief the crew on the entry or hot-work hazards before the shift.
In-depth guides
- Confined space entry: the permit-required guide
- Who dies in confined spaces: 1,030 deaths & the rescuer trap
- Hot work permit & fire watch (1926.352 vs NFPA 51B)
- Why hot work keeps killing: 15 CSB investigations & the OSHA rules
- Construction Subpart AA vs general-industry 1910.146
- Confined space training by role
- Is exactly 10% LEL safe to enter?
- Digital permits for hot work & confined space
Safety permits FAQ
What defines a confined space under OSHA?
A confined space must meet ALL three criteria: (1) large enough for an employee to bodily enter and perform work, (2) has limited means of entry or exit, and (3) is not designed for continuous employee occupancy. Examples include tanks, vessels, silos, storage bins, hoppers, vaults, pits, manholes, tunnels, and some crawl spaces.
What makes a confined space 'permit-required'?
A confined space becomes permit-required (PRCS) if it contains or has the potential to contain: a hazardous atmosphere, material that could engulf the entrant, an internal configuration that could trap or asphyxiate (converging walls, sloped floors), or any other recognized serious safety or health hazard. For construction work this is governed by 29 CFR 1926.1202 (1926 Subpart AA — Confined Spaces in Construction); 1910.146 is the general-industry analog and does not apply to construction.
What atmospheric readings are required before entry?
Test the atmosphere BEFORE entry in this order: (1) Oxygen (O₂): 19.5–23.5% is acceptable, (2) Flammable gases (LEL): must be below 10% of its LFL, (3) Toxic gases. For H₂S the 10 ppm this tool uses is not a recommendation — it is your enforceable construction limit, 29 CFR 1926.55 Table 1 (10 ppm, 8-hour TWA), and NIOSH sets the same 10 ppm as a 10-minute ceiling, which is what a pre-entry reading actually measures. The 20 ppm ceiling you may have seen is Table Z-2, general industry, and does not govern construction work. For CO the tool alarms at 25 ppm, deliberately below the 50 ppm construction PEL. For construction, continuous monitoring of the atmosphere is required during entry (29 CFR 1926.1204(e)). Test from outside the space first using extension probes.
Who are the key roles for a confined space entry?
Three roles are required: (1) Entry Supervisor: authorizes entry, verifies conditions, terminates entry. (2) Attendant: remains outside, monitors entrants, maintains communication, initiates rescue. Must NEVER enter the space. (3) Authorized Entrant: enters the space, must know hazards, communicate with attendant, exit immediately upon order.
Do I need a separate permit for hot work?
Usually, yes. Construction fire prevention for welding, cutting, grinding, and other heat- or spark-producing work is 29 CFR 1926.352, and a fire watch is required wherever more than a minor fire might develop or appreciable combustibles are within reach of the sparks (29 CFR 1926.352(e)). Most employers document this with a hot-work permit. The common 35-foot combustible clearance comes from NFPA 51B (recognized industry practice OSHA references), whose post-work fire watch is a minimum of 60 minutes and has been since its 2019 edition. The 30 minutes often quoted alongside it is OSHA general industry, 1910.252(a)(2)(iii), and does not reach construction work — 1926.352(e) fixes no duration at all.
What are the OSHA penalties for a confined-space or hot-work violation?
Confined-space and hot-work requirements are cited like any other construction standard: up to $16,550 per serious violation and $165,514 per willful or repeated violation at 2026 amounts (29 CFR 1903.15(d)). Because an entry can involve multiple missing controls — no permit, no atmospheric testing, no attendant, no rescue plan — a single unsafe entry often draws several citations at once.
Sources
- osha.gov/laws-regs/regulations/standardnumber/1926/1926.1204
- osha.gov/laws-regs/regulations/standardnumber/1926/1926.1202
- osha.gov/laws-regs/regulations/standardnumber/1926/1926.352
Confined-space program, permit, atmospheric-testing order, roles, and rescue duties per 29 CFR 1926.1202/1204/1211 verified against osha.gov on July 21, 2026. Hot-work fire-watch duty per 1926.352(e); the 35-ft/30–60-min figures are NFPA 51B recognized practice, not CFR text. General guidance, not legal advice; State-Plan states may impose additional requirements.
Get the Binder in Order Before the Inspector Arrives. Are You Ready?
OSHA does not give advance notice of inspections (29 CFR 1903.6). Get the binder in order before the opening conference, not during it.
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per violation (max)
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