Sheet 29Mix-up sheet · Electrical safety, lockout and hot work
Hot work: combustibles first, then the fire watch
29 CFR 1926.352 sets the order for hot work in construction: move the work away from combustibles, or move the combustibles away from the work, and shield them only when neither can move. A fire watch comes in when those steps still leave a fire risk, and it stays for a sufficient period after the work ends. The construction rule gives no fixed number of minutes.
29 CFR 1926.352 beside the general-industry rule and NFPA 51B, as of October 2026scroll →
Point
Construction, 1926.352
General industry and NFPA 51B
Watch after the work
A sufficient period to catch smoldering fires
At least 30 minutes
Distance to combustibles
No set radius: move them or shield them
35 ft radius sets off the precautions
Extinguisher
Immediately available in the work area
Immediately available in the work area
A site may adopt 30 minutes or longer as its own rule. Where the construction standard is the measure, the 1926 wording is the one that counts.
≠ marks the rows where the two differ.
Talking point 02
Why moving beats covering
Sparks and slag travel well past the welder's line of sight, and fire-resistant covers shift, tear and leave gaps at the seams. Distance takes the fuel out of the problem, while a cover only stands between the two. That is why 1926.352 starts with moving something and treats guards and shields as the fallback for what cannot move.
Read from the top. Each band is what you fall back on when the one above cannot be done, 29 CFR 1926.352.scroll →Talking point 04
A permit describes one place
The construction standard sets precautions rather than a permit form, and hot work permits are a site practice, often modeled on NFPA 51B. The logic follows the standard: someone looks over the specific spot for combustibles, floor openings and neighboring work before signing. A different spot has different fuel and different paths for sparks, so the signature on the first one no longer describes it.
Talking point 05
Checks at the cutting spot
Combustibles moved, or the work moved, and anything left shielded with fire-resistant guards.
An extinguisher in the work area and ready to use.
Drums, tanks and other containers that held flammable material cleaned and vented before heat touches them (29 CFR 1926.352(i)).
Oxygen and fuel-gas cylinders in storage kept 20 ft apart, or separated by a noncombustible barrier 5 ft high rated for half an hour.
Oxygen never used to ventilate a space or blow dust off clothing.
Talking point 06
Hot work, card by card
Several cards offer a precaution that is sound but comes too late in the order. Look for the step that belongs first.
Card 1 of 6 · 0 right
Card 1
Before a welder cuts a steel bracket on a deck littered with wood scraps and form lumber, what is the FIRST fire-prevention step the supervisor should require under OSHA construction rules?
Pick an answer. A short note for each option, A to D, appears here.
AFire-resistant covers are the fallback when neither the work nor the combustibles can be moved, not the first step.
BA fire watch supports the job but responds to fire rather than removing the fuel, so it does not come first.
CCorrect: the construction hot work rule first calls for moving the object being cut, or the fire hazards, to a safe place.
DAn extinguisher must be at hand, but it only responds to a fire and does not separate sparks from combustibles.
Card 2
A welder must cut a steel embed next to wood formwork that cannot be moved. The area is congested with other trades. What should the supervisor require before cutting starts?
Pick an answer. A short note for each option, A to D, appears here.
AAn extinguisher is required nearby but only responds to a fire, leaving the forms unprotected from sparks and slag.
BWetting helps only briefly, and a welder focused on the cut will miss sparks that land behind or below.
CA toolbox talk and signatures build awareness but neither shield the formwork nor assign anyone to watch for fire.
DCorrect: combustibles that cannot be moved must be shielded with fire-resistant guards, and a fire watch covers the congested area.
Card 3
A plumbing crew plans to solder copper pipe in a room where the painting contractor is spray-applying a solvent-based primer. What should the supervisor do FIRST?
Pick an answer. A short note for each option, A to D, appears here.
ACorrect: torches must not operate where spraying creates flammable vapor, so the supervisor separates the two activities in time or space.
BOpen windows may dilute vapors but do not verify the room is below a flammable concentration before torches are lit.
CA fire watch reacts after ignition and cannot prevent a flash fire in a vapor-laden room.
DSwitching to rollers reduces new vapor but leaves the solvent vapor from spraying in the room.
Card 4
Laborers working near an arc welding station complain of eye irritation from the arc's glare. What is the BEST control?
Pick an answer. A short note for each option, A to D, appears here.
ACorrect: Arc welding should be shielded by noncombustible screens wherever practicable, an engineering control that protects everyone in the area at once.
BClear safety glasses do not block the arc's ultraviolet glare, which needs filtered protection or screening.
CTelling workers not to look depends on each person remembering, and reflected glare still reaches them.
DWelding helmets for every nearby laborer are impractical for their tasks and leave the arc unscreened.
Card 5
A welder wants to roll an oxygen cylinder and an acetylene cylinder to the next bay with the regulators still attached, to save setup time. They are not on a cylinder cart. What should the supervisor require?
Pick an answer. A short note for each option, A to D, appears here.
AClosed valves still leave the regulators exposed. A regulator knocked off a full cylinder can turn it into a projectile.
BCorrect: Unless the cylinders ride on a carrier made for them, the regulators come off and the valve caps go on before moving.
CCylinders should stay upright. Rolling them on their sides risks valve damage and loss of control of a heavy load.
DTying them together does not protect the regulators, and the pair can topple as one heavy, unstable load.
Card 6
A fire watch is needed for torch cutting near combustible formwork that cannot be moved. What should the supervisor confirm about the worker assigned to it?
Pick an answer. A short note for each option, A to D, appears here.
ACorrect: Workers assigned to a fire watch are instructed in the specific fire hazards of the job and in using the firefighting equipment provided.
BWelding skill is not what the watch is for. The watch's job is to spot and put out a fire.
CPermit authority is an administrative role. It does not prepare someone to fight a fire at the cut.
D1926.352 asks for instruction in the hazards and the equipment, not a competent-person designation.
Talking point 07
How long the watch stays, and permits
How long does a fire watch last after hot work in construction?
29 CFR 1926.352(e) keeps the watch for a sufficient period of time after completion of the work to ensure that no possibility of fire exists, without a number of minutes (as of October 2026). The 30-minute figure comes from the general-industry rule and NFPA 51B.
Is a hot work permit an OSHA requirement in construction?
1926.352 lists precautions rather than a permit. A permit system is a site practice that records the inspection those precautions depend on, and many contractors require one.