Fire watch (hot work)
Fire watch is the supervised post-hot-work observation period (typically 60 min) after torch-on membrane, grinding, cutting, or welding near combustibles.
Ask Chalkline about this →A fire watch is the supervised post-hot-work observation period required after torch-on membrane application, cutting, grinding, or welding near combustible substrates. A designated person stands watch with a charged extinguisher to hand, watching for smouldering ignition that can flare into a fire long after the tool has been put down.
When fire watch is required
- Torch-on membrane application (modified-bitumen rolls heated and bonded with an LPG torch).
- Angle-grinding generating sparks near timber, paper-faced plasterboard, or insulation.
- Welding and oxy-cutting in any non-clear area.
- Heat-shrink wrap of plumbing insulation or fittings.
Each of these can leave a smouldering ember in a hidden cavity that takes 20 to 60 minutes to develop into open flame.
Protocol
- 60 min minimum typical; longer for torch-on near voids.
- Designated person with assigned watch role (not the operator).
- Charged water + dry-powder extinguisher within arm’s reach.
- Line-of-sight of all heated/cut surfaces and adjoining cavities.
- Smoke = immediate extinguish + supervisor call.
SWMS and insurance
Construction-works insurers typically condition cover on a fire-watch for hot-work activities. Hot-work SWMS names the watch person, duration, and equipment.
For a builder
- Schedule the watch into the day. Torch-on at 3 pm = watch until 4 pm minimum.
- Pair watcher with right extinguisher. Water for combustibles; dry-powder for fuel/electrical; never water on live electrical.
- Log the watch. Daily site log = insurer-claim defence.
Category: WHS / hot work.
Related
See also
Last updated: 2026-05-29. Verified: 2026-05-29. Quarterly review for currency.