Guides · Fire safety · 4 min read
Fire watch during hot work: making welding, grinding and soldering safe
For welding, cutting and soldering work, the work permit usually requires a fire watch with a follow-up check. Duties, duration and typical mistakes.
In short: Hot work is among the most common causes of fire in businesses and on construction sites. In areas at risk of fire, a permit and, as a rule, a fire watch during the work and a follow-up check afterwards are therefore required.
What counts as hot work
Welding, flame cutting, cut-off grinding, soldering, thawing and hot-melt gluing – in other words, anything that produces sparks, flames or high temperatures.
Tasks of the fire watch
- Observe the work area and its surroundings, including adjacent rooms and floors
- Keep suitable extinguishing agents ready and intervene immediately
- Check that combustible materials have been removed or covered
- Keep checking after the work ends – smouldering embers often ignite only hours later
How long does the follow-up check last?
This is set by the permit. Several hours with patrols at fixed intervals are usual; for concealed cavities or insulation, longer monitoring may be necessary.
Typical mistakes
- Underestimating flying sparks – sparks travel many metres
- Neighbouring rooms and openings not checked
- The fire watch has other duties on the side
- No follow-up check after the end of the working day
The permit
Outside fixed welding workstations, work involving fire hazards may only be carried out with the written permission of the client. The permit records where and when work is carried out, what hazards exist and which protective measures apply before, during and after. It also names the fire watch and the duration of the follow-up check. Nobody should pick up a torch without a signed permit.
Before work starts
- Remove combustible materials in the surrounding area; cover anything that cannot be moved with non-combustible blankets
- Seal openings, joints and penetrations in walls, ceilings and floors
- Switch off smoke detectors in the work area in agreement with the operator – and switch them back on afterwards
- Provide suitable extinguishing agents: fire extinguisher, fire blanket, and if necessary a connected hose
- Check adjacent rooms and the floor below
Sparks and glowing droplets fly and roll further than you think – ten metres or more are not unusual, and through openings they reach other rooms and floors too.
During the work
The fire watch positions themselves so that they can see the work area and the surrounding area at risk. They keep the extinguishing agent within reach, know the nearest manual call point and the way outside, and stop the work if the situation changes. The welder can barely see what is happening behind them through the protective shield and shower of sparks.
After the work
Many fires after hot work do not break out immediately but only after the working day has ended: a spark smoulders in insulation, dust or a cavity until it gets enough oxygen. That is why the fire watch stays on site after work has finished and checks the work area and neighbouring rooms at fixed intervals, including by hand on walls and ceilings to feel for heat. The permit specifies how long this lasts.
Particularly critical work locations
- Flat roofs with bitumen membranes and insulation
- Timber-beam ceilings and old roof structures
- Ventilation ducts, shafts and false ceilings
- Storage areas with cardboard, plastics or solvents
- Rooms with dust deposits
Your own people or an external fire watch?
The fire watch must not have any other task. On many building sites there is simply no free person for this, least of all for the follow-up check after the end of the working day. An external fire watch takes on both and documents every inspection round. For what applies when a fire alarm system fails, see the guide Fire alarm system out of order.
Frequently asked questions
Who issues the permit?
The client or operator, that is, the person responsible for the work location, not the contractor alone.
Is a fire watch needed for every welding job?
No. Not at fixed welding workstations set up for that purpose. In areas with a fire risk, the permit specifies whether a fire watch is provided and for how long.
Is a fire extinguisher nearby enough?
It is necessary but does not replace the fire watch. What matters is that someone notices the fire early and intervenes immediately.
Matching service: Fire watch from Pandemedics – quote within 2 hours on working days.
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