On site
What is hot works?
Hot works are operations producing heat, sparks or flame — welding, grinding, cutting, soldering and torch-on roofing. They are a leading cause of fire on construction and refurbishment sites.
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<figure>
<img src="https://buildoptix.co.uk/glossary/hot-works/diagram.svg" alt="hot works — diagram from BuildOptix" width="880" height="620" loading="lazy">
<figcaption>
<a href="https://buildoptix.co.uk/glossary/hot-works">What is hot works?</a> — diagram by
<a href="https://buildoptix.co.uk">BuildOptix</a>
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</figure>The fire usually starts somewhere the operative cannot see: in a void, behind a surface, or in material that smouldered for an hour after the work finished.
That delay is why a watch period after the work is part of the control rather than an optional extra, and why closing a permit at the moment the torch goes off defeats the purpose.
Detection in the work area normally has to be isolated to prevent unwanted alarms, and reinstating it is part of closing the permit rather than something to remember later.
What goes wrong in practice
- Permit closed immediately with no watch period.
- Fire detection isolated for the works and not reinstated.
- Combustible material in adjacent voids never checked before starting.