Welding Near Flammable Materials

Welding near flammable materials is one of the most common causes of fire on construction sites.
Sparks, spatter, and hot slag from welding can travel up to 10 metres and ignite combustible materials.
Flammable materials include timber, insulation, solvents, paint, plastic sheeting, and accumulated dust.
A hot works permit is mandatory before any welding takes place near combustible or flammable materials.
A fire watch must be maintained during welding and for a minimum of 60 minutes after work stops.
Timber frame buildings, occupied buildings, and roofing projects are particularly high-risk environments.
Fire blankets and spark-proof screens should be used to contain sparks and protect adjacent materials.
A suitable fire extinguisher must be positioned within arm's reach of the welding operation at all times.
The Regulatory Reform (Fire Safety) Order 2005 requires fire risk management for all hot works activities.
Insurers typically impose specific hot works conditions — non-compliance can void fire insurance cover.

Prevent site fires	Welding sparks ignite flammable materials causing devastating fires that destroy buildings and kill workers.
Legal requirement	The Fire Safety Order 2005 and site fire risk assessments require formal hot works controls and permits.
Insurance compliance	Most insurers require hot works permits and fire watch procedures — breach can void the site fire insurance.

Do

Don't

Obtain a hot works permit before welding anywhere near flammable or combustible materials
Remove or cover all flammable materials within 10 metres of the welding operation
Position fire blankets or spark-proof screens to contain sparks and hot spatter
Keep a suitable fire extinguisher within immediate reach during all welding activities
Maintain a fire watch during welding and for at least 60 minutes after completion
Check below, behind, and above the work area for hidden combustible materials
Seal gaps in floors, walls, and penetrations where sparks could reach concealed spaces
Brief the fire watch person on their duties and the location of firefighting equipment
Inspect the hot works area again at the end of the shift for any signs of smouldering
Record all hot works on the permit including the fire watch completion time

DON'T weld near flammable materials without a valid hot works permit in place
DON'T assume sparks will not reach flammable materials — they travel up to 10 metres
DON'T leave the fire watch post early — maintain for the full 60 minutes minimum
DON'T rely on nearby fire extinguishers — bring one to the immediate work area
DON'T weld above open containers of solvents, paints, adhesives, or flammable liquids
DON'T forget to check behind walls and under floors where sparks can reach unseen
DON'T allow accumulations of sawdust, packaging, or plastic near welding operations
DON'T carry out welding on timber frame structures without a site-specific fire plan
DON'T leave hot slag or spatter on the floor where it can smoulder unnoticed
DON'T treat the fire watch as optional — it is a permit condition and insurance requirement

See also: Hot Works Fire Prevention | Fire Safety Awareness on Site

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