Hot work: the fire regulations behind the gas torch

When you light the gas burner to weld roofing paper you perform what insurance and fire protection calls hot work: work processes with or producing flames sparks or flammable heating. Roofing is specifically mentioned as one of the typical examples. It's no coincidence — fires from roof work over the years have cost buildings and companies dearly so a fixed system of rules and routines has been built around the work.

§The framework: DBI's fire engineering guidance 10

In Denmark it is the Energy Agency that administers the frequency plan and sets what frequency bands can be used for what.

§Certificate and agreement form — the papers must be in order

The one who carries out hot work must either have hot work as part of their vocational training or have completed a hot work course with a valid certificate. The course includes practical fire extinguishing — in other words you must have had an extinguisher in your hand yourself, not just watched a video. In addition a contract form must be filled out and signed before work begins.

• 01The agreement form is signed by the building owner or his representative (client), the executing company/person and the fire watch.
• 02The form describes the work place, the nature of the work and the fire safety measures that have been agreed.
• 03All parties must know the safety requirements in BtV10 – the form is also a checklist that forces you to review the risk together.
• 04Without a signed agreement insurance coverage may be at risk if fire occurs.

§Before you turn on: clear, cover, and have extinguishing equipment ready

Most roof fires can be prevented before the flame even ignites. Flammable material in and around the work area must be removed or covered, and you must be especially careful with hidden cavities: roof eaves, overhangs, linings and penetrations where sparks and heat can penetrate to old, dry wood and bird nests. Fire extinguishing equipment must be ready at the work site — according to the guide, there can be a maximum of 25 meters on the same level from the work site to the fire extinguishing material, and any hose reels must be rolled out and water-filled before work begins.

§Before and after: the fire watch's role.

During the work there must be supervision of sparks and heat exposure. When the hot work is completed fire watch must be kept for at least one hour with rounds—typically at 10-15 minute intervals—where you check the work area and adjacent cavities for smoke heat and odor. For special risks such as protected and heritage buildings post-inspection is typically tightened to up to two hours. The fire watch must be instructed in the task know the work area and be able to operate extinguishing equipment—and confirms on the agreement sheet on par with the executor.

§Can open flame be avoided?

Yes – and development is going that way. With details close to flammable materials, at roof edges and on buildings where open flame is directly prohibited, roofers increasingly use hot air units and heat guns or self-adhesive membranes where welding occurs without flame. It doesn't remove the need for care – hot air can still ignite – but it significantly reduces the risk. A skilled roofer knows both techniques and chooses the method based on the substrate, not on habit.

“The cheapest fire is the one that never starts. An hour of fire watch costs nothing compared to a burnt-out top storey.”

— Old roofer rule of thumb, entirely in line with BtV10