What Is Hot Work? (Definition, Risk And How To Control It)

Hot work is dangerous work. It introduces new risks to your workplace that need to be managed. Hot work may be permanent, or temporary. But whenever, and wherever, it happens - it needs to be controlled.

So what is hot work?

Is it work in hot weather?
Work in hot temperatures?
A task or activity where you work up a sweat?

No, no and no.

These are examples of work that makes you hot, but that's not the definition of hot work.

Hot work is any activity or process that generates a source of ignition - this could be through a flame, heat or a spark.

Hot work examples

Hot work can be direct where the equipment or tool creates a flame or produces heat - e.g. welding or using a blow torch. Other times hot work may be indirect - e.g. using an abrasive wheel to cut metal which creates sparks.

Hot work is any process that generates flames, sparks or heat. It includes welding, cutting, grinding and sawing.

Examples of hot work include:

• Welding
• Flame-cutting
• Bitumen boilers
• Soldering
• Torching
• Brazing
• Grinding
• Sawing
• Drilling
• Use of disc cutters
• Use of an open flame

Using hot work techniques in your workplace needs careful consideration. While some of these tasks might like everyday activities, they can introduce serious, sometimes fatal, risks.

Hot work risks

Hot work is dangerous because it generates a source of ignition which can introduce a risk of fire or explosion.

Hot work can be deadly. At Dusseldorf Airport in 1996, hot work caused a fire that resulted in hundreds of injuries and 17 deaths.

Fires and explosions caused by hot work have claimed the lives of many workers over the years. The risks have been known for many years but accidents still happen and people are still getting killed.

When hot works go wrong, it can also be costly. A report by Zurich on hot work insurance claims reported handling cases with loss estimates of up to £20m.

Cutting or welding an empty tank or pipe might seem safe if you're using the equipment correctly. But what did it contain before? Was it flammable? Are there any residues? Just a teaspoon of fuel in a tank can be enough to cause an explosion when heated up and turned into vapour.

Controlling hot work

To manage the risks, hot work needs to be controlled. Not just during the activity, but before and after as well. Every workplace is different, and a risk assessment should be carried out to check it is safe to carry out hot work in the environment.

Consider what other work is being carried out in the workplace, the presence of flammable substances, the training of the operative and the condition of the equipment.

A hot work permit should be used as a further control measure, especially in workplaces not designed for hot works.

For example, when hot work is carried out during a construction project or as part of maintenance work, a hot work permit will ensure a series of checks are made before authorising any hot work to start.

Some work areas are especially high risk for hot work. Like confined spaces, or places where flammable substances are or have been stored. It's always worth looking at alternative options before planning hot work.

Before hot work

A careful assessment of the work area should look to identify and remove or cover any combustible materials. This could be floor coverings, fixtures or fittings. Look for gaps in the floor or walls, where sparks could escape into other areas.

There should be no flammable substances (in liquid or vapour form) where hot works happen. Dust can also create flammable atmospheres and increase the risk when completing hot work.

Before hot work:

• Check equipment
• Check workers have suitable training and competence
• Check that the correct fire extinguishers and extinguishing media are present in the work area
• Remove or cover combustible materials
• Remove flammable substances
• Issue a hot work permit

During hot work

Even if it's safe to start hot work, don't assume that things won't change. What if someone moves the fire extinguisher or the worker places hot equipment down on an unprotected surface?

Regular checks, or even supervision in high-risk areas, will help you spot problems before things go wrong.

During hot work:

• Keep firefighting equipment in an accessible location
• Ensure and maintain suitable ventilation
• Use insulating bases where necessary
• Use non-combustible screens to contain sparks
• Remove empty cylinders when used
• Only work while the hot work permit remains valid

After hot work

After hot work is finished, the risk hasn't gone. Although you might think the hazard has been removed.

Fires can take a while to start, and sparks can remain burning for some time after you are done. A fire watch is an important precaution to take once hot work is completed.

The fire watch is usually carried out for 60 minutes after the work is done, depending on the type of hot work, with further checks up to 120 minutes. Never sign off a hot work permit until the fire watch has been carried out.

After hot work:

• Remove equipment to safe storage
• Carry out fire watch for the duration specified in the risk assessment and/or hot work permit
• Sign of completion of the hot work permit

Some work areas are especially high risk for hot work. Like confined spaces, or places where flammable substances are or have been stored. It's always worth looking at alternative options before planning hot work.

What is a hot work permit?

A hot work permit is a documented process that allows hot work to take place in a controlled way.

There will always be at least two people involved in a hot works permit.

1. The permit issuer (the supervisor)
2. The permit receiver (the worker)

This gives you a second pair of eyes to make sure that all the necessary safety measures are in place when work starts, and that the area has been made safe when the hot work finishes.

The permit issuer will only issue a permit for a specific hot work task, on a specific day and time, so that each time hot work happens, a new permit must be issued, meaning new checks and precautions will be put in place.

If the hot work needs to continue beyond the timeframe the permit issuer has agreed, the worker will need to request an extension or a new permit. The permit issuer can then check if it is safe (considering the task, area, and other works happening) for the hot work to continue.

Find out more about permits to work and what they are used for in The Purpose Of A Permit To Work System blog post.

Alternatives to hot work

Because it's high-risk, if you can eliminate hot work from your workplace, you should.

For example, it might be safer (and cheaper) to replace items, rather than use hot work to repair them. Or to get pre-fabricated items manufactured off-site in a factory to the correct size so you don't need to cut them.

Other methods like cold cutting with high-powered water jets can reduce or remove heat from the process altogether.

Alternative methods like cold cutting or prefabrication might not eliminate all risks. Cold cutting can introduce other risks and still needs to be carried out safely. Prefabrication may just move the risks to another, albeit more controlled environment.

But you don't need to eliminate all risks - you need to reduce them as low as reasonably practicable (ALARP).

If using an alternative to hot work is an option and a safer option that reduces the residual risk of an activity, then it's an option you should be taking.

Need to control hot work in your workplace? Use the hot work risk assessment and hot work permit to manage the work, and the hot work toolbox talk to raise awareness of the risks.