Hot work fires on construction sites are on the rise, but safety steps can be taken to mitigate risk, says Ian McKinnon.
The British Standards Institute (BSI) defines ‘hot work’ in BS 999 (1) as “any procedure that might involve or have the potential to generate sufficient heat, sparks or flame to cause a fire”.
It includes welding, flame cutting, soldering, brazing, grinding and the use of other equipment incorporating a flame, such as tar boilers.
Combustible materials can be ignited by a stray spark and harm people and damage buildings. Indeed, more than a quarter of accidental fires on construction sites are sparked by ‘hot work’, according to insurer Zurich. It is therefore vital that your workplace establishes a suitable safe working system for hot work before people carry it out.
Know the risks
Insurer Zurich says 15 per cent of the total cost of all UK fires in commercial and industrial properties involve hot work.
Fire hazards posed by hot work include flying sparks; heat conduction when working on pipes; flammable swarf, molten metals, slag, cinder and filings; hot surfaces; and explosive atmospheres.
Areas of particularly high risk include torch-applied roofing, where there are roof voids present and work such as angle grinding close to combustible materials.
BS 9999 states that “hot work should only be undertaken if no satisfactory alternative method is feasible”. Every possible alternative for completing a task should therefore be considered before deciding to proceed with hot work. When hot work must be undertaken, follow these steps.
1. Secure your hot work permits
Issued for a maximum of one day by a competent and authorised person before work begins, the permit details:
- Who will carry out the work (staff or contractors);
- What the work will involve;
- Hazards identified and actions taken to remove them (e.g. flammable liquids, combustible materials);
- Fire watch procedures;
- Site inspection procedures; and
- Emergency procedures.
The permit system provides a formal means of recording findings and authorisations required to undertake hot work. It is an extension of the safe system of work – it does not, by itself, make the job safe.
Use a contractor who is accredited by a recognised health and safety scheme such as the Contractors’ Health and Safety Assessment Scheme.
2. Be compliant
Guidance from the Health & Safety Executive (HSE) details many of the areas seen on checklists for hot work permits. For example, on the importance of good housekeeping with regard to welding (4), the HSE says to clear away flammable material before starting a welding job as heat, sparks and drips of metal can start fires.
The HSE also says that if work cannot be carried out in a safe area or combustible material cannot be removed, a fire watch should be maintained during and up to 30 minutes after hot work. Where an unintended ignition may be difficult to detect or slow to develop, increase this to 60 minutes.
3. Install thermal imaging cameras
Organisations looking to go above and beyond compliance should use thermal imaging cameras, which cost as little as £400 and could detect more hot spots before they ignite. The devices can also be used to take time-stamped photos to demonstrate fire watches have been carried out.
Zurich is pressing for a voluntary licensing system for contractors. Before carrying out or supervising hot work, contractors would complete a one-day training course, giving them a licence valid for five years.
Scandinavian countries have had a similar ‘passporting’ approach in place since the 1980s, which is said to have significantly reduced hot work fires to less than 5 per cent of fire losses over the last decade.
The Fire Protection Association offers a hot work passport scheme in the UK. It is designed for supervisors and operatives who carry out risk assessments to complete hot work permits.
More than 2,850 hot work passports have been issued to date and these are valid for five years from the date of completion.
Ian McKinnon is managing director at supply chain risk management firm CHAS