Safety suggestions relating to ‘Hot work’ – including fires and injuries – in the construction sector and how to reduce the risk from Cesafety via Designing Buildings Wiki, host partner to the IHBC’s Conservation Wiki.
Hot work refers to any task that requires using open flames or applying heat or friction which may generate sparks or heat.
More specifically, it is defined by the British Standards Institution (BSI) in BS 9999 as: “Any procedure that might involve or have the potential to generate sufficient heat, sparks or flame to cause a fire.” Examples of hot work includes welding, flame cutting, soldering, brazing, grinding and the use of other equipment incorporating a flame.
Hot work poses a particular threat within the construction sector as the cause of multiple fires in buildings.
For example, according to figures from the Scottish Fire & Rescue Service, who we contacted with a Freedom Information Request, there were 180 fires in the construction industry in 2018/19, a staggering 143 (79 per cent) of which were the result of hot work.
Fifty-one fires during this period were caused by welding or cutting equipment, 22 by manufacturing equipment and 23 by kilns or other services. These fires resulted in 21 casualties.
The most common examples of hot work and those that can pose significant risks without proper safety precautions are for example:
- Brazing and soldering
- Gas/electric welding cutting apparatus
- Grinding wheels and cutting discs
- Thawing pipes
- Open flames, blow lamps and blow torches
- Bitumen and tar boilers
- Hot air blowers and lead heaters.
A variety of industries, construction in particular, may require hot work to be carried out in their premises as part of routine work activities. It is also frequently carried out as part of contractual work, which is common in construction. However, no matter who does it, they must know what kind of hazards hot work presents and how to prevent it from causing harm.
The fire hazards posed by hot work
Flying sparks are the principal risk posed by hot work and they can easily get trapped in cracks, pipes, gaps, holes and other small opening, where they could potentially smoulder and cause a fire to break out.
The debris and residue which hot work creates, such as flammable swarf, molten metals, slag, cinder and filings, are often combustible.
Hot work can cause pipes to substantially heat up and easily transfer, through the process of conduction, to another flammable surface and cause a fire.
Failure to remove flammable materials or substances from a surface before commencing work means that they could easily become hot and cause a fire.
In certain environments, there may be potentially explosive vapours or gases in the air which are highly combustible and could ignite if exposed to hot work. In a similar vein, hot work could generate fumes which, in turn, create an explosive atmosphere.
The consequences of these hazards can be severe and costly for any business. Injuries can result in workers taking time off work, while a serious fire could damage a building irreparably. Both of these could even lead to legal consequences under certain circumstances. Therefore, it is crucial to understand how to implement appropriate safety controls.
Injuries caused by hot work
There are direct personnel hazards to those involved in the task or those working nearby.
Hot work may cause injuries, such as:
- Skin burns, eye burns and electric shock
- Overexposure to welding or flame cutting fumes
- Personnel working in the area or passing by can be also injured from sparks. Especially if the area is not properly isolated, access is restricted or there is no additional protection such as fire blanket.
Control measures to minimise the risk of hot work fires
Due to the high risk nature of hot work, the BS 9999 and the Health & Safety Executive (HSE) outline various safety procedures which organisations must adhere to. Their aim is to protect workers from dangerous aspects of hot work and to prevent fires from breaking out.
Measures to make hot work safer
BS 9999 states that “hot work should only be undertaken if no satisfactory alternative method is feasible.” Therefore, it is important to consider every possible alternative for completing a task before deciding to proceed with hot work.
For example, instead of welding, determine whether bolting is a suitable solution. In a similar vein, avoid torch cutting by using a handheld hydraulic shears instead.
In some situations, hot work is unavoidable. If this is the case, a permit must be created before the work starts. A permit is crucial as it sets out the safety measures which everyone must follow to minimise the risks associated with the work.
Creating a Hot Work Permit
Due to the level of risk posed by hot work, preparing a hot work permit is mandatory. According to BS 9999 “a hot work permit procedure, which may be part of an overarching safe system of work/hot work permit procedure, should be followed before any hot work is allowed in or near a building. This is to ensure that correct actions are taken before hot work commences, during the operation and afterwards.”
To fulfil this requirement, people need to know how to create a hot work permit.
For background see DBW