Toolbox Talks · Mandatory · Construction

Toolbox Talk — Fire Safety on Site

A toolbox talk on fire safety including escape routes, assembly points, fire extinguisher types, and hot works controls.

Last reviewed: 29 March 2026 — This guide reflects UK law as of this date. RRO 2005 remains current with no amendments enacted as of 29 March 2026. Next scheduled review: 29 March 2027.

Legal basis	Regulatory Reform (Fire Safety) Order 2005 (RRO) + Construction (Design and Management) Regulations 2015 (CDM 2015) + Fire Prevention on Construction Sites: Joint Code of Practice (7th edition)
Why high-risk	Construction sites combine multiple ignition sources, large quantities of combustible materials, incomplete fire detection and suppression systems, unfamiliar layouts, and a transient workforce
Fire triangle	Fire requires three elements: an ignition source (heat, sparks, flame), fuel (combustible materials), and oxygen. Remove any one element and the fire cannot start or sustain itself
Hot works	Hot works (welding, cutting, grinding) are one of the leading causes of construction site fires. A permit to work is required for all hot works outside a designated safe area
RACE mnemonic	Rescue anyone in immediate danger, Alarm — raise the alarm, Contain — close doors to limit fire spread, Evacuate to the muster point
Enforcing authority	Health and Safety Executive (HSE) and Fire and Rescue Service

1. Construction Sites Are High-Risk Environments

Construction sites are inherently high-risk environments for fire. They combine multiple ignition sources — hot works, temporary electrical installations, heating equipment, smoking materials — with large quantities of combustible materials including timber, insulation, packaging, solvents, adhesives, and LPG cylinders. Unlike occupied buildings, construction sites typically lack completed fire detection systems, automatic suppression (sprinklers), fire-rated compartmentation, and permanent means of escape. The workforce is transient, the layout changes daily, and familiarity with escape routes cannot be assumed.

The Regulatory Reform (Fire Safety) Order 2005 (RRO) requires the responsible person to carry out a fire risk assessment and implement appropriate fire precautions. On a construction site, the principal contractor typically holds this responsibility. CDM 2015 reinforces this with the requirement to manage site safety, which explicitly includes fire risk. The Joint Code of Practice on the Protection from Fire of Construction Sites and Buildings Undergoing Renovation (7th edition) — commonly known as the Joint Code of Practice — sets out the industry-agreed standards for fire prevention on construction sites. While not itself law, it represents the standard against which compliance will be judged.

The fire triangle is the fundamental concept underpinning all fire prevention. Fire requires three elements to exist simultaneously: an ignition source (heat, sparks, open flame, electrical arcing), fuel (any combustible material), and oxygen (present in the air). Removing any one of these three elements will prevent a fire from starting or will extinguish one that has already begun. The practical application of this on a construction site means separating ignition sources from fuel, controlling combustible waste, managing hot works through a permit system, maintaining temporary electrical installations, and ensuring that LPG and other flammable gases are stored and used correctly.

RACE — the fire response sequence every worker must know

RACE is the mnemonic for the correct sequence of actions when a fire is discovered. Rescue: if anyone is in immediate danger and it is safe to do so, help them move away from the fire. Alarm: raise the alarm immediately using the site alarm system, air horn, or by shouting “Fire” loudly and repeatedly. Contain: close doors and windows as you leave to slow the spread of fire and smoke. Evacuate: leave the building or site by the nearest safe escape route and proceed directly to the designated muster point. Do not stop to collect personal belongings. Do not re-enter the site until authorised to do so by the fire service or site manager.

2. Key Talk Points

The following table sets out the key points that must be covered in a fire safety toolbox talk. Every worker on site must understand these points, and the talk must reference the specific site arrangements, not generic fire safety principles.

Talk point	What to cover
Know the alarm	Identify the fire alarm signal used on site (continuous siren, air horn, or other). Ensure every worker can distinguish the fire alarm from any other signal used on site. If the site uses a manually activated system (air horns, handheld sirens), confirm who is responsible for raising the alarm and where the activation points are located.
Muster point	Identify the location of the muster point. Walk the evacuation route from the current work area to the muster point if possible. Confirm the roll-call procedure — who takes the roll call, how visitors and subcontractors are accounted for, and what happens if someone is unaccounted for. The muster point must be at a safe distance from the building and not obstruct fire service access.
First aid firefighting	Identify the locations of fire extinguishers on site and the type of extinguisher at each location. Confirm that workers understand the basic types: water (red label) for general combustibles, CO2 (black label) for electrical fires, dry powder (blue label) for mixed risks, and foam (cream label) for liquid fires. Emphasise that first aid firefighting is only appropriate for small fires in the early stages — if the fire has taken hold or is spreading, evacuate immediately.
Hot works permit	Any work that produces open flames, sparks, or heat (welding, cutting, grinding, brazing, soldering, torch-applied roofing) is classified as hot works and requires a permit to work before it can commence. The permit confirms that a competent person has assessed the area, combustibles have been removed or protected, a fire watcher is assigned, and fire extinguishing equipment is in place. No permit means no hot works — there are no exceptions.
Combustible waste	Combustible waste — packaging, offcuts, timber, insulation, rags — must be removed from the work area regularly throughout the day and not allowed to accumulate. Combustible waste provides fuel for fire. On well-managed sites, waste is cleared from each work area before the end of every shift. Skips must not be positioned against the building where a skip fire could spread to the structure.
Temporary electrics	Damaged cables, overloaded circuits, and improvised connections are common causes of electrical fires on construction sites. Report any damaged cables, scorched sockets, tripped RCDs, or burning smells from electrical equipment immediately. Never repair temporary electrical installations yourself — this is the responsibility of a qualified electrician. Only use electrical equipment that has been PAT tested and is in good condition.
LPG cylinders	LPG (liquefied petroleum gas) cylinders must be stored outdoors in a secure, well-ventilated compound at least 3 metres from any building, boundary, or combustible material. Cylinders must be stored upright and secured to prevent them falling. Only the minimum number of cylinders required for the day’s work should be brought into the building, and they must be removed at the end of the shift. LPG must never be stored in basements, cellars, or enclosed spaces below ground level because the gas is heavier than air and will accumulate in low points.
Emergency exits	Escape routes and emergency exits must be kept clear and unobstructed at all times. Materials, equipment, and waste must never be stored in stairwells, corridors, or in front of emergency exits. Emergency exit doors must open in the direction of escape and must never be locked, wedged shut, or blocked from the inside while people are on site. Emergency exit signage must be visible and illuminated where required.

Most construction site fires start outside working hours

A significant proportion of serious construction site fires start after the workforce has left for the day. Smouldering material from hot works, electrical faults in temporary installations, and arson are the most common causes of out-of-hours fires. This is why fire watches must continue for a minimum of 60 minutes after hot works (4 hours where timber is present), why temporary electrics must be isolated at the end of each shift where practicable, and why site security is a critical element of the fire prevention strategy.

3. Common Mistakes

Allowing combustible waste to accumulate

Combustible waste is fuel. Packaging, timber offcuts, insulation material, cardboard, plastic wrap, and solvent-soaked rags are all readily ignitable materials that accumulate rapidly on construction sites. When these materials are allowed to build up in work areas, on access routes, or in skips positioned against the building, the fire load increases dramatically. Good housekeeping is the most basic and most effective fire prevention measure. Combustible waste must be cleared from work areas regularly throughout the day and removed from the site at frequent intervals.

Blocking emergency exits with materials or equipment

Emergency exits and escape routes must be kept clear at all times. Materials, plant, scaffold components, pallets, and waste must never be stored in front of emergency exits, in stairwells, or in corridors designated as escape routes. This is one of the most commonly cited fire safety failures on construction sites and one of the easiest to prevent. A blocked escape route in a fire is not an inconvenience — it is a death trap. Daily checks of all escape routes must be part of the site safety routine.

Not reporting damaged temporary electrical installations

Damaged cables, scorched distribution boards, overloaded extension leads, and improvised connections are common causes of electrical fires on construction sites. Workers often notice these defects but do not report them because they assume someone else has already reported the problem or because they do not want to cause disruption. Every electrical defect must be reported immediately. Damaged equipment must be taken out of service and labelled until it is repaired or replaced by a qualified electrician.

Carrying out hot works without a permit

Hot works without a valid permit to work is one of the most serious fire safety failures on a construction site. The permit system ensures that the area has been assessed, combustibles have been removed or protected, a fire watcher is in place, and fire extinguishing equipment is available. Without a permit, none of these controls have been formally confirmed. Angle grinding is frequently carried out without a hot works permit because workers do not recognise it as hot works — but grinding produces significant sparks and falls squarely within the definition.

Storing LPG cylinders indoors or in enclosed spaces

LPG is heavier than air and will accumulate in low-lying areas, basements, and enclosed spaces where it can form an explosive atmosphere. LPG cylinders must be stored outdoors in a well-ventilated, secure compound separated from the building by at least 3 metres. Only the minimum number of cylinders required for the day’s work should be taken inside, and they must be removed at the end of the shift. Storing LPG in basements or below-ground spaces is never acceptable under any circumstances — a gas leak in a confined low-level space creates an explosion risk that cannot be managed by ventilation alone.

4. Frequently Asked Questions

What does the RACE mnemonic stand for?▾

RACE stands for Rescue, Alarm, Contain, Evacuate. Rescue: if anyone is in immediate danger and it is safe to do so, help them move away from the fire. Alarm: raise the alarm using the site alarm system, air horn, or by shouting. Contain: close doors and windows as you leave to slow fire and smoke spread. Evacuate: leave by the nearest safe escape route and go directly to the muster point. The sequence is important — raising the alarm must happen immediately after any rescue attempt, before you attempt to contain or fight the fire. If at any point the fire is beyond first aid firefighting or your escape route is threatened, skip straight to evacuate.

When should I attempt to fight a fire myself?▾

You should only attempt to fight a fire if all of the following conditions are met: the fire is small and in its very early stages; you have raised the alarm; you have a clear and unobstructed escape route behind you; you have the correct type of extinguisher for the fire; and you have been trained in extinguisher use. If the fire has taken hold, is spreading, is producing thick smoke, involves hazardous materials, or if you are in any doubt about your ability to control it, do not attempt to fight it. Evacuate immediately. Your life is more important than any building or its contents.

How long should the fire watch continue after hot works?▾

The fire watch must continue for a minimum of 60 minutes after the last hot works activity. Where timber framing, insulation, or other materials with slow combustion characteristics are present in or near the work area, the fire watch must continue for a minimum of 4 hours. The Joint Code of Practice recommends additional checks before the site is left unattended, particularly overnight or over a weekend. The fire watcher must be a dedicated person who does not perform other duties during the watch period, must have a clear view of the work area and adjacent spaces, and must have access to appropriate fire extinguishing equipment.

Which type of fire extinguisher should be used for an electrical fire?▾

CO2 (carbon dioxide) extinguishers, identified by a black label or band, are the primary choice for fires involving electrical equipment. CO2 is a non-conductive gas that will not cause further electrical hazard. Dry powder extinguishers (blue label) can also be used on electrical fires but leave a residue that can damage sensitive equipment. Water and foam extinguishers must never be used on live electrical equipment because water conducts electricity and creates a risk of electrocution. If the electrical supply can be safely isolated, a water extinguisher may then be used on the residual fire. In all cases, the electrical supply should be isolated as soon as it is safe to do so.

Generate your Toolbox Talk — Fire Safety on Site on Construction Suite

Construction Suite walks you through every required section with a guided Q&A — built to RRO 2005 — and generates a professionally formatted document in minutes.

Get started free