How to Write a Fire Risk Assessment

A fire risk assessment for construction and site work sits across two pieces of legislation. Where a building or premises is occupied or managed, the **Regulatory Reform (Fire Safety) Order 2005 (RRO)** places a duty on the Responsible Person to carry out and maintain a suitable and sufficient fire risk assessment. For the contractor's own task — the activities that generate ignition risk — the duty derives from **Management of Health and Safety at Work Regulations 1999 (MHSWR), Regulation 3**, which requires every employer to carry out a suitable and sufficient assessment of the risks to employees and others. Where flammable or explosive atmospheres are a possibility, the **Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR)** also apply and require classification of hazardous zones.

These are not interchangeable: the RRO addresses the premises and its occupants; MHSWR and DSEAR address the task and the worker. A thorough fire risk assessment for a construction activity typically needs to satisfy both.

The Five Steps

The HSE and the Fire Safety Order both endorse a five-step process: identify fire hazards; identify people at risk; evaluate the risk and reduce it; record findings and emergency arrangements; review and update when circumstances change.

Key Hazards and Controls — Hierarchy Order

**Identify the fire triangle.** Ignition, fuel, and oxygen must all be present for fire to occur. Controls should aim to remove or separate at least one element.

**Eliminate or substitute first.** Before introducing any ignition source, consider whether the task can be redesigned. Hot-works cutting can sometimes be replaced with cold-cut mechanical methods, removing the ignition hazard entirely. Water-based or low-flammability materials should be substituted for flammable solvents where practicable.

**Engineering controls.** Where hot works cannot be avoided, the area must be cleared of combustible materials to a minimum safe radius before work begins. Fixed or temporary fire-suppression systems, local exhaust ventilation to prevent accumulation of flammable vapours, and physical barriers (fire blankets, fire-rated enclosures) are all engineering measures applied before relying on human action.

**Administrative controls.** A **hot-works permit** is mandatory for any task involving open flame, grinding, or cutting near combustible material. The permit must specify the work location, duration, precautions in place, and the name of the competent person authorising the work. A **fire watch** must be maintained throughout the works and for a minimum period after completion — typically 60 minutes, though the risk assessment must justify the specific period based on the materials present. Site induction, training in fire emergency procedures, and clear communication of escape routes are also administrative measures.

**PPE last.** Fire-retardant clothing and gloves are a last-resort supplement, not a substitute for the controls above.

Means of Escape and Detection

The assessment must confirm that means of escape are maintained and unobstructed at all times, including during the works. On construction sites this is a dynamic consideration — hoarding, scaffold, and stored materials can block escape routes inadvertently. Smoke detection appropriate to the environment must be in place, and the alarm system must be audible in all occupied areas, including temporary welfare facilities.

Extinguishers must be selected to match the classes of fire risk present (Class A for solid combustibles, Class B for flammable liquids, CO2 for electrical equipment) and must be within the travel distances specified in the relevant guidance.

Common Failings That Lead to Rejection

- Generic or template assessments not tied to the specific site, task, or phase of work. - Hot-works permits referenced but not attached or not yet issued at the point of submission. - No fire watch duration specified, or fire watch limited to the duration of the works only, ignoring smouldering risk after cessation. - Escape routes described as "existing building routes" without confirming they remain accessible during the construction activity. - Extinguisher types listed without confirming they match the actual fire classes present. - No named Responsible Person or competent assessor identified.

What the Document Must Include

The completed fire risk assessment must contain: the scope and location of the works; identification of ignition sources, fuel sources, and the people at risk (including site operatives, building occupants, and members of the public); the controls applied in hierarchy order; details of the hot-works permit system; fire watch arrangements with timings; means of escape and assembly point; detection and alarm provision; type and location of extinguishers; emergency contact information; the name and competency of the assessor; and a review date or trigger event (such as a change in scope or fire incident).