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Construction Site Fire Safety UK: Rules & Duties

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Written by Brad Askew Solicitor (non-practising)
Brad is on the roll of solicitors of England & Wales but does not hold a practising certificate and does not provide legal advice.
Updated June 2026 · England & Wales
Construction sites carry some of the highest fire risks of any working environment. Hot works, timber, flammable liquids, temporary wiring, and an ever-changing layout all combine to create conditions where a small ignition can escalate quickly. On top of that, sites are often occupied by people who change day to day, which makes communication and training harder than in a settled workplace. This guide sets out, in plain terms, how UK fire safety law applies to construction sites, who carries the legal duties, and what practical steps those running a project are expected to take. It covers the core legislation, the role of the responsible person, how risk assessments should work in a live build environment, and the common pitfalls that tend to attract enforcement action.

Overview

Fire safety on a UK construction site is governed by a mix of general workplace fire law and construction-specific health and safety duties. The two main pillars are the Regulatory Reform (Fire Safety) Order 2005 and the Construction (Design and Management) Regulations 2015.

Together, they require whoever has control of a site to identify what could catch fire, reduce those risks so far as is reasonably practicable, plan how people will get out if something goes wrong, and keep those arrangements under review as the site changes. Because construction projects evolve week by week, fire safety is not something that can be signed off once and forgotten.

Scaffolding goes up, compartmentation is breached, new materials arrive, and subcontractors come and go. The law expects these arrangements to move with the site, with responsibilities clearly allocated between the client, principal contractor, principal designer, and other contractors working on the project.

Key steps

  1. Identify who holds the legal duties. Work out who the 'responsible person' is under the fire safety order and who is acting as client, principal designer, and principal contractor under CDM 2015. On most commercial builds this will include the developer, the main contractor, and any subcontractor with control over part of the site. Write the allocation down so there is no doubt.
  2. Carry out a site-specific fire risk assessment. A generic template will not do. The assessment should cover ignition sources such as hot works and temporary heating, fuel sources including timber, packaging, fuels and flammable liquids, means of escape for everyone on site, detection and warning arrangements, and how the fire service would access the site in an emergency. Record it and revisit it regularly.
  3. Put control measures in place. This usually means hot works permits, safe storage of flammable materials away from escape routes, housekeeping rules to manage waste and packaging, clearly marked and maintained escape routes, suitable extinguishers, and a means of raising the alarm that can be heard across the whole site. Temporary accommodation and welfare units need their own arrangements.
  4. Train and brief everyone on site. Fire safety induction should form part of the standard site induction, with refresher briefings when the layout or risk profile changes. Cover the alarm signal, escape routes, muster points, and who to report concerns to. Keep a record of who has been inducted, and make sure visitors and delivery drivers are not overlooked.
  5. Monitor, record and update. Inspect the site regularly, check extinguishers and alarms are in working order, and update the risk assessment whenever the build reaches a new phase or something significant changes. Keep paperwork tidy, because inspectors from the Health and Safety Executive or the local fire and rescue authority will expect to see it.

Common questions

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Common questions

Q Who is the 'responsible person' on a construction site?
Under the Regulatory Reform (Fire Safety) Order 2005, the responsible person is whoever has control of the premises in connection with their trade or business. On a live construction site this is usually the principal contractor, though the client and individual subcontractors can also hold duties for areas under their control. More than one party can be a responsible person at the same time.
Q Does the fire safety order apply during construction, or only once the building is finished?
It applies throughout the construction phase, not just to the finished building. As soon as people are working on site, there are duties to assess fire risks, provide means of escape, and give staff appropriate information and training. The specific measures will change as the build progresses, which is why the risk assessment needs to be kept under review.
Q What role do the CDM 2015 Regulations play in fire safety?
The Construction (Design and Management) Regulations 2015 require fire risks to be considered from the earliest design stages through to completion. Designers must reduce foreseeable fire risks where reasonably practicable, and the principal contractor must plan, manage and monitor the construction phase, including fire precautions. Fire safety should be addressed in the construction phase plan.
Q Do I need a written fire risk assessment?
If five or more people are employed, the significant findings of the fire risk assessment must be recorded in writing. In practice, any construction project of meaningful size should have a written assessment regardless, because it is the main piece of evidence that duties under the fire safety order are being met if something goes wrong or an inspector visits.
Q What are the main fire risks on construction sites?
The most common risks are hot works such as welding and cutting, temporary heating, smoking, electrical faults in site power and lighting, flammable liquids and gases, accumulated waste and packaging, and timber-framed construction before fire-stopping is complete. Arson is also a recognised risk on sites that are not properly secured out of hours.
Q Who enforces fire safety law on construction sites?
The Health and Safety Executive is generally the main enforcing authority on active construction sites. Local fire and rescue authorities also have powers under the fire safety order, particularly where parts of a building are occupied or handed over in phases. Penalties for serious breaches can include unlimited fines and, in the worst cases, imprisonment.
Q What should a site fire plan include?
A site fire plan typically covers the alarm and detection arrangements, escape routes and muster points, location of extinguishers, hot works controls, storage of flammable materials, emergency contact details, and access for the fire and rescue service. It should be site-specific, updated as the build progresses, and communicated to everyone working on site.
If you're dealing with this kind of situation, a call with an experienced legal adviser can help you work out the right next step — from £89.

Sources

This guide is based on primary UK law and official guidance.

Brad Askew, Solicitor (non-practising)

Written & reviewed by

Brad Askew Solicitor (non-practising)

Brad is on the roll of solicitors of England & Wales but does not hold a practising certificate and does not provide legal advice. LegalDocuments.co.uk is not a law firm and does not provide regulated legal advice.

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Legal disclaimer
This article is for general information only. It is a tool to help you find your way — not legal advice, and not a substitute for speaking to a qualified adviser about your situation.