If your business commissions maintenance, refurbishment, or construction work on its premises, you will almost certainly encounter the term hot works permit at some point.
It is one of the most important documents in any fire safety management system, and one of the most frequently overlooked.
Understanding what a hot works permit is, why it is needed, and what it should contain could be the difference between a safe, well-managed works programme and a catastrophic fire.
What is a Hot Works Permit?
A hot works permit, sometimes referred to as a hot work permit to work, is a formal written authorisation for a specific activity that involves the use of heat, flame, or sparks.
It is a document that sets out what work is to be carried out, where it is to be carried out, who is authorised to carry it out, what precautions must be in place before work commences, and what checks must be completed after the work is finished.
It is not simply a form to be filled in and forgotten.
It is a live safety management tool that must be actively used, monitored, and enforced throughout the duration of the works.
What Activities Require a Hot Works Permit?
Any activity that generates sufficient heat, sparks, or flame to ignite combustible materials should be subject to a hot works permit.
This includes welding, both arc and gas welding, cutting and grinding with angle grinders or disc cutters, brazing and soldering, the use of blowtorches and heat guns, the use of bitumen boilers and tar kettles during roofing works, the use of lead melting equipment, and any other activity that generates open flames or significant heat in a building or on a construction site.
It also includes activities that may not immediately appear to be hot works but that carry a significant ignition risk, such as the use of petrol-powered equipment in enclosed spaces, the use of gas-powered equipment near combustible materials, and certain types of electrical testing and commissioning work.
If there is any doubt about whether an activity requires a hot works permit, the answer should always be yes.
Why Are Hot Works So Dangerous?
Hot works are responsible for a significant proportion of serious fires in commercial, industrial, and heritage buildings across the United Kingdom every year.
The Health and Safety Executive and fire and rescue services consistently identify hot works and contractor activity as among the leading causes of fire in non-domestic premises.
The reasons for this are well understood.
Hot works generate sparks, spatter, and radiant heat that can travel considerable distances from the work location and ignite combustible materials that may not be immediately visible to the person carrying out the work.
Smouldering fires caused by hot works can remain hidden within wall cavities, roof voids, insulation materials, and accumulated debris for hours after the work has been completed, developing into fully established fires long after the contractors have left the site.
The fires at Uppark House in 1989 and the Glasgow School of Art in 2018 are among the most high-profile examples of this phenomenon, but they are far from isolated cases.
Hot works are often carried out in locations that are inherently difficult to monitor, including roof spaces, plant rooms, service voids, and other confined or restricted areas.
And hot works are frequently carried out by contractors who may be unfamiliar with the specific layout, construction, and fire risks of the building in which they are working.
What Does the Law Say?
The legal basis for hot works permit systems draws on several pieces of legislation.
Under Article 9 of the Regulatory Reform (Fire Safety) Order 2005 (SI 2005/1541), the Responsible Person is required to carry out a suitable and sufficient fire risk assessment that identifies all hazards, including those arising from maintenance and repair activities involving hot works.
Under Article 11 of the RRO, the Responsible Person is required to implement and maintain appropriate fire safety arrangements, which must include arrangements for the management of high-risk activities such as hot works.
The Management of Health and Safety at Work Regulations 1999 (SI 1999/3242) require employers to assess the risks to health and safety arising from work activities, including contractor activities, and to put in place appropriate control measures.
The Construction (Design and Management) Regulations 2015 (SI 2015/51) require that fire safety risks during construction and refurbishment works are identified and managed, and that appropriate procedures are in place for controlling high-risk activities.
The Health and Safety Executive’s guidance document HSG250, Guidance on Permit-to-Work Systems, sets out the principles of an effective permit-to-work system and is an essential reference for anyone responsible for managing hot works in any type of premises.
While there is no single piece of legislation that specifically mandates a hot works permit system by name, the combination of these legal requirements makes it clear that a formal system of control for hot works activities is a legal necessity for any Responsible Person managing premises where hot works are carried out.
What Should a Hot Works Permit Contain?
An effective hot works permit should contain a number of essential elements.
It should clearly identify the location where the hot works are to be carried out, including the specific room, floor, or area of the building, and the nature of the surface or structure on which the work is to be done.
It should describe the nature of the hot works activity to be carried out, including the equipment and materials to be used.
It should identify the person or persons authorised to carry out the work, and confirm that they are competent to do so.
It should identify the person authorising the permit, who must be a competent person with sufficient knowledge of the building, its fire risks, and the precautions required.
It should set out the precautions that must be in place before work commences, including the clearance of combustible materials from an exclusion zone around the work location, the provision of firefighting equipment at the work location, the confirmation that fire detection systems are operational, and any other specific precautions required by the risk assessment.
It should specify the duration of the permit, including the start and end times of the authorised works.
It should require a mandatory fire watch period after the completion of the works, specifying the duration of the fire watch and the identity of the person responsible for carrying it out.
It should include a formal sign-off section at the end of the work, confirming that the fire watch has been completed, that no signs of fire or smouldering have been detected, and that the work area has been left in a safe condition.
And it should be retained as a permanent record, available for inspection by the Responsible Person, the fire and rescue service, or any other enforcement authority if required.
The Exclusion Zone
The exclusion zone is one of the most important elements of any hot works permit.
It is the area around the work location from which all combustible materials must be removed or adequately protected before hot works commence.
The standard minimum exclusion zone radius recommended by the Health and Safety Executive and most industry guidance is five metres in all directions from the point of hot works, including above and below the work location where floors and ceilings are involved.
In practice, the appropriate exclusion zone will depend on the nature of the hot works, the type of equipment being used, and the characteristics of the building and its contents.
In heritage buildings, buildings with combustible construction materials, or buildings with significant fire loads, a larger exclusion zone may be required.
Where combustible materials cannot be removed from the exclusion zone, they must be protected with fire-resistant covers or screens, and the adequacy of this protection must be confirmed before work commences.
The Fire Watch
The fire watch is the single most important control measure for managing the risk of smouldering fires following hot works.
It must be carried out by a competent person who understands what they are looking for, who has a serviceable fire extinguisher available, and who has the authority and means to raise the alarm and call the fire and rescue service immediately if any sign of fire or smouldering is detected.
The minimum duration of the fire watch after the completion of hot works is generally regarded as one hour, though many organisations specify two hours or more, particularly where the works have involved penetration of walls, floors, or ceilings, where combustible materials are present in hidden voids or cavities, or where the building is to be left unoccupied after the work is completed.
During the fire watch, the responsible person must check all areas in and around the exclusion zone, including any voids, cavities, or concealed spaces that may have been exposed to heat during the works.
They must check for any signs of smoke, smouldering, or unusual warmth in surfaces, materials, or structural elements in the vicinity of the works.
And they must confirm that all detection systems that were temporarily isolated during the works have been fully reinstated before the fire watch is concluded.
Common Failures in Hot Works Management
The investigation reports from fires caused by hot works reveal a number of common failures that appear with depressing regularity.
The most common is the absence of any formal hot works permit system, or the existence of a permit system on paper that is not followed in practice.
The second most common is an inadequate fire watch, either because no fire watch was carried out at all, because it was carried out for an insufficient duration, or because it was carried out by someone who did not understand their responsibilities or did not check all relevant areas.
The third is an inadequate exclusion zone, either because combustible materials were not removed from the vicinity of the works or because the exclusion zone did not extend to hidden voids and cavities where smouldering could develop undetected.
The fourth is a failure of contractor management, including the use of contractors who were not competent to carry out the works safely, who were not adequately briefed on the fire risks of the building, or who were not supervised to ensure that the agreed procedures were followed.
And the fifth is a failure to reinstate fire detection systems after the works were completed, leaving the building without adequate detection at the time when the risk of a smouldering fire developing was at its highest.
Who is Responsible for Issuing a Hot Works Permit?
The hot works permit must be issued by a person with the authority and competence to assess the risks involved and to specify the precautions required.
In most organisations, this will be the Responsible Person, the facilities manager, or a designated fire safety manager.
The person issuing the permit must be sufficiently familiar with the building, its construction, its fire risks, and the nature of the proposed works to be able to make an informed judgement about the precautions required.
They must not simply issue permits as a matter of routine without genuinely engaging with the specific risks of each activity and each location.
And they must have the authority to refuse to issue a permit where the precautions required cannot be put in place, or to stop work and withdraw a permit where those precautions are not being maintained.
Integrating Hot Works Permits Into a Broader Fire Safety Management System
A hot works permit system should not exist in isolation.
It should be an integral part of a broader fire safety management system that includes a current and comprehensive fire risk assessment, a contractor management policy, a system of work for managing all high-risk activities on the premises, adequate fire safety training for all staff with responsibilities under the permit system, and regular review and audit of the permit system to ensure that it is working effectively in practice.
The fire risk assessment must specifically address the risks arising from hot works and contractor activity, and must be reviewed and updated whenever a significant programme of works is planned.
The contractor management policy must set out the requirements for contractor vetting, induction, supervision, and performance management, and must make clear that compliance with the hot works permit system is a condition of being permitted to work on the premises.
And the review and audit process must include a check that permits are being issued correctly, that the precautions specified are appropriate, and that the fire watch and close-out procedures are being completed as required.
We Can Help
At ESI: Fire Safety, we work with building owners, facilities managers, and Responsible Persons to develop robust hot works permit systems and contractor management frameworks as part of a comprehensive approach to fire safety management.
From fire risk assessments that properly address the risks of hot works and contractor activity, through to the development of permit-to-work documentation, contractor induction procedures, and staff training, we provide the expertise and support you need to manage hot works safely and in full compliance with your legal obligations.
If you are concerned about the adequacy of your current hot works management arrangements, or if you are planning a programme of maintenance or refurbishment works and want to ensure that fire safety is properly managed throughout, get in touch with our team today.
Further Reading and Key Legislation:
Regulatory Reform (Fire Safety) Order 2005 (SI 2005/1541): https://www.legislation.gov.uk/uksi/2005/1541/contents/made
Management of Health and Safety at Work Regulations 1999 (SI 1999/3242): https://www.legislation.gov.uk/uksi/1999/3242/contents/made
Construction (Design and Management) Regulations 2015 (SI 2015/51): https://www.legislation.gov.uk/uksi/2015/51/contents/made
HSE Guidance on Permit-to-Work Systems (HSG250): https://www.hse.gov.uk/pubns/books/hsg250.htm
HSE Hot Work guidance: https://www.hse.gov.uk/fire/hotwork.htm
HSE Fire Safety in Construction (HSG168): https://www.hse.gov.uk/pubns/books/hsg168.htm
National Fire Chiefs Council fire safety guidance: https://nfcc.org.uk
This post is intended as a general guide. Always seek advice from a qualified fire safety or legal professional for guidance specific to your premises and circumstances.
