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Fire stopping

Find out more about fire stopping, who can carry out the work and what the requirements are.

What is fire stopping?

Fire stopping is part of the passive fire protection for a building and is the practice of reinstating fire compartmentation or barriers which have been penetrated. It is important that suitable products offering the equivalent fire protection are used, an example would be when containment or cables pass through fire-rated compartments in a building. The purpose is to prevent or slow down the spread of fire and smoke and keep it within zones or compartments, to prevent escape routes from becoming smoke logged to facilitate escape.

What are the requirements in BS 7671:2018 for fire stopping?

BS 7671:2018 Regulation 527.2 sets out the requirements for the sealing of wiring system penetrations, Regulation 527.2.1 states that:

“Where a wiring system passes through elements of building construction such as floors, walls, roofs, ceilings, partitions or cavity barriers, the openings remaining after passage of the wiring system shall be sealed according to the degree of fire-resistance (if any) prescribed for the respective element of building construction before penetration.”

Whilst BS 7671:2018 states that fire stopping is a requirement, it does not detail how it should be carried out or who should do it. For this, it is important to seek further guidance from specialist contractors and manufacturers.

Are there any statutory requirements to carry out fire stopping?

The Regulatory Reform (Fire Safety) Order 2005 (RFO) is a statutory document which sets out the requirements for fire safety. Prior to 2005, fire safety was covered by approximately 70 separate pieces of fire legislation, but it was decided to simplify the legislation into one document – the RFO – which replaced any previous legislation issued under the Fire Precautions Act 1971. It intends to provide a minimum fire safety standard in all non-domestic premises (with some exceptions) and requires the responsible person to have a risk assessment carried out by a competent person to identify any shortfalls in fire safety requirements which should include fire stopping provisions.

Local fire and rescue services carry out inspections to ensure buildings are compliant and can take action on non-compliant businesses, ranging from providing information and advice to prosecuting the responsible person for the building.

What other requirements are there to carry out fire stopping?

The Building Regulations for use in England only state basic requirements and do not provide technical information on how to specify the correct fire stopping products.

 Approved Document B 2019 Volume 1 ‘Dwellings’, Section 9 sets out the requirements for fire stopping and states that openings through a fire resisting element for pipes, ducts, conduits or cable should be all of the following, as few and small as possible and fire stopped.

 Section 9.28 states that;

“Best practice guidance on the design, installation and maintenance of measures to contain fires or slow their spread is given in Ensuring Best Practice for Passive Fire Protection in Buildings produced by the Association for Specialist Fire Protection (ASFP).”

 Approved Document B 2019 Volume 2 ‘Buildings other than dwellings’, Section 10 states that;

 “The performance of a fire-separating element should not be impaired. Every joint, imperfect fit and opening for services should be sealed. Fire-stopping delays the spread of fire and, generally, the spread of smoke as well.”

Whose responsibility is it to carry out the fire stopping works?

BS 7671:2018 imposes requirements on the electrical installer to ensure penetrations for wiring systems are sealed to prevent the spread of fire, however, the electrical designer may decide to employ a specialist contractor to carry out the works.

On smaller projects, it is likely that the electrical installer will be the only person involved in the works, so it will be their responsibility to ensure that the fire stopping works are completed adequately.

On larger projects, it can be sometimes assumed that the fire stopping will be carried out by the main contractor, but this is not always the case. It is important to establish where the responsibility lies at an early stage, such as when tendering for a project as it is likely to cost a significant amount of money. The architect will likely be responsible for specifying fire stopping works but this should be clarified with the principal contractor during the tender process. This will require close coordination with the electrical contractor and specialist fire stopping contractor.

Who is competent to carry out fire stopping works?

Fire stopping is a very specialised part of the building works which requires training, experience and a good knowledge of the relevant products. It is important that the product selected has been tested in the relevant scenario and is suitable for the application.

As stated by the HSE, competence can be described as the combination of training, skills, experience and knowledge that a person has and their ability to apply them to perform a task safely. Unless suitable training has been undertaken, it is unlikely that an electrical installer would be able to demonstrate competence in fire stopping works.

What is third party certification?

Third-party certification applies to both fire stopping products and installation. Below looks at the different kinds of certification:

First-party certification

An individual or organization providing the goods or service offers assurance that it meets certain claims. (The installer says it’s compliant).

Second-party certification

An association to which the individual or organization belongs provides the assurance.

(An association that the installer is a member of or the supplier of materials says it’s compliant).

Third-party certification

Involves an independent assessment declaring that specified requirements pertaining to a product, person, process or management system set out in a scheme document or BS/EN/ISO Standard have been met.

Third-party certification should always be provided by a certification body, in the UK they should be accredited by UKAS as this gives further value to their decisions meaning that the certification body themselves are competent to deliver certification and are subject to scrutiny by a national body.

When a product is tested by a UKAS accredited fire test laboratory, it should adequately demonstrate the suitability of a fire stopping product for use within a specific application or range of applications. It is not the job of test laboratories to police the use of claims by manufacturers of fire stopping materials. The third-party schemes which review the test data and carry out factory audits and clearly define the limitations of the product, for example, maximum hole size, protection time and application type.

Third-party product certification provides confidence that the product is fit for purpose, is manufactured using a defined quality control system and links factory production with what was actually tested by a fire laboratory and proved under certain conditions.

Some of the third-party accreditation requirements for product manufacturers:

  • factory production control via initial factory inspection and routine surveillance visits
  • initial type testing of the product
  • an appraisal of the product test and assessment evidence against a technical schedule to ensure that the certification gives the widest scope of application
  • traceability of the product from raw material to the factory to site, and
  • labelling of the product to provide confidence to end-users and to assist with traceability

A list of UKAS accredited organisations for certification can be found on the UKAS website.

Not only is it important that the products are correctly certified, but the installation is also equally as important. Third-party installer certification provides confidence that the products will be installed professionally and as they were originally tested and certified.

Below are some of the requirements for members of an accredited installer scheme:

  • verification of the skills and training of management, designers and estimators
  • the use of materials and products which have been shown by certification, testing or assessment to have the appropriate fire performance
  • operatives and supervisors to be assessed for competence
  • random inspection of sites to monitor the quality of work
  • provision of a certificate of conformity for completed work, and
  • provision of an audit trail.

Correctly specifying and installing fire stopping products is fundamental to the fire safety of the building. Therefore, it is important that the products are installed to the same quality as when they were originally tested. It is in the interests of the client that fire stopping work is carried out by a registered third-party installer and certified for compliance. Part of the works will require that each hole or penetration through the fabric of the building is provided with an identifying label and that information is recorded in a register which will include items, such as hole size, fire-stopping material and the installers details. In the event of any issues at a later date, this information can be tracked to prove compliance.

Problems and hazards

It is common to see electrical contractors carrying out the fire stopping works themselves. Lack of knowledge of the products is a big issue, for example, polyurethane (PU) foam, usually pink in colour, is used in large quantities across building sites, there is a common misconception that it is suitable for carrying out fire stopping of service cables and pipes. This is not the case as it is combustible and therefore should not be subjected to direct flames as toxic black smoke is emitted from the foam when in contact with fire for just a few seconds. It is also important to consider how the chemicals in the foam will affect the cable insulation.

Some manufacturers of PU foam state that their product will provide four-hour fire protection, how can this be true? The fire rating is only applicable to the conditions which it was tested under, this information can be found in the product certification, which will state the exact conditions that it was tested under to achieve this rating.

One example of a test scenario involves the pink PU foam sandwiched between two 200 mm solid concrete walls, and the fire being in the room adjacent to one of the walls, this scenario is quite different to being subjected to direct flames, as it would be if it was used for fire stopping.

Toxic smoke causes more fire-related deaths than fire, whilst fire stopping is imperative to maintain the safety of the building, preventing the spread of smoke is equally important. Smoke travels extremely fast, to give an idea, if a 6 m x 6 m room with a ceiling height of 3 m has a hole the size of a pencil between fire compartments, it would take less than four minutes to fill with smoke from a fire in an adjacent room.

Fire stopping should be considered at all stages of a construction project and not just on completion. A construction site can pose significant fire hazards, and with over ten fires a day, they are considered to be high risk in terms of fire. This is due to activities such as hot works and escape routes changing on a regular, sometimes daily basis.


Whilst it is not forbidden for the electrical installer to carry out fire stopping works, it is unlikely that without the relevant training, skills or knowledge, the fire stopping works would be completed adequately or they would not be deemed competent in a court of law to carry out the works.

Manufacturers can provide information on their products and some can provide training on how to install them.

A specialist third-party accredited installer is best placed to carry out fire stopping works, they would provide the necessary certification for the work and assurance to the client. The responsibility for these works should be established at an early stage of the project.