Fire stopping regulations in the UK require that every gap, joint, and service penetration through a fire-resisting wall or floor be sealed so the element retains its designed fire resistance, with duties running from design and construction under the Building Regulations 2010 through to ongoing management under the Regulatory Reform (Fire Safety) Order 2005, the Fire Safety Act 2021, and the Building Safety Act 2022. Get it wrong on the most serious counts and the penalty is an unlimited fine, up to two years in prison, or both.
What the Law Actually Requires
The primary legal hook sits in Schedule 1, Part B of the Building Regulations 2010. Requirement B3 states that where reasonably necessary a building must be subdivided with fire-resisting construction, and that the unseen spread of fire and smoke within concealed spaces in the structure must be inhibited.1Legislation.gov.uk. The Building Regulations 2010 – Schedule 1 Every gap, joint, and service penetration through a fire-rated wall or floor falls within that fourth sub-paragraph of B3.
Approved Document B is the practical guidance. Volume 1 covers dwellings, Volume 2 covers other buildings, and both have been amended multiple times since 2019, with the most recent collated amendments taking effect in 2026 and 2029.2GOV.UK. Fire Safety: Approved Document B The document is not the law, but following it creates a presumption of compliance. Depart from it and you carry the burden of showing your alternative achieves at least the same level of safety.
The rule that governs fire stopping day to day is set out in Volume 2, Section 10: every joint, imperfect fit, and opening for services through a fire-separating element must be sealed with fire stopping so the fire resistance of that element is not impaired.3GOV.UK. Approved Document B Volume 2: Buildings Other Than Dwellings
How Long Fire Stopping Must Resist Fire
Fire stopping has no fixed rating of its own. It must match the fire resistance period of the element it protects. If a compartment wall needs to hold for 60 minutes, the seal around every pipe, cable, and duct passing through that wall must also achieve 60 minutes. A 30-minute seal in a 60-minute wall defeats the compartment.
Table B2 of Approved Document B Volume 2 sets the minimum periods for non-domestic buildings by purpose group, height, and whether sprinklers are fitted:3GOV.UK. Approved Document B Volume 2: Buildings Other Than Dwellings
- 30 minutes for ground and upper storeys in low-rise buildings up to 5 metres across most purpose groups, and for offices up to 18 metres with a sprinkler system.
- 60 minutes for blocks of flats, offices, shops, and assembly buildings between 5 and 18 metres without sprinklers, and for basement storeys in sprinklered offices, shops, and similar buildings.
- 90 minutes for basement storeys in most building types without sprinklers, and for upper storeys of industrial and storage buildings up to 18 metres without sprinklers.
- 120 minutes for basement storeys of industrial and storage buildings without sprinklers.
Sealing Service Penetrations
For pipe penetrations, the preferred approach is a proprietary tested sealing system that maintains the fire resistance of the wall, floor, or cavity barrier. Where a proprietary system is not used, the opening around the pipe must be kept as small as possible and fire stopped, and the pipe diameter must not exceed the limits in Table 10.1. Pipes made of lead, aluminium, fibre-cement, or uPVC up to 160mm internal diameter can pass through with a high melting point metal sleeve as an alternative, provided the sleeve arrangement meets the specified conditions.
Testing standards matter for demonstrating what a seal actually achieves. Fire dampers and the ductwork itself must be tested to standards such as BS 476 or BS EN 1366. BS EN 1366-3 specifically covers penetration seals and assesses their ability to maintain integrity and insulation where the separating element has been penetrated by a service.
Cavity Barriers
Cavity barriers stop fire travelling unseen through voids in walls, floors, and roof spaces. They must provide at least 30 minutes of integrity and 15 minutes of insulation when tested from each side. Acceptable materials include steel at least 0.5mm thick, timber at least 38mm thick, polythene-sleeved mineral wool compressed into the cavity, or calcium silicate and cement-based boards at least 12mm thick.3GOV.UK. Approved Document B Volume 2: Buildings Other Than Dwellings
Cavity barriers must be tightly fitted to rigid construction and mechanically fixed. Where a tight fit is impossible, for instance at the junction with slates, tiles, or corrugated sheeting, the gap itself must be fire stopped. Openings through cavity barriers are limited to fire doorsets rated at a minimum of 30 minutes, pipes installed in accordance with Section 10, cables or conduits, and ducts that are either fire-resisting to 30 minutes or fitted with an appropriate fire damper.
Fire Dampers
Where ventilation ductwork passes through a fire-separating element, a fire damper is required to close automatically and block the passage of flame through the duct. The damper and the surrounding installation must be tested to the relevant BS 476 or BS EN 1366 standard for the classification claimed.
Ongoing Duties on the Responsible Person
Once a building is occupied, the Regulatory Reform (Fire Safety) Order 2005 takes over. It applies to virtually all non-domestic premises in England and Wales, including the common parts of residential buildings with two or more sets of domestic premises.4Legislation.gov.uk. The Regulatory Reform (Fire Safety) Order 2005
The duties fall on a “responsible person.” In a workplace that is the employer if the premises are under their control. For other premises it is the person who controls them in connection with a trade or business, or the owner where no such person exists.5Legislation.gov.uk. The Regulatory Reform (Fire Safety) Order 2005 – Article 3 The responsible person must carry out a fire risk assessment and keep it under regular review. That assessment must examine the condition of fire compartmentation and the effectiveness of fire stopping seals around service penetrations. When layouts change or new utilities are routed through fire-rated elements, existing fire barriers are breached, and the responsible person must ensure those breaches are identified and resealed.6GOV.UK. Fire Safety Order – Supplement to Guidance Note 1: Enforcement
The Fire Safety Act 2021 clarified that the responsible person’s duties under the Order extend to the structure, external walls (including cladding, balconies, and windows), and flat entrance doors that open into common parts of multi-occupied residential buildings. The Act also introduced risk based guidance: failure to follow it can be used as evidence of a contravention in enforcement proceedings, and compliance with it can be used as evidence that no contravention occurred.7Legislation.gov.uk. Fire Safety Act 2021 – Section 3
Higher-Risk Buildings and the Golden Thread
The Building Safety Act 2022 layers additional requirements on higher-risk buildings. Under section 65 a higher-risk building is one in England that is at least 18 metres in height or has at least seven storeys, and contains at least two residential units.8GOV.UK. Criteria for Determining Whether a Building Is a Higher-Risk Building The Building Safety Regulator acts as the building control authority for these buildings during both the design and construction phase and the occupation phase.
Every higher-risk building must have at least one accountable person, and where there are several, one must be designated the principal accountable person. Accountable persons are responsible for assessing and managing the risks of structural failure and fire spread in their parts of the building.9GOV.UK. Safety in High-Rise Residential Buildings: Accountable Persons
The Act also introduced the golden thread of information: a digital record of building safety information maintained throughout the building’s lifecycle. It must cover the information needed to show the building meets applicable building regulations and to identify, manage, and reduce the risk of fire spread and structural collapse. It must be kept digitally, stored securely, maintained as the single source of truth for the building, and made available in a usable format to those who need it.10Building Safety Regulator. Understanding the Golden Thread
For fire stopping, that means documenting every installation, modification, and inspection. If a pipe penetration is sealed in a compartment wall during construction, the product used, the tested system it forms part of, and the installer’s records should all be captured. If the seal is later replaced during maintenance, the record must be updated.
The Documentation You Must Hand Over
Regulation 38 of the Building Regulations 2010 requires the person carrying out building work to hand over fire safety information to the responsible person no later than the date the work is completed or the building is first occupied, whichever comes first.11Legislation.gov.uk. The Building Regulations 2010 – Regulation 38 This applies to all relevant buildings, not just higher-risk ones.
Approved Document B sets out what the fire safety information should include. For all buildings, an as-built plan should show escape routes with exit capacities, the location of fire-separating elements including cavity barriers, fire doorsets, detection and alarm equipment, sprinkler systems, smoke control systems, and any high-risk areas. Specifications for fire safety equipment and routine maintenance schedules should be provided, along with any assumptions about building management that informed the fire safety design.3GOV.UK. Approved Document B Volume 2: Buildings Other Than Dwellings
For more complex buildings the guidance calls for a detailed fire safety strategy, procedures for operating and maintaining fire protection measures, a cause-and-effect matrix, and records of all passive and active fire safety measures. Fire stopping documentation sits here: certificates of installation confirming products were fitted to the manufacturer’s instructions, technical data sheets showing tested performance, and fire strategy drawings that map every fire-rated wall and floor. Without those records the responsible person inherits a building they cannot properly manage, and later maintenance risks breaching fire compartments no one knows exist.
Third-Party Certification for Installers
No law in England currently mandates that fire stopping must be installed by a third-party certified contractor. FIRAS, operated by Warringtonfire and accredited by UKAS, is the most widely recognised voluntary certification scheme for passive fire protection installers. Certified companies must demonstrate compliance with industry standards and manufacturer installation instructions, maintain quality assurance procedures, and document their work.12Warringtonfire. FIRAS Certification
Using a FIRAS-certified installer does not guarantee compliance on its own. The certification confirms the company is capable of meeting the scheme’s standards; it remains the company’s job to achieve them on every project. Even so, the Building Safety Regulator’s emphasis on competence and the golden thread requirement for higher-risk buildings make it much harder to justify using an uncertified installer when questions arise later about whether the work was done properly.
Inspection and Enforcement
Enforcement is split between two regimes. During construction, building control bodies (either local authority building control or registered building control approvers) inspect work for compliance with the Building Regulations. For higher-risk buildings the Building Safety Regulator itself acts as the building control authority. After the building is occupied, the local fire and rescue service enforces the Fire Safety Order and can inspect premises at any time.
Inspectors examine both the physical installations and the supporting paperwork. A well-sealed penetration with no documentation is almost as problematic as a missing seal, because the responsible person cannot demonstrate compliance and future workers cannot verify what system was used. Where inspectors find deficiencies they have several tools:
- Informal advice for minor issues, with guidance on what needs correcting.
- Enforcement notices specifying the improvements required and a deadline for completion.
- Prohibition notices, where the risk to life is serious enough, restricting or preventing use of all or part of a building until the deficiencies are resolved.
The criminal penalties under Article 32 of the Fire Safety Order scale with severity. Summary conviction carries a fine up to the statutory maximum. On indictment, the most serious breaches, including failing to carry out a fire risk assessment, failing to comply with general fire precaution duties, or putting persons at risk of serious harm, carry up to two years’ imprisonment and an unlimited fine.13Legislation.gov.uk. The Regulatory Reform (Fire Safety) Order 2005 – Article 32 Where a company commits an offence with the consent or neglect of a director, manager, or similar officer, that individual is personally guilty of the offence as well. Prosecutions following fire deaths have resulted in significant fines and custodial sentences.