CPD 03 2023: Understanding fire stopping and liability

This CPD module, sponsored by ROCKWOOL, explores the importance of designing for effective compartmentation and the legal liability regarding the provision of fire protection

A key element of compartmentation is resisting the spread of fire from the room of origin

Fire stopping is a vital component for successful passive fire protection strategies.

By helping to contain the spread of flames and smoke, investing time and resources into fire stopping can make the difference between regulatory compliance and subpar levels of protection.

Fire-protection regulations have undergone numerous changes as a result of the inquiries in the wake of the Grenfell disaster. Regulatory requirements can vary significantly based on a building’s size, intended usage and a host of other factors. Industry professionals should therefore refamiliarise themselves with these regulations.

It is important to remember that if you are involved with the provision of fire protection at any level, then you share liability for its usefulness and operation in the event of a fire.

This CPD will provide insight into how you can fulfil your legal responsibilities.


  • Understand your legal liability in respect to the provision of fire protection.
  • Gain knowledge of how fire behaves and how to be confident in a product’s combustibility.
  • Learn the importance of designing and installing to achieve effective compartmentation.

Let’s start with legislation

There has been a long history of legislation regarding building fire safety in the UK, and there are a number of regulations requiring us to fire stop.

Focusing on new buildings, the primary pieces of legislation in England include the Building Act 1984, the Regulatory Reform Fire Safety Order (RRFSO) 2005, the Building Regulations 2010 and the recently introduced Building Safety Act 2022.

The Building Act 1984 sought to consolidate previous legislation concerning the construction process, and the design and specifications for buildings. Amendments have been issued, notably with enhanced fire-safety measures.

Within the Building Regulations 2010 it is stated: “A wall common to two or more buildings shall be designed and constructed so that it adequately resists the spread of fire between those buildings.”

It goes on to add: “Where reasonably necessary to inhibit the spread of fire within the building, measures shall be taken, to an extent appropriate to the size and intended use of the building, comprising either or both of the following…

  • “A. Sub-division of the building with fire-resisting construction;
  • “B. Installation of suitable automatic fire suppression systems.”

Following the Grenfell Tower fire in 2017, changes to the Building Regulations banned combustible materials from being used in the external walls of certain categories of building over 18m in height. However, the use of combustible cladding and insulation materals continues to be permitted in the external walls of buildings outside the scope of the ban. In 2019, fire spread rapidly across the facade of The Cube, a student accommodation building in Bolton. As the building was only 17.84m tall, regulations did not prevent combustible materials from being used in its external walls.

Extensions to the ban in 2020, and the introduction of the Building Safety Act in 2022, have changed the landscape further, with rules becoming more stringent and a greater onus falling on construction firms with regard to design and installation and record-keeping.

The Building Safety Act includes the following key elements:

  • A more onerous safety regime accompanied by new obligations which must be met throughout a building’s lifecycle, including its delivery, design, construction and operational phases.
  • The introduction of a new Building Safety Regulator, along with revision of the training and competency standards.
  • A framework of measures designed to deal with breaches, including fines and prison sentences.
  • Financial levies on developers to fund remediation.
  • The period for making claims for safety-related defects has been extended to 30 years for claims arising before 28 June 2022, and to 15 years for claims arising from now on.

The two principal objectives of these initiatives were: to create a robust, stringent safety regime for the construction, operation and maintenance of higher risk buildings; and to ensure the remediation of non-compliant buildings at no cost to leaseholders living in unsafe buildings.

Outside these pieces of legislation, there is further government guidance to help navigate fire-stopping responsibilities, including Approved Document B (ADB) Building Regulations fire safety guidance, the Regulatory Reform Fire Safety Order (RRFSO) guidance notes, Building Bulleting 100: Design for fire safety in schools, and the Heath Technical Memorandum (HTM) 05-02, which provides information on fire safety in the design of healthcare buildings.

Guidance documents can provide information on practical ways to meet the requirements of the building regulations. However, they cannot be relied upon as the sole method for achieving this.

Liability under the Defective Premises Act (DPA) is strict and applies to all dwellings in England and Wales. The main takeaways are:

  • The limitation period for claims has increased from six to 30 years for work completed on buildings before 28 June 2022.
  • The period for claims on buildings completed from now on has been extended from six to 15 years.
  • It is not a valid defence for the defendant to claim to have followed established practice at the time.

Anyone responsible for the defective work is potentially liable, including builders, contractors, architects and designers.

Common service penetrations include pipes and cables running through compartment walls and floors

The golden thread

For “higher-risk” buildings in England, the Building Safety Act requires the client to ensure that a “golden thread” of the design, operation and maintenance information needed to keep a building safe is recorded, updated and maintained.

A digital record of all project and asset data, the golden thread will record every decision, giving a clearer accountability trail to reduce risk and improve safety.

It also introduced a three-stage gateway process to improve fire-safety standards, with the requirement for a safety case review at each gateway:

  • Gateway one (planning) – requires all fire safety matters to be incorporated into the planning stage.
  • Gateway two (building control approval) – requires clients to submit a building control approval application to the Building Safety Regulator before construction can commence.
  • Gateway three (completion certificate) – assurance that the building is safe for occupation must be provided for the Building Safety Regulator to issue a completion certificate; including signed declarations from the principal contractor and designer that the works and building comply with the Building Regulations.

Fire knowledge

Understanding fire and how it behaves is essential for any individual involved with the selection, design and installation of fire-stopping and fire‑protection measures.

A fire needs three elements in order to ignite: fuel, oxygen and heat energy. Removing any of these three elements will stop a fire.

  • Fuel is a flammable material that begins the process of combustion. When fuel is heated past its flash point, it enters the gas phase and releases vapour pressure that can ignite in air and support combustion.
  • Oxygen supports burning due to oxidation. This is when gases released by fuel heat up, break apart and recombine with oxygen, resulting in burning.
  • Heat energy is produced during combustion due to the reaction being exothermic. Since these reactions are ongoing, combustion releases enough heat to make the fire self-perpetuating.
Euro-class EN 13501-1Materials
A1Stone wool, glass wool, cellular glass
A2-s1, d0Some faced stone or glass wool products
B-s2, d0Phenolic foam (TYP EU)
C-s2, d0Phenolic foam (TYP UK), some PIR
D-s1, d0Some PIR
E-s2, d0Flame retardant EPS/XPS, PUR
F-s1, d0EPS, PIR
Euroclass rating of insulation materials

Product combustibility

Understanding a product’s combustibility helps to understand whether a product is going to add fuel to a fire’s load. The European Reaction to Fire classification system is the EU common standard for assessing the qualities of building materials in the event of fire. This information is relevant for the UK and for the Republic of Ireland.

The Euroclass system (see table, left) determines a product’s fire performance by measuring a comprehensive set of characteristics, including ignitability, flame spread, heat release, smoke production and propensity for producing flaming droplets/particles. The classifications run from A1 to F, with products achieving A1 and A2 classifications considered non-combustible.

Class 0 references do not determine a product’s combustibility and have now been removed from Approved Documents.

By law, all building insulation products subject to a harmonised EN standard must be CE marked, meaning manufacturers must declare a fire performance classification for each of their products.

The Euroclass rating of a product can often be missing from its data sheet, but manufacturers are legally bound to report this information in the product’s declaration of performance (DoP). Documents should be freely available from the manufacturer’s website, but you may have to request a copy.

Fire protection of the structure prevents a building from premature collapse

The importance of compartmentation

A vital part of fire-safety design, compartmentation can make the difference between a fire in a building and a building on fire.

Helping to prevent the spread of fire, smoke and toxic gases by subdividing the building into manageable areas of risk, compartmentation ensures each compartment is reinforced by fire‑resistant materials.

Even the smallest hole in any dividing wall could compromise the effectiveness of a building’s compartmentation, allowing fire to spread throughout the building.

Fire-rated elements have an integrity and insulation rating under the EI classification. The letters “EI” represent insulation, followed by the duration (in minutes) it provides fire resistance.

The required fire-resistance rating depends on the building type, the application, the area or the use of the building, the occupation levels, and the height of the building.

The key factor in compartmentation is addressing whether you require fire protection or fire stopping. Understanding the difference between the two terms is crucial.

Fire protection

Fire protection is focused on protecting structural elements of the building by integrating fireresistant materials into the fabric of the building.

Protecting the structural elements of the building from high temperatures is key. This will help to maintain the load-bearing structure of the building, reducing the risk of the building collapsing.

Reducing damage also increases the likelihood of the building being able to be reused in future.

There are products that are suitable in providing fire protection to a building’s structural elements. Structural steel fire protection can help maintain a building’s load-bearing strength in the event of a fire, while concrete protection for concrete soffits adds a layer of protection to concrete floors.

Fire stopping

Fire stopping is used to reinstate a fire-rated compartment following the installation of building services or any gaps which are formed within the walls or floors.

Linear gap seals installed at compartment junctions, and buildings services which penetrate through compartment walls and floors, must demonstrate that they achieve the same integrity and insulation ratings as required by the building compartment.

In addition to preventing the transfer of fire and heat between building compartments, passive fire-protection measures such as linear gap and penetration seals should also inhibit the passage of smoke and toxic gases, which are the main cause of death in a fire.

To summarise, achieving successful compartmentation requires looking at the following factors:

  • Protection to the structure of the building, giving occupants time to escape and allowing the fire service to access the building to rescue people, find and fight the fire.
  • Inhibiting the passage of smoke and toxic gases.
  • Resistance to the spread of fire from the room of origin.

Fire safety from the design stage

For anyone approaching design, the lowest-risk route to take is with standard tested solutions.

Third-party tested materials and third-party accredited installers are assessed independently, which acts as a seal of approval to ensure the installed products will perform as intended.

However, tested standard solutions are not always available. There are two alternative options:

  • Speak to the manufacturer to see whether they can provide a tested solution or make a judgment based on their standard test data.
  • Have an assessment carried out by a UKAS accredited laboratory or a fire engineer. Accreditation, experience and the necessary qualifications are essential.

When installing fire stopping or fire protection in a building, you should be aware of your role and the level of liability that entails with regard to fire protection. Likewise, knowledge of the firestopping and fire-protection requirements of the specific project is essential.

Change is constantly hitting the construction industry, and it is important that you stay informed and always make safety the key priority.

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