Firestopping guide for building services contractors

Why should Firestopping be a priority for building services contractors?

MIDFIX join forces with an experienced voice within the firestopping world – Andrew Kay from Protecta. Protecta are an international UK-based manufacturer of fire-stopping products. In today’s podcast we discuss:

• What is firestopping?
• What does a contractor need to consider when specifying the correct firestopping product?
• Type of firestopping product
• How can a contractor ensure a compliant installation (required accreditations and standards)
• What type of tests are required for a firestopping product?
• Why mixing different brands of products disseminates firestopping
• When should a contractor prioritise firestopping?

Andrew has over 20 years in firestopping and over 40 years in the construction industry. He has also been a chair for the association for specialist fire stop protection. Andrew has also been ex vice chair for the fire stopping forum.

What is firestopping?

Buildings are designed with fire compartments formed from fire resistant walls, floors, doors, etc. Confining the fire to its original zone for a specific time allowing occupants to exit the building. Firestopping products protect against the passage of flames, deadly gases and toxic smoke through openings and gaps in fire compartments.

It is a legal requirement that every breach of fire compartment walls and floors has to be reinstated to an effective fire barrier. All building services passing through a fire compartment require firestopping. All joints and gaps, such as between walls and ceilings and around fire doors, require firestopping.

The whole principle is to subdivide buildings into fire compartments, if we look at the Grenfell tragedy – if the fire could have been contained within the flat where it originally started then we wouldn’t have seen the number of fatalities.

What are firestopping products?

There is usually an element of firestopping required in all building services installations. Some of this will be undertaken by specialist contractors and some by the building services contractor. Typically, the building service contractor does not have in-depth firestopping knowledge. It is important that firestopping is made as simple as possible using products that are tested in the widest range of applications that he will encounter.

Are fires more common than we think?

Andrew points out: “Schools in the UK have over 1,000 fires a year but it never reaches the news because the fire is contained fairly quickly in smaller areas and dealt with so it doesn’t grow out of the compartments” – this is an example of effective firestopping.

Where should I install firestopping equipment?

Every single joint and gap within the built environment. Between walls and ceilings and around fire doors require firestopping. As soon as you build a fire compartment you are going to denigrate the firestopping effectiveness by putting building services through it whether it is cable trays or mechanical surfaces within a building. All of these are potential routes for fire and smoke to spread between fire compartments. Another example is plastic pipe going through a wall, once that burns away in a fire you are left with a 110mm hole through the wall. Installing a firestopping product around the pipe is going to fill in gap before the fire and smoke can travel through.

Can a Mechanical and Electrical contractor be contracted for firestopping?

When an M&E contractor arrives on-site and starts to carry out building services such as punching a hole in a wall for cable fixing that ruins any fire integrity of that wall. If a surface has been penetrated then firestopping needs to be reinstated. The issue is that it is very rare that an M&E contractor has specialist knowledge on firestopping.

Firestopping legislation and regulation and testing has been brought into a sharper focus for contractors

For a contractor it has never been so important to install the correct firestopping products with the correct regulation, to ensure a compliant installation. The first point of concern is that the product carries third party certification. Although it is not a legal requirement to use a third-party accredited product it is highlighted as best practice in the building regulation. Main contractors are now insisting that contractors are third party accredited (having their work checked from an independent company). The third-party audit should be carried out in the design stage right through to the manufacturing (the third party will verify the manufacturer is following correct factory processes) and the installation of a firestopping product.

Are there any firestopping classifications?

Traditionally firestopping products have been rated as mostly 2 hour or 4-hour fire resistance. This is misleading and inaccurate as the rating is dependent on the actual situation the product is being used in, including the service type and wall or floor construction. Protecta products all follow the European classification system and publish an EI figure in the installation instructions for every tested application. This means the contractor has an accurate fire resistant rating directly applicable to the installation.

EI classification

E = Integrity: the time it takes for fire to physically spread through a fire seal
I = Insulation: the time it takes for the temperature to increase by 180C on the non-fire side of the first seal or services. This replicates the lowest possible temperature that could potentially start a new fire in the presence of any combustible material

• With EN1366 standard a contractor can compare the testing data between different manufacturers
• Often a manufacturer will test in a worst-case scenario such as dry wall often for wall construction, if it passes the highest fire risk then the standard states you can use it for other applications.

For further information on the BS EN1366 and how the standard applies to different building services please download the documents found here.

What else does a building contractor need to consider when selecting a firestopping product?

A building contractor should examines the performance of the firestopping product when there is movement of joints. Post Grenfell the industry has now recognised that firestopping products should be tested on the application that it is being installed on. There have been calls for every product to be CE marked, however a manufacturer can gain a CE mark if they do one fire test with one application. However, it becomes redundant if there are any variables from testing to installing on-site. Variables could include;

• The thickness of the wall
• Type of wall
• Type of surface

Protecta carry out fire testing every week ensuring their product range is compliant to a wide variety of applications.

Is it essential that I specify products that have been tested on all services?

The short answer is yes. If I am penetrating a dry wall for building services I should only select the firestopping product tested in dry wall. Surfaces can be broken down into three areas:

1. Combustible surfaces: these are surfaces that are going to burn away and leave a hole that needs to be sealed
2. Non-combustible surfaces: metal and copper pipes, they are not going to combust in a fire, they are subject to movement through the natural expansion and contraction. For a pipe with hot water running through the pipe’s circumference and length will expand. Thist must be taken into consideration
3. Various movement joints within the building: block work wall with an expansion join in it, a curtain wall or a rain screen facade where movement joints are installed on the edge of the building.

Fire wall penetration is extremely common on construction sites, how important are the surface suspension points either side of the wall?

Extremely important. Unfortunately this is rarely understood in the construction industry. For example, an electrical contractor will be installing cable tray, some trays as wide as 1 metre are going through walls. For fire stopping a dry wall you will use a 50mm thick piece of mineral wall (Protecta FR Board) which can only be held in place with sealant. Once the cable tray moves, which it will naturally in a fire then the product is not going to give the rigidity that you need. Testing standards now state that no more than 400mm should be either side of the wall or floor penetration when putting up supports.

Why are gap seals so important?

Understanding the size of the aperture can help you specify the correct firestopping product. The larger the aperture the more critical the performance of the product.

M&E contractors often underestimate the required quality of the install

Regardless of the quality of the laboratory tests carried out on a firestopping product if it is not installed correctly or inferior products are installed then the performance test are irrelevant. Take a basic sealant, there are different qualities of sealants available. All sealants look good on the first day but for cheaper sealants used with fillers by day 3 sealants will dry and crack. Smoke can then travel through the gap and cause harm. When a fire starts in a room positive pressure builds. Even a 1mm aperture on a single surface can force toxic gasses through.

As a contractor we should always think about removing all gaps. To understand if an installation of a firestopping product has been installed correctly then you need to ask a few questions:

1. Are the service supporters for cable trays positioned close enough to the compartment wall or floor in order to comply with Firestop manufacturer’s tested system?
2. If the M&E contractor is responsible for putting fire wraps around combustible pipes, can he be sure that the products later used by a Firestop contractor to fill around the pipe are compatible?
3. If framed openings are being used for services in drywall, is there sufficient separation between the openings to comply with Firestop manufacturer’s testing?
4. Do services passing through framed out openings have enough spacing to both seal edge and between services to comply with Firestop manufacturer’s testing?

Firestop contractors will need details of pipe types/composition as well as insulation type/thickness.

How do you provide evidence that the installation is compliant, what steps do contractors need to take?

Third-party programmes (common ones are Boris or Bolster) contractors can record all of their firestopping details. Every penetration should be photographed, logged and included in the O&M manual with labels fixed next to it. One of the main issues is the handover period, it is may be a year later after a building services contractor has signed off a project. If building service contractors have previously been on-site to penetrate services and have not recorded, labeled & photographed the installation, M&E contractors will not know if they should reinstate firestopping.

"It is common practice for M&E contractors to mix and match different firestopping products to save time and reach the project deadline but this can impact the effectiveness of firestopping".

Building control departments and third-party auditors visit many sites and see that different firestopping products are installed onto one wall.  This can be problematic because unless each of those products has been tested on the application that they are being installed on it can cause issues.

When should firestopping be discussed with a tier 1 contractor?

A meeting needs to take place before anything has come up from the ground. Between the M&E contractors, firestopping contractor and the principle contractor. It is important to ensure the different types of surfaces and insulation are firestopping compliant. Products should only be chosen if they are tested on the application this would reduce the number of firestopping concerns.

Are there any recent examples of best practice?

Post Grenfell, there are some principle contractors who insist on building a demonstration wall prior to the site commencing work. The demonstration walls have firestopping information and guides on display.  When a contractor visits they know exactly which wall to reinstate.

Useful resources

Videos

The Association for Specialist Fire Protection have an easy to understand video highlighting the basic guidelines for passive fire protection. Watch the video here.

Fire Associations

The intumescent Fire Seals Association (IFSA) provides technical advice and guidance on all matters to fire seals. Read the guide.

Advice

The Life Safety Services posted an article that explains the differences between passive fire protection and active fire protection. The article discusses why they’re both extremely important. Read the article

MIDFIX supply a comprehensive range of firestopping products from stock and recommend the Protecta system as particularly suited to the building services contractor. Protecta products are comprehensively tested in hundreds of applications which are covered in detailed installation instructions that mean achieving a compliant installation is more straightforward without specialist knowledge.

Find our how MIDFIX can support you with firestopping strategy.

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