Fire stopping is essential to maintain the integrity of fire compartments, according to Keith Wells, who shows how this maximises time available for evacuation and emergency response
PASSIVE FIRE protection systems are designed to prevent the spread of fire and smoke, subdivide buildings into manageable areas of risk and provide adequate means of escape.
The person who is responsible for fire safety in a building has a duty of care towards occupants, as well as any members of the emergency services, for example firefighters, who may be required to enter the premises to tackle the fire. Ensuring the integrity of the passive fire protection systems and so slowing the spread of flames, smoke and hot gases will ensure that the emergency services are able to carry out their role in as much safety as is expected.
One important element of creating an effective passive fire protection system is ensuring that buildings are designed with fire rated compartments. These compartments protect means of escape routes – such as corridors and stairwells – from the building.
Occupants rely on the integrity of such fire compartments to ensure that they can evacuate safely, especially in larger buildings. In multi storey residential buildings, each flat is generally treated as its own ‘cell’, which means that prevention of fire spread from one cell to another will have been designed in from the outset.
Over the years, as buildings are renovated or altered, fire compartments can be compromised. Simple changes, such as drilling a hole through a wall for services (new heating, ventilation and air conditioning [HVAC], IT services etc) can result in a breach. Even a drill hole the diameter of a pencil that has not been adequately fire stopped can allow the rapid spread of smoke in just minutes and lead to potentially devastating consequences in the event of a fire.
In order to ensure the safe means of escape of building occupants, it is a requirement that fire compartmentation is regularly checked. Consequently, this should be an integral part of any existing fire risk assessment. Building owners and facility managers need to verify that the person undertaking the fire risk assessments includes a review of a building’s fire compartmentation, focusing on whether penetrating services have been suitably fire stopped and properly supported, and are in good condition and complete.
In addition, they should check for third party certification of products used and the identification of installers. All fire stopped penetrations need to be labelled and recorded. The fire risk assessment should be carried out by a competent person or external fire inspection company.
At some stage, most buildings undergo alterations. For instance, offices are regularly refurbished to attract new occupants, IT systems are updated and floor plans are changed. Before any of these works are begun, it is good practice to carry out a pre works survey. This will ensure that any penetrations in fire rated compartments are identified and an appropriate fire stopping solution is selected, if required. These can then be added to the work schedule, to help ensure that the work is completed – it is still common for fire stopping to be missed on busy or large projects – and that the completed fire stop is correctly logged and documented.
Carrying out an assessment of existing fire compartments will also identify any pre existing breaches, which can be an issue in buildings that are older. When an amount of refurbishment work has been carried out, it is common for the original plans to be out of date and certainly not reflective of the current state of the fire compartments. A detailed survey is the only way to ascertain the true condition of the fire compartments, and this usually includes the location and condition of compartmentation, a record of penetrations and a recommendation of remediation works.
The benefit of this is that it can form the basis of a working document for use alongside costing exercises and planning for any remediation fire stopping works. This approach helps to make the best use of available resources and ensures that critical safety aspects such as fire stops are given the priority they deserve.
Although there are many issues that arise with compartments due to service apertures not being correctly fire stopped during refurbishments, anomalies can also occur while the building is being constructed. Particular attention should be paid to fire stopping being installed incorrectly or missed altogether. If a fire compartment has not been correctly fire stopped, it will not achieve the required degree of containment in the event of a fire. This will allow the fire to spread quickly to other areas of the building and seriously restrict the amount of time that occupants have to safely evacuate via the means of escape.
Approved Document B of the Building Regulations requires buildings to be subdivided into a number of discrete compartments, using construction materials to prevent the passage of fire from one cell to another for a given period of time. These passive fire protection systems effectively compartmentalise a building by creating fire resistant walls and floors, typically with 30, 60, 90 or 120 minute protection. Firestopping products used to maintain the integrity of these compartments must be tested to current standards, including BS EN 1366-3: 2009 and BS 476-20: 1987.
It is also worth seeking out those firestopping products that have a CE mark, which a growing number now have. If a product has been certified by a notified body, you will see a four digit number after the mark that denotes which test house has tested and certified the product. Choosing fire stopping products that have Type X Durability also means they can be exposed to weathering. This is an important consideration on a live construction site, because the element that has been fire stopped may be left exposed while the next phase of construction is being completed.
In response to a growing awareness of the importance of effective firestopping to retain compartmentalisation, we have introduced a one stop shop system which is aimed at specialist firestopping contractors, as well as drylining and partitioning installers looking for high quality products that have undergone comprehensive testing. As part of the system approach, we offer technical back up and this results in quicker, more efficient installations; while for commercial teams, it can present an enhanced value proposition at tender stage.
Our new firestopping system comprises Fire Batt, Intumescent Acrylic Sealant, Fire Protection Compound, HPE Intumescent Graphite Sealant and Continuous Intuwrap. All the products have undergone rigorous testing as a complete system, so contractors avoid having to source different products from multiple suppliers. These products are made in the UK, sourced from a single supplier, and tested and supported with full technical back up.
Compartmentation of buildings was introduced to contain fires and reduce the risk of them spreading and causing a much larger, more destructive incident. Recent events have highlighted the importance of ensuring effective fire compartmentation of buildings in enabling occupants to evacuate to safety. Larger fires are obviously more dangerous to occupants and fire services, as well as those living and working nearby.
Retaining the integrity of fire compartments maximises the amount of time that is available for people to escape from the building. If fire compartments don’t perform as designed in multi storey buildings, in particular, people could be trapped on upper floors. Also, when a fire compartment doesn’t perform as it should, fire and rescue services are prevented from reaching occupants.
For modern buildings it is important to document all information relating to fire stopping, wherever possible. Older buildings may require a detailed fire risk assessment and a structured, reasoned approach – depending on the age of the building – in order to determine the current integrity or otherwise of fire compartments.
Even though there exists widespread awareness of the dangers of fire spread, in a worrying number of cases the firestopping of service apertures is often an afterthought. This results in poor choices of product or incorrect installation. At the earliest possible opportunity, guidance should always be sought from both the manufacturer and the specialist contractor, to ensure that firestopping is carried out effectively. The use of a system approach backed by test evidence, and of accredited installers who can provide certification, will ensure that the compartment performs as intended at the design stage.
It is worth bearing in mind the fact that the pencil sized hole in a wall referred to earlier would allow smoke to pass into a compartment to the extent that a person would be unable to see an object half a metre in front of them within only a few minutes. Making sure that fire stopping is effective really is playing for time.
Keith Wells is managing director at Quelfire. For more information, view page 5