EXTRA CARE needs to be taken by building contractors and owners to ensure that they put measures in place to limit the spread of fire through roof voids and basement areas of their buildings. These types of fires spread quickly and unseen with potentially devastating consequences.
Even the smallest hole in a compartment can cause a fire to grow out of control, creating a dangerous situation for occupants and people in the vicinity of the building. These types of fires make it difficult for people to escape safely, putting lives at risk; cause fire and rescue services difficulties in tackling the blaze and pose potential danger to them; and are also likely to cause serious damage to the fabric of the building.
Service penetrations that are fire-stopped in order to achieve full and proper compartmentation are largely hidden above ceilings and below floors, where they are out of sight. As a result, it is far more likely for breaches to go unnoticed. Most building owners wouldn’t know there was an issue, because they wouldn’t know what to look out for and would have assumed that the builder knows what they are doing.
Report findings
The dangers of inadequate compartmentation were outlined in a BRE Global report in 2015, which reviewed fires reported to the Department for Communities and Local Government (DCLG) between 2003 and 2013. It found that almost a third of the fires investigated were due to ‘concealed fire spread’.
Of the 106 fires BRE Global reviewed, 34 were due to failures in compartmentation, cavity barriers and ducting; 11 were solely related to compartmentation in roof voids; 10 had issues with cavity barriers; six had combined issues with compartmentation and cavity barriers; and four resulted from ducting problems. The remainder had a combination of ducting, compartmentation and cavity barrier issues.
There were a number of reasons for the fires spreading. The junctions of the compartmentation wall were either not fire stopped, or the fire stopping was inadequate and not continued to the roof. Inadequacies were found where mineral wool in wire netting was used as a cavity barrier in the roof space, as a result of holes in the barriers. A number of push-fit cavity barriers were either incorrectly installed or moved after construction. In a couple of cases, ducts passing through compartment walls were not fire stopped. However, in most of the cases, cavity barriers were either absent or poorly fitted. On a more positive note, in three cases, compartmentation in roof voids was effective and prevented fire from spreading through the void.
BRE’s report concluded that adequate compartmentation and correctly specified cavity barriers were effective in limiting fire damage.
Compartmentation is key
Fire compartmentation is designed to divide the structure or building to limit the spread of fire, smoke and fire gases; reduce the risk of a fire becoming large; and reduce the impact of rapid fire spread through concealed spaces or from compartment to compartment. As regards compartmentation, it is attention to the smallest details that makes the difference. This can prevent the loss of a floor or entire building, create time for a staged evacuation of the building and provide safe spaces for people to take refuge.
Compartmentation must be top of the agenda at every stage of the building lifecycle. Careful consideration is required during the planning and construction phase. Building owners need to evaluate how the building is to be used, the fire load of the building, height of the building and whether sprinkler systems are to be used. Each compartment wall should form a complete barrier between fire compartments and provide a minimum level of fire resistance.
The entire structure of the building needs to be intelligently divided and subdivided so that, if a fire starts, it does not spread as quickly to adjoining areas. In planning fire compartmentation, every aspect of the use to the building must be thought through including escape routes, firefighting and protected staircases, protected corridors, vertically rising shafts such as lifts and risers, and walls common to more than one building.
Special attention needs to be paid to buildings in which people live, work and sleep such as hotels, hospitals, care homes and residential complexes. Within these buildings, areas that pose a high risk of fire – plant rooms, for example – will need a higher level of fire resisting compartmentation, as will parts of buildings that are business critical or that contain irreplaceable or high valuable items.
Post-construction maintenance of the compartmentation is just as critical, particularly when building works and alterations are taking place and a building is at greatest risk of fire spread. If installed properly, fire compartmentation is very effective but weaknesses may creep in when alterations are made to services, such as the running of new cabling or wiring, or when refurbishment projects are undertaken.
Who’s responsible?
Everyone is responsible for ensuring that safe compartmentation standards are maintained, including building owners, occupants, facilities managers and external contractors. Building occupants and staff need to be educated about where fire barriers are, why they are there and the importance of maintaining them. Facilities management and maintenance teams need to keep an easily accessible record of compartment and sub compartment lines, and the location of fire hazard rooms, so that they can identify any breaches to fire rated construction and keep track of any material alterations. External contractors must be made aware of the impact of any works carried out and report any breaches in the fire protection fabric.
‘DIY fixing’ a breach is dangerous. Always consult fire engineers with specialist knowledge of fire compartmentation, to ensure breaches are repaired to the same level of fire resistance as the rest of the compartment. Global HSE sees far too many instances where breaches have been repaired using materials that are not adequate or properly reinstated as a result of lack of knowledge and experience.
A professional fire engineer understands how the building operates, which areas to protect and how fires behave. This knowledge of buildings and fire safety enables them to provide sound advice on how to protect buildings, which parts to focus on, which materials to use in each instance and how to achieve the right level of fire resistance. For example, access points and shafts may require 60 minutes’ fire resisting compartmentation, while other areas may only require 30 minutes. It is all about understanding the bigger picture and paying attention to the detail.
Thinking about future service requirements when passive fire protection is installed can help to avoid many unnecessary changes further down the line. Simple inclusions, such as installing fire sleeves, will allow cables to be quickly and safely run through compartment walls without the subsequent need to penetrate the wall or floor, creating a breach.
Dealing with breaches
Specialist provider of fire prevention systems, Hilti, says: ‘Walls and floors that provide fire separation must form a complete barrier, with the equivalent level of fire resistance provided to any openings such as doors, ventilation ducts, pipe passages and refuse chutes. The passing of services such as heating pipes or electrical cables through fire-resisting partitions leaves gaps through which fire and smoke may spread’. It is at these intersections and areas, where services connect adjoining areas, that compartment breaches are most likely to occur.
Breaches can occur in cable trays and trunking; fire dampers and ductwork; high voltage bus bars; mechanical floor risers; waste water pipes; head of walls and linear gaps; fire doors and frames; below raised access flooring; slab edge curtain walling;
rain screen cladding systems; and electrical socket and light switches.
Delaying the repair of a breach can be very costly. Facilities management is responsible for ensuring that people are able to report breaches, with clear procedures of who to report the incident to and what to do next. However, both external contractors and facilities management need to be made aware that they should not try to repair the breach themselves if they are not adequately trained to repair fire walls and floors. It is best to leave the job of repairing the breach to fire engineering professionals who understand what materials to use in each instance and how to make the compartment fire resistant to the required levels.
It is advisable to capture information electronically. Using a web portal for reporting incidents to facilities management enables them to take timely and appropriate action. It also enables building owners to keep a log of any breaches, demonstrates a clear procedure for dealing with them and can help to prove compliance.
As a minimum, the following data needs to be captured:
• date breach first occurred (or discovered)
• who reported breach
• what caused breach, eg new ducting
• exact location of breach
• size of breach (depth and breadth)
• penetration of compartment wall
• adjoining compartments affected (to assess risk to critical areas)
• potential impact of breach (if known)
Right side of the law
The authorities take fire compartmentation safety breaches extremely seriously, particularly after a number of fatal fires, such as at Lakanal House in 2009, where the fire spread rapidly because maintenance work compromised the compartmentation of the building. Chief executive of the ASFP, Wilf Butcher, said of this fire: ‘The systematic deconstruction of fire resistance of the building over time and multiple refurbishments led to fire and smoke spreading horizontally and vertically.’
Because of this and other serious fires, enforcers can visit a premises without notice and ask to see a fire risk assessment and enforce necessary works, fines and prosecution if they feel there is a breach in any areas of fire safety.
Building owners are strongly advised to have a regular full fire risk assessment undertaken by professional fire engineers such as Global HSE, which specialises in retrofitting fire engineering solutions and often gets involved with projects where there has been a serious breach regarding enforcement, stepping in quickly to resolve serious building fire safety issues. On a daily basis, it sees failings mostly due to inexperienced installers, who do not fully understand the original fire strategy and building design requirements. It has also seen shockingly poor compartmentation repair, in which incorrect materials have been used and have not been installed in accordance with the manufacturer’s test evidence and install data. There have been cases where the original compartmentation was installed with little forethought about future maintenance, often resulting in barriers being breached within months of first install.
It is critically important that the industry addresses this serious lack of understanding of the value of compartmentation and how to maintain safe compartmentation. Inadequate repair of the building fabric and fire compartmentation can cause the works to be condemned and this can land building owners in serious trouble. There are numerous examples of landlords and owners being prosecuted and receiving fines of tens of thousands of pounds, or in some cases, fines of more than £100,000. Increasingly, prison sentences are being handed out for breaching fire safety regulations.
In too many of these cases, the breaches are due to inadequate fire compartmentation, where fire could penetrate an escape route or cause a fire to spread quickly through a building, putting lives at risk.
With such a poor track record, it is not surprising that insurers are now demanding that works are completed to a third party approved standard. They specify that companies not only provide evidence that the quality of the installation meets the requirements of a third party approved scheme such as FIRAS, but also that contractors can demonstrate the competence of the people who have undertaken the works.
Andrew Cooper is managing director of Global HSE Solutions Limited. For more information, view page 5