Steve Cooper considers what could be done to ensure greater fire safety in buildings in the future.
After decades of declining fire incidents, the UK’s fire and rescue service attended 182,825 incidents in 2018/19 – an increase of 9% year-on-year.
As a fire engineer and a former firefighter, I have seen first-hand the ways that the fire regulatory system and building design and management have become broken over the past 20 years.
The Hackitt report, commissioned by government following the Grenfell Tower fire, acknowledges that fundamental changes to fire safety and the way buildings are managed must be made to move forward. Proposed new measures will go a long way towards ensuring the buildings we live in are safer from a fire risk point of view. However, the safety of residents in buildings relies on a range of parties – government, local authorities, the fire and rescue service, property developers, contractors and architects – all taking responsibility and accountability for ensuring buildings are designed, built and managed to a high standard at all times.
Material considerations
When carrying out inspections on existing housing stock, I am seeing more issues with the types of materials being used and the installation of those. Some subcontractors and builders have a lack of knowledge about what the material is and does, and a lack of knowledge concerning how to install it correctly.
For example, I have seen many cases where cavity barriers have not been installed because the architect hasn’t included them in the drawings. In at least one instance, cavity barriers designed solely for use in a horizontal orientation had been installed in line with compartment walls and in a vertical orientation. Installed like this, they simply won’t prevent fire and smoke spreading through the wall cavity.
Cavity barriers come in different types. Some are mineral fibre stuffed into a plastic “sock”, and these are intended to be installed in line with compartment floors and walls to stop fire and smoke spreading up the building and passing from floor to floor. Others are a thin, flexible material that will swell up, or “intumesce”, when heated by the fire – again, closing the gap between the cladding and the wall of the building.
Cavity barriers don’t look like much and cost very little. Fitting them doesn’t require any particular skill or equipment, but both the installer and the architect need to understand how important these seemingly innocuous products are to building safety.
I recently attended two fires where the buildings were completely destroyed. The lack of effective cavity barriers was largely to blame for the unprecedented fire spread and damage. In most of the buildings that I have investigated, cavity barriers have been completely absent from around windows. And yet, the window is probably the most likely route by which a fire inside the building will spread into the external wall.
Other common problems I see include the use of combustible materials within the external wall construction that are not supported by relevant large-scale fire test data. There is a reason that the use of combustible materials in the external walls of tall buildings is restricted unless supported by a fire test, and the results of those tests are non-transferable.
If the test was on a system using components A, B and C, you cannot rely on that test to support your use of components C, D and E. Retrospectively replacing the thermal insulation on a completed and occupied building is not only expensive, but also requires a great deal of planning and coordination.
Errors such as this end up costing the developer, the building’s tenants and, ultimately, society more in the long run. Building correctly in the first place is always cheaper than correcting defects retrospectively. There are things we can learn from the past to help us design, construct and manage buildings better in the future.
Lessons from the past
The way we design and construct buildings has changed over the past 40 years, moving away from natural materials such as stone and brick to synthetic materials such as plastic, in effort to make construction easier and cheaper for the developer and contractors.
In the 1970s and 80s, a drive for buildings to be more sustainable and energy efficient led to the rise of the design-and-build method of construction, streamlining the building process and changing the procurement route. Increasingly stringent energy conservation targets have led to the greater use of foamed polymers for thermal insulation.
It is no secret that these materials are combustible, and we’ve moved to a position where we don’t just have fires in buildings but buildings on fire – where the fabric of the building is alight. This is not something that our fire services were trained and equipped for.
However, not all synthetic materials are bad – many are extremely eco-friendly and easy to use. There will be lots of buildings that are wrapped in polymeric thermal insulation that are perfectly safe and will encounter few problems.
When developers build with combustible materials, not only in terms of the thermal insulation but also in their choice of the building fabric itself, it is critically important that the systems required to maintain an acceptable level of safety are designed, installed and maintained correctly. These systems cannot, and should not, be omitted, reduced or redesigned.
In the past year, I have attended three serious fires where the timber-framed buildings – all large, multi-storey residential blocks – were destroyed.
We know that timber-framed buildings are a greater fire risk during the construction phase but, once completed, they should pose no greater risk to the occupants than any other building, so long as the fire safety measures are designed, specified and installed correctly.
In this type of construction, correctly installed cavity barriers play an even more important part in limiting fire spread given that the structure itself is combustible. Having said this, I don’t think that we should stop building with timber, but we do need to understand the increased risk, and design and build accordingly.
Improving Building Regulations
Building Regulations are intended to provide “reasonably” safe buildings and are expressed as a set of functional requirements. They’re telling us what is to be achieved but not how to do it.
However, the flexibility and ability to innovate that is inherent in the functional approach, requires technical expertise of a higher level than would otherwise be the case. In many cases, fire engineers, where they have been appointed, have failed their clients in not providing the right advice. This may be, in some cases, due to pressure from the client, but it is often because the engineer doesn’t have the right knowledge – a point raised by Dame Judith Hackitt. In many cases, however, a fire engineer isn’t appointed at all and it is left to the architect.
In the 1980s, the fire brigade played an instrumental role in assessing buildings at the design phase and was sometimes criticised for either responding late or requiring measures that were over and above those required by the building control department of the local authority. Today its role is different and, although still a statutory consultee, it is often consulted too late or not at all during the design process.
The changes needed to keep us safe
Fixing the industry requires unlearning many bad habits. The government, fire safety professionals, developers and designers must all make changes in order to repair a broken system. The overarching need is for competence across the entire construction sector.
Clearer regulation
Clearer regulation from the government about design, construction and ongoing management is critical to increasing safety. This needs to be done with a gentle hand if we want to maintain the flexibility we currently have in the way we design buildings.
There have been complaints that the guidance provided to meet the Building Regulations – the approved documents – are confusing and open to misinterpretation. I agree that some of the guidance can appear to be misleading, but I believe that problems usually arise because the people attempting to use those documents are not qualified to do so.
Clearer compliance networks
In addition to increased regulation, the fire safety industry needs to increase the adequacy of the compliance process. At its core, this is a matter of integrity and competence. Fire safety regulators need to say “no” when a building is truly unsafe.
It isn’t right that the independent building control authority has ceased to be truly independent, but this is being changed, and quite rightly.
Building safety as a system
Safety must be prioritised during the design phase for a safer, more resilient building when it comes to fire and other extreme events. If these measures are considered at the early stages of a design, the cost can be minimised.
A series of checks and balances should be employed to catch issues before the building is completed, with safety-critical items – such as cavity barriers, fire compartmentation inside the building and the stopping of services where these pass through fire-separating elements – being inspected during and after installation. This should be a minimum.
The technical experts and engineers must have the integrity to tell their clients the truth, even when it’s not what they want to hear. When they lack the knowledge themselves, they should insist that relevant experts are appointed to advise.
Building a safe and resilient building isn’t enough, though; the building must be maintained and maintainable for its entire lifetime. Building managers need to understand how the building was designed, and why, and be able to manage and maintain the systems in the building, whether these are complex active fire safety or suppression systems, or the seemingly simple passive fire protection elements, such as fire doors, dampers and walls.
These are not fit-and-forget systems. They are critically important life safety systems that are installed for one reason: to safeguard the health and safety of the occupants. They need to be designed, installed, managed, inspected and maintained correctly, and by people who understand the importance of their role.
A badly installed or maintained fire door is likely to end up being just a hole in a fire-resisting wall, and one that may put the safety of people in that building at serious risk.
The construction industry has learnt some tough lessons, and improvements have been made. It is fair to say that we, as an industry, still have some way to go, and “people over profit” may be a good mantra for us all going forward. The government has committed to making changes to building fire safety, and only time will tell whether we have gone far enough.
Steve Cooper is a partner with responsibility for fire engineering at Hollis
