Professor Jim Glockling discusses the challenges of responding to changes within the built environment and considers whether UK scientific expertise can provide pre-emptive assessment of risk to speed up the required regulatory adaption
Change follows disaster – we hear this phrase a lot when discussing UK fire regulation, and with good reason. Intentional or not this does seem to support the long history behind our fire code development. More recently though, disasters have not been followed by change, or the rate of necessary change has been glacial. The Grenfell tragedy will prompt further change I’m sure, but seven years on from that fire and with the release of the inquiry report, you do wonder what damage is being done in the meantime and whether there is still a need to wait for change.
Before covering the main topic of this article, it is worth considering some of the factors that are holding back pre-emptive change – the most efficient, beneficial, and lowest consequence form of intervention regulation can make. Top of the list must be that dreadful statement of ‘show me the bodies’. Every word speaks of a perverse intransigence, a willingness to only change once the most catastrophic outcome has occurred – it is the very definition of failure against a life-safety remit, yet its speaker is afforded the protection of often long statistical timescales that I assume they hope will never manifest during their period in post or lifetime. It also devalues the role of professionals in the industry who try to raise issues before they become a problem.
Experts and experiments
The UK is blessed with many professionals and institutions dedicated to fire safety and property protection, yet they struggle to exert influence or be heard by those in control of regulation who clearly purport to know better or are answering to a different remit. As we make the very necessary changes towards net zero construction methods, which we know to introduce much more combustible and possibly toxic material into construction in the form of timber structures and plastic insulation materials, incorporated in ‘void heavy’ assembly methods, a similarly problematic stance is the fanciful pursuit of safety parity when compared to the non-combustible material and methods they replace.
There is no ‘free lunch’ when faced with changes to fundamental material properties, change follows change, and either these need to be recognised and ameliorated through enforcement of additional safety measures in the form of active and passive protection and beefing up of fire service response, or an honest reassessment of (acceptable) anticipated life and property loss to fire needs to be made and openly declared – a perfectly OK thing to do, just be honest.
Denial of the combustibility of timber is rife – a thing that anyone with an ounce of common sense or a log burner would find ridiculous. On LinkedIn recently a statement was made about tests showing that mass timber could be considered “basically non-combustible”- perhaps a new definition which will cause as much confusion as ‘limited combustibility’ does to this day. I find arguments such as this to be as abhorrent and reckless as “show me the bodies” – we must not forget that the background to Grenfell was a small group of people managing to convince a large group of people (by fair means and foul), that materials which were unsafe for use and would promote fire, were safe to use and would not promote fire.
Having run fire laboratories for over 35 years I could easily devise a test to show that a sprinkler system supplied with petrol will put a fire out faster in an enclosure than water, but what’s the sense in that? Experimentation supporting safety must be performed with honest intent and generally in a worst-case setting. Input parameters are not to be unreasonably forced and success criteria curtailed to give the result sought – those willing to forgo scientific reason in rapid pursuit of their goal, no matter how well meant and needed will ultimately hinder the change that they seek and the world needs, as mistakes and mistrust stunt progress. Against a possible future life-loss event a day may come when those describing wood as ‘essentially non-combustible’ will have to stand in court and describe exactly what they were hoping to achieve with that statement. But if enough people start believing them, the foundations of another major tragedy have already been laid.
In the same LinkedIn thread, concrete was described as a ‘necessary evil’ which is troublesome on two counts. Firstly, it ignores the immense progress made in decarbonising the entire cement supply chain, and secondly, it completely fails to appreciate that the sensible and limited use of concrete is actually the greatest ‘enabler’ for the increased use of timber in the built environment and meeting our carbon reduction ambitions – it is a friend, not a foe. Fortunately, the wider mass timber sector and others appreciates and understands this, and the wisdom and benefits of protection and material hybridisation is published in Built By Nature’s ‘Mass Timber Insurance Playbook’ (available to download from the ASBP website), but it is not yet reflected in legislation.
A fresh look
Post-Grenfell, many groups of ignored experts can stand tall and say ‘I told you so’, but there’s little solace in that for anybody. From personal experience of supporting insurers over many years, a capable and expert sector who see firsthand the consequence of lax regulation, the choice often boils down to using their research resources to lobby an intransigent government, or produce guidance designed to cope with the known and uncorrected imperfections in the built estate. The sad truth is the latter is usually more successful – the ‘long-game’ is proving too long for those who need solutions now and as insurers flex their muscles in some quarters, such as large mass timber buildings, they are becoming the de-facto regulator who decides what gets built – a role they certainly never wanted but are forced to adopt.
Specific to all new construction methods, just as we need our building regulations to adapt, so too must all other guidance that contributes to compliance, operability, and insurability. It requires a fresh-eyed look at the basis of all supporting systems (guidance and standards) and a consideration of whether their history is based upon an assumption of traditional building methods, contents, and space usage, and whether adjustment is required when redeployed in other forms of construction, such as light timber, mass timber, light steel, and modular. It will no doubt sound odd, but a good case in point might be an apartment’s bathrooms. Traditionally thought of as ‘inert’ spaces that do not warrant the installation of sprinkler systems or special consideration, in a ‘modern’ setting of a timber building the risk profile can look very different:
- The replacement of non-combustible porcelain and glass fittings with plastic and fibreglass alternatives can mean they have a very high fuel loading for their floor area.
- Requiring access to all major services, they are often adjacent to the major vertical service risers which might be voids with combustible linings – an opportunity for uncontrolled vertical fire spread.
- In hotel settings they often form one wall of the room’s only escape route.
- The penetrations to service risers are large in size (e.g. sewer pipes) and high in number. Fire stopping through combustible walls into combustible voids places an enormous importance for correct function on these specialised devices.
- It is not uncommon for bathrooms to have a false ceiling above which air conditioning units are housed and loft hatches providing access to these spaces can provide a weak spot for fire spread.
- And of course, the ventilation duct, with no requirement for fire stopping can provided a route for both fire ingress and egress with both the wall’s interior (cavity) and exterior surface of the buildings cladding.
Not to be overlooked is the sensitivity of timber to water damage through long term exposure and rot. One UK cross-laminated timber building, built only in 2017 may well be pulled down simply because of the damage caused to the floor cassettes through what can only be described as normal bathroom usage and the imperfect use of silicon sealant. In this environment a shower curtain that falls only one inch low than the bath lip might be insufficient to avoid early demolition of a building that should stand the test of time much better.
Asking simple questions
Pre-emptive change demands an impact analysis be made and both sides of the equation must be considered that includes:
- What are the likely sources of fire?
- What is the likely outcome?
Simple questions are useful for demonstrating the extent of change that need consideration. All testing of timber structures is done using timber fires, but, given the example above, should there not be a plastic component to them? At the very least, the inclusion of plastic is known to raise temperatures and flame lengths, and I personally also wonder from what I have seen whether burning liquid plastic negates any protection afforded by wood char. Similarly, e-scooters are increasingly a prevalent source of fire of an intensity and growth rate like little else found in standard contents – how might this impact building response and are test standards for material fire stopping capability still relevant?
The likely outcomes of fire need consideration too. Regulation seeks to assure life safety and nothing else. In construction methods rich in wall voids, which might be combustible, protection is rather all or nothing. If the fire breaks into a void, out of reach of detection and suppression systems or fire service response, what detects and stops it? Are those in the building at higher risk of entrapment and just how long will the fire service need to remain on site following a timber building fire to manage smouldering and rekindling? My guess is two to three days. I wonder what their view is on having to do that.
Conclusion
In closing my final point is that ‘fire science’, is not ‘rocket science’. Many of the key challenges we now face do not need a crystal ball or the development of a statistically relevant body of evidence or worst still, to be ‘shown the bodies’, to demonstrably be important and in need of attention. The associations are simple and of the ‘if this, then that’ variety.
Time should not unnecessarily be wasted invoking change, the system needs to use the independent expertise of the UK to logically and pre-emptively address the emerging challenges – particularly those associated with meeting net zero.
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Jim Glockling is a Visiting Professor University of Central Lancashire. He can be contacted at jim@glockling.co.uk