Cladding focus


strongest arguments for using timber in housing is that it will help address the CO2 problem by sequestering carbon into our built environment. During discussions, it strikes me that very little consideration is given to what the customer actually wants. Market research overwhelmingly shows that people do not want to live in combustible buildings. Regulations are required to protect these customers because there is not the same freedom of choice when buying a house as there is when buying a car or a mobile phone. People also have total faith in the misplaced notion that meeting building regulations will ensure that the building is built to a standard of resilience which will protect the biggest investment they will make in their lifetime. This is something that would be addressed in my earlier point of reviewing the purpose of MHCLG and the aim of the regulatory body. Another popular view I have a problem with is that the design of buildings should be risk based and not prescriptive. I find the view that prescriptive regulations compromise creativity absurd. History has constantly shown that restrictions drive innovation and I’ve seen more new products since the combustible ban was introduced than in the previous two decades.


Risk based design issues


There are many issues with an exclusively risk based approach, first and foremost (and coming back to my original point) being who decides what is an acceptable risk. I believe this should be society’s decision, not some academic or engineer that thinks ‘one or two unfortunate cases’ is acceptable. Even if you could quantify the level of acceptable risk, this concept has a fundamental problem as it leads to ‘minimum’ standards for systems, components or materials that could be vastly inferior to what could be achieved at a similar cost. Almost the opposite way of thinking is using


an ‘as low as reasonably practicable’ (ALARP) principle – an approach that is also not ideal in our situation. It would be reasonably practicable to use significantly more expensive materials during construction for very little benefit. The ideal solution is a combination of both approaches, using a combined analysis of risk and consequences (failure mode and effects analysis) to set boundaries on what is ‘reasonably practicable’. This is why a combustible ban is deceptively effective and the beauty is in its simplicity to implement. To many it sounds like a clumsy tool or a knee jerk reaction, but in my view it encapsulates an effective solution, due to the nature of construction


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materials and the way their fire performance is classified under EN-13501-1: Fire classification of construction products and building elements. Classification using data from reaction to fire tests. For example, ALARP protagonists would say


(as the Royal Institute of British Architects did following Grenfell) that all external wall materials should be A1, as there are many to choose from at very little cost premium to A2 etc (often natural materials, but also coated metals in any colour or pattern you wish). However, A2-s1 d0 materials consistently prove to be no more practically dangerous and open up a much wider range of materials to choose from. A risk based analysis, on the other hand, might show that Class B (generally regarded as the ‘fire retardant’ materials) is sufficient. These are significantly better performing than unmodified (with flame retardant) materials and, if well engineered, are capable of meeting requirements necessitated by fire and rescue capabilities. However, for every Class B material, there is arguably an A2 alternative of comparable cost and significantly superior fire performance. A further problem with risk based designs


is that they are based on numerous variables that are hard to quantify accurately, such as the capabilities of the fire and rescue services (FRSs). As I’ve written before, I believe that buildings should be designed so that the FRSs can do their job, but the specification should not be based on their capabilities. That is akin to specifying the brakes on a car based on how well the airbag


FOCUS


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