As speculation grows about the impending release of the full Hackitt report, will the sector be able to provide the required answers to the most pressing concerns?
As the spring publication of Dame Judith Hackitt’s final review into fire safety of buildings draws closer, speculation about the impact of changes to building regulations is bound to increase.
Hackitt has already made it clear in her interim report, published in December, that building regulations are “not fit for purpose” and signalled big changes ahead.
Until there is clarity over the future regulatory landscape the industry can’t plan ahead – should developers with residential tall buildings with planning approval pre-empt likely changes to regulations with a redesign? And what about the effect on land values, and how should residential developers calculate viability for schemes further ahead?
One outcome of the Hackitt review is almost certain: the build costs of tall buildings will increase; the question is by how much
The impacts could be significant – some are suggesting the construction costs of tall buildings could increase by as much as 20%. The reasons for this increase come down to changes such as the use of non-combustible insulation on tall buildings, which takes up more space than foam-based alternatives, fitting sprinklers and providing a second means of escape.
Cost increases of this magnitude are said to threaten the future of high-rise residential buildings outside the price-inflated London luxury market and usher in a new era of mid-rise blocks that scrape in below the regulatory height cut-off for enhanced fire safety measures.
One outcome of the Hackitt review is almost certain: the build costs of tall buildings will increase; the question is by how much. In some instances costs have been driven down with an armoury of techniques including substituting products specified at design stage for cheaper alternatives, pushing the interpretation of building regulations to the brink and making the most of a fragmented, underfunded enforcement regime. Like a junk food addict, the industry needs to wean itself onto a much healthier and more expensive diet.
A focus on single, magic bullet measures like sprinklers or multiple escape stairs isn’t the answer. A holistic approach to fire safety – what Hackitt is calling for – is likely to be much more effective and doesn’t have to be exorbitantly expensive.
If the industry – in partnership with government – can provide answers to these issues, then buildings should be better-quality and safer without breaking the bank
Part B, the regulations that deal with fire safety, were designed to ensure tall residential buildings are sufficiently resilient to keep occupants safe in a building fire without the need for immediate evacuation. If Grenfell had performed according to the intent behind Part B, then the fire wouldn’t have spread as catastrophically as it did.
If this principle still holds, then measures including the use of non-combustible cladding materials above a certain height and the inclusion of resilient, fire-break floors designed to stop the spread of smoke and flames at regular intervals could be one answer. Escape stairs must be robustly isolated from other parts of the building and smoke extract systems up to the job of keeping the way out clear. Sprinklers have been required on buildings more than 30m high since 2006; these should already be more resilient than older buildings.
If the principle of residents staying put in a fire is abandoned, then there may be a case for multiple escape stairs, necessitating a larger core and building footprint. Escape stairs have limitations in tall buildings as it takes people a long time to descend them. An alternative to multiple stairs could be provided by stipulating the use of fire-resistant lifts, which wouldn’t take up more space than existing lifts and have the added benefit of enabling faster evacuation of buildings.
Other issues Hackitt says need addressing include:
- There isn’t a formal system for ensuring people making critical fire safety decisions are up to the job; their competence must be backed up with appropriate qualifications and experience.
- Extrapolating the fire performance of systems made up from a number of components using desktop studies that draw upon the test data of the combination of different components is questionable and should be restricted or curtailed.
- The use of small-scale tests to certify the fire performance of products needs revisiting – Grenfell’s ACM cladding behaved very differently in a real fire outside the lab. Although expensive, there is really no substitute for full-scale tests.
- Design and build would be enhanced with the use of design-to-site audit trails of the fire safety strategy and of the products used on site, backed up by the return to site of the clerk of works. Some developers are already reviewing design and build procedures and have reintroduced the clerk of works, Derwent being a notable example. The role of Building Control is to ensure that buildings conform to regulations and are safe; introducing competition and driving down costs is counterintuitive and needs an overhaul. Once buildings are handed over, there needs to be a robust, properly resourced fire safety management and monitoring regime.
If the industry – in partnership with government – can provide answers to these issues, then buildings should be better-quality and safer without breaking the bank.
Thomas Lane is group technical editor at Building