Residential Conversions: Do We Understand the Fire Safety Risks?

The number of change of use schemes is set to rise as clients respond to a post-pandemic market, but project teams need to bear in mind the associated fire safety challenges, says Nigel Morrey, Technical Director at Etex Building Performance.

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Nigel Morrey

is a Technical Director at Etex Building Performance. With over 30 years of passive fire protection expertise, Nigel is responsible for the technical performance of Etex products. He sits on the Association of Specialist Fire Protection (ASFP) Council and is also a Director of the Finishes and Interiors Sector (FIS).

The change of use market is primed for growth. COVID-19 has reshaped the way we work, shop and live, accelerating the move to online shopping and establishing a precedent for more flexible working. No doubt retail and commercial asset owners will be reviewing their portfolios, assessing whether they are over-exposed in a post-pandemic world and if there are opportunities to flip offices and stores to residential.

John Lewis is a case in point. It has already mooted the idea of switching excess retail space into private rented housing. With the Government extending permitted development rights for these sorts of schemes, we’re likely to see many more projects coming down the track. But refurbishments and change of use developments aren’t without their challenges. When you alter how a building is used, you also change the measures required to make it safe – and that includes fire safety. Do specifiers, designers and contractors fully understand the fire protection requirements for conversion schemes?

The Government is bringing forward wide-ranging reforms to current fire safety regulations, but there are some basic principles that project teams need to follow, regardless of changes to national policy.

Establishing the facts

Common residential conversions, such as of former office blocks into new apartments, as well as structural changes, all require increased periods of fire resistance. A holistic consideration of passive and active fire protection measures is needed to meet this raised performance, as well as looking at how the strategy will need to be adapted for different areas of a building. In an apartment block, for example, escape routes like public corridors and staircases need greater protection than the flats themselves to allow time for people to evacuate and for firefighters to tackle a blaze.

However, before the specification can be buttoned down, teams need to know what they are dealing with. Many assets with potential for conversion in today’s market will have been built in the 1960s and 1970s with reinforced concrete. These refurbishments come with pre-existing issues. Dirt, damage and contamination, as well as the structural design, can all impact the fire protection specification. Has a concrete slab been painted? If so, that paint might be incompatible with fire-resistant materials applied on top. Will an increase in loading cause the concrete structure to deflect? If so, will mesh reinforcement need to be added to the fire protection system?

Teams won’t always have the facts to hand. Depending on a building’s age and the quality of records, it can be hard to know what was installed previously. On one project Etex supported, the team was unable to determine the level of concrete cover for the reinforcement in the building’s concrete decks. The safest option, in this case, was to choose a solution that covered all circumstances, that meant using specialist fire-rated boards.

Reviewing the numbers

Whatever the route taken, teams need to plan early and think about how their decisions will impact a project’s wider design. Upgrading passive fire protection can increase a building’s footprint. To return to our concrete structure example, a concrete column’s fire resistance is influenced by its size, the position of the reinforcement and the amount of concrete cover over the reinforcement. In a refurbishment, those factors are predetermined, so if you want to increase the period of fire resistance, you’ll need to affix additional material to the column. That; in turn, means cutting down on lettable or saleable floor space – something which will need to be factored into clients’ financial calculations for a development.

People, product, performance

Once a strategy is set, and its implications understood, the final step is responsible procurement. The Grenfell Tower tragedy has shone a light on the importance of clients, architects and contractors asking more demanding questions about products’ provenance and testing processes. A desired level of performance might have been set out in the specification, but it’s important to know that material systems can live up to this.

Proper installation is key. As well as matching fire protection measures to the needs of each building, project teams also need to make sure that the people responsible for installing and maintaining fire safety materials in the long-term have the required knowledge to do so accurately and safely. This means only using accredited specialist contractors.

Fire safety is higher up the development and construction industries’ agendas than it has ever been. There have been calls for greater knowledge sharing and collaboration across the supply chain and a cultural commitment to doing things in the right way. This is our chance to make those aspirations a reality as clients explore live development opportunities in towns and cities across the country, delivering successful schemes and creating homes that are safe.

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