WHAT ARE THE FIRE IMPLICATIONS WHEN A BUILDING OWNER PLANS TO ADD THREE EXTRA STORIES TO A TOWER BLOCK?
By Iain Cox, Chair of the Business Sprinkler Alliance
A property owner has submitted a planning application to add three additional stories to a north London residential tower blocks to help fund the removal of unsafe ACM cladding on the lower 14 floors. Whilst the concept might be sound on paper, the design has considered the fire safety aspect and how to keep people safe in a building that will be changed?
The owner of Premier House, in Edgeware, north London, is planning to add three additional stories and a rooftop garden to the building to partially fund the remediation work on the rest of the building. This planned alteration also brings into sharp focus the 2020 change to Permitted Development Rights (PDR) allowing building owners to add up to two storeys on top of existing detached and purpose-built blocks of flats through a fast-track process. In either case, it is critical to ask the question, how has the risk changed by adding these floors?
Upward extension such as the one proposed at Premier House need to be carried out after careful consideration and assessment of the existing building and its fire strategy. Which sort of evacuation plans are in place for the current building? How many extra people will be altered residents in the building? Will the staircase and door widths accommodate these additional people and provide access to firefighters? The new extension which material is going to be made? Will it alter materially the fire load? The changes need to be considered holistically not on the addition alone.
There is a tendency to think about the structure, aesthetics and thermal efficiency of the new sections of the building when undertaking such alterations. What is needed is to reconsider the fire safety of the building from the ground upwards. Renovations and changes such as these are often intended to make the building better for its tenants. Unfortunately the law of unintended consequences often means that these intentions are not realized.
Another consideration is the new 11-metre storey height sprinkler threshold that came into force last November. This will be an interesting case to follow as this change will have implications for the overall building. Regardless of this change, from a fire safety perspective sprinklers make a lot of sense and are a key component in the long-term strategy of any building. If considered early in the design process, they can be included and implemented whilst balancing costs. Developers need to have an open mind to other fire safety solutions, particularly sprinklers, and think about the best solutions to employ for such a change considering the building as a whole
Early consideration of automatic sprinkler systems in the design process, opens up a number of significant design opportunities which could provide solutions, to the challenges such projects will inevitably face. This will only happen when the fire strategy for the whole building is considered at the start of a project. We must stop thinking of fire safety as an ‘add on’.