The Building Regulations in England and Wales, and also those in Scotland, are framed quite flexibly. Although the statutory requirements of the regulations are not laid out in great detail, they allow innovations both in terms of new products and in terms of unusual layouts, provided that the building remains adequately safe. In addition, specific guidance is provided in order to "set the bar" appropriately. The same is true of the Housing Act and the Fire Safety Order, when it comes to the ongoing operations of a building.
Approved Document B (Volume 2 Appendix F section 4) describes how fire suppression is one of the tools that can be used to mitigate a specific fire risk, within a risk assessment approach to fire safety. The LACoRS guide agrees: in sections 26.8 to 26.9 it discusses potential design freedoms enabled by water suppression systems and states:
"as part of a comprehensive overall fire risk assessment they can be a key component in the overall solution and can contribute to a safe building. In particular the provision of a suitable water suppression system can, in some circumstances, allow for relaxed provision of certain other fire safety measures (but not all). Some examples of design freedoms which have been applied include reduced fire separation/compartmentation, an alternative to a secondary means of escape where impracticable, extended travel distances and relaxed requirements for inner rooms. ... These trade-offs or ‘design freedoms’ are not prescribed in any statutory guidance and must be agreed with the relevant local housing authority, building control authority and fire and rescue authority for each individual case. Each case will have different factors and must be considered on its own merits. A blanket approach to the allowance of design freedoms should not be applied."
Studio Flat Example
Let's take the example of a studio flat which has its kitchen area near the exit. Approved Document B (Volume 2 section 3.33) normally prescribes that in small premises,
"Any kitchen or other open cooking arrangement should be sited at the extremity of any dead end remote from the exit(s)".
However, with fire suppression installed, it may be acceptable to vary this layout, and there can be good reasons to do so. For example, placing the kitchen remotely from the door may compromise a view, destroying the architect's concept for the premises. The flexibility inherent in UK law allows layout variations for aesthetic reasons as long as they are coupled with fire suppression (or other appropriate measures) to render them appropriately safe. When Automist is used in this way, its use may need to be supported with a risk assessment or fire engineer's report, and the authorities will evaluate such projects on a case-by-case basis.
Lack of fire rated doors
Another example of using Automist to address a specific risk is where a period building has original doors which are not fire rated, but the plans are otherwise compliant with Approved Document B's principles. In such a situation, it is possible to use Automist to reduce the requirements on the doors, in conjunction with an analysis of the proposed doors' material properties and likely fire/temperature performance.
As shown in the BRE fire testing, Automist was capable of limiting temperatures at or below approximately 100°C within the fire compartment. Providing the chosen door performance is capable of maintaining its integrity at temperatures of 100-150°C and the accommodation falls within the design parameters for Automist coverage, this proposal can be justified as achieving an equivalent level of performance.
View some case studies - Automist used to mitigate a fire risk.