BS 9991: 2024 and Water Mist Systems – Understanding the Guidance
There has been some confusion regarding the omission of water mist systems from BS 9991: 2024, leading some to believe that this standard excludes their use. However, this is not the case. The absence of a specific reference to water mist does not mean it is unsuitable – rather, BS 9991: 2024 solely provides guidance on sprinkler systems. For any other type of fixed firefighting system, specifiers should refer to BS 5306-0: 2020.
Understanding BS 9991: 2024
BS 9991: 2024 establishes fire safety principles, particularly for residential buildings, and provides recommendations for sprinkler systems. However, it does not cover other types of fixed firefighting systems. The document explicitly states:
“This British Standard does not give recommendations for any type of fixed firefighting system other than sprinklers. Guidance on the selection and key design considerations of fixed firefighting systems is given in BS 5306-0: 2020.”
Additionally, it clarifies that:
“As a code of practice, this British Standard takes the form of recommendations and guidance. It is not to be quoted as if it were a specification.”
“Users may substitute any of the recommendations in this British Standard with practices of equivalent or better outcome.”
Where Does Water Mist Fit In?
iMist specialises in high-pressure water mist fire suppression systems, not sprinkler fire suppression systems. Given that BS 9991: 2024 is limited to sprinkler system guidance, specifiers intending to specify a water mist system should instead refer to BS 5306-0: 2020, which clearly identifies water mist as suitable for domestic and residential properties, as shown in Table 1 of the standard.
Compliance with Industry Standards
iMist high-pressure water mist fire suppression systems are designed, manufactured, installed, and serviced in full accordance with BS 8458: 2015 – the recognised standard for residential and domestic water mist systems. BS 5306-0: 2020 states that water mist is suitable for use when it fully complies with BS 8458: 2015.
Summary of Relevant Standards
- BS 9991: 2024 – Provides fire safety principles and guidance on the need for a fixed firefighting system. Clause 17 states that the standard applies only to sprinkler systems. For any other system, refer to BS 5306-0: 2020.
- BS 5306-0: 2020 – Offers guidance on selecting fixed firefighting systems, including water mist. Table 1 confirms that water mist is acceptable for domestic and residential buildings.
- BS 8458: 2015 – Specifies the design, installation, and performance requirements for water mist systems. iMist fully complies with this standard, ensuring it meets the necessary criteria set out in BS 5306-0: 2020.
Frequently Asked Questions (FAQ)
Q: Approved Document B states that I must use a sprinkler system, can I still use iMist?
A: HSE documentation states:
“Nothing in the Building Regulations or Approved Documents prevents the person carrying out the works from adopting higher standards or demonstrating compliance by other means.”
No published document directly compares and cross-references the performance and effectiveness of a domestic iMist™ water mist system designed to BS 8458: 2015 and sprinkler systems designed to BS 9251: 2021. Therefore, to assist specifiers, we have put together this overview that highlights how iMist is a viable solution.
Conclusion
Water mist systems remain a viable and effective solution for domestic and residential fire suppression. While BS 9991: 2024 does not provide guidance on water mist, it does not preclude its use. Instead, it directs specifiers to BS 5306-0: 2020, which recognises water mist as a suitable alternative to sprinklers when compliant with BS 8458: 2015.
For those seeking a high-performance fire suppression system, iMist offers a fully compliant, proven water mist solution that is specifically designed for individual residential and domestic settings. For further details, see our test reports and accreditations or get in touch with our team for more guidance.
