Building standards - ministerial view: automatic fire suppression systems (ref. V2023/1)

Ministerial view of a case relating to automatic fire suppression systems which was referred to Building Standards Division (ref: V2023/1, section 2 - Fire, functional standard 2.15, domestic building).

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Functional Standard 2.15 Automatic fire suppression systems

Standard 2.15 states: Every building must be designed and constructed in such a way that, in the event of an outbreak of fire within the building, fire growth will be inhibited by the operation of an automatic fire suppression system.


This standard applies only to a building which:

(f) is a building containing a flat or maisonette

Clause 2.15.1 Automatic fire suppression systems

Alternative suppression systems - The applicant and the verifier should satisfy themselves that the alternative system has been designed, tested and approved for use in domestic and residential buildings and are fit for their intended purpose (see Section 0).

Watermist systems, for example, are bespoke to individual manufacturers and may be sensitive to small design changes. Therefore, a watermist system should be designed and installed in accordance with BS 8458: 2015 - TC (tracked changes) and the nozzles should comply with BS 8663-1: 2019 (provided the building is within the scope of the standards). Fire performance tests are critical as BS 8458 relies on this data to determine the system design.


South Lanarkshire Council

Technical Context

The building warrant application is for the development of 3 blocks of flats, each block containing 6 flats, with 2 flats on each storey. The height to the topmost storey is 6.3m.

The referral relates to mandatory standard 2.15 and to guidance clause 2.15.1 of the domestic technical handbook. Since the fire performance of the system in accordance with BS 8458 has not been fully demonstrated and the electronic nozzles do not meet BS 8663, there is doubt about compliance with the mandatory standard.

The view of Scottish Ministers

On behalf of Scottish Ministers, the Building Standards Division has considered all the information submitted in this case including the following supporting documentation:

  • Replicating the activation time of electronically controlled watermist system nozzles in B-RISK (Spearpoint et al., 2022)[1]
  • Plumis Suppression System Reliability Research Issue 02, Project Reference AF2809 (Ashton Fire, 2022)
  • BS 8663-1: 2019 and electronically controlled nozzles (Plumis, 2022)
  • Does Automist comply with the guidance within the associated British Standard? (Plumis, 2022)
  • Estimating the Suppression Performance of an Electronically Controlled Residential Water Mist System from BS 8458:2015 Fire Test Data (Hopkin et al., 2022)[2]
  • Automist hydra pre-engineered water mist system manufacturer’s declaration of conformity (mdoc) - For manufacturer supplied components and fire testing results (Plumis, 2022)
  • Verification Certificate No. VC 712581 – Automist Smartscan Hydra (BSI, 2022)
  • Automist Smartscan Hydra - Design, Installation, Operation and Maintenance (DIOM) Manual, Version 3 (Plumis, 2022)
  • BS 8458: 2015, Annex C: Method for Measuring the Capability of a Watermist System to Control a Fire – Room Fire Test for Watermist Systems with Automatic Nozzles. (Warringtonfire, 2022)

Building warrant applicants do not require to follow the guidance contained in the technical handbooks and can submit alternative designs.  Clause 2.0.8 states it should be appreciated that, due to the generic nature of the guidance it cannot cover all building designs or, for example, innovative or new methods of construction. In such cases the designer or engineer will be required to show, by alternative means, that compliance with the building standards will be achieved in the completed building.”

  • The Automist Multi-Room Smartscan Hydra system is a dry-pipe system with wall mounted electronic nozzles. The nozzles automatically scan for a fire on a signal from point detection within the compartment of fire origin. The installation uses hardwired detectors connected to a separate circuit. These detectors are independent and additional to the early warning alarms which are specified to meet the requirements of Standard 2.11. The infra-red sensor on the spray head searches for the point in the room where the temperature is increasing the fastest or reaches a peak temperature beyond a threshold and targets the hottest visible area.
  • The system has been tested in accordance with BS 8458: 2015, Annex C: Method for Measuring the Capability of a Watermist System to Control a Fire – Room Fire Test for Watermist Systems with Automatic Nozzles (Warringtonfire, 2022). These tests included multiple fire locations and forced ventilation introduced with a fan. The system successfully kept the temperatures below the pass criteria in each test. All relevant deviations have been recorded within the report. The system complies with clause 6.1(a) and (b) for domestic premises at a maximum room size of 80 m2 and a maximum ceiling height of 3.5 m.  
  • Electronic nozzles must be located in accordance with the manufacturer’s instructions and DIOM (2022) to avoid potential obstructions. Nozzles will be checked and verified  as suitable and clear during an initial site visit and subsequent annual maintenance. If any head is found to be obstructed, the Plumis Authorised Reseller Installer will issue the customer with a non-compliance notice and offer them a solution. Note that an information pack will be handed over to new owners or tenants and a QR code will be placed on each nozzle which directs owners or tenants to educational videos and advice. Given that the proposed system is not a common type of AFSS installation, it is recommended that the local authority impose a Continuing Requirement on the building warrant to reinforce to owners the importance of keeping the wall-mounted electronic nozzles free of any obstruction, decorative finish or other material to enable continued effective operation.
  • Plumis have conducted various fire tests with simulated real-life scenarios, including white goods fires, oil cooking fires, challenging fires under the spray head and concealed fires. In addition, five fire tests were also conducted with slow-growing fuel packages in a 4 m by 4 m room to evaluate the system's fire suppression performance against a traditional concealed sprinkler head. In each instance, the automist activated between 2 and 13.7 times quicker than the concealed fire sprinkler heads (Spearpoint et al., 2022)
  • In lieu of a UK certification program for electronically controlled nozzles, Plumis have completed a bespoke component testing programme on its product, including first-party (internal) and third-party (external) assessments. This programme uses many of the best practices from the ongoing UL certification of the US version of the product, and uses BS 8663-1 test protocols, or equivalent international certification protocols such as UL 2167. Plumis intend to complete a verification process with BSI against BS 8663-1 by the end of 2023 (dependant on BSI timings).

Having carefully considered all the information submitted in this case, it is the view of Scottish Ministers that the proposals do meet the requirements of Standard 2.15

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