The recently updated BS 9991 and dual power supplies

Posted by Conor Logan on 01/12/15 12:00

BS_9991_2015_Fire_safety_in_the_design_management_and_use_of_residential_buildings.jpgA major update to BS 9991 “Fire Safety in the Design, Management and Use of Residential Buildings - Code of Practice” has been published by BSI and will come into effect on 31 December 2015. The Smoke Control Association, which I chair, played an instrumental role in this update.

Dual power supplies for smoke control systems are mandated. However this Standard now permits a lot more flexibility in their provision, which is very welcome given how often it is difficult to obtain them.

The scope of BS 9991

The previous version of BS 9991 provided for an “enhanced smoke management system”. This enabled designers, occupiers and approving authorities to allow a degree of flexibility in the provision of fire safety measures as part of the overall design package. This guidance remains.

As before, BS 9991:2015 gives recommendations and guidance on the design, management and use of residential buildings so that they attain reasonable standards of fire safety for all the people who are in and around them.

The standard applies to the design of new buildings, and to material alterations, extensions and material changes of use to existing buildings.

BS 9991:2015 also provides guidance on the ongoing management of fire safety in a building throughout the entire lifecycle of the building. This includes guidance for designers to ensure that the overall design of a building assists and enhances the management of fire safety. The recommendations and guidance given are intended to safeguard the lives of building occupants and fire-fighters.

New recommendations for power supplies

Where practicable, power supplies should be provided via two separate intakes into the building from the same external substation or via a single intake and a standby generator.

Where neither of these options is technically viable, e.g. a risk assessment has been undertaken which concludes that a life safety generator would not be suitable, a single intake from the external substation may be provided as the only alternative option remaining, based on the installation meeting a number of criteria set out in the Standard.


Conor Logan Conor Logan is a Technical Manager of Colt UK, Smoke and Climate Control Division. Conor designs innovative smoke control and HVAC systems and is also Chairman of the Smoke Control Association.

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Topics: Smoke Control, Regulations