Lloyd Preston 
23 April 2024 
What are BS 9251 guidelines?
BS 9251:2021 guidelines provide a code of practice for fire sprinkler systems in domestic and residential buildings. They cover the design, installation, and maintenance of sprinkler systems in buildings of any height.
Compliance with the BS 9251:2021 guidelines is essential to ensure that fire sprinkler systems are installed and maintained to the highest standards, providing effective fire protection.
Building owners and managers can comply with the guidelines by reviewing them to ensure their sprinkler systems meet the requirements and by working with relevant experts and authorities to ensure compliance.
What is the BS 9251:2021 standard?
On June 30th 2021, BS 9251:2021 came into effect and superseded the previous BS 9251 2014 fire sprinkler guidelines. BS 9251:2021 specifies the design, installation, components, water supplies and backflow protection, commissioning, maintenance, and testing of fire sprinkler systems installed for life safety purposes in residential and domestic premises.
The new standard contained quite a few significant changes, with one of the biggest being the introduction of a new category of sprinkler system, category 4. Category 4 applies to residential and domestic buildings over 18 m in height, or above 4 storeys, whichever is shorter.
Overview of the categories:
Category 1: Typically a domestic dwelling for a single family. Calculations must allow for 1 or 2 sprinkler heads, with an average flow of 84-100 litres/minute, storage for 10 minutes supply and a tank size of 1 m³ to 1.5m³.
Category 2: Typically, a block of flats below 18m in height. Calculations must allow for 1 or 2 sprinkler heads operating, with an average flow of 84-100 litres/minute, storage for 30 minutes supply and a tank size of 3 m³ to 4.5 m³.
Category 3: Typically a residential Care Home. Calculations must allow for up to 2 or 4 sprinkler heads operating with an average flow of 168-200 litres/minute, storage for 30 minutes supply and a tank size 6 m³ to 9 m³.
Category 4: Typically a block of flats 18 m and above. Calculations must allow for up to 2 or 4 sprinkler heads operating, with an average flow of 168-200 litres/minute, storage for 60 minutes supply, split tank size 6 m³ to 9 m³ (2 x tanks required).
How do I comply with the BS 9251:2021 changes?
Sprinkler systems falling under this category must be equipped with a backup power source and automatic switchover capability. This entails having two power supply sources: a mains power connection serving as the primary source, and an uninterruptible power supply (UPS) serving as the secondary source. An automatic transfer switch should be in place to seamlessly shift the load from the mains to the UPS in the event of a mains power failure while the sprinkler system is operational.
Given that backup power supplies, such as UPS systems, are already mandated for other life safety systems with specified autonomy and runtime recommendations (including alarm systems, extinguishing systems and emergency and exit lighting), it was inevitable for BS 9251 to have these added as part of their revisions; incorporating more strict safety guidelines for sprinkler systems as well.
Following the Grenfell tragedy in 2017, significant resources were allocated to enhance the safety of occupants and visitors in high-rise buildings. Whilst the amendment to BS 9251 regulations refers to new constructions, it is highly advisable for existing buildings to consider updating their sprinkler systems to enhance the safety of their residents and visitors.
BS 9251:2021 Compliance with Dutypoint
If you are developing or refurbishing a residential building 18 m or more in height, it is likely that you fall within the remit of Category 4, and our expert engineers are here to help you find the right system.
All of our Dutypoint ResiSHIELD fire sprinkler pumps provide an instant response, intelligent system, designed specifically to meet the revised BS 9251: 2021 regulations and provide fail-safe continuous pressure to your fire sprinkler systems.
We also have ResiPOWER, our UPS system, which works alongside our ResiSHIELD range. ResiPOWER is an Uninterruptible Power Supply for fire sprinklers, which has a compact, modular design, a high overload capacity and a purpose-designed range of water ingress protection enclosures.
Learn more about the ResiSHIELD and ResiPOWER ranges today.
