Changes to BS 9251:2021 – Secondary Power Supplies Now Mandatory Tuesday, Dec 07, 2021 What is the BS 9251:2021 standard? The new BS 9251:2021 came into effect on the 30th of June 2021 and contains some quite significant changes that could see many landlords and residential building owners being caught out. The standard gives recommendations for sprinkler systems installed for life safety purposes with additional benefits for property protection. The biggest update is the introduction of a new category of sprinkler system, category 4, which applies to residential and domestic buildings over 18m in height or above 4 storeys (whichever is shorter). How do I comply with the updates? Sprinkler systems in this category should be ‘provided with a back-up power supply and automatic changeover functionality’. This means two power supplies should feed the sprinkler system. A mains supply as the primary power source, and an uninterruptible power supply (UPS) as a secondary power source, with an automatic transfer switch to transfer the load from mains to UPS in the event of a mains power failure while the sprinkler is in use. Since the Grenfell tragedy in 2012, a lot of money has been spent on making high-rise buildings safer for their residents and those in the building. This has largely been achieved through regulatory updates surrounding life safety equipment. Backup power supplies such as UPS systems are required on other life safety systems with recommended autonomies and runtimes, so it was only a matter of time before BS 9251 was also updated to include stricter safety recommendations for sprinkler systems. A reliable power supply is critical during an emergency as most life safety systems are reliant upon electricity to operate. A drop or fluctuation in power could result in the failure of these life-critical systems resulting in a risk to life. The recent storm Arwen showed just how vulnerable the mains power infrastructure is. As winds of over 98mph tore down power lines on Saturday 26th November, over 3,000 residential buildings in the North East of England lost their power supply for over a week. By Monday 6th December there were still 86 residential properties without power in Cumbria and 30 in Scotland. Had there been an emergency such as a fire during this prolonged outage, those without a secondary power supply would have been without power to their life safety systems. Sprinklers would have been out of action putting the lives of residents at risk. With storm Barra forecast to hit the UK this afternoon (Tuesday 7th December 2021) many more will be left without power with a danger to life in some parts due to the conditions. For owners of residential buildings, it is crucial to ensure residents are kept safe if a fire were to occur by keeping up to date and adhering to safety regulations such as BS 9251. Residential property owners must also note that should a battery backup be used as the secondary power supply to support life safety systems, it should be compliant with BS EN 50171 regulation. More information about this regulation can be found here. Contractors, Engineers, Surveyors and Architects are among a larger list of people who need to be aware of the amendments to the 2014 edition of BS 9251. Although the amendment to BS9251:2021 only applies to new constructions, it is recommended that existing buildings update their sprinkler systems to ensure the safety of residents. Power Control Ltd specialise in retrofitting uninterruptible power supplies (UPS) and central power supply systems (CPSS) into existing infrastructure. The secondary power supply specialist can also put you in touch with partners who specialise in sprinkler systems and other life safety equipment for domestic and residential premises. Power Control has been specifying, supplying, installing, commissioning and maintaining life UPS for safety systems for over 25 years and has built long standing relations with renowned UPS manufacturers. Both Borri Spa and Legrand use quality European parts and manufacture their central power supply systems (CPSS) to the highest standards.