Quality cabling plays critical role for sprinkler system safety

Calls have been made recently by a number of influential industry bodies to make the installation of sprinklers mandatory in public buildings following a number of tragedies. Graham Turner of AEI Cables explains why the quality of cabling providing power for these systems is critical.

Sprinkler systems are a very simple fire safety device to protect people and property in the event of a fire. When the temperature in a room fitted with a sprinkler reaches 60-70°F, the sprinkler sprays water across the room and suppresses the fire that has caused the rise in temperature.

Providing continuous power to sprinkler systems is a key component of improving fire safety in buildings nationwide and enhanced fire performance cabling plays an essential role.

Buildings such as tower blocks, hospitals, schools, shopping malls, airports and those areas with large numbers of people moving about need cabling which will continue to operate in a fire and provide power for the highest fire protection requirements.

This ensures fire and rescue services can safely evacuate people and that sprinklers will continue to operate in the event of a fire and importantly, helps to reduce the risks to firefighters during operations.

Cables can be designed for these specific environments and tailor-made solutions are relevant particularly in high risk areas such as intensive care areas of hospitals, care homes or schools.

These solutions require a high level of performance from the components of the building services including electrical supplies Installers of cables for these applications should check the guidance provided under BS 8519 which aims to ensure that the level of circuit integrity for life safety and fire-fighting applications are not compromised by other components of the whole electrical distribution system, including cable glands, terminations, joints and cable support systems.

BS 8519 gives guidance and recommendations on the selection and installation of power and control cable systems, while making reference to three categories of circuits required to maintain their circuit integrity under defined fire conditions for varying fire survival times of 30 minutes, 60 minutes and 120 minutes.

It also identifies the need for dual redundant electrical supplies run via diverse cable routes, installed within separate fire compartments, and the need to incorporate automatic changeover devices, located within the same fire compartment as the life safety and fire-fighting equipment.

Sprinkler systems rely on continuous power supply using cables of the highest quality designed and manufactured to the very highest standards and third-party approved by leading organisations nationally and internationally such as BASEC, LPCB and Lloyds.

At AEI Cables, we have been developing fire performance cables which ensure critical fire-safety circuits can continue to operate in the event of a fire from 30 minutes up to 120 minutes. Using the very latest in technology and science, the Firetec Total Fire Solutions range offers diverse cable types, accessories and technical support from one source and working with parent organisation Ducab, it offers tailored design, manufacture and supply of cabling for these applications.

The ultimate fire performance cable is Mineral Insulated Cable (MIC), guaranteeing data transmission and security of power by exceeding the requirements of BS 8519 and providing circuit integrity up to to 950°C. With a solid copper conductor and compressed magnesium oxide powder insulation and solid copper sheath, MIC is inorganic and will not burn in the event of a real fire.

Also at the higher end of requirements, Firetec Impact Power is designed to meet the application of fire, direct impact and water jet making it suitable for use as 120 minute rated category 3 power cables under BS 8519, while Firetec Enhanced cable is suitable for fire alarm systems meeting the requirements of category 1, 2 and 3 control circuits as defined in BS 8519. The mica glass tape is applied directly over the conductor to ensure the best possible enhanced fire performance. 

The effectiveness of sprinkler systems is well known and calls have been made from numerous influential bodies including the Royal Institute of Chartered Surveyors (RICS), the Royal Institute of British Architects (RIBA) and the Chartered Institute of Building (CIOB) to make the installation of sprinklers mandatory in all residential buildings, hotels, hospitals, schools and care homes taller than 11 metres. The same organisations have also called for sprinklers to be retrofitted where possible.

Ultimately, sprinkler systems provide protection from fire damage and, most importantly, they give people a greater chance of escape if there is a fire. By reducing the damage and severity of a fire, they can also save money, too, and are a benefit for asset owners when considering insurance premiums.

The fire safety measures of any building rely on compartmentation which needs to be in place to stop the spread of fire. This can sometimes restrict the design of the building’s internal layout. If sprinklers are fitted, the restrictions can be reduced, so a designer has more creative options within the internal space of the building.

Facts and figures validate why sprinkler systems are a key consideration as the fire safety industry examines strategies to make our buildings safer in the wake of numerous tragedies including Grenfell.

Studies have shown that sprinklers operate on 94 per cent of occasions and when they do, they extinguish or contain the fire in 99 per cent of incidents. They also reduce fire injuries and fire damage by 80 per cent. 

Indeed, the recommendation from the Fire and Rescue Service is that the Government lowers the height threshold at which automatic fire suppression systems (AFSS), such as sprinklers, are required from 30 metres – which equates to 10 storeys – to 18 metres or lower depending on the outcome of the Government’s reviews of Approved Document B and other aspects of building safety. 

The FRS also wants to see AFSS, such as sprinklers, installed in all new premises where vulnerable people sleep, such as care homes and residential schools. 

For these applications, independent third-party approvals are important and all AEI Cables products are approved by relevant industry bodies including BASEC and LPCB covering design, manufacture and supply. AEI Cables also holds approvals from organisations including Lloyds, the MoD, Network Rail and LUL and works to international standards around the world.

The installation of automatic sprinklers allows more freedom of design of new modern buildings for architects, leading to savings in initial capital costs, lifecycle costs and the construction programme. For example, installation allows larger compartment sizes, reduced structural fire protection requirements, reductions in fire-fighting shafts and reduced circulation areas, leading to an increased useable area.

The Hackitt Review into the Grenfell disaster sets out a series of proposals to make tower blocks safer to live in but stops short of recommending a mandatory requirement for sprinklers to be fitted. With the appropriate other components, sprinkler systems seem to be a crucial step in helping to make our buildings safer.

Not only are these measures proven to be more effective in enhancing building safety, but introducing them provides reassurance to residents and others moving about in these buildings who are becoming increasingly concerned about their safety.

Graham Turner has more than 40 years’ experience of working in the cabling and electrical engineering industry and provides advice for organisations across the fire performance industry. Email enquiries@aeicables.co.uk or tel 0191 410 3111. Seewww.aeicables.co.uk

Author: Cable Technology News Team

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