EB-10 Residential Sprinklers

Residential Sprinklers

A sprinkler system can be defined as a series of pipes and sprinkler heads that is intended to spray water over a fire with the objective of controlling and suppressing it. Residential sprinklers are a relatively new concept in the UK, although sprinkler systems in industrial and commercial premises have demonstrated their effectiveness and usefulness over a number of years. It is for this reason that they are now being considered for use in homes, and the Home Office and the fire service now recommend this technology for residential premises.

Residential sprinklers were first used in the United States, as a result of the large number of deaths and injuries occurring in residential premises. These suppression systems are now well developed and are used all over the world to improve fire safety in homes.

Installation
Installing a residential sprinkler system is not as complex as putting in a plumbing system. The materials used for the pipes can vary from PVC to copper, and the overall cost of an installation is approximately £1500 in a typical three-bedroom house.

An average sized room (15m²) only requires two sprinkler heads to ensure an adequate level of protection.

Today’s levels of research and technology mean that sprinkler heads and pipes can fit into the décor of the premises. They can be installed in the ceiling and walls, and the sprinkler heads can remain hidden in the ceiling until needed to operate.

The water pressure required for a sprinkler system is surprisingly low, as it acts when the fire is still small. The system can usually be directly connected to the domestic water supply, with no need for extra water supplies or pumps. There will be some instances when the water supply provisions are poor, and cannot be used to supply the sprinkler system. In such cases, additional equipment such as pumps and water tanks may be necessary.

Operation
Residential sprinklers operate on a head-by-head basis, triggered by the heat released from the fire. Each sprinkler head contains a fusible link that will activate at temperatures typically ranging from 57^oC to 79^oC. Once operated, the system reduces:

The temperature of the fire and surrounding area
The size of the fire
The production of smoke and toxic fumes

The residential sprinkler system can, as an additional safety feature, activate the house’s fire alarm system (should it be fitted with a means of warning), alerting occupants in other rooms.

Accidental water discharge is a possibility when installing any type of sprinkler system. But statistics and past experience have shown that the probability of accidental discharge of an adequately installed and maintained residential sprinkler system is very low.

What about maintenance?
The point has been made a number of times that homeowners and building managers will be incapable of adequately maintaining a residential sprinkler system, which is very similar to a central heating system, but less complex. The problem for homeowners and building managers is therefore similar to arranging servicing for their central heating pipes and boilers.

The water in a residential sprinkler system is static in the pipes, so there is a possibility of freezing in the winter. This problem can be avoided if the system has been properly installed and suitably lagged to recognised standards.

Life-safety benefits
The life-safety benefits provided by residential sprinkler systems cannot be easily calculated for the UK, as they constitute a new technology in this country. But information and statistics from the USA are encouraging. Research over a ten-year period has shown the following:

No fire deaths
80% reduction of fire injuries
80% reduction in property damage
95% reduction in water usage for fire control

With statistics like these, the US government has decided to support a nationwide campaign to promote the installation of residential sprinklers.

Property protection
A general misconception about sprinkler systems is that they operate throughout the building when a fire has been detected. This idea is misleading, and it should be remembered that sprinkler systems operate on a head-by-head basis.

Residential sprinkler systems provide a number of property protection benefits.

Firstly, the quick reaction of the system and the rapid dousing of a fire will limit the extent of damage that the fire could have caused.

Secondly, a residential sprinkler system is designed to use less water to control or extinguish the fire than the fire brigade. A sprinkler discharges, on average, between 38 and 40 litres of water per minute. A fire-fighter’s hose will discharge up to 250-plus litres per minute at the same fire.

Sprinklers therefore reduce not only the extent of damage caused by the fire, but also the amount of water needed to extinguish it. This can only have benefits for property protection.

Applicable legislation
The first mention of residential sprinklers in UK legislation was in the 2000 draft document 251: Sprinkler systems for residential and domestic occupancies – Code of practice. Two years later, DD 252 was released – Components for residential sprinkler systems – Specification and test methods for residential sprinklers; a document which has to be used in conjunction with DD 251. In 2005, DD 251 was superseded by the new BS 9251, putting in place prescriptive requirements for the design and installation of sprinkler systems in residential premises.

Designers are increasingly considering the provision of sprinklers in residential premises. This trend has been encouraged by comments made in forthcoming legislation. BS 9999 and the new Approved Document B allow for design flexibilities when sprinklers are installed in a building.

Design flexibility
The consideration for residential sprinklers within the coming fire safety guidance allows for a certain degree of flexibility when proposing alternative solutions in a building’s design. As an example, the new Approved Document B (Still a Draft Document) allows the removal of one exit route in a typical four-storey house or multi-storey apartment if a residential sprinkler system is installed.

The Building Research Establishment has published a research paper on the effectiveness of sprinklers in residential premises. The experiments undertaken considered typical fire scenarios in a typical three-storey house. The tests compared the fire conditions (toxicity, visibility and heat) in the house when equipped with a residential sprinkler system, and without. The results are self-explanatory and show a high level of effectiveness when the sprinkler system is provided.

This new technology will certainly have an impact on the level of life safety in residential premises, and will allow architects and designers to consider additional uses, as an alternative solution to either a new design or a non-compliance issue.

The fire brigade
A number of fire services – Wiltshire, Merseyside, and West Yorkshire, for example – have participated in projects looking at installing sprinklers in residential premises. These systems not only have a positive impact on the safety of the building’s occupants, but also on the protection of the fire-fighters. When attending fires in premises where a residential sprinkler system has been installed, fire service personnel face a lesser risk of personal injury.

Conclusion
The installation of residential sprinklers provides significant benefits. Experience in the USA has shown that they can save lives and protect properties. With the incorporation of residential sprinklers in future fire safety legislation documents, we believe that these systems will be increasingly used throughout the UK.