The construction industry is due for a shake up when the government introduces reforms to fire safety rules, which will abolish fire certificates. B&E hears from Russell Harri, Technical and Marketing Officer with Arcelor Construction about how contractors can use the building envelope to improve fire safety.

STATISTICS produced by the former Office of the Deputy Prime Minister show UK Fire and Rescue Services attend over 500,000 fires each year.

The number of fire-related deaths reported each year now exceeds 600 and that of fire-related injuries exceeds 16,000, while the financial loss to the UK economy in terms of business disruption is measured in billions of pounds.

Statistics such as these have led to growing concerns about fire risk among building occupiers, owners and insurers, which in turn has focused attention on the fire performance of construction materials in general, and composite or sandwich panels in particular.

Industry accreditations, such as LPCB approval, are increasingly being used by product manufacturers to provide additional comfort but specifiers need to understand what these accreditations mean and how these relate to the fire regulations.

It should go without saying that sandwich panels do not start fires on their own. Indeed, fire statistics confirm that fire spread via the external envelope is not common.

A technical briefing by the Association of British Insurers (ABI) on the fire performance of sandwich panel systems states that where these systems have been implicated in fire spread, the fire has often started in high-risk areas such as cooking areas, subsequently spreading as a result of poor fire risk management as well as prevention and containment measures.

Prevention of ignition and containment of early fire spread are critical, and specific and detailed risk assessment is crucial. Where high levels of risk management are not achievable, due to the nature of the processes of the business and/or the quality of the management, and the risk of ignition is high, the use of panel systems with high fire performance characteristics should be considered. Systems meeting accreditation schemes such as LPS 1181 or LPS 1208 demonstrate such characteristics.

In the fire performance of construction materials, wall panels form a critical element of a building so the composition of these panels is vitally important and should be considered no later than at design stage. There are an increasing number of composite panel products available in the UK, most of them claiming excellent fire performance but specifiers also need to be aware that these products are not all the same, to ensure they select a product that meets their requirements.

The fire performance of a fire-wall construction is time-related, with half an hour, an hour or two hours denoting the minimum time period the product must fulfil its fundamental requirement as a firewall.

The wall must not allow the passage of flame or hot gases one from side to another since clearly, if flame or hot gases pass through gaps or joints the product has failed to meet the fundamental requirement.

The temperature of the face of the wall away from the fire must also be maintained within prescribed limits since if the face of the wall reaches a temperature which could cause a flashover, then the construction has failed.

Only when the fire performance of a wall panel is tested and proven for both internal and external fire exposure can it be suitable for compartment walls or external walls situated less than a metre from a boundary.

In order to obtain LPCB certification (to LPS 1208 for elements of construction used to provide compartmentation), manufacturers have to put their composite wall panel products through an extensive series of tests to demonstrate their ability to resist fire from both directions.

A key distinction is between composite panels manufactured with PIR foam core and a mineral wool core. Despite the fact that many PIR panels are accredited to LPS 1181, these products are generally only suitable for fire exposure from the inside of the building, which limits their application to firewalls situated away from the boundary.

By contrast, composite panels with a mineral wool core are typically suitable for a much broader range of applications. Products such as these have been tested and proven for both internal and external fire exposure on the three key criteria for firewall construction - stability, integrity and insulation. As such, they can be used for compartment walls and external walls situated less than a metre from a boundary, as well as in more standard applications.

In the case of Promfire, for example, a range of different panel thicknesses and fixing regimes were tested, satisfying the LPCB that the panels can provide fire resistance for up to two hours (to LPS 1208 for elements of construction used to provide compartmentation). The tests were conducted in accordance with EN 1364-1 – Fire Resistance Tests for Non-Loadbearing Elements (Walls).

The installation requirements for fire-resistant insulated panels also vary depending on the type of product. For example, some PIR cored panel systems (that in any case are only suitable for locations one metre or more from a boundary) have to be installed in maximum two-metre lengths and require additional joint restraint fasteners and internal joint cover plates fixed at 250mm centres.

Mineral wool panels on the other hand, can typically be installed in lengths up to 13 metres with a maximum span of four metres, and require no additional fasteners or internal cover plates. These differences in installation requirement can become important in terms of construction times and access costs. Much of the damage caused by fires is smoke damage rather than damage caused by the flames and an additional benefit of utilising composite panels with a mineral wool core is that these products give off less smoke than PIR cored panels in the event of a fire. For instance, Promfire achieved A2-s1,d0 to EN 13823 (Single Burning Item Test).

As part of the Government’s commitment to reduce death, injury and damage caused by fire, the Department for  Communities and Local Government is reviewing fire safety law and is making a number of changes that are designed  to make the law easier to understand and comply with.

These changes, which form the Regulatory Reform (Fire Safety) Order and relate to non-domestic premises, come into force shortly when fire certificates will be abolished and cease to have legal status.

No better time then for specifiers and contractors to review their approach to building fire safety into buildings long before the foundations are laid.