Building regulation requirements

Insurance requirements

Building requirements are expressed in terms of minimum class.

In very few situations (e.g. boundary buildings of specific purpose in Scotland ), non-combustible materials are required. In these situations the paint coating prevents pre-finished steel from technically qualifying for non-combustible status.

In all other cases, Colorcoat® products meet the performance requirements from the Building Regulations.

The most demanding situations for surface performance are boundary buildings and high-rise buildings. Colorcoat products can be used in both of these situations because all Corus Colorcoat productscomply with the class 0 requirements.

A material is deemed to be class 0 in the building regulations (class 0 is not a classification identified in any British Standard) if:

• The material is ‘non-combustible’ when tested to BS 476 Part 4,or
• The material has achieved a class 1 spread of flame when tested to BS 476 Part 7. And, when tested to BS 476 Part 6, it has performance indices of I<12 and I1<6.

Note: the term class 0 is not used in the Scottish regulations. However, the requirements are similar, i.e. class 1 when tested to BS 476-3, I<12 and I1<6.

The combustible mass and calorific value of the surface paint layer is insignificant when considered in relation to the overall fire load of a building.

For these reasons, none of the insurance risk-based tests make any reference to the surface paint layer used.

Fire performance of the pre-finished steel is not an issue when designing a building in Colorcoat. All Colorcoat products meet the highest fire performance class defined in the standards.

Building regulation requirements

Insurance requirements

Building Regulations require minimum levels of resistance to fire expressed in terms of timespans of load-bearing capacity, integrity and insulation. For the majority of external walls, the requirement for each of the three properties is typically 30 minutes, although these requirements can vary, depending on the proximity of other buildings and the building type and size. In some cases, 60 minutes or even 90 minutes will be required.

Both built-up systems and composite panels, if appropriately designed, will meet the building regulations requirements. Manufacturers publish the fire performance of each of their systems.

Some high-profile fires have attracted media attention over the last few years which raised the question of the behaviour of composite panels in the event of a fire. The confusion in the marketplace probably came from the lack of differentiation between composite panels used externally and those used internally in food processing areas.

The comprehensive ABI research programme managed by the Building Research Establishment (BRE) for the period 1999-2002 eventually concluded that “published fire statistics tend to show that external claddings constructed from sandwich panels are not a major fire risk, particularly if the chances of an arson attack can be reduced and its effect minimised.”

The report identifies factors critical in fire ignition risk and spread:

• Buildings containing hazardous processes.
• Buildings with high fire load.
• Buildings with a potential for arson attack.
• Buildings with storage risks.
• Buildings which are not sub-divided with fire-resisting compartmentation and have a floor area in excess of 4000 m2.

The ABI report also states that “there are far fewer instances of external envelopes being the cause of severe fire spread compared to insulated internal envelopes used for example to enclose food processing areas in food factories.”

The ABI report concludes that LPCB-approved panel  have a better fire performance.

However, it also explicitly says states that LPCB-approved panels are a requirement only when the financial exposure is high or when high levels of risk management are not achievable.

It is, however, possible that some non-LPCB approved panels are of good design. FM-approved panels are also widely accepted by insurance companies. In any case, it is recommended that architects or building designers contact insurers at the design stage to obtain their view.

• Insurers do not consider built-up systems as fire hazards.
• In some cases (for example when the building is classed ‘high-risk’ or has a high financial exposure), insurers will require LPCB or FM approval if the architect or building designer specifies composite panels.
• Designers should always check with insurers at an early stage.