Risk Management Guidelines

Transcription

1 Composite Panels Introduction For many years, there has been increasing awareness of the environmental issues surrounding the temperature control and energy efficiency of buildings, and the use of insulating materials in building construction has risen significantly. Requirements for high levels of thermal insulation, together with fast-track construction, have lead to the development of both traditional and new materials to meet these demands. In turn, this has lead to further developments to meet the needs of specific industries, particularly where demands for hygienic surfaces and minimal air leakage, together with ease of assembly within existing structures, are prime concerns. To meet increasingly stringent legislation, coupled with speed and ease of building, single piece insulated panels widely known as composite or sandwich panels are specified more frequently, and over an increasingly wide range of building types. Composite (or sandwich ) panels are frequently found in external walls and roof claddings, mainly to industrial buildings, but are also used as claddings to commercial buildings, and as internal partitions. Many incorporate combustible cores and lack satisfactory overall fire resistance. The 1990 s saw a significant rise in the use of combustible composite panels primarily (but not exclusively) in buildings occupied by the Food Industry. Many such premises used polystyrene panels for internal construction which, although hygienic and easily put together, do present an increased fire load. Polystyrene panels are highly combustible and, if used in significant quantities, will usually give rise to a total loss in the event of fire. When coupled with types of food industry processing such as deep-fat frying, the risk of fire is further enhanced. It is, therefore, of little surprise that over this same period, there has been an increase in the number and size of fire losses in buildings where these panels have been present. Panel Construction Single piece composite panels are factory produced, and usually consist of two metal sheets (normally steel), approx. 1m wide and in varying lengths between 5m and 20m, bonded to a core of insulating material. The cores can be rigid or expanded foamed plastics, glass fibre or high density mineral fibre (when a degree of fire resistance is required). The sandwich thus formed is made in various thicknesses. Other materials such as foamed glass and phenolic foams have been used, but only in small quantities. In the food industry the facings are usually coated with a PVC covering, to enable easy and efficient cleaning. RMG 69 v4 12/ Royal & Sun Alliance Insurance plc

2 Other systems, often referred to as insulated cladding, are built up on site. The components are assembled individually onto the building frame, usually with an external profiled metal sheet, an insulating core (glass fibre, mineral fibre, or foamed plastic slab), and a liner of non-combustible board or profiled metal sheet. This method was more common in the 1980s but is still widely used in both wall and roof construction. Types of Core Insulation Polystyrene Polystyrene is a thermoplastic material, which melts and ignites relatively easily, and can rapidly burn in between the metal facing sheets of a composite panel. This allows extensive and violent fire spread, and makes fire fighting almost impossible. Even fire retardant polystyrene panels do not significantly reduce the fire load, rate of fire spread or, ultimately, collapse of the panels. Polystyrene composite panels are mostly used internally, but some buildings have been constructed with polystyrene panels within the external wall claddings and will be very vulnerable to fires from external sources such as rubbish skips and idle pallet storage. Polyurethane (PUR) Rigid urethanes are thermosetting materials that tend to char in a fire, at least initially. It has so far been rare for polyurethane composite panels used in external applications to be implicated in the early stages of fire, although they often become involved as a result of fire spread from burning contents. Polyurethane cored materials contribute significantly to fire load. Polyisocyanurate (PIR) Polyisocyanurate is the fire-rated version of PUR but, as a term, it includes many different individual foam compositions, with varying degrees of performance. This material is generally accepted as performing better in a fire than Polystyrene and PUR although still contributing to fire load. The better grades of Polyisocyanurate are incorporated in Loss Prevention Council (LPC) approved products and should not become involved in a fire until very late in its development. Mineral Fibre/Glass Wool The mineral fibres themselves are non-combustible although bonding agents and any breather membrane do make a small contribution to fire load and smoke emission. RMG 69 v4 12/ Royal & Sun Alliance Insurance plc

3 High Density Mineral Fibre Panels containing this material are primarily used where a specific degree of fire resistance is required or for high-risk applications. N.B. all panel systems are damaged to some extent by fire irrespective of the insulating core. The method of fixing can have a bearing on structural integrity in a developing fire. Usage In new build applications, consideration should always be given to the use of panels with non-combustible cores or LPC approved products. The vast majority of Insurers emphasise building construction as an important feature of risk and the use of readily combustible composite panels can affect both premium and acceptability. Building materials used should form part of the general risk assessment process in the design of any new building or extension. As a minimum measure, any hazardous processes should be separated from the remainder of the building by non-combustible walls and ceilings, with a minimum of 60 minutes fire resistance. In existing buildings, the core materials of any composite panels should be identified from purchasing records or spare panels (if possible), and the appropriate levels of risk management introduced. Replacement of, or the addition of non-combustible linings to, those panels deemed to present an unacceptable risk may be an option for improvement. Further specific fire protection measures may also need to be considered to address the increased risk. Liaison with the local Fire Brigade is recommended at the earliest possible stage. Brigades will require certain information before they will risk firefighters lives. This could take the form of suitably annotated floor plans indicating the location and extent of combustible cored composite panels, any separation by fire resistant compartment walls and provision of fixed fire protection systems. There are a number of Panel Marking schemes, in which standard indicator plates are fixed by entrances to buildings so as to inform the Fire Brigade of the type of panels to be found Management of Composite Panels Where combustible composite panels are identified within a building, a high standard of risk management is essential, backed by a written policy for panel management to ensure that: Composite panels are identified and clearly marked as to the combustibility of the panel core. Panel facings and joints are maintained in good repair in order to prevent exposure of combustible cores to ignition sources. RMG 69 v4 12/ Royal & Sun Alliance Insurance plc

4 Exposed top and bottom edges of external panels are closed off with steel capping, and any penetrations of the panels are sealed with suitable fire-resisting material. The fire resistance of any non-combustible panels is maintained. Fire cannot spread easily into any voids behind the panels. In addition: There must be a suitable Permit to Work system in place, with specific comment required regarding composite panels. Periodic electrical examination and test frequency should be increased to reflect the proximity of equipment and cabling to unsuitable panels. Storage of combustibles in yards must not be against or within exposure risk distance of walls containing composite panels (at least 10 metres). Approved Products The LPC listing of approved panels mentioned above is available from There are two different LPS specifications (LPS1181 and 1208), and discussions should be held with the insurers to decide the appropriate standard. There are also a number of products that have been approved by agencies in other countries. Depending on the test method, these may also be acceptable. Fire Risk Assessment The presence of Polystyrene panels is regarded as being a significant finding for the purposes of statutory Fire Risk Assessments, due to the potential for extremely rapid fire spread and the release of large volumes of toxic smoke. RMG 69 v4 12/ Royal & Sun Alliance Insurance plc

5 These and other Risk Management Guidelines addressing a wide variety of risk control issues are freely available from: The information set out in this document constitutes a set of general guidelines and should not be construed or relied upon as specialist advice. RSA does not guarantee that all hazards and exposures relating to the subject matter of this document are covered. Therefore RSA accepts no responsibility towards any person relying upon these Risk Management Guidelines nor accepts any liability whatsoever for the accuracy of data supplied by another party or the consequences of reliance upon it. Royal & Sun Alliance Insurance plc (No ). Registered in England and Wales at St. Mark s Court, Chart Way, Horsham, West Sussex, RH12 1XL. Authorised by the Prudential Regulation Authority and regulated by the Financial Conduct Authority and the Prudential Regulation Authority