There has always been some degree of confusion in relation to Sandwich or Composite Panel Systems.
Broadly three systems have been in use as follows:
1. Polystyrene – pre 1980’s
2. Polyurethane (PUR) 1980’s and 90’s.
3. Polyisocyanurate (PIR) 2000 on.
The “problem panel” is polystyrene which is a thermo-plastic or open cell product. The majority of serious fires involving composite panels have been in the food and drinks industry and the vast majority of these fires have involved polystyrene board panels used as internal structures or partitions (ref ABI-TBD 2003).
The Association of British Insurers (ABI) issued a Technical Briefing Document in 2003 on the fire performance of sandwich panel systems which stated that “fire stats clearly show that unsuitable use of and management of sandwich panel systems in food facilities is the principle reason for rapid spread of fire”, in other words where cooking or other hot processes are involved.
Fire Services are generally less concerned where sandwich panels are used as external roof and wall cladding which are fixed to the structural frame of the building. In this respect according to the Fire Protection Association (FPA) the majority of fires attributable to external claddings of any kind was due to arson and that external claddings constructed from sandwich panel systems are not a major fire risk particularly where the risk of arson can be reduced. In this respect Composite Panel Warranties will invariably have a requirement that items be stored a minimum of 5metres from the external building envelope etc.
All composite panels (polystyrene, PUR, PIR) have some combustible elements i.e. glue etc. The real issue is how a specific system will perform in a real fire scenario and whether it acts as a non-combustible building element by not contributing to fire propagation and PUR and PIR perform accordingly.
External cladding and internal panel systems must now be LPCB or FM approved and in this respect most thermo setting or rigid urethane PIR panels are LPCB and FM approved. These panels are difficult to ignite (see propane torch test under BS476 etc).
Policyholders need to be careful where they have composite panel systems as invariably a composite panel warranty will apply which will include capping or sleeving of openings and fire stopping with high density mineral fibre (Rockwool etc).
Building drawings may indicate what panel system was used and Kingspan systems have UV markings showing the type of insulation and date of manufacture. LPCB or FM Plaques may be insitu or certificates available. Otherwise it is relatively easy to identify whether the panel is polystyrene or PUR or PIR by inspection expecting an exposed edge or drilling a small aperture etc.
As part of our Value at Risk (VAR) service we will comment on the type of construction to include reference to panel systems and where appropriate make reference to the Grade of Construction in accordance with LPC criteria etc. Otherwise I deal with composite panel systems as part of my “Grades of Construction” presentation which is CPD accredited.
If you require any further assistance or information please do not hesitate to contact me.
Alan FitzGerald, FCII. FCILA, FUEDI-ELAE.