by Mark Harris
There has been a rapid growth in the popularity of insulated panel systems for roofing and cladding applications. This may be due to their undoubted benefits in terms of energy efficiency and sustainable building, which have led to their widespread use in all kinds of non-domestic construction.
The degree to which these systems (sometimes also referred to as sandwich or composite panels) perform in a fire depends on a number of factors, but both testing and real case studies have provided evidence that PIR-cored insulated panel systems can make a real contribution to the passive fire protection characteristics of a building envelope.
Not all panel systems have a PIR core and in the past there has been a tendency to place them all in the same category, despite very different levels of fire performance. For example, a number of serious fires in the food and drinks industry in the UK a few years ago created concern about all types of insulated panels; yet these fires mostly involved polystyrene-cored panel systems used as internal structures.
It is also important to look at the building construction in context. Probably the most significant contributing factors in ‘risk potential’ are the scale and fire load of the building contents. In terms of overall risk it is vital to consider issues such as what the building is used for, how many people are likely to occupy it and what the chances are of an arson attack. In statistical terms the risk is far greater in a school than in a distribution warehouse.
The only reliable way of predicting how a particular panel system will perform in a fire is to create a test situation based on a real life installation. Large scale tests and standards such as LPS 1181, LPS 1208 and FM 4880 are ideal in this respect.
The LPCB test, sometimes referred to as the ‘garage test’, comprises a 10m long, 4.5m wide, and 3m high enclosure clad in the materials under test. The enclosure is open at the front and has a ventilation window at the side. A wooden crib, which generates a 1MW fire load, is ignited in the corner and the fire development is monitored. Although there are a number of pass /fail criteria, the key parameter is that there should be no fire propagation beyond a 1.5m zone around the crib.
FM Global uses FM 4880 (2005): Approval Standard for Class 1 Fire Rating of Insulated Wall or Wall and Roof / Ceiling Panels, Interior Finish Materials or Coatings, and Exterior Wall Systems. There are various levels of performance, with the key level being Class 1 Approval with no height restriction. The varying levels and grades of performance defined by these tests allow the specific panel system performance to be matched to the specific risk. the real issue is related to how a specific system will perform in an actual fire scenario and whether it acts like a non-combustible building element by not contributing to fire propagation.
EN 13501 Part 1 is the European Standard that sets out the reaction to fire classification of construction products and building elements. The applicable test methods for panels such as Kingspan PIR core panels are ISO 13823 (also known as the Single Burning Item test or SBI) and ISO 11925-2 (also known as the small flame test).
Kingspan considers fire performance as a top key priority of its panels. Kingspan has achieved such an excellent fire performance rating for its insulated PIR panels by working closely with many of the leading British and European fire testing labs. It also has its own fire testing facilities and in-house polymer engineers who fine-tune the product formulations and properties.
For more detailed information on these tests or the results of Kingspan Panels, please contact me on Mark.firstname.lastname@example.org.