Architects, building certifiers, fire engineers and relevant authorities are being urged to ensure correct methods are being followed while installing rigid insulation boards in concrete soffits applications. Insulation manufacturer, Kingspan Insulation is warning of the serious fire safety risks if these concerns are not addressed by stakeholders.
In applications such as carparks or exposed internal ceiling linings, where insulation boards are left exposed in concrete soffits, the National Construction Code (NCC) requires that they are tested to AS ISO 9705, from which a Group Number fire classification is then calculated. The AS ISO 9705 test method also requires that ‘the product to be tested shall, as far as possible, be mounted in the same way as in practical use’.
The NCC requires a Group 1 classification to be achieved for several applications. Group Numbers higher than ‘1’ will have limitations on how and where they can be used.
According to Kingspan, a number of manufacturers of rigid polyisocyanurate (PIR) insulation boards are claiming a Group 1 fire performance classification with testing to AS ISO 9705; however concerns have been raised that the on-site installation of these boards are not consistent with the methods used for installation in the fire test.
Kingspan's Technical Manager Mr Keith Anderson explains that the Group 1 classification can no longer apply where on-site installation methods differ from that of the test. Citing an example, he said that a PIR insulation board was installed in the test using angle iron brackets around the perimeter as fasteners. Another test report detailed test installation methods that also included the use of a high temperature sealant to fill the seams between boards.
To claim Group 1 status, the insulation board has to be installed the same way, strictly adhering to the test methods on site. However, the reality is that the real-life installations are not representative of the test conditions and, therefore, the Group 1 classification cannot apply in these cases.
Commenting that this situation presented serious fire safety risks for the building and its occupants, Anderson urged all design professionals, fire engineers and certifying authorities to be vigilant in verifying that insulation installation methods on-site matched those of test reports where AS ISO 9705 testing was concerned.