Fire Testing for Temporary Wall Cladding
A look at how a peel and stick weathertightness membrane performs in a fire when used as a temporary cladding.
Combustible, not combustible, smoke development, spread of flame. Closed cavity, intumescent seals, peak heat release, total heat release. Too much information? What was the question exactly?
The performance of materials in a fire situation has been a hot (I had to use it) topic for a long time, long before a certain fire in London (1666 of course).
Where products are to be used in a wall >7m high, fire performance must be available to provide part of a compliance pathway. The ISO 5660.1 is one accepted method for showing compliance. The test apparatus (Cone Calirometer) throws a controlled amount of heat at a product sample for a certain time period and is able to accurately measure what happens, how fast, how hot, how much smoke etc. If you like to burn stuff like Ricky Baker, BRANZ has a video on YouTube here.
So what’s our connection to this? Pro Clima has a peel and stick weathertightness membrane SOLITEX EXTASANA ADHERO® which is being commonly specified over a rigid substrate in buildings that sit outside NZS3604 and are classed as a temporary cladding (weathertightness) before being covered by a final cladding material. What we need to know is how will it perform in a fire. Will it ‘add significant fuel load’?
The first round of data to share involves two fibre cement products with the peel and stick ‘ADHERO’ attached, both of these passed the requirements for ‘Peak heat release’ and ‘Total heat release’ when tested to ISO 5660.1 standard (cone calirometer). There is other available data related to our ADHERO product on its own including Flammability Index and this is stated in BRANZ Appraisal No. 989 (2017).
Type A external cladding has no restrictions at >7m high, within 1 metre of boundary. The requirement of ‘limited combustibility’ cladding is to achieve a Peak Heat Release rate <100 kW/m², and Total Heat Release rate <25 MJ/m² during the ISO 5660.1 test.
James Hardie’s RAB (6mm) with ADHERO
Cone Calirometer testing with SOLITEX EXTASANA ADHERO® over JH RAB 6mm. Confirming acceptable performance with ADHERO applied to outside face, JH RAB achieves: Peak heat release below 100 kW/m². Total heat release below 25MJ/m².
Pacific Build Supply’s RWU ‘Shera’ (6mm) with ADHERO
Cone Calirometer testing with SOLITEX EXTASANA ADHERO® over Fibre Cement (Shera 6mm). Confirming acceptable performance with ADHERO applied to outside face, Shera achieves: Peak heat release below 100 kW/m². Total heat release below 25MJ/m².
For both Fibre Cement products: Group number classification is 1-S. (C-VM2 Appendix A). Testing based on ISO 5660.1-2015 (Cone Calorimeter method).
Control of Internal Fire and Smoke Spread
As SOLITEX EXTASANA ADHERO® Self-Adhesive Underlay is not exposed to view in occupied spaces, the product does not need to meet the requirements of NZBC Acceptable Solutions C/AS2 to C/AS6, Paragraph 4.17.8 b), for the surface finish requirements of suspended flexible fabric. It may, therefore, be used with no restrictions in all buildings.
Prevention of Fire Occurring: Separation or protection must be provided to SOLITEX EXTASANA ADHERO® Self-Adhesive Underlay from heat sources such as fireplaces, heating appliances, flues and chimneys. Part 7 of NZBC Acceptable Solutions C/AS1 to C/AS6 and NZBC Verification Method C/VM1 provide methods for separation and protection of combustible materials from heat sources.
NZ testing vs International testing
We continue to test other substrates with and without our products attached to be able to provide quality advice and give assurance that our products are applicable to local requirements, materials and building methodologies. While some test data like fire is exactly comparable worldwide, claims of UV stability are not, which is why we ensure our products can survive exposure to NZ sun for the times we claim, including 180 days for SOLITEX EXTASANA ADHERO®.
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