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Fasteners
When mechanically attaching single ply membranes to a structure, the following are key factors in determining the optimal performance of the finished roofing system:
- Interface performance of the structure
- Membrane
- Fastener
- Pressure plate
To ensure that a roofing system's resistance to wind uplift can be correctly calculated, the individual combination of fastener type, membrane type and substrate type should be tested in accordance with UEAtc directive; “Supplementary Guide for the Assessment of Mechanically Fastened Waterproofing” and Factory Mutual FM 4470.
The results of this test will provide the membrane manufacturer with a design load per fastener, incorporating a safety factor, which can be used when calculating the number of fasteners required to secure the roofing system to the substrate. As this information is generally kept confidential to the membrane manufacturer, it is critical that the manufacturer provides the designer with the design specification calculated to British Standard BS6399: Part 2: 1997 (Incorporating Amendment 1) Code of Practice for Wind Loads. The Single Ply Roofing Association requires members to provide this information to the specifier on each individual project.
The Sarnafil Technical Services Department carries out these calculations, using software specially developed by the BRE. The results of these calculations are included in the Sarnafil specification and provide the Sarnafil Registered Contractor with the information they require for tendering and installing the roofing system. This information is also used by the Sarnafil Field Technician to check the installation against the original specification for guarantee purposes.
To ensure the correct fasteners are used in every Sarnafil roofing system, Sarnafil Ltd has a range of fasteners including tube based pressure plates and fasteners manufactured to our specification by SFS Intec Ltd. This enables Sarnafil Ltd to provide a guarantee that covers the roofing system* and its attachment method for both product failure and resistance to wind uplift, backed by Product Liability insurance and Professional Indemnity Insurance.
* The entire roofing system (deck, vapour control layer, insulation membrane and ancillary components) is only covered if a Sarnafil Extended Products guarantee is used. If a waterproofing system guarantee is required, only the membrane and its attachment are covered.
© 2006 Sarnafil Ltd. Legal Disclaimer
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