What are fastener performance values?
- Read time: 3 minutes
- Date: 21 Jun 2021
- Flat Roofing
- Rainscreen & Façades
- Sheeting & Cladding
Fastener performance values provide information about the maximum forces that the fastener can withstand. BS 5427:2016 Code of practice for the use of profiled sheet for roof and wall cladding on buildings details the procedures to obtain and publish the data. This data is required by structural engineers to ensure the correct fasteners in sufficient quantities are used on the build.
There are three key types of data:
Pull-out values
The pull-out performance of a fastener describes its ability to withstand tensile loadings – i.e. its resistance to being ‘pulled out’ from the substrate.
Pull-through values
Pull-through (pull-over), describes the fastener’s ability to resist a sheet material pulling over the head of the fastener.
Shear values
Describes the fastener's resistance to lateral forces. If lateral loads are applied, failure of a connection may occur in either the fastener itself, in the materials being connected or in the attachment of the fastener to the substrate.
How are performance values measured?
Performance values are measured in kilonewtons (kN), a measure of force. One kN can displace a mass of 1,000kg at 1 m/s2.
Where can performance values be found for a fastener?
Details of the fastener performance values can be found in the manufacturer’s product datasheets and must be used to check the right fastener is being used for the application.
My substrate is different to the substrate in the datasheet – can I still use my chosen fastener?
If you are not planning to use the fastener in a standard application or if the substrate has deteriorated, contact the manufacturer. They may have existing data about your planned substrate.
If not, reputable manufacturers will conduct on-site or in-house testing on your behalf to ascertain performance values.
Never use a fastener if you are unsure whether the performance values are correct for the chosen substrate, build-up, or application. Using the wrong fastener could invalidate the warranty and cause the fastener to fail.
