Currently BS476 can still be used where Building Control Approval was secured before the publication of the new standard. In this case BS476 will stay valid for the duration of your project. However it must be recognised that the ASFP guidance is based only on an assessment ascertained from circular hollow sections.
But beware, those trying to secure a validation test before BS476 is no longer valid. Allegedly the ASFP guidance deters you from retesting to BS476 part 20 and 21. It demands that BS EN 13381- parts 4 and 8 be used. These standards require a more rigorous regime which is not required under BS476 resulting in stickability and tension testing. It throws the whole procedure into a useless document destined for the bin. Test houses are citing the ASFP guidance clause resulting in an ambiguous test report which is no use to man nor beast as it raises more concerns than it satisfies, as we found to our cost.
We were alerted to this new standard while at the fire test station in Warrington fire and it is something that we have been promoting for some time now. This standard was enacted on 20 June 2020.
It had already been proved through anecdotal data from ad hoc unofficial tests that the performance of solid rods in a fire was in fact not the same as hollow section data using the same A/V values.
In summary, it is no longer permissible to use hollow section data for the calculation of the fire protection to solid rods less than 130mm diameter. In this case the solid rods must be subject to independent fire tests using the accepted test and assessment procedures i.e. BS EN 13381 Part 4, 8 and 10. This applies to all types of fire protection products including board and composite systems.
The following excerpt is from the British Standards Institute (BSI) webpage giving the Overview of the article BS EN 13381-10:2020 Test methods for determining the contribution to the fire resistance of structural members. Applied protection to solid steel bars in tension.
This document specifies a fire test method and an assessment procedure for determining the contribution of fire protection systems to the fire resistance performance of circular and rectangular steel bars used as tension members. This document applies to fire protection materials that have already been tested and assessed in accordance with EN 13381 4 or EN 13381 8. For other section shapes such as angles, channels and flats, reference can be made to EN 13381 4 and EN 13381 8.
This document does not include steel, or any other cold formed bar used as reinforcement in concrete construction. For other solid bar geometries such as oval or triangular cross section, these are subject to a separate test package in accordance with the principles of Clause 5 of this document.
Fire protection performance is determined by testing of unloaded tension members, although additional loaded test evidence can be required for certain product types subject to certain conditions specified in the document. The method is applicable to all fire protection systems used for the protection of solid bar up to a maximum diameter of 130mm and includes sprayed fire protection, reactive coatings, cladding protection systems and multi-layer or composite fire protection materials.
In the case of rectangular bar, the maximum side length is limited to 130mm with a maximum aspect ratio of 2:1 against the shorter side length.
For dimensions greater than 130mm it is appropriate to use rectangular or circular hollow sections tested and assessed in accordance with EN 13381 4 and EN 13381 8 provided they have been tested. The method is applicable to all fire protection systems used for the protection of solid bar up to a maximum diameter of 130mm and includes sprayed fire protection, reactive coatings, cladding protection systems and multi-layer or composite fire protection materials. In the case of rectangular bar, the maximum side length should be limited to 130mm with a maximum aspect ratio of 2:1 against the shorter side length.
For dimensions greater than 130mm it is appropriate to use rectangular or circular hollow sections tested and assessed in accordance with EN 13381 4 and EN 13381 8 provided they have been tested in the same orientation. The evaluation is designed to cover a range of thicknesses of the applied fire protection material, a range of steel bar dimensions, a range of specified temperatures and a range of valid fire protection periods.
The test method is applicable to fire protection systems which are intimately in contact with the bar, or which include an airspace between the bar and the protection system as given in EN 13381-4. This standard also provides the assessment procedure, which prescribes the analysis of the test data and gives guidance on the procedures to undertake interpolation. This Standard caters for testing in both vertical and horizontal orientations. Results from horizontally orientated bar may be applied to any orientation, whilst results from vertically orientated bar should only be used for horizontal bars when the data has been corrected in accordance with Annex C.
This standard gives the fire test procedures, carried out to provide data on the thermal characteristics of the fire protection system, when exposed to the standard temperature/time curve specified in Clause 5.1.1 of EN 1363 1. The assessment procedure is used to establish: a) on the basis of data derived from testing steel bar, any practical constraints on the use of the fire protection system under fire test conditions (the physical performance); b) on the basis of the temperature data derived from testing steel bar the thermal properties of the fire protection system (the thermal performance). The limits of applicability of the results of the assessment arising from the fire test are defined together with application of the results to different steel types and sizes over the range of thicknesses of the applied fire protection system tested.
Interact has completed a series of fire tests which have been certified by Warrington Fire, a copy of which can be sent to you upon request. The test results confirm that our 9mm thick casting (minimum thickness + 2mm adhesive for our Retrofit product) can fire protect most tension rods for two hours. The benefits of our system is that we have tested without the reliance of adhesion to the substrate and therefore, in the case of retrofitting fire protection, any existing coats do not need removing. Interact have certification for the Easy-Over system which is a standard 9mm including an encapsulated support tube. This system reduces installation time considerably and comprises a casting in one piece that is slipped over the tension rod during or prior to assembly.
The full scope of Interact’s fire protection is up to 3 hours.
We would welcome the opportunity to discuss our systems of fire protection further and look forward to hearing from you.