This joint webinar between UKAS and the Health and Safety Executive (HSE), held on Tuesday 6 May 2025, provided clarity on the proposed deviation from the 2-point “No Asbestos Detected” (NAD) methodology in HSG 248 (Edition 2), as well as the accreditation process for laboratories wishing to adopt it.
Why was a deviating methodology proposed for HSG 248?
Following the publication of HSG 248 (Edition 2), concerns were raised about the mandatory use of a 2-point approach for all NAD samples, including those that are clearly non-asbestos. Feedback suggested this was not proportionate and had not been adequately consulted on. The deviating methodology aims to address these concerns by allowing specific non-asbestos materials to be counted as 1-point samples.
What is the main difference between the current and proposed methodologies?
The key difference is that under the proposed approach, certain well-characterised non-asbestos materials can be assessed using a 1-point NAD instead of the default 2-point. This more accurately reflects the minimum time required evaluation the sample, while maintaining quality and control.
A laboratory customer will not and should not be able to determine how a sample was analysed as both methodologies are deemed suitable and the laboratory should be making an informed decision on how to deal with samples.
Is the deviating methodology mandatory?
No. Adoption of the deviating approach is entirely optional. Laboratories satisfied with the current 2-point system can continue using it without change or cost.
What is required to gain UKAS accreditation for the deviating method?
Laboratories must:
- Review the alternative methodology in detail (the finalised methodology document is available within the Expression of Interest published on the UKAS website)
- Conduct a gap analysis and develop suitable procedures and controls
- Submit an Expression of Interest, and if there is sufficient drive for this change then it will be formally confirmed as progressing
- Then submit an Extension to Scope and supporting documentation (including a UKAS declaration, evidence supporting all changes and an AC4 form)
- Undergo a successful desktop assessment, suitably address any resulting findings and support the post-grant site visit
When will the revised methodology be formally included in HSG 248?
HSE confirmed that a revised version of HSG 248 will include the deviating method, but that publication is unlikely before mid-to-late 2026 due to guidance update constraints. The change must appear in the official HSE guidance before UKAS can formally accredit laboratories against it.
Can laboratories start preparing now?
Yes. While accreditation cannot be granted until the HSG 248 update is published, laboratories are encouraged to start preparation now, so they are ready when the amendment is in place.
Will laboratories be allowed to market the use of this methodology?
No. Laboratories using the deviating method must not market it as a separate service. Reports and UKAS schedules must not distinguish between laboratories using the 1-point or 2-point approach. UKAS will be tracking those organisations accredited for this methodology but all testing must be to HSG 248 overall with no implication of any preference with either methodology. No report, contract or public facing material must state if the organisation has the ability to perform this deviation methodology. This is purely an internal process within the laboratory. The confidence in the result output must not be compromised for either methodology and any marketing or public display will result in removal of accreditation for the deviation.
What changes to sample analysis timings are proposed?
The revised approach defines minimum examination times of:
- 5 minutes for 1-point NAD samples
- 10 minutes for 2-point NAD samples
This replaces the blanket 15-minute requirement previously applied to all NADs.
What constitutes sufficient uptake to justify the change?
There is no set number of laboratories. UKAS and HSE will jointly review the range, impact, and context of interested laboratories to determine whether the change should proceed. This is why detailed Expressions of Interest are important but must be backed by a drive to progress and Extension to Scope (ETS) in 3-4 months and there will be financial commitment of 0.5days effort for a scoping charge as standard for all UKAS applications for ETS If there is not sufficient committed interest then we will remain on the current methodology.
If this change is progressed, then any laboratory could perform only the 2-point methodology and continue with that or be assessed and granted the 1-point deviation to manage internally using both methodologies. This would be available to new applicants in asbestos testing too following its publication in HSG 248.
Can UKAS implement this change through its own technical guidance?
No. UKAS cannot act independently of HSE guidance as they are the UK regulators. Accreditation must align with the officially published version of HSG 248 as already referenced on UKAS schedules. A formal amendment is required before schedules can reflect the revised approach.
Why is this different to a lab accredited for asbestos analysis using SEM/TEM, whose methods are not detailed in HSG248?
A defined methodology for SEM/TEM is not included in HSG 248 and not referenced on UKAS schedules for this activity, so the laboratory must define their own method that is assessed. As Bulk ID and its procedure using PLM are fully defined within HSG 248 edition 2 then any deviation from that must be documented and aligned to be accreditable.
Has consideration been given to using the deviating samples clause in 17025, to exclude materials which were obviously non-asbestos, e.g. wood; plasterboard etc. from the analytical process, particularly as such sampling is client driven?
Clause 7.2.1.7 of ISO/IEC 17025:2017 states “Deviations from methods shall occur only if the deviation has been documented, technically justified, authorized and accepted by the customer. Note: Customer acceptance of deviations can be agreed in advance in the contract.”
This clause should already be in use in laboratories. It is the responsibility of the laboratory to ensure they document their expert knowledge on justifying why eg wood, should be dealt with appropriately. There is a responsibility on the laboratory to assist the sampler in their understanding of its relevance to looking for asbestos. Care must be taken for any mixed materials/layered sample eg wood sample with paint on it, as this should be handled as a 2-point NAD sample.
Any client contract must not state that the organisation specifically has the 1-point deviating methodology but purely that they will follow published HSG 248 methodology as appropriate as this could be deemed marketing within a contract and will not be allowed.
Where can I access the documentation and register interest?
All relevant information—including the proposed methodology, a drafted UKAS Declaration outline, and Expression of Interest form—is available on the UKAS website. The deadline to express interest is 30 June 2025.