SFE organised a technical evening to promote a discussion on the curtain wall standard BS EN 13830.
The SFE Technical Committee recognises the ongoing uncertainty surrounding the application of BS EN 13830 in the UK, particularly regarding consequence classes and the associated reduction of load factors for curtain wall components.
1. Applicable Versions of BS EN 13830
The latest published version of the standard is BS EN 13830:2015+A1:2020.
However, the currently harmonised version—i.e., the version listed in the EU Official Journal for CE marking purposes—remains the 2003 edition.
This distinction is a key source of industry confusion, and designers must be aware of the regulatory implications.
2. Use of Consequence Classes and Reduced Load Factors
Although BS EN 13830 allows the use of consequence classes for curtain wall kits, with the possibility of adopting reduced load factors, the SFE advises that:
- These reduced factors must not be applied by default.
- Their use must only be considered where fully justified by project conditions through risk assessment.
3. Requirement for Project-Specific Risk Assessment
Before adopting any reduced load factors or modified consequence class:
- A project-specific risk assessment must be carried out.
The risk assessment should consider the risk and consequence of loss of human life or personal injury, as well as economic, social and environmental consequences. - The assessment must justify the proposed design approach and demonstrate that safety, performance, and regulatory obligations are not compromised.
- Discuss this with the Client to explain the consequence of adopting reduced load factors.
4. Need for UK National Annex
EN 13830 allows member states to define the consequence class and corresponding load partial factors through national annex. There is no indication that The UK National Annex to BS EN 13830 is currently under development by BSI. SFE expect the UN NA should:
- Provide clearer national direction on the application of consequence classes
- Address ambiguities around load factors
- Align UK practice with regulatory expectations and industry safety standards.
5. Interim Position
Until the National Annex is published and further clarity is available:
- Designers should adopt a conservative approach
- Continue to apply professional judgement
- Undertake project specific risk assessment where reduced load partial factors are used
- Avoid unsubstantiated reductions in load factors
- And ensure all design decisions are documented, justified, and communicated transparently to clients. It is of particular importance to obtain confirmation by the party employing the Façade Engineer that there are no requirements in the development agreement, funding agreement or any right of any third party that prevents working to the latest edition of BS EN 13830.