MCRMA Publishes New Guidance for Fire-Rated Capable Members in ‘Boundary Elevation’ Cladding

The MCRMA has published a new guidance document to help everyone involved in the metal building envelope supply chain understand who is responsible for ensuring the correct type of fire-protected structural support, known as a ‘capable member’, is used in structural steel framed buildings with a boundary elevation.

Developed collaboratively by MCRMA members, GD 42 Cladding Industry Guidance for ‘Boundary’ Elevations involving Capable Members has been written to complement and extend the guidance offered in a document Technical Specification for ‘’boundary’’ elevations published by the BCSA (British Constructional Steelwork Association).

Its publication reflects the need for earlier and closer collaboration in projects between the steelwork contractor, cladding system manufacturer and cladding installer to ensure safety and security is maximised in the finished building envelope.

The location showing the positioning of capable members within a gable end boundary elevation, as explained in the new MCRMA Guidance Document GD42.

Fire-Rated Capable Members

A ‘capable member’ typically refers to a hot-rolled, intumescent coated structural beam designed to carry the load from the hung cladding and transfer the load to the main frame.

Designed at elevated temperatures based on the level of protection provided, it is ordinarily positioned at the top of a cladding system “drop”, or lengths of cladding sheets/panels, calculated with connections, although additional, intermediate capable members may be required in tall elevations or when cladding arrangements require them.

The fire resistance offered by capable members in boundary elevation facades is critically important, which is why it has attracted much greater interest and scrutiny since the publication of the Building Safety Act.

Correctly designed, specified and installed, the capable member will perform a key role in maintaining the integrity of the façade should a fire occur within the building, hence why they are so important in minimising the risk of fire spreading to neighbouring buildings and sites.

Capable members must be incorporated within façades classed as boundary elevation to reduce the risk of fire spreading to neighbouring buildings, as explained in the new MCRMA Guidance Document GD42.

New Guidance Document

The guidance document clarifies that it is the responsibility of the Principal Designer for ensuring capable members are correctly integrated into the structural steelwork for the cladding system to attached to and hang from. It also explains what the specification should be for these safety critical elements, including considerations when using both carbon steel and stainless steel fasteners, making it essential reading for anyone involved in cladding projects with a boundary elevation.

The recommended position of capable members in boundary elevations, both side elevation and gable end facades.

Carlton Jones, MCRMA Director, commented: “It is crucially important for the construction industry to be continually reviewing the potential for fire performance weaknesses in building design and build, and to ensure everyone involved in the supply chain knows where it is their responsibility to make the right decisions.

“In developing GD 42, we have sought to provide clarification for the industry as a whole in one very specific, but safety-critical element of façade design and installation, and ensure applicable projects comply with the requirements of today’s more stringent building safety regime.

“Through our long standing links with the BCSA, we have been able to create a document that complements the work that they have been doing in respect of capable members, so I would like to thank them for their input. I would also like to thank our members who have been instrumental in drafting this document through the dedicated working group.

“The resulting guidance document is an excellent example of how member collaboration is supporting the metal cladding and roofing industry as a whole to deliver the highest quality projects, as well as staying fully compliant with the Building Regulations and safety regulations.”

The Metal Cladding and Roofing Manufacturers Association (MCRMA) is the only industry association representing the complete metal building envelope supply chain. Its members include many designers and manufacturers of products, systems and components, including insulation and fasteners, installers, independent building envelope inspectors and businesses that provide testing, design and specialist services, such as design calculations, structural engineering and market development.

Download the GD 42 guidance document here.

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