The scenario. Protected and unprotected steel beams and purlins often penetrate fire-rated compartment walls, creating gaps that, like all penetrations, should be correctly firestopped.
The context. Purlins are horizontal beams that support the roof and walls of a building, while steel beams are larger components that form the framework of the structure. A protected steel beam/purlin has fire-resistant material applied to it, such as an intumescent coating, whereas an unprotected one does not.
The issue. As it stands, there is no fire-test standard for these types of penetrations, which makes compliance difficult. To combat this, ad hoc fire testing conducted in accordance with relevant fire-resistance test standards can be performed, but is often required to be recognised by a qualified party.
Why this is a problem
Without a specific test standard, there are few actual tested solutions within the construction industry to consider.
What makes this more difficult is that steelwork differs from services like steel pipes; steel pipes are tested to the standard service penetration test standard.
Structural steel must follow different test standards and methods because it needs to consider load-bearing capabilities.
Many might not realise how structural steel sections and the fire-resistant products used around them for protection are actually tested for fire resistance.
Often, this testing is performed in floor furnaces so a loaded weight can be applied, and these steel sections can bend or deflect significantly as the steel weakens at its critical temperature.
Therefore, when it comes to steel beams and purlins, it is not just a case of ‘filling the gap’ around the steel.
Because of the complex nature of these penetrations, a technical assessment will almost always be required, while keeping the following considerations in mind:
- How will the steel beam be protected? For example, intumescent coatings require expansion space to function properly in the event of a fire.
- Have you thought about any potential compatibility issues between coatings, sealants, and other systems?
- How will the steel move or deflect in a fire? When steel begins to lose its structural stability, even protected steel can damage the seal or the compartment wall.
That's why we mentioned earlier that it's more than just ‘filling a gap.’
How we can help
Unfortunately, since there’s no universal test standard, we’re unable to provide a standard solution for this kind of application.
However, we understand that this is a frequent challenge on site, so we have carried out ad hoc testing of several steel specimens – unprotected purlin, unprotected beam, and boarded beam – using the QuelStop Fire Batt System, in accordance with the principles of BS EN 1366-3:2021. This is the fire-resistance test standard for service penetrations.
The fire test reports can be provided directly to a qualified fire engineer or an accredited body to support the technical assessment, but we do not generally distribute them.
We ask that the qualified person undertaking the assessment contacts our technical team directly at technical@quelfire.co.uk. We're always here to help and look forward to supporting you on your projects!
Key takeaways
- Engage early to prevent these types of penetrations or, if unavoidable, to understand the recommended process;
- Reach out to a qualified and competent fire engineer who will be able to assist with technical assessments;
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Contact Quelfire for test evidence to support the assessment.
