PFKG demands higher standards for MEP service penetration seals

Critical vulnerable areas in UK building safety have been identified by the Passive Fire Knowledge Group (PFKG). As a result, the group is now warning that a widespread reliance on untested or ambiguously defined fire-stopping methods for MEP (Mechanical, Electrical, and Plumbing) service penetrations is creating an "unacceptable risk" to life and property. Despite individual components often being certified, there is currently no recognised standard to prove how these vital junctions perform as a collective system in a fire, potentially undermining a building’s entire fire compartmentation strategy and its ability to contain flames and smoke.

Regardless of what some older guidance documents might suggest, the PFKG emphatically states that only the application of third-party tested or certified penetration seal details can genuinely evidence compliance with fire safety requirements and a building's critical fire strategy.

Current Building Regulations are clear, say the PFKG and state that where it is reasonably necessary to inhibit the spread of fire within a building, measures shall be taken, to an extent appropriate to the size and intended use of the building, comprising the sub-division of the building with fire-resisting construction. In response, fire engineers develop a building's fire strategy by defining compartmentation to contain flames and smoke and by demanding that all services penetrating these barriers are sealed to reinstate the fire resistance of the construction element.

However, practical guidance within documents like Approved Document B (England) and Building Standards Technical Handbooks (Scotland) sometimes references instances where the use of untested fire-stopping systems may be permissible or where fire-stopping may even be omitted for certain service types and sizes.

For example, Section 2.1.14 of the Building Standards Technical Handbook (Scotland) outlines specific exemptions for small diameter pipes or cables under certain conditions. Similarly, Approved Document B: Volume 2 section 10.4 suggests that - where a proprietary sealing system is not used as a fire-stop around a pipe, the opening should be kept as small as possible, but offers no specific guidance on the number of services or aperture dimensions. Section 10.5 of the same document even suggests "a pipe with a maximum nominal internal diameter of 160mm may be used with a sleeve made out of a high melting point metal," even though such sleeved services often lack supporting test evidence under standards like BS EN1366-3:2021.

"This vagueness in some guidance documents creates a dangerous loophole," said Richard Fordyce for the PFKG. "While the Building Regulations' functional requirements are clear, the 'practical guidance' can be misinterpreted. The reality is, without the application of a third-party tested or certified penetration seal detail, it is simply not possible to evidence the overall fire resistance performance of that system in accordance with a project's fire strategy. An unsealed penetration, or one sealed with an unproven product, becomes a potential pathway for the rapid spread of smoke, heat, noxious gases and flames, leading to premature failure of the compartment and devastating consequences."

To ensure unequivocal compliance with requirements of a fire strategy and to safeguard building occupants, the PFKG strongly recommends a singular, non-negotiable approach - the exclusive use of tested or certified sealing systems for all MEP service penetrations. This, claims the group, is the only robust way to provide verifiable evidence of a penetration seal's performance as a complete system, incorporating both the service itself and the substrate it passes through.

This recommendation is powerfully supported by leading industry bodies, including the Association for Specialist Fire Protection (ASFP). Their publication, "ASFP Advisory Note 2: Firestopping of combustible pipes with an internal diameter of 40 mm or less," emphatically urges the use of proprietary fire-stopping systems in all instances, explicitly rejecting alternative provisions suggested in less stringent guidance documents. Crucially, fire resistance testing of unsealed penetration seals conducted by the ASFP have demonstrated premature failures well in advance of typical minimum compartmentation requirements, providing clear evidence of the dangers involved.

This means, says the PFKG, that all MEP services penetrations must rely on the provision of a tested or certified penetration seal detail, strictly in accordance with relevant BS EN standards such as BS EN 1366-3:2021. There is no room for ambiguity when it comes to fire safety. By adhering to these stringent standards, the built environment can truly ensure its structures perform as designed, protecting lives and property when it matters most.

For more information visit: www.pfkg.org