Three new documents have been published by the Passive Fire Knowledge Group (PFKG), seeking to address misunderstandings related to the specification of passive fire protection systems across the built environment

Tackling common specification errors and “persistent confusion”, the knowledge share documents consider the safety requirements of active fire curtains, fire barriers, and cavity barriers.

As explained in the documents, “Confusion commonly arises around the relevant standards, fire strategy requirements, product performance, and certification pathways. This leads to inappropriate product selection and misaligned specifications.”

The latest publications from PFKG include:

  • PFKG Knowledge Share 10: Active Fire Curtain Standards
  • PFKG Knowledge Share 11: Active Fire Curtains – Insulation vs Radiation
  • PFKG Knowledge Share 12: Fire Barriers and Cavity Barriers – What’s the Difference?

As PFKG explains, confusion continues between the usage of smoke-leakage-classified active fire curtains and simple smoke curtains, with their differences “poorly understood across the construction industry”. While simple smoke curtains provide no fire resistance (integrity) performance and are used only to control and direct smoke towards smoke control systems, smoke-leakage-classified active fire curtains are tested to fire resistance standards. The document warns that using the term “smoke and fire curtains” in specifications can be misleading and result in the selection of incorrect products.

Also highlighted is a legacy misunderstanding between the insulation (I) and radiation (W) classifications for active fire curtains, arising from outdated standards. Such performance requirements for active fire curtains are also not defined in Approved Document B and BS 9999, leading to a “lack of clear guidance on their specification”.

Finally, PFKG addresses the common confusion between fire barriers and cavity barriers. The document notes that fire barriers and cavity barriers are designed to serve fundamentally different purposes within building regulations guidance. Notably, a fire barrier may be capable of performing both functions. 

“It is also possible to see a cavity barrier coincide with a non-fire resisting partition in order to subdivide a cavity above or seal the edges. Despite these overlaps, different products exist to fulfil each of these functions. Whether they were tested for the application, the relevant interfaces, and/or with any penetrations is crucial to ensuring compliance.”

By providing “clear, practical guidance in areas where poor terminology, legacy standards, and inconsistent interpretation continue to undermine compliance”, the cross-construction industry initiative led by PFKG emphasises the need for early engagement between fire engineers, designers, contractors, and manufacturers

Commenting on the latest publications, Will Pitt, Chair of PFKG, said: “These Knowledge Shares are about removing ambiguity from some of the most frequently misunderstood aspects of passive fire protection.

“Incorrect assumptions around standards or performance don’t just create technical issues – they introduce avoidable compliance risk into fire strategies and ultimately undermine safety. Clear terminology and evidence-led specification are fundamental.”

The three publications are available to download for free here.