PFKG addresses persistent confusion in Passive Fire Specification

The Passive Fire Knowledge Group (PFKG) has published three new Knowledge Shares to address widespread misunderstanding in the specification of passive fire protection systems across the built environment.

The new publications are:

· 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?

Together, the documents provide clear, practical guidance in areas where poor terminology, legacy standards, and inconsistent interpretation continue to undermine compliance.

Knowledge Shares 10 and 11 focus on common specification errors associated with active fire curtains. Knowledge Share 10 addresses frequent confusion between smoke-leakage-classified active fire curtains and simple smoke curtains. Simple smoke curtains are intended solely to control and direct smoke towards smoke control systems and provide no fire resistance (integrity) performance. This is in contrast to smoke-leakage-classified active fire curtains, which are tested to fire resistance standards. The document cautions against the use of the term “smoke and fire curtains” in specifications, as it is misleading and can result in the selection of incorrect products.

Knowledge Share 11 highlights the frequent misapplication of insulation (I) performance where radiation (W) classification is more appropriate for active fire curtains. Insulation fire resistance (I) refers to the time taken for the temperature on the non-fire side of a curtain to rise more than 180°C above ambient under test conditions, a performance that most active fire curtains do not achieve for any significant duration. By contrast, the radiation criterion (W) measures the time taken for heat radiation at 1 m from the non-fire side to exceed 15 kW/m². This typically provides a more realistic and meaningful measure of performance for active fire curtains, particularly when combined with integrity (E) to form an EW classification.

Knowledge Share 12 addresses another long-standing area of confusion: the distinction between fire barriers and cavity barriers. The document explains the different regulatory roles these systems perform, along with the differing fire resistance requirements that apply to each. It also highlights how misunderstanding can lead to non-compliance, particularly where products are installed within cavities, above ceilings, or beneath raised access floors without appropriate supporting evidence.

Across all three publications, PFKG emphasises the importance of early engagement between fire engineers, designers, contractors, and manufacturers to ensure specifications are clear, achievable, and supported by suitable test evidence.

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

All three Knowledge Shares are available now as free downloads from www.pfkg.org, supporting PFKG’s ongoing commitment to improving competence and consistency across the fire safety community.