At Specwall, performance is not a claim, it is something we back up with evidence.
We are pleased to confirm that Specshaft has successfully passed a smoke leakage test on a large PBSA project in Leeds, achieving a measured leakage rate of 2.4m³/m²/h, comfortably within the allowable limit of 3.8m³/m²/h.
This was an on-site air and smoke test carried out on a live installation spanning 7 floors (basement through roof), with a total height of 22 metres, and importantly, no steel duct was required.
This result is an important step in demonstrating the real-world effectiveness of Specshaft and reinforces our commitment to supporting safer building design through independently verified performance.
Why smoke leakage performance matters
In the event of a fire, smoke spread is one of the biggest risks to life safety. Smoke can travel quickly through buildings, reducing visibility and making escape routes unsafe long before flames reach a space.
That is why smoke control measures, and the integrity of risers and shafts in particular, are critical. A smoke leakage test helps confirm whether the system is doing what it should: reducing the risk of smoke migration by limiting air and smoke movement through the shaft system.
Test result summary
The test confirmed:
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Smoke leakage test: PASSED
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Allowable leakage rate: 3.8m³/m²/h
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Specshaft achieved leakage rate: 2.4m³/m²/h
In short, Specshaft’s performance came in well under the allowable threshold, demonstrating strong airtightness across the installed smoke shaft.
What this means for specifiers and contractors
Achieving this result demonstrates that Specshaft is capable of delivering dependable performance when it matters most, helping project teams meet the expectations of modern construction, regulation, and building safety standards.
For architects, main contractors, and fire engineers, verified evidence like this supports confidence in specification and delivery, particularly on complex multi-storey schemes such as PBSA.
Built for compliance, made for site
We design Specshaft systems to support not only technical performance, but also practical installation on site, where consistency and quality matter.
This test performance demonstrates the value of:
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robust system design
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controlled installation approach
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attention to detailing at interfaces and penetrations
Want to know more?
If you would like further technical details, specification support, or information for your current project, please get in touch with our team today.
