Smoke Shaft Air Testing UK: Why Testing Matters
Smoke shafts are an important part of the fire safety strategy in many high-rise and multi-storey buildings. When correctly designed, installed and tested, they form a key part of a smoke control system, helping to remove smoke from protected areas and maintain safer escape routes during a fire. However, the performance of a smoke shaft depends on more than its design and mechanical equipment. The shaft itself needs to be sufficiently airtight.
This is why smoke shaft air testing is an important stage of the construction and commissioning process.
If a smoke shaft is too leaky, it may not achieve the required performance. This can result in a failed air tightness test, potentially delaying the completion and sign-off of the fire safety system.
What is smoke shaft air testing?
Smoke shaft air testing is used to determine whether a smoke shaft is sufficiently airtight to meet the required performance criteria.
During the test, specialist fan equipment is used to pressurise the shaft and measure the amount of air leakage through the shaft envelope. The results are then compared against the required air leakage target.
The commonly specified target for smoke shafts is 3.8 m³/hr/m², although the required criteria should always be confirmed against the relevant project specification and design requirements.
Testing provides an important indication of whether the smoke shaft is likely to perform as intended as part of the wider smoke control system.
Why does a smoke shaft need to be airtight?
It is easy to assume that a small amount of air leakage won’t make much difference. However, smoke control systems rely on carefully controlled airflow and pressure differences.
Unwanted leakage through joints, doors, service penetrations, access panels or other parts of the shaft envelope can affect the amount of air the system needs to move.
If leakage is greater than expected, the smoke control system may not achieve its designed performance.
This is why smoke shaft air tightness testing should be treated as an important part of the commissioning process rather than simply a final box-ticking exercise.
What happens if a smoke shaft fails its air test?
A failed smoke shaft air test can be frustrating, particularly when it occurs late in a project.
However, a failed test doesn’t necessarily mean that extensive remedial work is required.
The first step should be to establish where the air is leaking.
Common leakage locations can include:
- Shaft wall joints and construction interfaces
- Access doors and inspection panels
- Service penetrations
- Cable and pipe penetrations
- Mechanical and electrical interfaces
- Dampers and associated components
- Gaps around doors and frames
- Poorly sealed joints or openings
Finding these leakage paths allows remedial work to be targeted at the areas responsible for the test failure.
Smoke shaft leakage testing and diagnostics
When a smoke shaft fails an air tightness test, simply applying additional sealant throughout the shaft can be inefficient and expensive.
A better approach is to carry out a smoke shaft leakage investigation.
Our diagnostic service combines air pressure testing with smoke testing and thermal imaging to help identify leakage paths within the smoke shaft envelope.
Smoke can be used to visually identify areas where air is escaping, while thermal imaging can help locate temperature differences associated with air movement and leakage.
This combination of techniques provides a practical way of investigating difficult-to-find leaks.
Targeted remedial works
Once the leakage paths have been identified, the findings can be documented in a detailed air leakage report.
The report gives the client and contractor a clearer understanding of:
- Where the leakage is occurring
- Which areas require remedial sealing
- The potential significance of individual leakage paths
- Where further investigation may be required
This means remedial works can be targeted rather than carried out on a trial-and-error basis.
Once the required sealing works have been completed, the smoke shaft can be retested to establish whether it now meets the specified air tightness requirement.
Smoke shaft testing for new and existing buildings
Smoke shaft air testing can be required as part of the commissioning process for new developments, but testing can also be useful when investigating problems with an existing smoke control installation.
If a smoke shaft has previously failed an air test, or if there are concerns about its performance, an independent leakage investigation can help identify potential problem areas.
Early testing can also be beneficial. Identifying leakage issues before the final stages of a project can give contractors more time to carry out remedial works without creating unnecessary programme delays.
AOV and smoke shaft air testing
Smoke shafts are often associated with AOV (Automatic Opening Vent) systems and wider smoke ventilation strategies.
Although the exact testing requirements will depend on the building design and fire strategy, it is important that the smoke shaft and associated smoke control system are considered as a complete system.
Air pressure testing provides measurable information about the airtightness of the shaft, while diagnostic techniques can help identify defects when the required performance isn’t achieved.
Why choose an experienced smoke shaft testing company?
Smoke shaft testing requires specialist equipment, appropriate calibration and experience interpreting test results.
At Air Pressure Testing, we have extensive experience carrying out air tightness testing on smoke shafts of different sizes and configurations.
We can provide both the initial smoke shaft air test and, where required, a diagnostic service to investigate failed tests.
Our service includes:
- Smoke shaft surveys carried out by experienced consultants
- Smoke shaft air tightness testing
- UKAS and ATTMA Level 2 accredited air testing
- Air test certification
- High-powered fan equipment
- UKAS-calibrated equipment
- Smoke leakage investigations
- Thermal imaging surveys
- Detailed air leakage reports
- Targeted diagnostic support
- Rapid testing and reporting
UKAS and ATTMA Level 2 accredited air testing
Air Pressure Testing is a UK air testing company with UKAS and ATTMA Level 2 accreditation, providing air tightness testing for buildings as well as specialist testing of smoke shafts and floor plenums.
Our experience allows us to provide more than just a pass-or-fail test. Where a smoke shaft doesn’t achieve the required result, we can help investigate the reason for the failure and provide practical information to support remedial works.
Arrange smoke shaft air testing
Whether you are a main contractor, M&E contractor, fire safety contractor, developer, consultant or building control professional, arranging smoke shaft air testing at the appropriate stage of a project can help identify problems before they become a cause of delay.
If your smoke shaft has failed an air test, our leakage diagnostic service can help identify the areas requiring attention so that remedial works can be targeted and the shaft prepared for retesting.
For more information about smoke shaft air testing, AOV testing and smoke shaft leakage investigations, or to request our smoke shaft checklist, contact Air Pressure Testing through our website.