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Expert Air Testing Solutions for Smoke Shafts

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Smoke Shaft Air Testing

Smoke shafts systems are commonly installed as part of a fire-engineered approach to safety in high rise buildings. Smoke shafts are an important element of a smoke control system; therefore, the air tightness performance of the shaft is paramount ? that?s why they need to pass an air tightness test. If the smoke shaft doesn?t meet the air tightness target (usually 3.8m3/hr/m2) it can have a negative impact to the overall system and cannot be signed off by the fire system contractor and/or Building Control.

We have a massive amount of experience helping clients pass testing all sizes of smoke shafts, we also offer a diagnostic service for failed smoke shafts, using both smoke testing and thermal imaging to identify air leakage paths within the smoke shaft envelope. On previous projects where the smoke shaft has failed the air test, we have managed to quickly identify the air leakage paths so cliento allow for targeted used smoke testing and thermal imagining to identify air leakage paths within the envelope of the smoke shaft. The findings our smoke surveys are collated into a detailed air leakage report, which then allows the client to undertake targeted remedial sealing works resulting in a test pass during the following visit.

Our premium smoke shaft testing service includes:

Air Pressure Testing is one of the few companies that is both UKAS and ATTMA Level 2 accredited for undertaking air tightness testing to buildings as well as smoke shafts and floor plenums. If you would like more information on our smoke shaft (AOV) testing and/or you would like to download our smoke shaft checklist, please contact us at: www.aptsoundtesting.co.uk

The Importance of Air Testing for Smoke Shafts

Air testing for smoke shafts is a crucial step in ensuring safety and compliance with regulations. In the event of a fire, smoke can pose significant risks to occupants, often causing more than 60% of fatalities due to inhalation. By conducting air tests, we ensure that smoke control systems are effective in evacuating smoke, protecting escape routes, and assisting firefighters. Don’t compromise on safety—trust APT Smoke Shaft Air Testing Services for thorough and reliable testing.

Why undertake Air Testing to Smoke Shafts?

All building that have a smoke shaft should have an air tightness test to the shaft I compliance with Legislation and standards, such as BS 9999 and BS 9991.

Air testing for smoke shafts is a critical step in ensuring safety and compliance. Let’s explore why it’s essential:

  • Smoke Control and Fire Safety: In the event of a fire, smoke is a significant contributor to deaths and injuries, often surpassing the impact of the fire itself.
  • More than 60% of deaths occur due to smoke inhalation, emphasizing the importance of controlling smoke.
  • Smoke control systems protect escape routes and assist firefighters, reducing fatalities and injuries.

Smoke Shaft Functionality:

  • Smoke shafts play a crucial role in evacuating smoke from buildings during a fire. 
  • To function effectively, smoke shafts must be airtight to allow mechanical Automatic Opening Ventilation (AOV) systems to extract smoke from escape/access routes.
  • Air testing confirms the shaft’s airtightness before AOV commissioning to allow the smoke shaft to be signed off by the builder. 

Building Regulations and Standards for Smoke Shafts

Smoke shafts are subject to an ever-evolving network of standards and legislation in the UK. For residential buildings, BS 9991:2015 provides updated fire safety guidance, including recommendations for smoke control.

Preparing for airtight smoke shafts

So how do you prepare your smoke shaft for the required level of air tightness? As shafts are at such a high risk of failure, you should seek the advice of UKAS accredited air tightness consultants early on in the process.

Regardless of the building materials/type of construction, the best approach is to treat the inside of the shaft as the primary air seal line. As such, the finish inside should be smooth and conscientiously sealed at all junctions and joints, sealing from the outside often leads to air test failures. 

Plasterboard – If there is an internal plasterboard finish, this needs to be sealed thoroughly across every joint and screwhead, again paying attention to all junctions and penetrations. Its often best to skim the inner shaft wall as this usually a robust option to maintain the seal line.  

Masonry – All masonry should usually be constructed out of high-grade paint finish blockwork. All mortar joints should be fully filled and pointed. To attain a high level of air tightness its usually best to paint the blockwork with masonry paint and/or render the inside face of the blockwork.

Service/Structural Penetrations  – carefully seal all ductwork and/or structural materials penetrating the inside line of the shaft, you will need to instruct each contractor on the importance of having a good and continuous air seal, paying particular attention to areas that are going to be hard to reach after installation e.g. when a steel supports may be flush against a wall junction or ductwork is close to structural junctions. 

How often should I air test a smoke shaft?

This can be quite a complicated answer. The frequency of smoke shaft air testing depends on various factors, including building regulations, insurance requirements and the specific characteristics of the building. Here are some general guidelines:

New Buildings or Major Renovations: For newly constructed buildings or significant renovations, newly installed smoke shafts should undergo initial testing to verify their airtightness. This ensures compliance with safety standards and confirms that the smoke shafts will function effectively during emergencies.

Periodic Testing and Regular Maintenance: After the initial test, smoke shafts should be retested periodically to ensure ongoing airtightness. The frequency of retesting can vary but is typically recommended every 12 months. Regular maintenance and inspections help identify any deterioration or damage that may compromise the shaft’s performance.

Works to the Smoke Shaft: Certain events may require additional testing:
  • Alterations to the smoke shaft:

    If modifications are made to the fabric of the smoke shaft or adjacent areas, retesting is necessary.

  • Fire Incidents:

    After a fire incident, smoke shafts should be inspected and tested to confirm their ongoing integrity.

  • Building Occupancy Changes:

    If the building’s use changes significantly, retesting may be required, i.e. an office building to residential.

  • Consult Local Authorities and Experts:

    Always consult with local fire safety authorities, building control officers, or fire engineers. They can provide specific guidance based on regional regulations and best practices.

Remember that maintaining properly functioning smoke shafts is essential for occupant safety during fires. Regular testing ensures their reliability and effectiveness in smoke extraction.

The consequences of not testing smoke shafts

Neglecting to undertake air testing to smoke shafts can have serious repercussions for building and occupant safety. Here are just a few of the potential consequences:

  1. Ineffective/Poor Smoke Extraction – Without regular testing, smoke shafts may become compromised due to wear, damage, or poor maintenance.

What is the best time to air test smoke shafts?

The optimal time for testing smoke shafts depends on several factors, including the building’s usage, occupancy, and operational schedule. Here are some considerations:

How often should I air test a smoke shaft?

When preparing and sealing a smoke shaft to pass an air test, there are several important factors to consider. Here’s a checklist to guide you:

Smoke Shaft Building Regulations and Standards:

There is a number of building regulations and guidance for undertaking air testing to Automatic Opening Vent (AOV) smoke shafts. Here’s a summary of the main regulations and standards:

Approved Documents: 

  • The Approved Document B – this provides guidance on fire safety and mentions the role of AOV systems in facilitating evacuation by clearing smoke. It’s important to refer to the latest version of this document for detailed guidelines.
  • BS EN 12101-2:2006 – AOV smoke shafts must comply with standards such as BS EN 12101-2:2006, which covers the design of smoke ventilation systems.
  • BS EN 9991 (2015) – Fire Safety in the design management and use of residential buildings.
  • Smoke Shaft Testing Requirements: all tests are carried out in accordance with the requirements of ATTMA TSL Issue 1, CIBSE T23:2000, BS EN 13829 and BS EN 12101-2:2006.
  • Smoke Shaft Testing Frequency: Annual air testing is required to ensure the AOV smoke shafts are running correctly.
  • Air Testing Body: The air test to the smoke shafts should be carried out by a Level 2 ATTMA member, Level 1 IATS, or a UKAS accredited testing laboratory
  • UKAS Calibrated Equipment: Testing should be carried out using UKAS calibrated equipment to meet ISO 17025 air permeability standards.

For the most accurate and up-to-date information, it’s recommended to consult the official documents and any recent amendments provided by the UK government and relevant authorities for AOV Smoke shafts.

How Long will a typical smoke shaft air test take

The duration of a typical smoke shaft air test can vary based on factors such as the size of the building, the complexity of the smoke shaft system, and the testing methodology. However, I’ll provide a general estimate:

What will be the Cost of a Smoke Shaft Air Test

The cost of smoke shaft air testing can vary based on several factors, including the size of the building location, the number and size of the smoke shafts and if the testing needs to be undertaken ‘out of hours. Here is the information we need to send across an accurate cost for smoke shaft air test: 

Smoke Leakage Testing in Smoke Shafts

Smoke Leakage Testing to identify air leakage paths in a smoke shaft is a valuable approach. Here’s how it can be done:

Thermal Imaging for Air Leakage Detection in Smoke Shafts

Thermal imaging to identify air leakage paths in a smoke shaft is a valuable approach. Here’s how it can be done:

Advantage: Thermal imaging reveals the pathways that cold/warm air follows, making it easier to identify air leakage paths within the envelope of the smoke shaft. 

Combining Thermal Imaging and Blower Door Testing:


  1. Shut all AOV doors, except where you will be setting up the equipment inline with our smoke shaft checklist.
  2. Set up small blow heaters, with the associated ductwork terminating into the smoke shaft. 
  3. Set up a blower door system to pressurise or depressurise the entire smoke shaft.
  4. Use thermal imaging cameras to capture images of the smoke shaft envelope.
  5. Produce a detailed thermal imaging report highlighting the air leakage paths through the fabric of the smoke shaft envelope. 

Benefits: Remember that thermal imaging provides a visual representation of heat loss and air leakage, helping you target the sealing of air leakage paths more effectively. 

Why use APT for your smoke shaft air testing?

We have been undertaking AOV smoke shaft testing throughout London and the South-East, on many prestigious projects such as Battersea Power Station, The Imperial War Museum and Clarridges and Berkeley Hotel.