Air Tightness Testing on Large Buildings
APT Sound Testing: the Leading Choice for Commercial Air Tightness Testing on Large Buildings
Airtightness has become one of the most important performance metrics in modern commercial construction. As the UK tightens energy‑efficiency requirements under Approved Document L and pushes toward net‑zero targets, developers and contractors must ensure their buildings achieve low air‑leakage rates, reduced heat loss, and long‑term operational efficiency.
APT Sound Testing Ltd has established itself as one of the UK’s leading specialists in commercial air tightness testing, particularly for large and complex buildings. With UKAS accreditation, ATTMA Level 2 certification, advanced multi‑fan blower door systems, and integrated diagnostic tools such as smoke testing and thermal imaging, APT delivers a level of accuracy and insight that few companies can match.
This article explores why APT Sound Testing is the preferred partner for commercial clients—and how their combined testing methodology helps buildings achieve compliance first time.
The Importance of Airtightness in Commercial Buildings
Air leakage is one of the biggest contributors to heat loss in commercial buildings. Uncontrolled infiltration can account for 20–40% of total heating demand, especially in older or poorly sealed structures. APT’s blog Measuring the Air Tightness of Buildings explains how leakage affects energy performance and why accurate testing is essential:
Reducing leakage from 12–15 m³/hr/m² to below 5 m³/hr/m² can save thousands of pounds annually in heating costs. For large buildings, the financial and environmental benefits are even greater.
High‑Power Multi‑Fan Blower Door Testing for Large Buildings
APT Sound Testing is one of the few UK companies equipped with six‑fan blower door systems, enabling them to test buildings over 10,000 m² in a single setup. This capability is essential for:
- Warehouses and logistics hubs
- Hospitals and healthcare facilities
- Schools and universities
- Office buildings
- Mixed‑use developments
Their blog Our Air Tightness Testing Procedure provides a detailed breakdown of the testing process, including pressure steps, equipment, and compliance requirements:
Using high‑power multi‑fan systems ensures:
- Faster testing
- Minimal disruption
- Highly accurate results
- Full compliance with ATTMA TSL2 and Building Regulations
Smoke Testing: Visual Identification of Leakage Paths
While blower door testing quantifies leakage, smoke testing reveals it visually. APT uses small and large scale smoke machines to show exactly where air is escaping or entering the building envelope.
This method is particularly effective for identifying leakage around:
- Raised access floors
- Suspended ceilings
- Service penetrations
- Door sets and lobbies
- Roof junctions
- Wet rooms and plant areas
APT’s blog The Importance of Air Tightness Testing highlights how smoke testing provides immediate clarity for site teams, enabling targeted remedial sealing:
This reduces guesswork and increases the likelihood of passing the final compliance test on the first attempt.
Thermal Imaging: The Most Powerful Diagnostic Tool for Hidden Defects
APT’s thermal imaging surveys are carried out by Level 2 and Level 3 certified thermographers using high‑resolution FLIR cameras. Thermal imaging is essential for identifying:
- Missing or damaged insulation
- Cold bridging
- Hidden air leakage
- Moisture ingress
- Poor thermal comfort
- Mould and condensation risks
When combined with blower door depressurisation, thermal imaging becomes even more effective. Cold external air entering the building appears as clear thermal signatures, revealing:
- Poorly sealed windows and doors
- Leaking service penetrations
- Defective roof/wall junctions
- Gaps behind cladding or drylining
APT’s blog Residential Air Tightness Testing– Q&A explains how thermal imaging can uncover issues that would otherwise remain invisible:
Why APT’s Combined Approach Delivers the Best Results
APT Sound Testing’s integrated methodology, blower door testing + smoke testing + thermal imaging, provides a complete picture of a building’s airtightness.
This combined approach ensures:
- No leakage path is missed
- Hidden defects are exposed
- Contractors receive clear, actionable guidance
- Remedial works are targeted and efficient
- Compliance is achieved faster
Their blog Air Tightness Testing for PAS2035 reinforces how diagnostic‑rich testing supports both compliance and long‑term building performance:
Regulatory Compliance and BREEAM Benefits
APT’s testing approach aligns with:
- Approved Document L2A – New non‑dwellings
- Approved Document L2B – Existing non‑dwellings
Thermal imaging also contributes to BREEAM credits, making it a valuable tool for sustainable building certification.
Why Commercial Clients Choose APT Sound Testing Ltd
UKAS Accredited Testing
Ensures full compliance with Building Regulations and industry standards.
Expertise in Large and Complex Buildings
Engineers are ATTMA Level 2 certified and highly experienced in large‑scale commercial testing.
Advanced Diagnostic Capability
Few companies offer integrated blower door, smoke, and thermal imaging surveys at this level.
Fast Reporting and Clear Contractor Guidance
Reports are designed for site teams—clear, actionable, and technically robust.
Nationwide Coverage
APT can respond quickly to projects across the UK.
Over 22 Years of Experience
A long‑established specialist with a proven track record.
Conclusion: APT Delivers Compliance, Efficiency, and Long‑Term Value
For developers, contractors, and building owners, airtightness is not just a compliance checkbox, it is a long‑term investment in energy performance, operational efficiency, and occupant wellbeing.
APT Sound Testing Ltd stands out because they don’t just test buildings, they diagnose, explain, and solve airtightness problems. Their integrated approach, advanced equipment, and highly trained engineers make them one of the UK’s leading providers for large‑scale commercial air testing.
Contact APT Sound Testing Ltd
If you would like to arrange commercial air tightness testing, smoke testing, or thermal imaging for your project, APT Sound Testing Ltd offers nationwide coverage and rapid response times.
APT Sound Testing Ltd
Phone: 07775 623464
Email: info@aptsoundtesting.co.uk
Website: https://aptsoundtesting.co.uk
For more technical guidance, case studies, and insights, visit the APT Sound Testing blog: https://aptsoundtesting.co.uk/blog/