Undertaking Airtightness Testing on Very Large Buildings
Airtightness testing for very large buildings demands more than standard equipment and routine methods. When a structure spans over 10,000 m², the internal volume, leakage pathways, and pressure stability requirements increase dramatically. Only a small number of companies in the UK have the capability, experience, and accreditation to test buildings at this scale with accuracy and confidence. For more than twenty years, we have been one of them.
As a UKAS‑accredited and ATTMA Level 2 airtightness testing company, we specialise in large‑scale commercial, industrial, and complex building testing. Our high‑capacity fan systems allow us to pressurise and depressurise buildings with exceptionally large footprints, delivering stable test conditions even in structures with significant leakage or challenging geometries. This capability has been built through decades of investment, technical refinement, and hands‑on experience across thousands of projects.
High‑Power Fan Systems for Large Commercial Buildings
Testing a building above 10,000 m² requires equipment capable of moving vast volumes of air while maintaining precise pressure control. Our multi‑fan systems are engineered to deliver the airflow needed to reach 50 Pa in large or highly permeable buildings, ensuring compliance with ATTMA TSL2 and EN ISO 9972 methodologies. Whether the building is a logistics hub, a retail distribution centre, a multi‑storey commercial block, or a large public facility, we have the capacity to test it effectively.
Our approach is not simply about power. It is about control, stability, and accuracy. Large buildings often require multiple fan banks, strategic placement of equipment, and careful management of internal and external conditions. Our team brings the technical understanding needed to design and execute these tests reliably, even in complex or time‑sensitive environments.
Expertise in Historic and Sensitive Buildings
Not all large buildings are modern. Many heritage structures require airtightness assessment for conservation, refurbishment, or performance improvement. These buildings cannot be subjected to high pressures or aggressive testing methods. Over the years, we have developed specialist techniques for blower door smoke leakage testing and diagnosis, allowing us to visualise leakage paths without risking damage to fragile materials or historic fabric.
This method is particularly valuable for older civic buildings, listed properties, and structures undergoing sensitive restoration. By combining controlled pressurisation with smoke tracing, we help project teams understand how air moves through the building and where improvements can be made without compromising heritage value.
Advanced Diagnostics Through Depressurised Thermal Imaging
For projects requiring deeper insight into leakage pathways, we offer depressurised thermal imaging surveys. By combining infrared thermography with controlled depressurisation, we can reveal hidden leakage routes that are invisible during standard thermal inspections. This technique is especially effective in large buildings where leakage may occur through complex junctions, concealed voids, or long‑distance pathways. This is especially useful in difficult to access areas, resulting in reduced Health and Safety issues, such as working at height etc.
Thermal imaging under pressure differential provides a level of diagnostic clarity that is invaluable during design verification, quality assurance, and troubleshooting. It is a powerful tool for both new‑build and refurbishment projects.
Experience with Passivhaus Commercial Buildings
Our team has consulted on and tested some of the only commercial buildings in the UK assessed against Passivhaus airtightness standards. These projects demand extraordinary precision, rigorous methodology, and a deep understanding of airtightness design and air seal line. Achieving such low permeability levels on large commercial structures requires close collaboration with architects and M&E specialists. Our involvement has ranged from early‑stage design advice of the air seal line, to final certification testing.
Two Decades of Airtightness Knowledge
Across twenty years, we have built a reputation for technical excellence and practical insight. We have been appointed as air leakage champions on major and prestigious developments, such as the Imperial War Museum, Battersea Power Station we have helped guide our clients site teams through detailing, sequencing, and on‑site execution to achieve ambitious airtightness targets. Our experience spans every building type, from warehouses and offices to heritage sites and high‑performance commercial buildings.
For more than twenty years, we’ve specialised in delivering airtightness testing for buildings of every size and complexity. Today, that includes some of the largest commercial structures in the UK. With our high‑capacity fan systems, we routinely test buildings with footprints above 10,000 m², providing stable pressurisation even in vast or highly permeable envelopes.
As a UKAS‑accredited and ATTMA Level 2 testing company, we work to the highest technical and reporting standards. Our team has supported major commercial developments, heritage restorations, and high‑performance buildings across the country. That includes consulting on and testing several of the only commercial buildings in the UK to be assessed against Passivhaus airtightness criteria, where precision and control are critical.
Detailed Air Leakage Investigations
Our experience extends far beyond standard pressurisation tests. We regularly carry out lower‑door pressurised smoke leakage investigations for historic and sensitive buildings, helping project teams understand leakage pathways without risking fabric damage. We also perform depressurised thermal imaging surveys, combining pressure differentials with infrared diagnostics to reveal hidden air leakage routes with exceptional clarity.
Across two decades, we’ve built a deep understanding of airtightness design, detailing, and sequencing. We’ve been brought in as air leakage champions on large and prestigious projects, helping design teams and contractors achieve demanding performance targets through practical guidance, on‑site support, and early‑stage strategy.
Whether you’re developing a logistics hub, a large retail unit, a multi‑storey commercial building, or a complex heritage site, our team has the equipment, accreditation, and experience to deliver airtightness testing at scale, and to help you achieve the results you need on buildings with air permeability targets of 1m3/hr/m2 or less!.
For more information call Air Pressure Testing now on 07775 623464; or email us at info@airpressuretesting.net