Duct Leakage Testing

Duct leakage testing (DLT) pressurises a section of HVAC ductwork and measures how much air escapes through seams, joints, access doors and penetrations. It proves the ductwork is airtight enough to deliver design airflow, and it has to happen before the ceilings close

Testing, Adjusting and Balancing

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Every Leak Is Cooling You Paid For and Never Received

Leaking ductwork means the AHU works harder, rooms at the end of the run fall short, and dust can be drawn into the air stream. In smoke management and hospital systems, leakage is also a safety and infection control issue. Testing early means fixes cost minutes, not ceiling demolition.

Duct Systems We Test

Supply air: low, medium and high pressure ducts, CAV, VAV and treated fresh air
Return air: main ducts, risers and branches
Exhaust air: general, toilet, car park and laboratory exhaust
Smoke management: smoke extract, stair and lift shaft pressurisation ducts
Specialised systems: hospitals, cleanrooms, pharmaceutical facilities and data centres

Leakage Points We Inspect

Longitudinal seams and transverse joints · Duct penetrations for sensors, probes and control wiring · Access doors, gaskets and frames · Flexible connections to equipment · Fire and smoke damper sleeves and retaining angles

How We Test Ductwork

Engineering review. Drawings and specifications checked for pressure class, leakage class and seal class.
Constructability review. We flag inaccessible ducts and missing isolation points before testing day.
Mechanical completion check. Supports, hangers, dampers, access doors and connections confirmed complete.
Surface area calculation. Allowable leakage worked out for each test section.
Leakage testing. Section sealed, pressurised to test pressure and leakage measured.
Investigation and rectification. Leaks traced, repaired by the contractor and verified.
Re-testing and certification. Section retested until it passes, then certified.

Standards We Follow

SMACNA HVAC Air Duct Leakage Test Manual and HVAC Duct Construction Standards, ASHRAE 90.1, BS EN 12237, BS EN 1507, DW/143, Eurovent 2/2, NEBB and AABC procedures.

What You Receive

Test section drawings and surface area calculations · Measured leakage against allowable leakage for each section · Deficiency and rectification records · Signed duct leakage test certificates

Duct Leakage Testing FAQ

Do you have any question?

1. What is a duct leakage test?

It is a test that seals a section of ductwork, pressurises it with a calibrated fan and measures how much air leaks out. The result is compared with the allowable leakage for that duct class.

2. When should duct leakage testing be done?

After the ductwork section is installed and sealed, and before insulation and ceilings close it in. Testing later makes leaks expensive to reach.

3. What standard is used for duct leakage testing in Saudi Arabia?

Many Saudi project specifications call for the SMACNA HVAC Air Duct Leakage Test Manual. Some projects use BS EN 12237 or DW/143. We test to whichever your specification requires.

4. What happens if a section fails?

We help locate the leaks, the contractor seals them, and we retest the section until it passes. Nothing is certified until it meets the allowable leakage.