Leak Testing


Leak Testing is a non-destructive testing method for detection and localisation of leakages in  pressure and vaccum systems.

„Leakage“ means liquid or gas passage through a leak independent from its physical size. A leak can be a crack, breakthrough, groove or hole which leaves or embeds a gas (e.g. air) or liquid (e.g. water) into/out of the construction.

Leakages could  endanger the operation safety of vaccum or pressure systems, such as pressure vessels,
significantly. Dangerous gases or liquids might emerge.

Leak testing is also applied for pyrotechnical facilities, electronic parts, air condition equipment, food packaging etc.

 Evidence of vessel decompression
using fluorescent concentrate H 849


The following table shows the relation of leakage rate, size of leakage and the leakage thus resulting :

Leakage rate   
[m³ Pa/s]          
Diameter of leaks
Leakage through leak at
Δp = 1 bar
10¹ 1.0 mm Water runs out
10-1 0.1 mm Water drops
10-3 0.03 mm Watertight, but permeable to gas
10-5 ≈ 3 µm 1 air bubble ( ≈ 1 mm³) in 10 seconds
10-7 ≈ 0.1 µm approx. 1 cm³ gas losses in 12 days
10-9  -- approx. 3 cm³  gas losses in 1 year
10-11  -- approx. 1 cm³ gas losses in 300 years