Leak rate

The term leakrate ql with ist unit (mbar × l)/s is used to declare a leakage.

ql= (∆p ×V)/∆t

It corresponds to a change of gas volume per time unit.

The leakrate of ql=1  (mbar ×l)/s is given, if in a closed container with a volume of 1 liter the pressure rises or falls by 1 mbar within 1s. 

Conversion of leakrates

Tn=0°C Pn = 1013mbar mbar*l/s cmE3/s cmE3/min Pa*l /s Torr*l/s
mbar*l/s 1 9,87E-1 5,92E1 1E2 7,5E-1
cmE3/s 1,01 1 6E1 1,01E2 7,6E-1
cmE3/min 1,69E-2 1,67E-2 1 1,69 1,27E-2
Pa*l/s 1E-2 9,87E-3 5,92E-1 1 7,5E-3
Torr*l/s 1,33 1,32 7,9E1 1,33E2 1


1 mbar•l/s = 59,2 cm3/min or 0,0169 mbar•l/s = 1 cm3/min

Relation between leakrate and leak-dimension

Diameter leak Leakrate {mbar*l/s]
1 cm 10E4
1 mm 10E2
0,1 mm 10E0
0,01 mm 10E-2
1um 10E-4
0,1 um 10E-6
0,01 um 10E-8
1 nm 10E-10
1 Anström = 0,1 nm 10E-12