Comparison of air leakage with fluid leaks

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For comparison of the actual fluid leakage to the measured air leakage is the "dynamic viscosity" used. The liquids must here also be taken into account the actual operating temperature, changed since the viscosity of the liquid change with temperature as well.

Here are some sample material data:

For a pure air-leakage of eg 4.0 cm³/min in the water space, this means

• at 20°C hot water, a water leakage of about 0.07 cm³/min
• at 80°C hot water, a water leakage of about 0.20 cm³/min
• at 100°C hot water, a water leakage of about 0.25 cm³/min

These considerations are impurities such as dissolved calcium in water or other additives are not considered.

In reality, between an air leakage and water leakage is a factor of about 65 - 70. For other liquids such as gasoline, diesel, oil or coolant, this factor is completely different. With oils can easily occur depending on the viscosity factors 2000 - 150000. Here must necessarily real operating conditions and the resulting dynamic viscosity of the medium are considered.

There are also various media such as gasoline or coolant, out gas in contact with oxygen. Here it may be necessary to test for a corresponding gas leaks.