The immersion technique is frequently used to locate leaks in sealed containers. Leaks in a container can be seen independently. Leak size can be approximated by the size of the bubble. It is not suitable for measurement of total system leakage.

The liquid film technique is widely applied to components and systems that can not easily be immersed and is used to rapidly locate leaks. An approximation of leak size can be made based on the type of bubbles formed, but the technique is not suitable for measuring leakage rate. It can be used with a vacuum box to test vessels which cannot be pressurized or where only one side is accessible.

Accuracy—This practice is not intended to measure leakage rates, but to locate leaks on a go, no-go basis. Their accuracy for locating leaks of 4.5 × 10−10 mol/s (1 × 10−4 Std cm3/s) and larger is ±5 %. Accuracy for locating smaller leaks depends upon the skill of the operator.

Repeatability—On a go, no-go basis, duplicate tests by the same operator should not vary by more than ±5 % for leaks of 4.5 × 10−9 mol/s (1 × 10−4 Std cm3/s).

Reproducibility—On a go, no-go basis, duplicate tests by other trained operators should not vary by more than 10 % for leaks of 4.5 × 10−9 mol/s (1 × 10−4 Std cm3/s) and larger.

1. Scope

1.1 This practice covers procedures for detecting or locating leaks, or both, by bubble emission techniques. A quantitative measure is not practical. The normal limit of sensitivity for this test method is 4.5 × 10−10 mol/s (1 × 10−5 Std cm3/s).

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4 This standard does not purport to address the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.