Leak detection has become a necessary quality task for some time now. The methods of detecting leaks have changed in recent history. Figure 1 shows those common leak test methods and what range of leak tightness can be achieved and measured. Within this article, we will discuss the questions that need to be answered and the choices that need to be made for your application. The choices will often be more than one at first, but will eventually be one of level or leak tightness (specification), time allowed and method to check for leak tightness (throughput desired) and of course budget for equipment and manpower.
The leak tightness specification usually comes from the end user (customer). He has taken into consideration what his “acceptable leak rate” is and what life expectancy may be placed on that part that needs to be leak tight. Whether the part will keep out some external influence or keep in some gas or liquid really doesn’t matter for leak detection. We will test for both conditions.