Hydrogen, the lightest element, can be an effective leak detection method.
Leak testing is an essential element in product quality testing with an assortment of methods that are appropriate for various applications. From the automotive industry to HVAC manufacturers, countless products and parts have to be tested for tightness to meet specifications and be granted the positive end of the accept or reject option. In fact, for many suppliers to the automotive industry, leak testing is an integrated part of production; 100% of their parts are tested against a leak standard to meet quality requirements.
Leak testing is almost always a matter of exactly measuring the leak rate of a manufactured part or product. Nothing is ever absolutely tight, but leak testing ensures that the product has been tested for maximum allowable leakage.