What is the most effective method to detect fuel leaks in newly installed or repaired fuel cells?

The most effective method to detect fuel leaks in newly installed or repaired fuel cells is the air pressure test. This technique involves filling the fuel cell with air at a pressure greater than atmospheric pressure and then checking for pressure drops over time. If there are any leaks in the fuel cell, the pressure will begin to decrease due to the escaping air.

This method is preferred because it allows for the detection of small leaks that might not be evident through other methods. It also provides a controlled environment wherein the integrity of the fuel cell can be thoroughly assessed without introducing any potentially hazardous substances.

In comparison, while a smoke test can be useful in some contexts, it is less precise and can be difficult to implement in all scenarios. Visual inspection is valuable as part of a routine maintenance check but may not reliably reveal all hidden leaks. The vacuum test can also be effective, but it typically is not as commonly used or reliable as the air pressure test for fuel cell integrity assessments.