What pressure is considered hazardous for air testing and may damage the tank?

In tank testing, particularly when it comes to air testing for underground storage tanks (USTs), understanding pressure limits is crucial for safety and effectiveness. The correct answer indicates that 5 psig (pounds per square inch gauge) is a significant threshold. At this level, the structural integrity of many tanks can be compromised, leading to potential damage.

Exceeding this pressure can cause undue stress on a tank’s seams, welds, and overall structure, which may result in leaks or catastrophic failures. It's imperative to perform air testing at or below this limit to ensure that the testing is both safe and reliable, confirming that any tanks being examined are sound and free from defects without introducing an unnecessary risk of damage.

Remaining pressures below this threshold are generally considered safe for testing, further ensuring the longevity and reliability of the tank system. Thus, recognizing 5 psig as the hazardous level provides a critical guideline for maintaining safety during tank inspections and repairs.