Final answer:
There is no specific PSI value mentioned for the inspection of pressure tanks to be pressurized within 3 hours. The pressure limits depend on the tank's design and safety factors, where a tank may be required to handle twice its normal operating pressure to ensure safety.
Step-by-step explanation:
When inspecting pressure tanks, there is no standardized PSI value provided that the compressor must reach within 3 hours, as it may vary depending on the specifications of the tank and the requirements set by industry regulations or manufacturer guidelines. However, it is important to note that pressure tanks are designed to withstand specific pressure ratings. For example, a common scuba tank can handle an internal pressure of between 2500 and 3000 psi. In engineering practices, when discussing the safety factor of a cylinder, it is indicated that the cylinder should be able to hold twice the pressure of the stored gas without failing. Hence, a tank designed for 200 atmospheres would likely not fail until reaching 400 atmospheres.
Understanding the compressibility of gases is crucial as gases can be compressed to fit into a smaller volume, which is an essential functionality in the use of scuba tanks and similar pressure vessels.