Which of the following statements is true regarding hydrostatic testing?

• A. It uses gas to test pressure
• B. It is performed at room temperature
• C. It tests pipe integrity under water pressure
• D. It requires a visual inspection of pipes

Answer: (C)

Hydrostatic testing is a method used to ensure the integrity and leak-tightness of pipes and pressure vessels by using water to test their maximum operating pressure. The process involves filling the system with water and then pressurizing it to check for any leaks or weaknesses in the pipe material. This is particularly effective because water is nearly incompressible, allowing for a clear assessment of the system's ability to hold pressure without failure.

When conducting hydrostatic tests, the focus is on the ability of the pipe to withstand high pressures under controlled conditions. This contrasts with using gas, which can compress and potentially mask leaks. Options suggesting the use of gas or specific temperature requirements might not apply to this testing method, as hydrostatic testing is specifically about using water, often at or near its ambient temperature to ensure accurate testing conditions.

Additionally, while visual inspections are important in the overall maintenance and assessment of piping systems, they are not a specific requirement of the hydrostatic test itself, which primarily focuses on pressure testing. Thus, stating that hydrostatic testing tests pipe integrity under water pressure accurately summarizes the purpose and method of this testing process.