California Designated Operator Practice Exam

What should the tightness test of primary piping generally be performed at?

1. 100% of the piping operating pressure

2. 90% of the piping operating pressure

3. 110% of the piping operating pressure

4. 125% of the piping operating pressure

The correct answer is: 110% of the piping operating pressure

The tightness test of primary piping is generally performed at 110% of the piping's operating pressure because this testing pressure allows for a reliable evaluation of the integrity of the piping system. It ensures that any potential leaks, weak points, or failures can be identified before the system is put into normal operation. Testing at 110% provides a safety margin above typical operating conditions, which is crucial for ensuring that the system can handle unexpected pressure spikes or variations in operating conditions without leading to leaks or failures. Conducting the test at this pressure helps to confirm that the materials and joints in the piping system are capable of sustaining the pressures they will experience during regular use, thereby enhancing the overall safety and reliability of the system.