How should the nozzle be opened to bleed off pressure in the test lengths?

• A. Fully Open Quickly
• B. Partially and Then Close
• C. Slowly
• D. Not Opened

Answer: (C)

Bleeding off pressure in test lengths should be done slowly. Opening the nozzle gradually lets the fluid release in a controlled way, which avoids hydraulic shock (water hammer) that can occur if pressure is dumped too quickly. A slow bleed also gives you time to watch the gauges and the line for leaks or movement, and it minimizes sudden surges that could damage hoses or fittings and endanger personnel.

Opening the nozzle fully and quickly releases pressure all at once, creating a rapid flow spike that can cause equipment stress, hose whipping, or injuries. Partially opening and then closing doesn’t provide a consistent, controlled reduction in pressure and leaves residual pressure that you’ll have to bleed again. Not opening at all means the pressure remains in the line, defeating the purpose of the test.

So, bleed off gradually by opening the nozzle slowly and monitoring the pressure as it falls to the safe level.