ANSI/ISA-75.19.01, from the American National Standards Institute and the International Society of Automation, provides requirements for the hydrostatic testing of control valves.
Scope
ANSI/ISA-75.19.01 applies to all control valves. It establishes the requirements for the structural integrity and leak tightness of the valves’ pressure retaining parts.
Test Procedures
In a hydrostatic test, the valve body is filled with testing fluid and then pressure is applied for a specified length of time. The valve is then inspected for any leakage.
Learn more about valve leakage tests.
Fluid
The testing liquid can be water, water with a corrosion inhibitor, or another liquid whose viscosity isn’t greater than that of water.
Pressure
The testing pressure depends on what material the valve is made of: steel, nickel-base alloy, cast iron, and so on. See the full standard for material-specific hydrostatic test pressures.
Time
The test duration depends on the nominal valve size and valve class.
| Nominal Valve Size | Class 150 & Lower | Class 250 to 600 | Class 900 to 1500 | Class 2500 & Higher |
|---|---|---|---|---|
| 2” & Smaller | 1 minute | 1 minute | 2 minutes | 3 minutes |
| 2 ½” to 4” | 2 minutes | 2 minutes | 4 minutes | 5 minutes |
| 5” to 8” | 2 minutes | 3 minutes | 5 minutes | 8 minutes |
| 10” & Larger | 3 minutes | 5 minutes | 8 minutes | 10 minutes |
Acceptance Standards
Three conditions can cause a valve to be rejected:
- There is visible leakage in the valve body assembly.
- There is leakage through static seals and gasketed joints (unless allowed by design).
- The hydrostatic test causes any distortion that impairs the valve operation.
A full copy of ANSI/ISA-75.19.01 can be purchased from the American National Standards Institute.