The Advantages of Hydro Testing using Weld Isolation (Dual) Tools

It is crucial to ensure the Weld isolation (dual) tools (also known as weld test plugs or weld isolation plugs) are commonly used in hydro testing processes. These tools are designed to isolate a specific section of a pipeline or vessel during the hydrostatic testing to ensure that the pressure is applied only to the intended area.

Here’s how weld isolation (dual) tools are used in hydro testing:

Hydro Testing using Weld Isolation (Dual) Tools


The weld isolation (dual) tool is inserted into the pipeline or vessel at the desired location to create a seal. It is typically placed on both sides of the weld joint that needs to be tested. The tool effectively isolates the weld area from the rest of the system, preventing the pressure from spreading throughout the pipeline or vessel.

Pressure Application

Once the weld isolation (dual) tool is in place, the hydrostatic test pressure is applied to the isolated area. Water or another suitable testing fluid is used to fill the isolated section, and the pressure is gradually increased to the specified test pressure. The tool ensures that the pressure is contained within the isolated area, allowing for accurate testing of the weld joint.

Leak Detection

During the hydrostatic test, the isolated weld joint is inspected for any signs of leakage. This can be done through visual examination using a pressure gauge or by using leak detection equipment to measure pressure drop. If there are no leaks or defects detected, it indicates that the weld joint is sound and can withstand the specified test pressure.


Once the hydrostatic test is completed and the weld joint is verified to be leak-free, the weld isolation (dual) tool is removed from the pipeline or vessel. Care should be taken to ensure proper depressurisation and drainage of the isolated section before removal.

Weld isolation (dual) tools are valuable in hydro testing as they provide a means to isolate and test specific weld joints without affecting the entire system. They help ensure the integrity and reliability of welded connections by subjecting them to the required test pressure while minimising the impact on the rest of the pipeline or vessel.

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