boiler hydro test

The Hydro Test Procedure for Boilers – How Does It Work?

Boilers form an integral component of several industrial heat generation systems. They provide the steam needed to drive thermal power generation and require strict safety testing to ensure they perform their function correctly. The hydro test is a process that can help manufacturers confirm the integrity of their boilers before routine operation.

What Is A Boiler Hydrostatic Test?

A boiler hydro test is a stress procedure used to determine the integrity of all aspects of a given boiler unit. The test involves filling the boiler with water and pressurizing to at least one and half times the maximum specified operating pressures for a short duration. During this test, if there are any defects in the boiler structure, the test will fail, and the boiler will not pass inspection for routine use.

Why Is It Necessary?

Standard boilers units in use in thermal power plants have multiple welded components, with each weld representing a potential point of weakness that could lead to equipment failure, leaks, and explosions. In addition, boiler hydrostatic testing ensures the boilers can withstand the extreme temperatures and pressures expected during routine operation.

Why Is Water Used for Boiler Testing?

In addition to being readily available/cheap to source, water has some physical features that make it ideal for use in boiler pressure testing. Firstly, water is non-toxic and poses no harm to the environment, making compliance with local environmental waste standards easy. Water is also nearly incompressible, making it easy to raise the pressures within a vessel filled with it. In the case of a boiler unit, raising the temperatures from atmospheric pressure to required test levels will be rapidly achieved.

Specific Requirements for Water Used In Boiler Hydrostatic Tests

For optimal testing results, water introduced into a boiler for testing should be maintained between 86°F and 122°F. Additional desirable parameters include:

  • pH range of 8.5 – 9.2
  • Silica 0.02 ppm
  • Conductivity between 5-10 mic S/cm
  • Water hardness of zero

boiler hydrostatic test

Boiler Pressure Testing Procedure and Requirements

The requirements for a boiler pressure test include the following:

  • A high-pressure displacement pump
  • Properly calibrated pressure gauges
  • Pressure bleed valves

To begin the test, the pressure displacement pump is connected to the boiler with an integrated gauge. Next, the boiler is rapidly filled with water with care taken to displace any air pockets within the vessel. The pressure within the boiler should be raised to 1.5 times the standard operating pressures and held at this level for at least 30 minutes by closing all bleed valves.

After holding the pressure at elevated levels, it should be reduced to normal operating pressures, and the boiler is then inspected for any leaks/wetting or defects. Once the inspection is done, the pressure within the boiler is further reduced to atmospheric levels, and the water is drained. The boiler hydro test must be witnessed by inspection officials who confirm the absence of leaks and then certify the boiler accordingly.

How Often Is Boiler Hydrostatic Testing Required?

The frequency of boiler pressure testing varies between locations and mainly depends on assessing various boiler criteria, including age, pressure requirements, and operating history. For the most accurate confirmation of testing frequency for your boiler units, you should contact the local or state inspectors in charge of your area of operation.

NiGen Offers Pressure Testing Services You Can Rely On

At NiGen, we offer the best pressure testing services designed to optimize the safety of your industrial applications while simultaneously ensuring compliance with local or state pressurized vessel regulations. We also have many compressed air dryer types, nitrogen generators for sale, booster air compressors, air dryers, industrial air filtration systems, and more.

If you are interested in learning more about the pressure testing solutions we offer, please contact us today.