HYDRO TESTING – HYDROSTATIC TESTING
Hydro testing is pre-commissioned procedure to test the integrity of lines and vessels,
Boilers, and HRSGs. Lines and vessels are tested to the accepted ANSI code depending on the plant they are in. This code is B31.3 for chemical plants and refineries, and B31.1 for power plants. For boilers and HRSGs, the test must conform to boiler codes applicable in the state where the boiler/HRSG is located. CCT can provide equipment to rapidly fill the equipment, then squeeze, pressure up the equipment to the desired pressure. This equipment usually entails a hydro test tree with a certified gauge, and relief valve to prevent over pressurization of the equipment, fill hoses, and high pressure hose. Depending on the conditions during testing CCT can also provide a circulating pump and heat exchanger to heat the water on a boiler/HRSG to the required 70°F skin temperature.
A hydrostatic test is a way in which pressure vessels such as pipelines, plumbing, gas cylinders, boilers and fuel tanks can be tested for strength and leaks. The test involves filling the vessel or pipe system with a liquid, usually water, which may be dyed to aid in visual leak detection, and pressurization of the vessel to the specified test pressure. Pressure tightness can be tested by shutting off the supply valve and observing whether there is a pressure loss. The location of a leak can be visually identified more easily if the water contains a colorant. Strength is usually tested by measuring permanent deformation of the container. Hydrostatic testing is the most common method employed for testing pipes and pressure vessels. Using this test helps maintain safety standards and durability of a vessel over time. Newly manufactured pieces are initially qualified using the hydrostatic test. They are then re-qualified at regular intervals using the proof pressure test which is also called the modified hydrostatic test. Testing of pressure vessels for transport and storage of gases is very important because such containers can explode if they fail under pressure.