{"id":34806,"date":"2024-02-29T17:55:03","date_gmt":"2024-02-29T16:55:03","guid":{"rendered":"https:\/\/arvengtraining.com\/?p=34806"},"modified":"2024-02-29T18:20:21","modified_gmt":"2024-02-29T17:20:21","slug":"pressure-and-tightness-testing-according-to-asme-pcc-2","status":"publish","type":"post","link":"https:\/\/arvengtraining.com\/en\/pressure-and-tightness-testing-according-to-asme-pcc-2\/","title":{"rendered":"Pressure and Tightness Testing According to ASME PCC-2"},"content":{"rendered":"

In industry, ensuring the safety, durability, and efficiency of systems is crucial, and pressure testing plays a vital role in achieving this. They are essential for verifying the structural integrity and sealing capacity of piping systems and equipment under pressure. The process involves subjecting a component or system to a pressure greater than its normal operating pressure to ensure that it is safe and reliable under the stipulated working conditions.<\/p>\n

Hidden defects are identified through pressure testing, such as cracks, porosity in welds, and problems with materials that could cause catastrophic failures under normal operating conditions. The main purpose of these tests is to verify the integrity of a pressure system and check it for leaks<\/strong>. In some cases, it\u2019s not necessary to verify the structural integrity of the system, so a hydrostatic test is not required, and an airtightness test<\/strong> can therefore be considered. An example of such cases includes when a repair is made, but it is known that the thinning of a pipe due to corrosion has not exceeded the lower limits of thicknesses required by the code.<\/p>\n

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The ASME PCC-2 code establishes detailed guidelines for performing these critical tests. Article 501 establishes a general practice to determine the type of test, the test pressure, and the procedure for testing the pressure and tightness of pressure equipment (vessels, pipes, exchangers).<\/p>\n

It\u2019s important to keep in mind that pressure tests can be carried out on the equipment or system as a whole (common practice in new systems to be installed), or they can also be carried out on a single part of it, when there\u2019s no possibility of performing the test on the entire system (provided it is properly isolated).<\/p>\n

Article 501 is limited to addressing tightness or field pressure tests on existing equipment and pipelines using either of the two fluid medias, liquid or gas, meaning it also includes pneumatic tests, although these are potentially much more dangerous. Vacuum testing is beyond its scope.<\/p>\n

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Some important definitions to keep in mind are:<\/p>\n

\u2192 Closure Weld: final weld that connects piping systems<\/strong> that have been successfully tested according to the applicable code.<\/p>\n

\u2192 Hydrostatic test: pressure or tightness test<\/strong> in which the test medium is liquid, usually water.<\/p>\n

\u2192 In-service leak test:<\/strong> test that uses the medium of the equipment under pressure, carried out when the equipment starts up<\/strong>.<\/p>\n

\u2192 Pneumatic test: pressure or tightness test<\/strong> in which a gas, usually nitrogen, is the test medium.<\/p>\n

\u2192 Pressure test: test performed to ensure the overall integrity of the pressure component<\/strong> in service that has undergone alteration or repair at its pressure limit(s), to ensure the overall integrity of the pressure component<\/strong>.<\/p>\n

Selecting a type of test<\/u><\/strong><\/p>\n

The requirements for pressure testing can be found in the applicable building code or post-construction code. When these do not specifically refer to any test, and it\u2019s therefore left in the hands of the repair person or equipment owner, Figure 501-3.3-1 of the ASME PCC-2 code<\/strong> can be used, which indicates a series of guidelines and recommendations to determine the type of test that can be performed.<\/p>\n

It\u2019s important to note that a pressure test for equipment or a piping system should be considered<\/strong> if an alteration or repair has been made, the equipment has been reclassified, or if it needs to be recertified to determine its integrity.<\/strong><\/p>\n

One case where a pressure test may not be required to reclassify equipment is when the equipment has a higher allowable stress, as the original test pressure may be higher than the test pressure required to reclassify.<\/p>\n

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Hydrostatic Test Exclusions<\/u><\/strong><\/p>\n

A pressure test is performed hydrostatically except in cases where any of the following conditions occur:<\/p>\n