Pipeline leak test

I’ll be lazy and not copy it; you can take a look by yourself – it’s explained very clearly! http://www.docin.com/p-380143043.html What is the difference between hydrostatic testing and leak testing?

It’s definitely different; pipes that require leak testing are usually those that are flammable and explosive. It’s essential to follow the design requirements to avoid any potential hazards.

So how should the leakage test be carried out?

0.6 Leakage tests and vacuum tests: \"Regulations on the Safety Supervision of Pressure Pipelines – Industrial Pipelines\": Article 93 Pipelines transporting extremely hazardous, highly hazardous fluids, as well as flammable fluids, shall undergo leakage tests. The leakage test shall meet the following requirements: (1) The leakage test shall be conducted after the pressure test is successful. Air is the preferred medium for such tests; when halogens, helium, ammonia, or other sensitive gases are used for sensitivity leakage tests, the procedures specified in the design documents or relevant technical standards shall be followed ； (II) The leakage test should focus on inspecting the valve stuffing box, flange or threaded connections, vent valves, exhaust valves, drain valves, etc.; no leakage as confirmed by a foaming agent indicates compliance ； (III) During the leakage test, the pressure should be increased gradually stage by stage. Once the test pressure is reached and the pressure is held for 10 minutes, all sealing points should be inspected by applying a neutral foaming agent (sodium dodecyl sulfate); no leakage is considered acceptable. 10.6.1 The gas leakage test of the piping system shall be carried out in accordance with the requirements of the design documents, and the test pressure shall be the design pressure. Inspection method: Process inspection, verification of test records. 10.6.2 The gas leakage test shall comply with the following provisions: 1 The leakage test shall be conducted after the pressure test is successful, and air is preferably used as the testing medium ； Page 73 of 85. 2 During the unit commissioning, the pressure for the comprehensive airtightness test should be sufficient to meet the requirements of the leakage test; with the approval of the project owner, the leakage test can be carried out simultaneously with the unit commissioning ； 3 The key inspection points for the leakage test should be the valve packing boxes, flange or threaded connections, vent valves, exhaust valves, drain valves, etc ； 4 Pipelines that have passed the pressure test and remain undismantled after the test may be exempted from the gas leakage test. Inspection method: Process inspection, verification of the test plan. 10.6.3 During the gas leakage test, the test pressure should be increased gradually step by step. Once the test pressure is reached, hold it for 10 minutes; thereafter, use a neutral foaming agent to inspect all sealing points – no leaks present indicates that the test is successful. Inspection method: On-site inspection and acceptance point by point. 10.6.4 After the gas leakage test of the piping system is successful, the pressure should be released slowly and promptly, and a test record should be filled out. Inspection method: Check the test records. 10.6.5 For vacuum pipeline systems, after passing the pressure test, a leak test shall be conducted using gas at a pressure of 0.1 MPa. The test shall be carried out in accordance with the requirements of clauses 10.6.2 and 10.6.3 of this specification. Inspection method: Check the test records. 10.6.6 After the vacuum pipeline passes the gas leakage test, a vacuum level test shall also be conducted during the joint trial operation of the vacuum system. The vacuum degree test should be conducted in an environment with minimal temperature changes. When the vacuum level in the system reaches the requirements specified in the design documents, pumping should be stopped to evaluate the system’s pressure buildup rate. The testing period should be 24 hours. The pressure increase rate should be calculated using the following formula; a value not exceeding 5% is considered acceptable: % 100 1 1 2     P P P P (10.6.6) Where: P1 – initial absolute pressure at the start of the test (MPa) ； Page 74 of 85 P2 — Actual absolute pressure at 24 hours (MPa) ； ΔP—pressurization rate over 24 hours (%). Inspection method: On-site inspection. 10.6.7 When the design documents specify that leakage tests be conducted using halogens, helium, ammonia, or other methods, such tests shall be carried out in accordance with specific technical regulations. Inspection method: Inspect in accordance with the relevant technical specifications.