Seeking help from fellow marine professionals (regarding the inspection of pipe flanges and other piping fittings)

The petrochemical standard SH3501-2001 and the national standard GB50235 contain clear provisions, with corresponding regulations established based on the characteristics of the process media (pressure, temperature, toxicity, etc.)

Are you referring to radiographic inspection of piping systems? The inspection of the flange should involve checking the weld between the flange and the pipe. For radiographic inspection of pipeline systems, it may be carried out in accordance with the provisions of 7.4.3 in the \"GB 50235—97 Code for Construction and Acceptance of Industrial Metal Piping Projects\". 7.4.3 The number of radiographic inspections for pipeline welds shall comply with the following provisions: 7.4.3.1 The following pipeline welds shall undergo 100% radiographic inspection, with the basic quality level not being lower than Grade II: (1) Pipelines transporting highly toxic fluids ； (2) Pipelines for transporting flammable or toxic fluids with a design pressure of 10 MPa or more, or a design pressure of 4 MPa or more along with a design temperature of 400°C or more ； (3) Pipelines for transporting non-flammable and non-toxic fluids with a design pressure of 10 MPa or more and a design temperature of 400°C or more ； (4) Low-temperature pipelines with a design temperature of less than –29°C. (5) Other pipes for which the design documents require 100% radiographic inspection. 7.4.3.2 For welds of non-flammable fluid pipelines and non-toxic fluid pipelines with a design pressure of less than or equal to 1 MPa and a design temperature of less than 400°C, radiographic inspection may be omitted. 7.4.3.3 Other pipelines shall be subject to sampled radiographic inspection, with a sampling rate of not less than 5%, and their quality shall not be lower than Grade III. The sampling ratio and quality grade shall meet the requirements of the design documents. Regarding leak detection, it can be carried out in accordance with the provisions of 7.5.5. 7.5.5 Pipelines transporting highly toxic fluids, toxic fluids, and flammable fluids must undergo leak testing. The leakage test shall be carried out in accordance with the following provisions: 7.5.5.1 The leakage test shall be conducted after the pressure test is successful, and air is preferably used as the testing medium. 7.5.5.2 The leakage test pressure shall be the design pressure. 7.5.5.3 The leakage test can be carried out simultaneously with the commissioning work. 7.5.5.4 The leakage test should focus on inspecting the valve stuffing box, flange or threaded connections, vent valves, drain valves, etc. It is considered qualified if no leakage is detected using a foaming agent. 7.5.5.5 Pipes that have passed the pressure test and have not been disassembled after the test may be exempted from the leakiness test. 7.5.6 After passing the pressure test, the vacuum system shall also undergo a 24-hour vacuum level test in accordance with the provisions of the design documents, with the pressure increase rate not exceeding 5%. 7.5.7 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 the relevant technical specifications. For your reference.

I mainly want to know which types of pipelines require 100% leak detection. For example, for pipelines carrying water, a 10% inspection rate for leak detection is sufficient; however, for pipelines carrying toxic substances, 100% detection is mandatory. Are there any relevant standards?