Is the control standard for water chloride ions used in the pressure testing of stainless steel pipes 25 ppm or 50 ppm?

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Is the control standard for water chloride ions used in the pressure testing of stainless steel pipes 25 ppm or 50 ppm? As is well known, stainless steel is a corrosion-resistant metal material. However, it is also very sensitive to chloride ions, as their presence can cause the antioxidant protective layer on the surface of stainless steel to fail, leading to corrosion. If stainless steel is used in an environment with chloride ions, intergranular corrosion will occur in it, ultimately leading to significant corrosion of the stainless steel. Due to the aforementioned factors, certain requirements are placed on the pressure testing water used during the testing of stainless steel pipes, stipulating that its chloride ion content must not exceed a specific value. If you search on the Internet or ask an AI, you might get an answer of 20mg/L. Note that this answer is incorrect. Upon investigation, its source is a database filled with articles generated by AI; such AI-generated articles invent a standard called GB/T 13808 \"Code for Pressure Testing of Steel Pressure Vessels\", when in fact the correct standard is GB/T 13808-1992 \"Extruded Bars of Copper and Copper Alloys\". The hazards posed by AI hallucinations are significant. Getting off-topic now; so, what should be the chloride ion content in the water used for pressure testing of stainless steel? I found three standards; the names of these standards and the requirements they specify are as follows: 1. GB/T 20801.5-2020 \"Code for pressure pipelines – Industrial pipelines – Part 5: Inspection and testing\". Hydrostatic testing must comply with the following requirements: a) Clean water should generally be used as the testing fluid. When testing austenitic stainless steel pipes or pipes connected to components or vessels made of austenitic stainless steel, the chloride content in water shall not exceed 50 mg/L. If water has an adverse effect on the pipes or the process and may cause damage to them, other suitable non-toxic liquids can be used. When using flammable liquids for testing, their flash point must be no lower than 9°C, and the environment surrounding the test area must also be taken into consideration. During the test, the temperature of the fluid should be no lower than 5°C. 2. GB 50235-2010 \"Code for Construction of Industrial Metal Piping Projects\" 8.6.4 The hydraulic test shall comply with the following provisions: 1 Clean water shall be used for the hydraulic test. When testing stainless steel, nickel, and nickel alloy pipes, or pipes connected to such pipes or equipment, the chloride content in water shall not exceed 25×10-6 (25 ppm). Other non-toxic liquids can also be used for hydraulic testing. When tests are conducted using flammable liquid media, their flash point must be no lower than 50°C, and safety precautions must be taken. 3. TSG D0001-2009 \"Regulations on Safety Technical Inspections of Pressure Pipelines – Industrial Pipelines\", Article 89: Hydraulic testing shall meet the following requirements: (1) Clean water is generally to be used; when conducting hydraulic testing on austenitic stainless steel pipelines, or on pipelines connected to such pipelines or equipment, the chloride content in the water shall not exceed 0.005%. If water has an adverse effect on the pipelines or the process, other suitable non-toxic liquids may be used. When flammable liquid media are used for testing, their flash point shall not be lower than 50℃ ； As can be seen from the above standards, the latest standard requires 50 ppm, while the more stringent standards require 25 ppm, which indeed makes it difficult to decide. Personally, I think: a) Companies that are very strict regarding the implementation of processes and standards should first use the 25ppm standard ； b. For processes that are highly sensitive to chloride ions and corrosion, a standard of 25 ppm is adopted; some companies even set their own standard at below 5 ppm ； c. For ordinary equipment for which no special requirements exist regarding corrosion, 50 ppm of testing water can be used ； d. When the conditions are not met, testing with water containing a high chloride content can be used, but it must be thoroughly cleaned and flushed out afterward. After all, under conditions of normal temperature and pressure with short-term exposure, chloride ions do not cause as rapid or severe corrosion of stainless steel; moreover, the corrosion-resistant protective layer can be regenerated after cleaning.