Are there any standards for selecting thickness measurement points for pipes?

Go and find a basic book on corrosion; it explains things in terms of device types, which is really good

Reply to 2# skun0919: Bro, do you have any basic books on corrosion? Or give some recommendations. . .

Thickness measurement points are generally selected at pipe bends and other areas prone to corrosion; when measuring thickness, the paint on the surface of these points should first be removed completely.

4.3 Principles for selecting points for fixed-point thickness measurement 4.3.1 The following areas prone to corrosion and erosion should be given priority when selecting measurement points: a. Areas where pipeline corrosion and erosion are severe: elbows, tees, crosses, as well as pipe sections near nozzles, valves, control valves, pressure reducers, and orifice plates； b. Areas with high flow rates (greater than 30 m/s), such as the atmospheric and vacuum distillation transfer lines, the outlet of the heating furnace tubes, and areas behind the outlet valves of pumps; c. The gas-liquid interface and liquid phases in environments subject to naphthenic acid corrosion; d. The gas phase and the gas-liquid interface in environments subject to sulfur corrosion; e. The downstream end of the fluid (including welds and straight sections of pipe), where severe erosion can occur; f. The hot end of the same pipeline ； g. Fluid inlet pipe ends of heat exchangers and air coolers ； h. The gas-liquid interface of towers, vessels, reboilers, and evaporators; i. The inlet sections of the shell sides of heat exchangers and condensers; j. Pipelines with a flow velocity of less than 1 m/s (including the tube bundles of water coolers), as well as areas where deposits are present and under-corrosion can occur; k. Blind spots and dead zones, such as drain pipes, sampling ports, bypass lines for control valves, start-up/stop bypasses, and cleaning nozzles. 4.3.2 For pipes transporting highly corrosive media, when the length of the straight section is greater than 20 m, three thickness measurement points are generally arranged longitudinally; when the length is 10–20 m, two points are usually arranged; and when the length is less than 10 m, one point can be arranged. 4.3.3 For pipelines with relatively low medium corrosivity, one thickness measurement point is generally arranged in the straight section (the pipe connecting two elbows), and another thickness measurement point is arranged at the elbow. 4.3.4 Thickness measurement points should be installed wherever possible at locations on the pipelines that are prone to corrosion and erosion, such as elbows, tees, and other similar components. 4.3.5 Considering the actual conditions on site, it is generally not advisable to locate online thickness measurement points in locations that are difficult for the personnel responsible for measurement to access (except in areas where corrosion is particularly severe and requires special attention). 4.3.6 For the placement locations of sensors in common pipe configurations such as tees, elbows, crosses, areas behind control valves or throttle valves, and collector pipes, refer to the attached drawings. 4.3.7 In principle, 4 thickness measurement points should be arranged at the same cross-section on the pipeline, generally located in areas where erosion corrosion is likely to be severe and near welds (mainly on the downstream side of the flow direction of the medium).