1. The American standard valves should be in accordance with API600, API6D or MSS SP-25. The Chinese standard valves should be provided with permanent marking according to G/T 12220 standard, and the valve marking should include the heat number of casting and melting or the casting mark of the manufacturer.

2. The valve plate should be firmly fixed in the obvious position of the valves, and its content must be neat, accurate, and in accordance with API regulations. The material of the plate should be made of stainless steel, copper alloy or aluminum alloy.

3. Only when it is not feasible to apply the required marking on the valve body, the valve marking can be applied on the valve nameplate. However, the marking indicating the flow direction of the valve must be marked on the valve body, no matter what standard the valve is.

4. The paint used for color coding and marking shall not contain any harmful metals or metal salts, such as zinc, lead, sulfur, copper, tin, chloride, etc. that can cause corrosion when hot, and the paint should be resistant to salt water, corrosion in tropical environments or similar conditions.

5. For small-sized objects that are difficult to mark, use stainless steel wire and stainless steel nameplate to mark them.

6. Regarding the marks engraved on the valve nameplate, generally the model, material, pressure, standard, applicable temperature, use medium, and production date are all indispensable. In order to facilitate the purchase of maintenance and replacement.