The identification of color-coded lines is one of the basics of PE pipes. Common color-coded lines are mainly blue, orange, yellow, and red. Blue corresponds to PE water pipes, orange and yellow correspond to PE gas pipes, and red corresponds to PE mining pipes. The following will introduce them separately:
1. Blue marking line
- Type: HDPE water pipe
- Use: Suitable for drinking water transportation, especially in municipal water supply and drainage, industrial water transportation, farmland irrigation and other fields
- Description: The blue marking line is usually used to indicate that the PE pipe is suitable for drinking water transportation, helping construction personnel and users to quickly identify the purpose of the pipe and ensure that the pipe is used to transport drinking water that meets sanitary standards.
Note: However, in actual applications, many PE drainage pipes and threading pipes will also have blue marking lines, which need to be carefully identified.
2. Orange/yellow marking line
- Type: HDPE gas pipe
- Use: Transport natural gas and liquefied petroleum gas and other gases
- Description: HDPE gas pipe is a replacement product for traditional steel pipes and polyvinyl chloride gas pipes. Gas pipelines have very high safety requirements. The setting of yellow/orange marking lines helps to clarify their use during construction and maintenance, and prevent misuse and potential safety hazards.
There are two types of marking lines for PE gas pipes, orange and yellow, as shown in the figure below:
Orange marking lines usually refer to gas pipelines with raw material grades of PE100 or PE-RC, which are also the most common gas pipelines.
Yellow marking lines usually refer to gas pipelines with raw material grades of PE80.
According to the national standard GB/T 15558.2-2023 for PE gas pipes, the color requirements for gas pipelines: at least 3 orange strips should be co-extruded on PE100 and PE-RC black pipes; at least 3 yellow strips should be co-extruded on PE80 black pipes, and the color strips should be evenly distributed along the circumference of the pipe.
3. Red marking line:
- Type: HDPE mining pipe
- Application: Mainly used for water supply, drainage, compressed air, grouting and gas extraction in coal mines
- Description: HDPE mining pipe has excellent flame retardant and antistatic properties. The setting of red marking line helps construction personnel and users to quickly identify mining pipes and ensure their safe use in high pressure, high wear and corrosive environments.
4. Colorless marking line:
- Type: HDPE drainage pipe
- Application: Urban drainage, rainwater discharge, sewage treatment and agricultural irrigation and drainage and other fields
- Description: HDPE drainage pipe is all black, except for the specified specifications, implementation standards, manufacturers and other information, without any color marking line.In addition, it should be noted that HDPE wire mesh skeleton composite pipe also has a blue marking line. I heard that there is also a PE pipe with a green marking line, but I haven’t seen it, so I won’t introduce it here. I’m just throwing out a brick to attract jade. If there are other ones, you are welcome to leave a message to supplement.