Written by Steve Hudgik
GB 7231 is the Chinese pipe marking standard for the the identification of industrial piping. It specifies the colors, symbols and pipe marker specifications for industrial pipes.
The following provides a simplified summary of the GB 7231 pipe marking requirements. Please read the GB 7231 standard for the specific requirements. Note that the GB 7231 standard references other safety standards such as:
GB 2893 Safety colors
GB 13495 Fire safety signs
GB 13690 Commonly used hazardous chemicals classification and marking standards
The GB 7231 pipe marking standard specifies eight colors for categorizing pipes:
- Water - white printing on a green background
- Water Vapor - white printing on a red background
- Air - White printing on a gray background
- Gas - black printing on a yellow background
- Acid or alkaline - white printing on a purple background
- Flammable Liquids - white printing on brown
- Other Liquids - yellow printing on black
- Oxygen - white printing on light blue
A label, with a minimum width of 150mm and indicating the direction of flow, should be included as at both ends of the pipe marker label. If the flow is bi-directional, then two-way arrows should be used.
GB 7231 specifies that pipe marker labels should be located:
- At least every 10 meters
- At pipe starting and end points
- At pipe intersections (T's and junctions)
- At all pipe bends
- On both sides of wall or floor penetrations
- Near valves
GB 7231 requires that the pipe length be given on the label; the contents of the pipe be identified, the flow direction shown; and critical process parameters be provided. These must be printed in a size large enough to be legible.
Either the full name of the pipe contents must be used (nitrogen, sulfuric acid, methanol), or the complete chemical formula (N2, H2 of SO4, CH3-OH ) must be used. Abbreviations may not be used.
Pipes that carry hazardous materials, as defined by GB 12690, should me marked with a 150mm yellow ring with black bands on the edges. GB 7231 specifies that the black bands be 25mm in width and be on both edges of the yellow ring.
Pipes used for fire fighting must comply with the provisions of GB 13495 and be marked with the special fire fighting identifier.
DuraLabel printers are the perfect choice for making pipe markers that comply with the GB 7231 standard. Using a DuraLabel printer GB 7231 compliant labels can be printed in Chinese or English, or both languages together.