AIR COMPRESSOR
& PIPES LEADER
& PIPES LEADER
1. Color standard for nitrogen pipeline flow direction identification
The flow direction identification of nitrogen pipelines must adhere to internationally recognized standards, with common standards including:
1. ANSI/ASME A13.1 (American National Standards Institute/American Society of Mechanical Engineers A13.1): It stipulates that the identification background color for nitrogen pipelines is yellow (Pantone Yellow 116 C), paired with black arrows and text, with the direction of the arrow indicating the direction of gas flow.
2. ISO 14726 (International Standard): The combination of yellow background and black marking is adopted for industrial gas pipelines, consistent with the ANSI standard.
3. China GB 7231: It requires that nitrogen pipelines be marked in light yellow (Y06), with arrows and text in black. The length of the arrow should account for more than one-third of the pipeline diameter.
Extended explanation: Yellow is chosen as the identification color for nitrogen due to its high contrast, which effectively warns personnel of the risks associated with non-reactive but high-pressure gas. If liquid nitrogen is present in the pipeline, the additional marking "LN₂" should be indicated.
Significance of Identification and Safety Design Logic
1. Color and hazard warning:
- Yellow represents "Caution", which is different from the warning colors of flammable and explosive gases such as oxygen (light blue) and hydrogen (red).
- The black arrow ensures clear direction visibility, avoiding misjudgments in low light conditions.
2. Requirements for text and symbols:
- The medium name (such as "NITROGEN"), pressure rating (such as "10MPa"), and flow arrow must be indicated.
- The spacing between arrows shall not exceed 6 meters (as stipulated in GB 7231), ensuring that the entire length of the pipeline can be identified.
3. Supplementary information for special scenarios:
- If nitrogen is mixed with other gases, it needs to be distinguished by yellow and black diagonal stripes, and the mixing ratio should be indicated.
- Temporary pipelines need to be labeled "Temporary" and made of corrosion-resistant materials (such as PVC or metal tags).
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