How are pressure pipelines classified as individual pipelines? In other words, what design standards determine whether each pipeline listed in the pipeline characteristics table should be considered an individual pipeline?

The classification of individual pipelines in the pipeline characteristic table is primarily based on three core principles: the design pipeline number, the logistics delivery path, and the device system to which it belongs; it must also comply with official registration and design specification requirements. According to the \"Rules for the Registration and Management of Pressure Pipelines\" (provisional), the registration unit for pressure pipelines – that is, the basis for categorizing individual pipelines in the pipeline characteristics table – can be determined in one of the following 4 ways; meeting any one of these conditions suffices to classify a pipeline as an individual unit: Based on the design pipeline number: From the starting point to the ending point of the pipeline, those pipelines corresponding to a specific pipeline number are considered individual pipelines; this is the most commonly used method during the design phase ； By logistics delivery path: The entire path from the output device to the input device is considered as a single pipeline ； By device/system: Classified as a single unit based on an independent pipeline within the device or system ； By project number: Each pipeline is determined directly based on the project number.

The classification principles you mentioned are very clear and are basically consistent with the design standards I am familiar with. In practical work, assigning numbers to pipelines is the most intuitive and commonly used method. However, sometimes a single pipeline number may correspond to pipelines made of different materials or with different pressure ratings; in such cases, it may be necessary to use the logistics flow path or the boundaries of the installation as a basis for further classification. Furthermore, different industries (such as the chemical industry and power plants) may have slightly different interpretations of what constitutes a \"single pipeline.\" It is recommended to follow the specific \"Pressure Pipeline Design Specifications\" applicable to your project, as well as the requirements set by the local inspection authorities, in order to avoid any misunderstandings during subsequent registration processes.