What does a pipeline layout plan mean?

The original poster has almost no knowledge of piping diagrams; it is recommended to first consult the \"Piping Design Symbols for Petrochemical Industries\" to learn some basic symbol meanings, before asking questions in a targeted manner.

From what you’re asking, these are all the most basic concepts. To cover them in written form via the internet would require a very long article; it’s better to consult some standard guidelines – the ones mentioned by the person above are quite suitable. What is called learning is nothing but studying and asking questions. If you have no experience with pipeline design, it is recommended to first study the relevant design standards. At the same time, seek advice from those who are more experienced around you; don’t be afraid to ask for help – it’s normal not to know everything when starting out, and there’s nothing embarrassing about asking others for guidance. If others are busy, learn on your own first and ask them once they are free. Nothing comes automatically; there’s no reason for others to rush to hand you knowledge – if you want to learn, you need to take the initiative yourself.

The original poster should take a look at the first page of these drawings; there are explanations on it

There should be markings in the legend; you can take a look

Some represent valves, some represent instrument tag numbers; there is also missing information in the diagram