A service classification or service class is a one to three letter designation that shows what service the line is in. It is typically shown on a Piping and Instrumentation Diagram as part of the line numbering system.
Most companies have their own standard or specification of calling out the pressure classification. However, as an example, some different service classifications are shown below. This is by no means an all inclusive list.
Before creating line numbers, check with your own companies specification.
|DE||Filter Aid Solution|
|EW||Eye Wash Water|
|IAS||Instrument Air Supply|