Service Classification

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.  

ID	Line Service
AI	Instrument Air
BR	Brine
CA	Caustic
CD	Condensate
CI	Chemical Injection
CO2	Carbon Dioxide
DE	Filter Aid Solution
DR	Drain
EM	Emulsion
EW	Eye Wash Water
FL	Flare Line
FG	Fuel Gas
GH	Gas Hydrocarbon
GL	Glycol
IAS	Instrument Air Supply
LH	Liquid Hydrocarbon
KW	Killwater
PW	Produced Water
SA	Salt
SN	Sodium Nitrate
ST	Steam
SW	Soft Water
UA	Utility Air
UW	Utility Water
WR	Water