This part of GB/T 5094 provides guidance and examples on the composition of technical item information and the selection of appropriate letter codes for use as reference designators.
GB/T 5094.3-2005 history
2018GB/T 5094.1-2018 Industrial systems,installations and equipment and industrial products—Structuring principles and reference designations—Part 1: Basic rules
2002GB/T 5094.1-2002 Industrial systems,installations and equipment and industrial products--Structuring principles and reference designations Part 1: Basic rules