The standard is intended to provide a uniform method of diagramming the physical interconnections of the instruments of a loop and to provide related information that is required for the installation of the instruments. The standard covers pneumatic, fluidic, electric, electronic, and other types of instruments that are interconnected to form a loop.

The standard is for the use of instrumentation system designers, construction people, maintenance people, and others who may be concerned with the installation arrangements for the various instrument loops of a project.


Ascertain how widespread is the use of instrument loop diagrams, and determine the degree of uniformity in symbology, semantics, and presentation among those loop diagrams.

Establish whether development of a standard is practical.

Recommend future action by the S&P Department.


For more information about ISA5.4 subcommittee, please contact Charley Robinson, ISA Standards.