ISA5: Documentation is more than symbols

• By Ian Verhappen
• March 31, 2020
• Standards

Summary

By Ian Verhappen

Many practitioners associate the ISA5 standards development committee strictly with ISA’s most widely used standard, ISA-5.1 Instrumentation Symbols and Identification. However, the ISA5 committee, “Documentation of Measurement and Control Instruments and Systems,” has a broader scope—namely to develop standards, recommended practices, and technical reports for documenting and illustrating measurement and control instruments and systems suitable for all industries. It is also looking for volunteers who want to make a difference.

Change in technology is one of the drivers in updating international standards. Technology has also changed the way standards committees work, with almost all development now done using web conferencing tools. The only requirements to being able to assist are some of your time and a willingness to share knowledge.

The following table presents the working group structure of ISA5:

As you can see, several publications, and hence the work of the working groups, have been subsumed by other documents or working groups. However, the work of ISA5 is not all about retirements and consolidation. ISA-5.7 working group chair David Hobart plans to focus on producing a recommended practice for the development and use of piping and instrument diagrams, which often exist under different monikers, such as mechanical flow diagrams, engineering flow diagrams, process and instrument diagrams, and process and control diagrams. Hobart welcomes assistance from others sharing his passion for this document, which will be the template for all subsequent instrument and control work in a project.

The ISA-5.9 working group was formed in 2019 in response to a need for improved documentation of the algorithms used in industrial control systems (e.g., PID controllers) and the measures of performance for these algorithms. The working group is also planning to develop documents providing guidance and aid in the selection and application of these algorithms to benefit manufacturing.

ISA-5.4, Instrument Loop Diagrams, was published in 1991 to provide a uniform method of diagramming the physical interconnections of the instruments of pneumatic, fluidic, electric, electronic, and other types of instruments interconnected to form a loop. With the increased adoption of Ethernet, wireless, and potentially virtual/self-configuring systems, this standard is ripe for updating.

Similarly, ISA-5.6, Documentation for Control Software Applications (2007), established a system of graphical symbols, charts, matrices, and diagrams to specify and facilitate implementation of software-based control systems for batch and continuous control using programmable controllers, computers, and distributed control systems. The International Electrotechnical Commission (IEC) and other organizations are working on related documents, so this group can help maintain ISA’s leadership role in international standards development. To do so, this working group needs leadership and volunteers.

Saving the big one for last: last published in 2009, with a large working group already, ISA-5.1 is due for an update. Chair Tom McAvinew has indicated that he will soon be circulating to ISA5 an addendum to the current standard to suggest slight modifications to refresh the document. Since the committee will have to review and vote on the addendum, it will also kickstart work on a full revision expected to be able to be published within two years. That revision cycle will be a further opportunity to incorporate ISA-5.5 and include new symbols for new sensing technologies, networking, and associated functions.

If you are interested in participating in any of the ISA5 working groups, contact Charley Robinson, ISA Standards, crobinson@isa.org.

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