Update To the ISA-5.1: Standard for Engineering Symbols And Drawings

The International Society of Automation (ISA), the leading professional society for automation for many years, has recently published an update to one of the most popular recognized standards, the ANSI/ISA-5.1 Instrumentation and Control Symbols and Identification.

ISA Electrical Drawing Standards

When designing process automation systems, it is important to follow a specific standard for symbols and naming within your schematics and instrumentation P&ID drawings. This way, other designers and technicians can understand your designs and create an effective troubleshooting process.

The ISA creates and maintains many standards used in all kinds of industrial automation. Image used courtesy of the ISA

Updates To The ISA Standard

As technology updates, so do the documentation and standards we use to develop automation that uses this technology. To help clarify the standard's information, the people at ISA have changed the name of the standard from Instrumentation Symbols and Identification to Instrumentation and Control Symbols and Identification. This name change, as it implies, serves to emphasize the fact that the standard contains symbols that affect control systems within these process industries.

As a standard is developed, many changes or updates simply get appended onto the last section. This can result in a messy document that is difficult to read. Another one of the recent updates is the simplifying and organizing of the entire document. This update will make the document easier to search and navigate, as well as simply easier to read through when trying to understand the scope of a project.

Technology in automation has grown quite a bit over the last twenty years, and unfortunately, the documentation has not followed suit. This recent update of the ANSI/ISA-5.1 has included new symbols to accommodate this new technology.

Engineering drawings must follow consistent and comprehensive standards in order to be useful. Image used courtesy of Unsplash

Technical Reports in the ISA-5.1

Another addition to the ISA-5.1 standard is the addition of technical reports. Two annexes from the previous standard in 2022 have been included as two technical reports: ISA-TR5.1.02 is the instrumentation and control identification system guidelines and ISA-TR5.1.03 which is the instrumentation and control graphic symbols guidelines.

These technical reports are to be used along with the standard as they describe how to apply standard requirements and show examples.

Automation of Processes

This style of automation is quite different from automation in assembly lines or in high-speed packaging. Process automation requires lots of measuring, mixing, and transporting of products throughout a processing plant. There is very little room for rejecting batches as they can often cost thousands or even millions of dollars. This is why it is so important, when developing a process automation system, to follow a standard correctly so that other technicians, designers, and engineers can all read the same drawing, P&ID, or schematic and understand the system that we have put in place.