• By David Lee
  • Standards

One of the questions I get asked most goes along the lines of “I know ISA has a lot of standards, but which ones should I be using?” It’s a reasonable question, and perhaps, given the breadth and depth of the standards available, an understandable one. More than 140 ISA committees, subcomittees, working groups, and task forces are involved in ISA standards. Almost 200 standards documents are available from the International Society of Automation (ISA), and more are currently in development.

You will also see many standards referenced as ANSI (e.g., ANSI/ISA-18.2). These are documents that have been adopted by the American National Standards Institute as U.S. national standards. ISA also has some international standards that are developed with the International Electrotechnical Commission (IEC), such as ISA/IEC-61511-1.

Document types explained

To start with, there are a few different types of documents:

  • Standard
  • ​Technical report (TR)
  • Recommended practice (RP)

Standards are documents that have mandatory statements such as “shall” that need to be complied with to meet the standard. Technical reports are typically documents that provide guidance on how to use the parent standard. Recommended practices are standalone documents that provide best practices that are encouraged to be adopted. Neither technical reports nor recommended practices have mandatory statements.

Although the lines can be a little blurred, we break down the standards into the following broad categories:

  • Process safety
  • Instrumentation
  • Control
  • Networking and security
  • Automation
  • Business systems

Standards are documents that have mandatory statements such as “shall” that need to be complied with to meet the standard.

Standards categories

Process safety is of paramount importance and there are two significant standards: ANSI/ISA-18.2 and ISA-84.00.01, in this space. ANSI/ISA-18.2 deals with alarm management in the process industries. It also has several technical reports that provide guidance on the application of the standard, including areas such as Batch and Discrete Processing (TR-6) and Packaged Systems (TR-7). IEC 62682, Management of alarm systems for the process industries, is based on ISA-18.2. ISA84 adopted the IEC 61511 standard, Parts 1–3 , which replaced ISA-84.00.01, Parts 1–3. Similarly, this has technical reports that cover burner management systems (TR-5), fire and gas systems (TR-7), and even cybersecurity for safety systems (TR-9).

Instrumentation provides the foundation of any automation system, and there are several key standards in this category. Perhaps the most basic of these is ANSI/ISA5.1 providing standards for instrumentation symbols and identification for P&IDs. There is also ISA-51.1 that provides guidance for instrumentation terminology. This standard is a little dated, last updated in 1993, but still contains a great deal of foundational information. Both of these should be in all automation professionals’ libraries. Another extremely useful standard is ISA-20, providing standardized specification forms for instruments, primary elements, and control valves. There are also several documents that address hardware specifications, calibration, and testing, such as ISA-75 (valves), ISA-37 (transducers), and ISA-67 (nuclear).

An engineer on a plant floor consults their laptop.

Building on the instrumentation layer is the control system itself, and there are important standards that deal with this. The first of these are the other standards in the ISA5 series dealing predominantly with the documentation of control logic along with instrument loop diagrams (ISA-5.4—who knew there was a standard for this?) and graphic symbols for process displays (ISA-5.5). The latter is somewhat dated, although still relevant, but has been partially replaced by ANSI/ISA-101.01, and its technical reports, providing guidance for the human-machine interface (HMI) for process automation systems. This standard has also been provided as the basis for the future IEC 63303. There is also a series of standards and technical reports under ISA77, which deals with fossil fuel plant controls and with documents relating to controls, simulation, testing, and HMI. There is also a set of recommended practices, ISA-RP60-x, that provides guidance on control center design. These documents are more than 30 years old, and we are looking to reform the committee to create a new control room standard.

In the network and security category there are three important standards. The first is ANSI/ISA-100 which deals with wireless systems. The second is the set of standards dealing with cybersecurity, previously ISA99 are now ANSI/ISA-62443-x. These are extremely important standards and are foundational to ISA’s cybersecurity training and certification and ISASecure system certification. Lastly there is the set of ANSI/ISA-62453 standards dealing with field device interface specifications.

The next category deals with automation, and there are two very important standards in this space. The first is the ISA88 set of documents that provides a framework and guidance for batch control systems. The second is the ISA106 set that similarly provides guidance for procedural automation for continuous process operations, for example state-based control. The parent ISA-106 standard is due to be released very shortly. A third standard that we are eagerly awaiting the publication of is ISA-112. This standard will provide much needed guidance for the implementation of supervisory control and data acquisition (SCADA) systems.

The final category concentrates on the business systems, especially the integration of enterprise level and control system level. There is only one set of standards in this space, ANSI/ISA-95, but it consists of nine separate documents. As we look at recent trends in digital transformation and integration of business and control systems, this set of documents provides guidance for informational transactions between the various software components.

Final thoughts

Hopefully this article has helped identify some standards that you can use in your jobs. These are all for sale on the ISA website, but one of the great member benefits is that you can view all ISA documents, with the exception of some IEC documents, online. Another service that ISA provides relating to standards is to help users with expert interpretation of standards. If, as you try to apply an ISA standard, you are struggling with how to interpret a requirement or recommendation, we have experts who can provide an official interpretation.

Lastly, standards are developed by volunteers; we are always looking for volunteers to participate in these activities, the S&P board or specific committee chairs would love to hear from you.

Reader Feedback

We want to hear from you! Please send us your comments and questions about this topic to InTechmagazine@isa.org.

Like This Article?

Subscribe Now!

About The Authors

David Lee, C.Eng, FIChemE is ChemPID's Past Director and Chair of ISA’s Standards and Practices Council. David spent 20+ years in industry in automation, project management and operations management. For the last 17 years he has been an automation and operator performance consultant. He is currently a Solution Consultant in Emerson’s Industrial Software division.