Ammonia refrigeration is a powerful technology, but these large systems are complicated and can be dangerous. Anhydrous ammonia is not the sort of stuff you want to go swimming in! To improve the safety of these complex systems, the International Institute of Ammonia Refrigeration (IIAR) publishes a guideline for labeling them. That guideline, IIAR Bulletin No. 114, was recently revised — and, as labeling experts, we’ve been getting frantic questions about the changes.
The Modular Label Format
First, a very quick overview of the IIAR’s recommended label format. The guideline describes a “modular” label for pipes: each part of the label is adjusted separately, and all the parts together convey the necessary information. One section of a label identifies the pipe’s purpose, another section shows its pressure category, another section shows the physical state of the ammonia inside, and another section shows the direction of flow with printed arrows. Standardized abbreviations are used, and each section is printed in a specific way. This format was in place in the previous revision of the guideline, so many engineers are already familiar with it.
Good news, engineers: the modular format hasn’t changed! This new revision doesn’t affect the content of an ammonia pipe label; instead, it changes the recommended color scheme for the label.
Orange is the New Yellow
While the previous version of the Bulletin used a design that was mostly yellow, the current labels are mostly orange. Why would the IIAR switch from yellow labels to orange ones? Simply put, they’re keeping up with broader industry standards.
When the yellow labels were recommended, this matched the widely-used ANSI A13.1 standard, which discusses general pipe labeling. That standard, created by the American National Standards Institute (ANSI), recommended a color code for pipe labels that indicated the type of contents with a color. Yellow pipe labels were used to mark any pipe containing a hazardous material. Naturally, anhydrous ammonia pipes were considered hazardous, and got yellow labels.
In 2007, though, the standard was revised. There were so many different pipes, carrying so many different chemicals, that the “hazardous” category wasn’t specific enough to be useful. ANSI A13.1 was rewritten by the American Society of Mechanical Engineers (ASME) to use a new color code, identifying each major type of hazard — flammability, toxicity, and so on — with its own color. The new version was adopted completely by ANSI. Under this new ANSI/ASME A13.1 standard, yellow labels were used for flammable pipe contents, while orange labels were used for toxic contents. Since the hazards of ammonia relate to its toxicity, and not its ability to catch fire, the labels should be orange.
What Else is New?
Most of the other changes to IIAR Bulletin No. 114 are fairly minor, fitting into the existing framework. They include preferred designations for several new types of equipment. After all, the last revision of the IIAR guideline was in 1991, and technology has changed here and there over the last 23 years! As a whole, though, the recommended label format has kept its shape.
Do the changes to the standard mean that you need to replace all of your existing labels? Not necessarily. The guideline specifically allows alternative color schemes, such as the one used in the older version of the IIAR standard — or any other color scheme that works well for your facility. There are two requirements for these alternate schemes:
- The same system must used across the entire facility.
- The system in place must be described in a clearly-visible posting.
Since these requirements were also part of the old standard, your facility is probably already in the safe zone. (If not, now is a great time to fix it!) As your facility changes in the future, or as you revise or replace labels, move to the newer recommendations — and you’ll continue to comply with the industry standards for safety and information.