Ammonia Refrigeration Piping Handbook Revised

What's the proper size for a defrost relief line? Where can I get help with drafting a new specification for marking A-53 carbon steel pipe? How do I size my relief valve discharge header to comply with the latest mechanical code?

Until a few years ago, finding the answers to these and many other piping-related questions for an ammonia refrigeration system was not always easy. Most, if not all, of the resource material published by unbiased sources focused on the operational aspects of major components. Little was available on an equally important -- some might argue even more important -- aspect of the system: the piping. What resources that were available were often scattered across multiple publications, including literature from various manufacturers and notebooks from engineers who had spent a lifetime working on ammonia refrigeration systems.

That all changed in 2000 when the International Institute of Ammonia Refrigeration published the IIAR Ammonia Refrigeration Piping Handbook. It is a guide to modern ammonia refrigeration piping as well as a comprehensive introduction to piping design and installation as it is practiced in the field. The handbook was a long time in the making. Its genesis can be traced back to casual conversations between industry veterans at IIAR Ammonia Refrigeration Conferences and Exhibitions back in the late 1980s. Work began on the book in earnest in the mid-1990s, when IIAR's Piping Committee was formed. The handbook took a long time to produce, for a lot of good reasons. IIAR Piping Committee meetings often involved long discussions with differing points-of-view, often about small points with potentially significant consequences.

The debate was worthwhile. When the handbook was published, it received rave reviews. It has been universally acclaimed as "one of the best publications ever produced by IIAR." I'm writing this article today to let you know that the "best" is now even better.

From the beginning, the intent has been to maintain the Ammonia Refrigeration Piping Handbook as a living document, with periodic modifications and updates to reflect new knowledge, approaches or concepts. Over the past couple of years, the IIAR Piping Committee has been hard at work revising Chapters 1, 2, 6 and 7 to reflect modern practices, current codes and standards, and to correct errata:

  • Chapter 1 was reorganized to improve the clarity of its text and revised to enhance the usefulness of its tables. It includes improved guidance on defrost relief piping and thermosyphon oil cooler piping; an expanded range of temperatures and pipe sizes for the table on flooded systems; and an updated steel pipe data table to reflect recent code changes.

  • Chapter 2 also was reorganized. It now includes new sections on impact testing, tubing materials and sealants, and product marking. It also has been updated to reflect changes to model codes.

  • Chapter 6 was edited to improve clarity and updated to reflect changes in model codes with regard to relief valve discharge piping.

  • Finally, in Chapter 7, tables were revised to reflect refined assumptions regarding application of insulation.

And, you can find the answers to the questions at the beginning of this article in the latest revision:

  • For Question 1: What's the proper size for a defrost relief line?

    Guidance for sizing defrost relief lines is provided on page 1-9, and line capacities are detailed in Table 1-13.

  • For Question 2: Where can I get help with drafting a new specification for marking A-53 carbon steel pipe?

    Chapter 2 has been reformatted to serve as a sample specification for ordering pipe. The sample specification for marking A-53 pipe is included on page 2-4.

  • For Question 3: How do I size my relief valve discharge header to comply with the latest mechanical code?

A method for sizing relief valve discharge headers using the new equation required by the latest version of the mechanical codes is detailed on pages 6-6 and 6-7, and two complete working examples are included on pages 6-8 through 6-11.

There's a lot more information contained in the Ammonia Refrigeration Handbook. It truly represents the collective knowledge of our industry on the topic of piping. There are many people who deserve a lot of gratitude for all of the work that has gone into this publication, probably enough names to completely fill this page. These folks continue to put forth their efforts, and more revisions and updates are currently in the works. But, I would be remiss if I did not mention at least one of them, the man whose words and wisdom normally occupy this page: George Briley. He played a key role in developing the concept, collecting the huge stack of materials that formed the foundation for this book, and distilling the information down to make it easy to use. Thanks, George. We miss you. Get well soon. PCE