JAN/FEB 2026 RETA Breeze

exchangers (and their piping) doing its job. The “good old boy” method of testing this was to wait until the cool of the night, shut down the liquid feed to your “load,” and check the vessel levels after the NH3 came back. SUMMER LOAD ADJUSTMENT A more “modern” method is to use an inventory spreadsheet and adjust the levels in the heat exchangers to reflect the summer load since the inventory spreadsheet should reflect the “normal operating conditions.”We should be mindful that if we are not using equipment, have it isolated for some reason, or if it is idle, then the majority of that inventory will end up back in the HPR for this system. The intricacies of doing either of these are better dealt with in the real world rather than an article, so let’s assume you have already checked this and you actually do need ammonia. OK, MAYBE WE DID LOSE IT! If you look into the situation and find out that you actually do need ammonia, there are a few considerations you should think of BEFORE you order that truck and start preparing for delivery. • Ensure all HXVs are correctly set and levels in other vessels are at their “normal” levels. • Use an inventory spreadsheet (or have an engineer do it for you) to figure out how much ammonia you need to get back to your “normal” level. • Review your charging standard operating procedure (SOP) with the refrigeration team to make sure you are all on the same page. This isn’t something you should be doing often so take this opportunity to review, validate and TRAIN on this procedure.  A common failure is not reviewing the SOP or performing the training which leads to inconsistencies impacting safety. • Document where you think that ammonia went! For most facilities, this is just calculating your “leak” rate as well as adding up any amounts lost from leaks which should be part of the incident investigations and odor complaints. This is your “justification” that you are replacing lost ammonia, not adding to your intended inventory level. JUSTIFYING THE CHARGE Assuming you didn’t have some sort of incident that clearly explains why you need ammonia, we should figure out how to justify the amount we’re adding. Most losses are easily justified by establishing a “loss rate” and comparing it to accepted norms. This acceptable loss would be caused by normal maintenance, auto purgers and fugitive emissions.

In our opinion, anything less than 5% is good, 2–3% is excellent. For what it’s worth, the IIAR has stated that up to 10% loss a year is “reasonable.” A loss rate of 3% or less a year can easily be explained from normal maintenance, auto-purgers and fugitive emissions. This is easier to explain with a worked example from a friend. In this case, their inventory level is supposed to be 5,800 lb. When they updated their inventory sheet to reflect the actual conditions at the facility, they saw a calculated current charge of 5,000 lb reflecting an 800 lb loss. That loss occurred since their last charge five years ago.

This percentage is easily explainable from maintenance and other fugitive emissions, and it’s also quite reasonable.

 Advanced knowledge —EPCRA 313 For Food Processors (we’re paraphrasing here) essentially allows for an 80/20 justification. Meaning, if something like your auto-purger discharge through the bubbler goes to a wastewater treatment system BEFORE that water leaves the property, then the wastewater treatment system captures “or is otherwise used” by the process (wastewater), leaving you with the remaining 20% as the fugitive emission. If you take the time to figure out the math above, and then document your calculations to justify your NH3 charge, it helps avoid unpleasant assumptions on the part of the EPA and OSHA in any future inspections. If an auditor comes in and sees an ammonia delivery receipt, a documented rationale why the ammonia was needed, a Safety Data Sheet (SDS) of the chemical charged, and you have a compli ant charging procedure, it would be very unlikely that the charging process would be questioned further. Of course, if your math shows a high leak rate, then you had better get an incident investigation going and figure out what’s wrong! Brian Chapin has over 25 years of Ammonia Refrigeration & Process Safety experience. He currently serves as the RC&E Compliance Services & Continuous Improvement Manager, and works with his Kelvin Group peers as an advocate for PSM excellence.

Victor Dearman, Jr., CIRO, CRST, is Director of PSM for JBS Foods, USA. He is the RETA-RSES Publications Committee Chairman.

The opinions shared are a reflection of our own personal views and not of any past, present or future employers.

RETA.com 23

JANUARY/FEBRUARY 2026