[This blog series derives from a technical paper written by Eli Macha, President of Macha PSM]
Operating Procedures (SOPs - Standard Operating Procedures) are an essential part of any PSM program. While there are some covered processes with much simpler processes (e.g., chlorine water treatment), ammonia refrigeration systems require a bit more detail to cover all major components and procedures. The objective of a PSM practitioner seeking to get their SOPs into compliance is twofold: ensure they cover all process equipment and ensure all PSM and RMP requirements are met.
If the facility has an auto-purger, do the SOPs include auto-purger procedures?
If the facility has both screw and recip compressors, do the SOPs include procedures for both?
If all equipment has been covered, the next step is to pull up the PSM and/or RMP regulations to ensure every prescriptive requirement is met. One should put themselves in the shoes of a regulator with an inspection checklist and the facility’s SOPs.
Can they find the following in the inspection:
all seven (7) operating phases
operating limits
safety and health considerations
safety systems and their functions
If SOPs are developed from scratch, ANSI/IIAR 7-2019 American National Standard for Developing Operating Procedures for Closed-Circuit Ammonia Refrigeration Systems should be utilized as a guide. [ Note: This standard is scheduled to be updated early 2025. ]
If the SOPs cover all equipment and meet the regulatory requirements, there are just a few mistakes to look out for. Review the procedures to ensure they align with the facility's actual practices. Start with the oil draining procedure. Perhaps the procedure says a half-face respirator with goggles should be worn, but the operators wear a full-face respirator. These are simple fixes one can make to incrementally improve their SOPs.
Another common mistake made in the ammonia refrigeration industry is developing detailed SOPs, which the operators know nothing about. If the SOPs are stored digitally on a shared drive or online in a PSM software, ensure the operators are comfortable accessing and using them. Many facilities find that printout SOPs in a binder is helpful for operators. If a binder is utilized, the PSM team must stay on top of updating it whenever changes are made to the digital version.
Apart from incrementally improving the accuracy of the SOPs, the best way to elevate a facility’s SOPs is to incorporate valve numbers. If valve tags are used (which they should be, though they are not explicitly required to be), there are three places where they must align:
physical tags
P&IDs
SOPs
Having accurate valve tags listed in the SOPs is extremely valuable. PSM practitioners should be cautioned in this endeavor as inaccurate valve numbers in the SOPs can pose a hazard. Any time the physical valve tag numbers or the P&ID valve numbers are changed, the SOPs must also be updated. The most efficient way to keep valve tables in the SOPs updated, is to restrict them to valve tables. Rather than having valve numbers spread throughout various procedures—where they could be missed if valve numbers were changed—the valve numbers should be placed in tables that can be referenced in the procedures. For example, if a procedure calls for the compressor suction isolation valve to be closed, the valve number would not need to be listed adjacent to this step. Instead, the operator would refer back to the compressor valve table, which should have the valve number listed in the suction isolation column.
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