While safely operating and maintaining ammonia refrigeration equipment remains top priority for plant owners, effectively achieving it is another story. Though trusted industry bodies and agencies outline proper engineering practices, maintenance and safety programs to prevent ammonia hazards, some facilities still have unsafe elements that could lead to dire consequences. How do I know? For years, Stellar’s refrigeration teams have focused on mitigating ammonia safety risks, visiting food facilities worldwide. Many of the safety issues we see stem from elements plant personnel have direct control over — and can correct.
Here are the 15 most common issues Stellar has seen when it comes to ammonia safety hazards in food plants (and how to correct them):
1. Poor housekeeping practices (oily or wet floors, storing items in the machine room)
- Correct it: A clean area is a safe area. Ensure your floors are clean, free of oil and water and do not use your ammonia machine room as a storage room.
2. Poor pipe quality beneath insulation
- Correct it: Check for corrosion under insulation (CUI) by conducting spot checks, often performed during your mechanical integrity audit. Prevent pipe corrosion by using a corrosion inhibitor or stainless steel pipe.
3. Absence of adequate pipe labels or no maintenance program of labeling
- Correct it: Follow International Institute of Ammonia Refrigeration (IIAR) Bulletin No. 114.
4. Equipment is operated outside design parameters—Materials are generally only rated for a specific temperature range. In the refrigeration industry, users may change a setpoint from -20℉ to -25℉ to try and improve production or make up for lack of capacity; however, the pipe may only be rated for -20℉. Running pumps or compressors at different design conditions than intended can overload the motors.
- Correct it: Operate your pumps and compressors within the designated design parameters and temperature range.
5. Failure to implement maintenance cycling program on valves—If your valves sit in one position for too long, they won’t work when you go to use them.
- Correct it: “Exercise” (open and close) your valves regularly.
6. Blocked escape routes from areas with ammonia present—It may seem obvious, but don’t store a big box in front of an exit. We see this mistake often.
- Correct it: Ensure escape routes are clear.
7. Operators with insufficient training of ammonia refrigeration operations and safety awareness
- Correct it: Per process safety management (PSM), ensure personnel involved with the operation and maintenance of the ammonia system receive initial training and refresher training every three years.
8. Unsafe access to frequently used valves, equipment, etc. for maintenance
- Correct it: Items that require maintenance should ideally be accessible from the ground (use a chain wheel). Items up high should have a catwalk or a clear path accessible via a scissor lift or ladder.
9. Leak detection systems that are either nonexistent, inoperable, not calibrated or not tied to ventilation systems
- Correct it: Perform annual testing on your leak detection systems to ensure alarms work properly.
10. Uncapped open valves
- Correct it: Ensure all valves open to the atmosphere have a pipe plug or cap.
11. Open oil draining valves—Because oil draining valves have a spring return, you personnel must stand in front of them and hold them open. Some personnel might take them off and just leave them open.
- Correct it: Avoid this issue by utilizing self-closing, spring-loaded valves.
12. Gas mask systems are not readily accessible
- Correct it: Keep your gas mask systems close to your ammonia source.
13. Heavy ice buildup on piping and components; not taking weight into consideration—Some pipes (those below 32℉) will build frost either because they are not insulated, or are not insulated properly. The ice will get thicker and thicker, creating considerable added weight. Pipe supports and the building are not designed to hold this extra weight.
- Correct it: Insulate your piping and components properly.
14. Not executing safety switch testing on a consistent schedule
- Correct it: Conduct annual safety switch testing.
15. Open electrical cabinets
- Correct it: Close your electrical cabinets to prevent risk of shock or fire.
Stellar is a fully integrated firm focused on planning, design, pre-construction, construction, refrigeration, mechanical & utility, building envelope, and total operations & maintenance services worldwide. Visit the company's blog at www.stellarfoodforthought.net