Q&A | Decommissioned Equipment
Question: Does decommissioned ammonia refrigeration equipment need to be inspected as part of the mechanical integrity program if it is still connected to the closed-circuit system, but valved-off and not under pressure?
Answer: The fundamental problem with the question is that ammonia refrigeration equipment cannot be decommissioned while it is still directly connected to the closed-circuit portion of the refrigeration system, even if the equipment is isolated from the system with valves. When the decision is made to decommission a piece of equipment, the following steps should occur:
- Equipment must be pumped down (ammonia removed)
- Equipment must be isolated from the closed-circuit system
- Pipes connecting the equipment to the closed-circuit system must be cut and capped so that there is no potential for ammonia to enter the decommissioned equipment
Once a piece of equipment has reached Step #3 it no longer needs to be included in the mechanical integrity program of the PSM and would no longer be subject to inspection and tests. As long as the equipment remains in Step #1 or #2 it should be included in the mechanical integrity program because there is potential for ammonia to enter the equipment if an isolation valve is opened.