We have several instances in our facility where we have an "installed spare". I believe it would be a best practice to rotate them into operation on some frequency. I would imagine that the frequency would vary depending on the equipment and process but I am struggling to convince the operations group to begin this practice. What are the current practices through out industry and what is everyone's experience with this?
You will never get full consensus on this topic and I am sure you can search for some similar threads in this forum. Some believe you should not rotate on-line and standby equipment but run them as primary and backup and only run the backup for test runs on a periodic frequency. Some will advocate to run a primary most of the time but run the standby on-line for short periods on a specific frequency and others (myself included) will advocate for doing even rotations.
At our power plant most of our "balance of plant" equipment has an installed spare. We switch from the A system to B system each month, so for even months (Feb, Apr, Jun...) the A side is running and on odd months (Jan, Mar, May...) the B side. This gives fairly even run times for the equipment and at all times we know that the standby side ran recently for a decent run time, so we have a good feel for it's condition. It also makes it easy for plant operations to know which one should be running and makes the switching reasonably clean and easy. We have had some instances where overhauls have had to occur fairly close to each other, one instance a pair of vertical turbine pumps had both run just over 60,000 hrs each and we overhauled each of these within a one year period. We also have a pair of boiler feedwater pumps with very similar run times, both with almost 90k hours each. They will both need to be overhauled around the same time (disadvantage for some maybe but not so much for a power station with fixed outage schedules - they will be overhauled at the next turbine major outage). I know not everyone will agree with this approach, but it works well for us. We now have a reasonable history of monthly rotations (~20 years) and have had success with it or most equipment.