CCPS defines Replacement-in-kind as:
An item (equipment, chemical, procedure, etc.) that meets the design specification of the item it is replacing. This can be an identical replacement or any other alternative specifically provided for in the design specification, as long as the alternative does not in any way adversely affect the use of the item or associated items.
A batch facility had a 1500 gallon glass lined reactor (Pfaudler) that was in service for many years and needed to be replaced. A written design specification was not available for the old reactor but it did have a U-1 form. The replacement was a 1500 gallon glass lined reactor (DeDietrich) with its own U-1 Form. The MAWP for the two vessels were identical. Functionally they were equivalent for our purposes but there were slight differences. In most instances the replacement vessel was better. Differences include wall thickness on the replacement vessel was slightly thicker, there were fewer nozzles on the replacement vessel, and the replacement vessel was older.
I didn't considered this to be replacement-in-kind but I would love to be told I'm wrong. What is your opinion?
"For a long time, people were saying that most accidents were due to human error and
this is true in a sense but it's not very helpful. It's a bit like saying that falls are due to gravity."
"What you don't have, can't leak..."
"Try to change situations, not people..."
Dr. Trevor Kletz
Principal Engineer I
Learn as if you were going to live forever; live as if you were going to die tomorrow.
Hello James,You are not wrong.
Guideline for replacement-in-kind should use it with caution. Though the two reactors are glass lined and of the same capacity, they are of different design details and their materials of construction are not mentioned. I believe the details are all included in the respective U-1 Form. Thicker vessel wall thickness not necessarily of superior design as it has to consider the thermal expansion and heat transfer coefficient should jacketed heating medium be used. Fewer nozzles on replacement vessel again have to consider if there is missing key connection such as for draining or venting, and to associated processes up-stream or down-stream. Replacement vessel of older age, or reused of reconditioned vessel has to thoroughly examine its metallurgy prior to using it. The entire consideration is part of management of change process.