MNK,
The probable cause of liftoff of the section of piping in the pipe rack could be due to thermal bowing. The lower surfaces of the jacket pipe are being kept cold by the chilled water, 5 to 10 deg C, while the upper surfaces of the jacket pipe could be at some temperature nearer ambient.
The pipe rack is higher elevation than the pipe sleepers, so that any air or vapor in chilled water would collect there in the pipe rack portion of the pipe run. The collected air prevents the cooling of the upper pipe surfaces by the chilled water, and so the upper portion is at different thermal contraction (expansion) than the bottom of jacket pipe. There is probably some contributing tension loads from the duplex SS gut pipe that contracts more (more thermal change in length, decrease) than the jacket pipe, to compress the jacket pipe to be deflected in a shape of buckling column. This assumes there is not an expansion loop in the jacket pipe on the pipe rack. There is probably not a concern about over-stress of pipe, but it is good to be careful in handling ethylene oxide.
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R Yee