[Russell in Tulsa]

I was hired to run water and a drain line to a test machine for rebuilt heat exchangers for commercial aircraft. This young, new engineer had his slide rule out and was studying it intently and told me to run something like 65' of 3/4" galvanized pipe through the bar joists above and then continue the remaining distance with 3/4" PVC plastic tube and discharge the drain into a stainless steel tank they used for anodizing aluminum. This length he surmised would dissipate the high heat from the discharge of the test module to the atmosphere and still have heat in the discharge for the effluent to be used in the anodizing process. Smart huh?
Well since our 3/4" galvanized pipe comes in 21' lengths, I didn't want to cut a new joint up for a two foot piece, so I installed all 4 joints of galvanized and then the last bit with 3/4" PVC.
Well when the time came to turn on the equipment it sounded like a jet engine and the engineer was watching the gauges and pressures on the machine and I stepped into the following rooms to check my discharge pipe for leaks.
The bar joists were maybe 8 to 10' apart and when I got to the PVC section I could see the PVC start to sag at the first foot of pipe. I ran back to the dude a told him to turn off the heat portion of the test and run cold water to cool the system, I ran back to the end hanging over the SS tank to watch it fall off into the tank just as the cold water hit it.
He told me to remove the PVC and replace it with galvanized pipe. I didn't see him anymore, even on the next test. Didn't ask where he was, he was probably being ribbed too much by the other engineers to come back in there.