76:
Have witnessed hundreds of hydro's and at times if a valve or blind flange could not keep up (on existing equipment), the contractor had to keep pumping to maintain the required test pressure.

The test was to verify the integrity of welds or equipment seals, etc. Not the integrity of other-older components. If the entire system you are testing is new, that is another story, no leaks, no pumping during hydro-time. This was the owners requirement and noted in the specifications.

I would not say if it was the right/wrong thing to do unless contracts or specs prohibited continuous pumping to maintain the test pressure.

Have also witnessed several hydro failures, they ranged from small-high pressure spray's barely noticable to catostrophic failures. Got hit in the leg once while testing RTR pipe in the ditch, glad it was not metal that wacked me. Tested a 72" header with numerous weld repairs at a very high pressure, that was the scariest one of all. Lots of creaking and groaning during the test. The proponent only permitted myself and one rep. from the contractor to assist me in the immediate vicinity of the test. I was the lab rat I thought while hurrying to put distance between me and that manifold.

Sometimes that 10 minutes seems like an eternity, doesn't it?