Why does nobody talk about the value of a slow, cold hydro test?

Last winter, we had a big pressure vessel job at the old paper mill in Everett. Everyone on the crew wanted to rush the hydro test, get it up to spec pressure fast and call it a day. I insisted we fill it with 40-degree water and bring the pressure up over four hours. Sure enough, at about 80% test pressure, we heard a tiny 'tink' and found a hairline crack in a longitudinal seam no one had spotted. That extra time saved us from a major failure later. Has anyone else had a close call that made them change how they run a test?

3 comments

3 Comments

paige4271mo ago

Hah, maybe @logan705 was onto something with the whole not-freezing thing. I mean, rushing a hydro test just sounds like asking for a bad day.

logan7051mo ago

Wish I could say my timing was that smart. Mostly I was just trying to stretch out the part of the day where I wasn't freezing my hands off. Turns out moving slow has its perks.

west.anna1mo ago

Four hours is a long ramp up. Did you base that time on the vessel's wall thickness, or was it more of a gut feeling from past jobs?