I was reading an old safety manual from the 80s and the pressure test numbers were way lower than today

Found it in a box of my granddad's stuff, a manual for a specific old boiler model. It said to hydro test at 1.5 times the working pressure. Now we do 1.5 times the design pressure, which is a lot higher on modern units. Makes you think about how much the safety factor has changed. Anyone else run into old specs that would be a red flag now?

3 comments

3 Comments

valsullivan1mo ago

I remember reading an article in an old engineering magazine from the 1970s that talked about how they tested pipe welds. They said you could just tap them with a hammer and listen for a solid ring. If it sounded hollow, you'd grind it out and redo it. That would never fly today. You'd get laughed out of the shop for suggesting a hammer test. I think you're right about the safety factors changing a lot. But I'm not sure it's all about worse materials these days. It's more that we have a better understanding of how things fail over time, so we build in more room for error from the start.

brookerobinson3mo ago

Yeah, I found an old wiring diagram that said it was fine to just wrap a junction in electrical tape and stuff it in the wall. No box, nothing. The note just said 'should be fine for a good while.' Really makes you trust the craftsmanship in some of these older houses, you know?

ericschmidt3mo ago

But what if the old way was actually smarter? They built things to last back then with simpler, tougher materials. Maybe that old boiler's steel was so good it didn't need crazy test numbers. Now we over-engineer everything with thinner stuff and just jack up the safety factor on paper. Could be we're just covering for worse craftsmanship now.