How dangerous is air testing pipework

I've air tested pipework for years, typically 4 bar for 30 minutes. I've never had an issue with any pipework that has passed that test, occasionally you get a small leak from the air test typically old cap ends/scratched pipe which shows up easily on the test without having to inspect anything, but once re-tested it is then water tight.

It wasn't until this week when someone joked about it being a pipe bomb that I suddenly thought, actually this could be really really dangerous. I can't find any calculations online to actually get a feel for how much energy is stored in a given system.

The system this week was large, by my calculations 45L of air in pipework plus 5x 6 column radiators and 3x 4 column estimating volume to be 210L, totalling 255L of air at 4 bar

As I see it the only dangerous part would be if something let go. Cap ends would be the most dangerous as they could point in a direction of someone. The other part would be a fitting rapidly failing but I see the damage as limited as long as pipes are clipped thoroughly as nothing could then become shrapnel

Is there anything I'm overlooking? Is this a bit of a non-issue or do I need to do this a little more safely?

Continue reading...