Pressure test with water for cast iron spigot pipes

[gulten]

I want to execute a pressure test with water at 8 bars for DN150 cast iron spigot pipes which are passing through DN400 steel protection pipe. So I have no any chance to cover the cast iron pipes with sand or soil. As far as I know this cast iron pipes can be bent 5 degrees from joint points. I wonder if somebody have such an experience to explain me without any additional fittings, only by standart joint of cast iron pipes if I can execute or not this pressure test.
Regards,
Thanks in advance!

 

[BRIS]

I have to start by saying I don't understand your question.

I assume that you have a cast iron(I assume it is in fact ductile iron) pipe made up of spigot pipes joined by some form of flexible coupling (Dresser type) within a DN 400 mm sleeve. Your concern is that because the pipe is not restrained within the sleeve it will fall apart when you pressure test it.

It probably will - but then again it will probably fall apart when you bring it into service.

The purpose of pressure testing is to demonstrate that the end product is sound and fit for purpose - installing temporary restraints solely to conduct the pressure test is defeating the object.

You need to give a clearer explanation of the problem.

If you are using flexible type couplings it may be possible to deflect the pipe at each coupling by 5 degrees (2.5 degrees per joint) but you should try and keep deflections lees than this - i would allow a maximum of 3 degrees.

You should have spiders or some other form of support to hold the DN 150 mm pipe within the 400mm sleeve.

Brian

Brian