Nooging around t'net I found this about pressure testing PolyPlumb piping and joints :-
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Pressure testing of the Polypipe 'Polyplumb' pipe system is essential however a successful pressure test using the following steps is not a guarantee of complete and correct installation and only ensures that pipes have been inserted into fittings passed both the ‘o’ ring and the grab ring. If pipes have been scored or scratched during the installation process a high pressure test as below may not highlight these issues.
1st fix installations
Pipe and fittings only should be tested. The system should be completely filled using water at not more than 20°C at a test pressure of 18 Bar which should be applied for not less than 15 minutes and no longer than 1 hour.
Joint security can be checked visually and by tugging at joints.
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18 bar is just over 260 psi. So looks like the cheap option will do fine for the likes of us.
6 mm nylon is a nice system, works a treat on my Range Rover P38 air suspension set up, but the pipe isn't uber cheap and you need to watch out for manifold and adapter costs when going up to normal BSP, air connector and pipe sizes. Had to do a mixed system recently with a couple of 6 mm pipe sections going up to the usual sizes and was quite surprised how the bits'n bobs added up. Nothing fancy. Just a basic compressor pressure switch control system with an extra unloader valve circuit.
Clive.
Edited By Clive Foster on 05/12/2016 11:09:26