AG601 appendix F

[doug thompson]

The pipe sizing tables in the back of the book(Australian gas code). How do they take into account the pressure setting of the regulator at the meter? Are these tables for the 1.35kpa regs? (NG)

[SelgasParticipant]

Hi there,
I am going to try and explain this pipe sizing system with my tongue stuck in my cheek and assuming that you are a qualified gasfitter who should already know the answer to your question – however he we go.
In any gas piping system REGARDLESS of inlet gas pressures, well at least for those up to say 7ka and below the codes provide a system whereby one can size a pipeline to ensure there is both sufficient capacity and pressure available to suit the appliance connected thereto.
The method used both in Australia and New Zealand does this by providing charts or calculations that allow for an accepted pressure drop overall from the main inlet pressure as set out on page 166 of AS5601, AG601 – 2000.
In the Australian standards you have a system where the pipe length, pipe diameter shows the mj capacity in a simple chart system under whatever clasification of pipe material is used, in New Zealand we have a long winded system that uses graphs and the like to achieve the same result, so needless to say a few of us here use the Australian Standard which is accepted as an acceptable solution here by our regulators.

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Selgas Services Ltd
Craftsman Gasfitters, Plumbers, Electrical Service Technicians

[SelgasParticipant]

Sorry – I should have included the answer to one of your questions earlier asking if these tables are for the 1.35kpa regs found on most domestic and small commercial gas meter sets – the answer is of course yes and all you have to do to use the charts is look up the chart that gives you the allowable pressure drop (10%) and follow the instructions therein.

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Selgas Services Ltd
Craftsman Gasfitters, Plumbers, Electrical Service Technicians

[zeligParticipant]

Hi Peter. Thanks for your reply. Since I posted the message I updated to AS5601 – 2004 which NOW has tables for both the 1.3kpa regulators and the 2.75kpa regulators. I can now use the tables to size for either of the common regulator sizes. Cheers

[Author]

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