flow and pressure

[learningplumin]

Hi I don,t understand either.
Say I have a large hole, in the ground and I have a 15mm pipe above the hole, and I tap into the 15mm pipe 5 times with a tee peice to fill the hole, will the hole be full quicker? than say tapping into the pipework once with a tee piece, hence more pressure????
Thanks.

 

[Alanc]

depends on the pressure

 

[migoplumber]

its really quite a heavy question.
flow is the amount of water that can flow through the pipe a 15mm will have less flow than a 52mm pipe with the same pressure.
pressure hmm, pressure is measure in many units. bar is the common one here. mca or metre per column of water is common in europe and is probably easier to explain.
1 bar atmospheric pressure is the equivalent of almost 10 mca (think its 9.81 but lets call it ten)
if you have a vertical pipe 10 metres high at the bottom of the pipe a manometer would read 10mca or 1 bar, half way down 5mca or 0.5bar 1 metre from top 1mca or 0.1 bar (all totally irrelevant to flow - i'm talking about a static column of water technically with no flow through it) the pressures would be the same if the vertical pipe of water had a diameter of 10mm/22mm 54mm or twenty miles.

if the column of water had holes drilled in where the manometer was and the water was no longer static ie moving and the diameter of the hole was different sizes at different heights then yo would have diffefernt flow rates. if the pipe was 2 miles diameter and at the bottom you had a 10mm hole - then water would exit that hole at a pressure of 1 bar but only a small flow, if at the top of pipe 1metre down that enormous pipe had a hole 54mm diameter, the flow of water would be large but the pressure would only be 0.1 bar.

its easier to learn than to explain me thinks. better answers on the way !!

 

[learningplumin]

Thanx, guys for replies.
Just can,t seem to get my head around it.

 

[migoplumber]

it will take a while, its probably the most fundamental plumbing rule that so many plumbers dont quite grasp - but manage to work with it all the same. then again you find the dodgy ones doing their tank outlets in 15mm and wondering why in the kitchen they measure 0.6 bar but the flow is crap.
there are all sorts or charts and spinning wheels available on internet!
good luck.

 

[learningplumin]

Thanx, shaun.
Will keep tryin too learn.
If you have anymore, on this please post thanx.