Pipe Size for Garden Taps

[DonL]

1.7m head, 27m of 25mm pipe with a few fittings, 3/4" tap. Time to fill a two gallon watering can 40 seconds which equals 13.5l/min.

[Blodders]

I reckon you'll be fine with your 32mm, 25mm and 3/4" taps. Don't worry too much about pipe sizing calculators, most of them are meant for sizing closed systems to maintain optimum flow velocity of between 1.5 and 3 m/s. Fiddle enough with a pipe sizing calculator and you'll reach a stage where the sums say that you will get no water out of the end of a horizontal pipe!

I did note from you first post that this system will just be a collection of taps for hand watering of trees etc, if you are doing all this work, why not install outlets to each tree, that should save water as well thanks to being more precise with water placement. That then gives the option of timers etc to automate it further.

[kristen]

Thanks Blodders.

Mostly this is hedges, which have leaky hose along them, so we just need to stretch a 50M (3/4") hose from the nearest tap. I've organised it so that there are 4 or 5 leaky pipes that end "near" the same point (so for a straight run a point would be the North end of one pipe, the South end of its continuation, and and East and West end of a hedge crossing at right angles.

We do have some trees but they are dotted about, and it would mean burying a pipe to each in order that the pipe wasn't "mowed" !!

I did some bucket-fill timing tests at the weekend, in case anyone is interested:

Time to fill 2 x buckets (at a guess 10 - 15L each)

From tap	1m12.5s
50M x 1/2"	1m52.1s	+55%
100M x 1/2"	2m14.1s	+85%
100M x 3/4"	1m26.8s	+20%
200m X 3/4"	1m35.2s	+31%
32mm Tap 1	1m20.1
32mm Tap 2 (200M)	1m28.1	+10%

Clearly no point using 1/2" hose for anything more than a handful of yards!

[MR GUS]

 remember the seasonal differences of localised water pressure based on local demand, unless yours is utterly consistent all year round you ought to have say a 60% flow measurement or similar that can be applied in times of wasteful users & their powershowers et al.
our water pressure is as miserable as me!  

[kristen]

I think I should have an automated valve based on water volume - so I can push, say, 500 Litres into my leaky-pipe, and then shut off.  Thus not pressure dependent (as a Timer would be).

[kristen]

Some observations:

I have constructed the taps using:

MDPE Right angle to BSP (plastic)

Plastic ball valve - BSP (brass) to tap and BSP (plastic) spout, connected to BSP Metal with tail and hose attached by jubille clip

The plastic-metal links are not great. I have been very careful not to cross-thread.  The tap-spout to hose connector is easily overtightened.

I'm thinking of replacing them all with brass. Although the quarter-turn ball valve is much appreciate by the users

Photo's show wear on the plastic thread - one-time-use of elbow, and "no" use of spout (spout nozzle delivered loosely attached, it has not yet been "installed / commissioned")

Can I improve things with PTFE tape or some sort of lock-tight?

[kristen]

Further question:

There is some sort of plastic insert in the tap-spout hose-connector.  Its not a filter (holes too large). It might be some crafty device to create linear flow and thus reduce friction (I'm probably dreaming!), but if it is just adding friction can I remove it and chuck it?