Pressure

[Dannyparty92]

I know that 1 metre = 0.1 bar so say if you have a cistern in a loft and a straight drop of pipe down 10 metres the pressure at that outlet will be 1 bar of pressure assuming its a straight drop with no fittings restricting the flow. Is this the same as working the pressure out at a point and if there's three metres of pipe going up then will the pressure be 0.3 bar below the pressure originally. Also is this rule the same for 15/22 mm pipe sizes. And also do you increase the distance of a pipe run by what fittings Are including in the run for the purpose of working the pressure out? Thank you in advance for any answers .

 

[erpkid]

Pressure is determined by head as you have described. Flow is influenced by fittings and the run of the pipe work.

 

[Dannyparty92]

So the 1 metre = 0.1 bar rule applies with pipe work going up and horizontal pipe work aswell?

 

[zzzjim]

Head is all about vertical height .

Static pressure (nothing moving) does not care about pipe size.

 

[MrMeek]

your doing it wrong, its 0.1 bar per meter head to the outlet. so measure the bottom of the tank to the outlet point

 

[Megaflo-Experts]

So the 1 metre = 0.1 bar rule applies with pipe work going up and horizontal pipe work aswell?

It is the vertical distance that matters; so if you drop 1m and across 3m, the (static) pressure is still 0.1 bar.

Pipe size doesn't affect static pressure, so 15mm or 22mm pipe will have the same static pressure.

Dynamic or working pressure is different, and this is affected by pipe runs, pipe size and fittings (as well as horizontal runs) due to pipe resistance.

Hope that helps.

 

[MrMeek]

this is what I think your asking.

 

[Dannyparty92]

Aw ok thank you everybody I assume to work out the flow rate at any given outlet is quite hard?

 

[MrMeek]

Aw ok thank you everybody I assume to work out the flow rate at any given outlet is quite hard?

flow cup lol

 

[zzzjim]

Each fitting reduces flow (sudden change in direction)

pulled (gentle) bends should reduce flow less .

 

[dancinplumba]

each fitting also reduces dynamic pressure

 

[MrMeek]

Aw ok thank you everybody I assume to work out the flow rate at any given outlet is quite hard?

this answers everything from pressure to flow
http://www.ukcopperboard.co.uk/literature/pdfs/Installation-Tips/Pipe-sizing-basic-principles.pdf

 

[Dannyparty92]

So say your adding an additional bathroom to a property? How would you work out that there will be enough flow to supply say a WC basin and shower?

 

[MrMeek]

but you wouldnt work out if there is enough flow, you would try to estimate if the tanks could supply the bathroom first or upgrade them to larger tanks, then tap into the hot pipe work and tank (shortest runs possible if you can) and you should be ok then work out what pressure the bathroom will have if its two low pump it.

thats what I would do anyway someone may have a better way
+ that link what i sent you tell you how to size pipes......

 

[Dannyparty92]

Thanks Mrmeek .