Calc: Calculating Volume of a Pipe

[qim]

I understand that the volume of a pipe is the circle pi x r (sq) x height

I have worked out the volume of water inside a pipe running from the shower to the boiler (cold water that will run through the tap before the hot water arrives) and it does not make sense. The pipe is 22 mm; the distance (h) is 11 metres

So: pi x 0.11 (sq) x 11 = 0.418 m3 = 400 l ?

It can't be, surely! 400 Litres? I guess it around 42 litres, but where did I go wrong with the decimal points?

Thanks

qim

 

[aub]

its 22mm is 0.022m not 0.22

 

[qim]

Thanks.

But now I get 0.004 which is 4 litres. It seems too little

 

[jscroft]

Your formula should be V = pi * (0.011 m)^2 * 11 m = 4.18e-3 m^3. A liter is 1e-3 m^3, so your answer is 4.18 liters.

The lesson here is to keep close track of your units, by actually WRITING THEM DOWN.

 

[qim]

Thanks!

qim