gas pipe sizing

[Inverness]

 

[Inverness]

here is some more gas sizing practise attempts.
I've think I've manage to grasp it now.

the main pipe run c-d to find out its progressive pressure drop you add the actual pressure drop from previous b-c progressive drop ?

 

[ShaunCorbs]

for the progressive pressure drop of lets say F



A-B + B-D + D-F = progressive pressure drop of F etc

 

[Inverness]

for each appliance to find out its progressive pressure loss you need to add all sections of pipe that feeds that appliance so by finding out f you have to plus all the actual pressure drop together ab- bd- df.

but what about pipe work that isn't feeding any appliances??

 

[ShaunCorbs]

for each appliance to find out its progressive pressure loss you need to add all sections of pipe that feeds that appliance so by finding out f you have to plus all the actual pressure drop together ab- bd- df.

but what about pipe work that isn't feeding any appliances??

yes and what do you mean like A-B and B-D ? just add upto that point

like you want to know the ppl of D

its A-B + B-D = ppl of D

 

[AlexGas]

View attachment 26896

Try to do your calculations using latest BS figures for pressure loss of fittings. See if you get the same result.

 

[Inverness]

Isn't the copper institutions bs figures?

 

[AlexGas]

Isn't the copper institutions bs figures?

Can you see the figures in my previous post?

 

[Inverness]

I have the bpec Gas saftey manual so I'll start and do more practice attempts with these pressure loss figures it even goes up to 35 mm.
Thanks again.
It takes time to understand it and the books are written in such away that it's designed to be taught by a teacher. But who needs a teacher when there is you guys.lol
I know it's early but I don't begin my gas until March next year so I'm studying for it now so when the teacher starts explaining things I'll no what he is talking about and I'll be able to explain it in a easier format to my friends in the class too.
My boss is gas safe but we don't to a lot just commissions boilers and sometimes re-rout gas pipe to suit new boilers. But with the plumbing forum I'm teaching my boss new things too.

 

[AlexGas]

All the best, hope it goes well for you.

 

[Inverness]

I can see the figures in your last post. But I thought .5 for each elbow and tee .3 for formed bend?

 

[Inverness]

I didn't know there is pin point figures from the bs6891 2015

 

[Inverness]

On the gastite website there is detailed pipe pressure losses for even couplings. Is this what you do for precise measurements?

 

[AlexGas]

I didn't know there is pin point figures from the bs6891 2015

It was new to me too. That's the latest British Standard.

 

[Inverness]

The book we have been given from college said this is all we need to know to pass. When did it come out?

 

[spanner]

Maximum allowance from meter to appliance 1mbar. From the meter work out the consumption rate of a a meter of pipe up to the maximum of 35mm diameter. The larger pipe bore the more retained.
Then reduce the sizing slightly further down the run. And not forgetting to + 0.5 of resistance for each and every fitting then adding in to actual length.