Commercial Gas Sizing Chart

[Spanner2k7]

Hi all,
Just a quick question which has probably been asked before. Can you use commercial gas pipe sizing chart for domestic pipe sizing.
Cheers
Spanner

 

[newcastle phill]

Domestic is upto 35mm so i wouldnt have thought there would be much crossover.
Im not commercial tho so just saying

 

[ShaunCorbs]

No as different pressures

 

[Spanner2k7]

What do you do where the gas flow rate goes beyond 30. For example:-
35mm Copper required flow rate is 4.96m3 at 30m 35mm allows for about 7.6m3.

 

[newcastle phill]

Well that wouldnt be a domestic size installation and is beyond the scope of /1B

 

[Spanner2k7]

The installation is:-
40kw boiler
13kw hob
16m to the 1st tee with 6 bends
4m from tee to boiler with 4 bends.

Can you please work out the sizing and see what you get and I can compare with what I got?

 

[newcastle phill]

Are they bends or elbows

 

[Spanner2k7]

1 allowed 0.5m for the bends.

 

[ShaunCorbs]

1 allowed 0.5m for the bends.

Isn't it .75 for gassed elbows and .5 for swept (domestic) ?

And will work it out later

Mans could you draw it out line dia will do (need cooker / any other appliances as well)

Also what meter is installed ?

 

[ShaunCorbs]

Rough work out on bar nap 42mm with a pressure absorption of .310mbar ( recommend) but 35mm would do will work it out later for Defo tho

 

[newcastle phill]

Its .3 for bends .5 for elbows

 

[newcastle phill]

Can you elaborate how far from 1st tee cooker is
I havent had a chance to dobit yet as busy but will do later

 

[ShaunCorbs]

Did you accomodate the meter iv into that.
I havent had a chance to dobit yet as busy but will do later

A stnd u6 yes

 

[Spanner2k7]

I will try and put a drawing on, for now I can give you:-
Meter to 1st tee = 16m with 6 bends.
1st tee to boiler = 4m with 4 bends
1st tee to hob = 3m with 5 bends

40 kW boiler
13 kW hob
U6 meter.

I have done 2 methods of calculation.
1st says I need at least 12m of 35mm.
2nd says I do not need any.

 

[newcastle phill]

If those figures are net you need to convert them to gross.
That has 2 sections so you need to double the effective length for a 0.5mb drop per section (1mb end to end)

 

[newcastle phill]

Ive had a quick calc.
This is assuming those Kw's are nett and i have switched them over to gross
And i have assumed 0.3 for swept bends as you havent mentioned elbows

1st 16m needs to be 35mm
To cooker from tee will be 15mm (just)
To boiler from tee to be 28mm


You will be within 1mb drop end to end as per regs

 

[Spanner2k7]

That is about what I got.
I had a little play with figures earlier.
Try this and see what pressure loss you get
Total length 19 m with flow rate of 4.96m3
Total length 19m with flow rate 7.58 both on 35mm.
Do not worry about meter size, treat it as a section.

 

[ShaunCorbs]

Ive had a quick calc.
This is assuming those Kw's are nett and i have switched them over to gross
And i have assumed 0.3 for swept bends as you havent mentioned elbows

1st 16m needs to be 35mm
To cooker from tee will be 15mm (just)
To boiler from tee to be 28mm


You will be within 1mb drop end to end as per regs

will be elbows dont know many people outside the com lot with 35mm benders

 

[ShaunCorbs]

Its .3 for bends .5 for elbows

think you will find thats only upto 28mm 😉

 

[newcastle phill]

He said bends so i did bends.
If he said elbows ill do elbows, as i enquired earlier.
Yep viper states upto 28mm [emoji12]

I have a good pdf see if i can post it

 

[ShaunCorbs]

He said bends so i did bends.
If he said elbows ill do elbows, as i enquired earlier.

viper book i-8

upto 28mm

bends = .3

elbows = .5

tees = .5



to prove im not bssing you

 

[newcastle phill]

Yes and 35mm is its 1m for elbows.
As i said a quick calc and end result is the same

Igm/up/2 for 35mm states 1m for elbows and bends

 

[ShaunCorbs]

Its .3 for bends .5 for elbows

Yes and 35mm is its 1m for elbows.
As i said a quick calc and end result is the same

Igm/up/2 for 35mm states 1m for elbows and bends

post 11 needs changing then doesnt it ?

 

[newcastle phill]

Ill do that now mr corbs [emoji12]

Ohh get you. You been swatting up since you made a **** of yourself with pipe swaging methods lol

 

[ShaunCorbs]

Ohh get you. You been swatting up since you made a **** of yourself with pipe swaging methods lol

nope and still dont accept them on gas dont care what anyone says, seen too many crack after a few years