Commercial gas pipe sizing

[Tranx]

You can`t design what you don`t understand and there lies the problem, you will not get the answer you seek from this gas safe minded forum so please give it a rest now.

I'll happily admit to a lack of knowledge, but what makes you think I don't understand what I need to do? I'm trying to calculate the required pipe diameter that will allow me to move enough gas ~40m^3 to supply 440kW of appliances, 90m from the meter to final destination. I need to ensure pressure drop across the run is minimal, and will allow the continued supply of 40m^3 gas.

All I want is a simple equation that will allow me to calculate this.

Otherwise I'll have to take it back to basic fluid mechanics & have to do lots of research into pipe roughness, calorific values, specific densities, the effects of pressure on pipe wall friction and velocities, the bloody Darcy-Weisbach formula, etc etc...

Surely there's a simple formula to calculate as accurately as reasonably practicable the required diameter? I can't imagine day to day plumbers having to do this every time they size a pipe.

 

[Tranx]

You haven't a hope in hell 50mm will be able to cope

May I ask who is installing the boilers ?

Also what's the op/mop ??

We will have to have a new gas meter installed anyway if the job goes ahead as the current one will be undersized. Can you shed some light on typical meter operating pressures? I understand that standard domestic is 21 mbar, the current meter on site just says <75mbar. What's likely to be the standard operating pressure of that meter? Can we go to higher pressures? and does that bring in more complications? I would guess the usual way is to keep pressures past the meter low and to increase pipe diameter?

Cheers.

 

[Scott_D]

You will need someone with commercial gas for the appliances
A local plumber can't do it

 

[Scott_D]

You will need someone with commercial gas for the appliances
A local plumber can't do it

 

[ShaunCorbs]

Right ok

Plumbers can't install the boilers or flues needs to be a commercial gas engy (as need to make sure safety devices and installed to current regs)

Regarding steel pipe with a distance of that length using 50mm will give you a pressure loss of around 8mbar with a low pressure system <75mbar (normally running around 21-35mbar op) which your only allowed a max of 1 mbar

So you can see your well off

Tbh you would be best to contact the services of a commercial gas safe engy in the designing stages will make the job run a lot smoother in the end

Any other questions please ask

 

[ShaunCorbs]

We will have to have a new gas meter installed anyway if the job goes ahead as the current one will be undersized. Can you shed some light on typical meter operating pressures? I understand that standard domestic is 21 mbar, the current meter on site just says <75mbar. What's likely to be the standard operating pressure of that meter? Can we go to higher pressures? and does that bring in more complications? I would guess the usual way is to keep pressures past the meter low and to increase pipe diameter?

Cheers.

You would have to speak to the network provider see what they can supply

If you go with steel tube get a commercial engy to work out what he requires, and get him to install it with a coded welder

 

[joni os]

Otherwise I'll have to take it back to basic fluid mechanics & have to do lots of research into pipe roughness, calorific values, specific densities, the effects of pressure on pipe wall friction and velocities, the bloody Darcy-Weisbach formula, etc etc...

Surely there's a simple formula to calculate as accurately as reasonably practicable the required diameter? I can't imagine day to day plumbers having to do this every time they size a pipe.

The "Pole Formula" is a simplified version of Darcy's but underestimates pressure drop as diameter of pipes decreases.
Boilers, even if domestic, will require fitting by commercial gas fitters because of meter and volume of gas in system.
Why is the option of bringing meter closer to plant not available.

 

[Riley]

Dear lord

 

[SimonG]

Dear lord

He'll be along in a bit

 

[rpm]

, the bloody Darcy-Weisbach formula, etc etc...

:hand:

 

[rpm]

, the bloody Darcy-Weisbach formula, etc etc...

:hand:

 

[Rickster123]

I'm closing this thread because I'm a "day to day plumber".

No gas advice given here.