pipe sizing – gas

Geez we all gotta do it most times – but if ya wanna make it real easy go buy a “Mears Circular Gas Pipe Sizing” Calculator.

I am not aware of any successful PC programme to do the donkey work but if someone has got one that does it I will be very interested in obtaining a copy – provided it covers all inlet gas pressures.

Pete, or should that be Peter. I dont want to upset the Ewes. The Institute of Plumbing Australia have developed a programme for pipesizing household water & large bore water lines to comply with AS 3500 & they were in the throes of developing a programme for gas. contact [email protected]
Bob

Robert or is that Bob and I don’t mind what anyone calls me so long as it is not late for a drink or two after work!!

Well well well I think maybe I am gunna write to them blokes and see if they have got any further with that programme – I’m all for saving a bit of time and effort.

Thanks so much for the tip – I greatly appreciate it.

Yer not that bad for an Auzzie hahahahaha.

hi,
as for residential gas, instead of looking at the sizing chart all the time, I came up with a simple system for sizing gas; From the meter measure your pipe to the furnace the first 40′ can be 3/4 pipe anything over that run 1″. you know that the water heater needs 1/2″ and the fireplace is 3/8″. every 40′ increase one pipe size and oversize your pipe by one until you get to your fixture shut off valve. the furnace must be hard piped out of the unit. install unions exposed between the gas cock and appliance. using wardflex to the fireplace, run wardflex in dead areas and not walls because you’ll have to protect the pipe with striker plates and sleeves. wardflex is strapped loosely about every 6-8′
so nails can push the pipe away. if it was strapped tight the nail would go right through it.
I run 1″ gas to my furnaces and branch off with 1/2″ to the w/h and f/p.
I also know that the w/h gas inlet is always on the left about 18′ high and the furnaces usually stubs out about 28′ and 3′ high.
when roughing in the gas i try to get the w/h on the left and furnace on the right and stub up between them 18′ and then install your gas cocks and capped. where i live they are starting to get in place gas meters that are read from a radar gun. my meters are within 5′ in front on the garage side. and stubbed out 26″ above ground level and from the left side of the meter measure over 16-18″ for the stub out. no window, door or vent within 30″.
now as for your drip leg there is suppose to be one at every fixture, a little common sense will tell you to put one on or not. i know that your main gas run is supposed to have fall towards the meter (i forget the measurement of fall). and the last thing i’m going to say is that a water heater or furnace, the burner must be off the garage floor 18″. a room that opens to the garage is considered the garage floor level.
well i’m rambling on and had better stop, if anyone has any questions my knowledge goes way beyond gas and I work with the latest technology.
ps. if they want you to use a mercury gauge, tell them that the mercury is outlawed and the epa would not be amused.

curtisbonner. Would you do that for commercial work?
Would you do that for first & second stage LP work as well?.
What about natural gas?
Bob

Chris

Just one wee small problem that could cause your “theory” to tip over some – The size of the gas piping depends on three major factors those being and in no particular order : Total gas lead over distances, inlet gas supply pressure and the net effective distances of total and branch pipe runs.
Although your concept works most of the time – please do not apply that formular to any work down here or else you will be in real trouble.
We have varying inlet gas pressures and varying gas types that we work with so the calculation needs to be somewhat more scientific or should I say accurate.
We have tables to work from but what I was seeking is a PC orientated programe that would allow me to input the required relevenat data and get out the sizes needed to save a considerable amount of time and effort.
Cheers

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Selgas Services Ltd
Craftsman Gasfitters, Plumbers, Electrical Service Technicians