Gas pipe sizing Q?

jim lockard

I recently gas piped in a 330 btu Nat. gas fired pool heater. The total length of the gas line was 13 feet then the pool guy moved the heater after I piped it in to extend the total length to 19 feet.
Here is where the inspector and I disagree: I have been taught to size from the appliance towards the meter so the 1st 9 feet I ran 3/4" black pipe at W.C pressure the book says 360 k btus the next 10 feet I ran in 1" black pipe which is good for about 740 k btus I believe I have sized the job right and all is good.
The inspector feels differant he believes that I should have run all 1" black pipe and for me to decrease in size in the middle of the run even if I have the capacity is a violation of the gas code.
I say the gas will never know the differance. So what do you guys think?

D lux_2

what part of the code

I can see in my minds eye that gas rushing down the 3/4 pipe and filling the 1 inch and slowing down to fill the pipe . however what would change if the 3/4 was last

jim lockard

The inspectors reply

was that he felt I was right but thats not how "they do it? he wants one inch all the way becuse that how the chart shows it.
I ran one inch off the meter 10 feet reduced to 3/4" for nine feet then into the appliance rated at 330k btu.

chuck shaw

Looking in my code book (Massachusetts)

I see it as a 1" run all the way. If you want, I can fax you the charts that I used.

One chart said with a 20' run, (with 19 feet you move up to the 20' column, 21' would take you to the 30' column), .5 psig or less and a pressure drop of .3 inches of WC 3/4 inch pipe has a capacity of 190,000 BTU, and the way the code is read in the Commonwealth, the capacity is the smallest pipe on the run. 1" has a capacity of 350,000 BTU

If you have a pressure drop of .5 inches of WC 3/4 inch pipe at 20' has a capacity of 250,000 BTU and 1' would have 465,000 BTU

I realize that not everyone is in Massachusetts, but that would be a failed inspection here.

If you want the charts, let me know, and I can fax them too you.

Chuck Shaw

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marc

this is why there our charts

if the chart says it needs to be 1 in. why argue, did you run 3/4 in. because that is what you had, what if the delivery pressure fluctuates, to many variables, i would pipe it per the charts. marc

Weezbo

really?

codes are codes standards are standards. when the code caaaaatches up with our standards fine.
.....
for me the codes are a Minimum. i piped a nat gas with 1&1/4 to the drip leg "T" from the wall...the pipe available was 1" had i not done so it would not have passed inspection as the supply was on the far end of the building! so ...sight unseen i'd think I'd say "plan for the worse and expect the best". Thats from a piece of my life when building buildings inside buildings to be placed somewhere else.

Darin Cook_3

What do you do?

New house under last phases of construction. Owner has inground pool put in. Decides to build pool house. He will house all pool mechanicals in pool house including pool heater. Then decides to install natural gas generator to provide electricity during a power outage. He has not picked out generator, does not know how much gas it will use. But due to other circumstances, has to get all underground utilities in right away. What do you do, not knowing all the facts? You run the biggest pipe you can get your hands on.







Darin

STEVEN MARKS

My book says 9 ft of 3/4 is only good for 278,000. Your short.20 ft 1" black is good for 350,000. I think the inspector is correct.

STEVEN MARKS

Is the gas pipe to close to the condener?

Darin Cook_3

What would give you that idea?

The fact that we had to stuff 4ilb's of ^%&%&% in a 2ib area.





Darin

Unknown

Darin, in many cases the

generator will need a dedicated line with higher gas pressure (for natural gas) and a special meter just for the generator.

I would get an estimate on the size of the pool and figure pool heater input from that, oversize will not hurt anything.

I have a calcualtor from Raypak for sizing pool heaters if you want I can send you one.

Weezbo

Darin ...

Go for a locate ... communication,electrical, sewer, gas underground...maybe first...tell owner the reasons to press an organized idea of what he intends to do.check set backs etc or utility corridors ..provide options...

Roy_4

Tim's correct on the Generator piping, depending on the model used, you'II have a "load" surpassing 300mbtuh @ 11" to 15" w.c.

the inspector is correct on the pool heater line btw......

Unknown

It is not a good idea

to put the pool heater in the same building as the filter system. The pool heater is better outside, most pool heater manufacturers prefer outside installs. The chlorine raises cain with the combustion situation on the pool heater.

Unknown

Simple solution for pool heaters

my rule when I was able to make rules with the gas company was minimum 1 1/4" pipe to pool heater, wrapped pipe (corrosion protection), 12" to 18" deep. This was run as a seperate line from the meter. Never had any problems doing it that way. We also had a rule that minimum to heating was 1" pipe.

For LP gas depends on location of the LP tank and if you are using single stage or two stage application.

Roy_4

1 1/4" to pool heater, underground, Tim? downstream plastic though right? We've NEVER been able to bury black iron here........

Weezbo

Jim...Just got news...hes remodeling A Gain!

Yes it is True! his buddy has a new musk ox delux buffalo baster...The only is is This particular outdoor combination lu au brasier pizza oven hambuger grill is not readily available in a market near You Now What?

Unknown

Roy, notice I said that

pipe was wrapped and corrosion protected. If you have never been able to bury black pipe what did you do before plastic? Maybe I am too old.

Some area will not allow plastic underground to outside on property equipment.

Plastic or CSST is the way to go nowdays just make sure you have a tracer wire.

Weezbo

Pex xx

Roy_4

Tim,
I did notice what you wrote. Still, the only guyz legally able to install Black Iron underground were the Gas Utility. If and whenever we HAD TO go underground, we had to but the downstream plastic pipe with the prebent galvanized riser's and tracer wire from the same utility. Now, we buy CSST or downstream plastic from the wholesalers.
(I did sneak the odd short piece of copper for the odd BBQ now and then) (g) Union Gas owned by Duke Energy