Hello everyone, hoping someone has dealt with a similar situation as mine:

I need to run some gas line to a stove in my house. Based on the gas pipe sizing charts I've found online and the specs of my house (--that is, 7" water column at the meter, 50' longest run, and BTUs needed by the appliance (~55,000)), I'm supposed to run 3/4" pipe off the main 1" line.

But there is already a tee with a 1/2" stub about 5' before the end of the main line (for a dryer that the previous owner never installed)--which is very tempting to use for the stove instead.

I'm wondering:

1. Can I get away with using this 1/2" stub and just continuing with 1/2" line to the stove? Will this really not deliver enough volume to the stove? I only have ~180,000 total BTUs required by the whole house (additional 70,000 for furnace and 45000 for water heater)

2. Will putting a 1/2" x 3/4" reducer on the existing 1/2" stub, and then using the 3/4" as specified (the stove is only ~5 feet off the main line) be a better option? Won't the smaller 1/2" opening off the main line negate the larger 3/4" diameter afterward. My dad and are debating the physics of this...

3. Or is it mandatory that I cut the line and install a 3/4" connection off the main 1" line?

I've worked with black pipe, but it was back when I was an apprentice fitter, and it was all new construction without any situations like this. Some people at the home depot have told me that the 1/2" should be fine with the existing connection off the main line, but I'm skeptical.

Normally I would just go ahead and cut the line, and put in a union with a 3/4" tee off the 1" line, but I am a full-time student, and time and money are very tight for me right now. Also, these will be some tight quarters the way the lines are situated in the basement, so the less work the better in this case.

I really appreciate you taking the time to read this. Thanks in advance.

Nick

 

Hi nick

From the info you give I may be able to help some,,

50ft is your farthust appliance.
1" coming in from meter supports 284k btu @50 ft
You have to stay in the 50ft column when doing all other calculations.

284k btu - 170k furnace = 114 k btu left ( Is it 1" to the first appliance then get reduced? )

114k btu - 45k btu HWH = 69k btu left ( somewhere after the first appliance on the line it should of reduced to 3/4 pipe )

If that last tee is 3/4 x 1/2 x 1/2 then you can supply 69k to your stove with 1/2" pipe..

But I have been doing this a long time. Is this a stove and oven? I have never seen a unit @ 55k btu. You must add the oven and all burners.. These are usually in the 100k btu area.

If its just a stove top counter unit then OK.

If its more then 69K you will need to up it to 3/4.

Give us the make and model of stove. If its 3/4 inlet I would say its not 55k btu.. ( Where did you get that the stove needs 3/4 Piping?)

 

Thanks a lot for the response Mike.

I forgot to include the attachment, which is a sketch of the run, but it seems like you understood it clearly from my post.
You are correct, it is a cooktop (Frigidaire Professional 30", five burners) that I'm installing, sorry for the misuse of the term "range".
It seems like I can use 1/2" sch40 then.
One follow-up question--what about csst? It seems like the charts I'm finding online are saying that it's not sufficient according to the 50' maximum length calculation. What do you think about that? It is only 5 feet of 1/2" off the 1" main line to the cooktop. Will this still limit the flow enough to harm the performance of the cooktop?

Thanks again for you help.

 

Charts is .5" wc

Yes 1/2 trac pipe would only carry 44k btu.. You need to change the tee if you use trac pipe and use 3/4"..

Best off hard piping it..

Get your measurments.. The home store will cut and thread pipe for you...

You can run 1/2 " blk pipe to the stove top

 

Lawrosa I'm not saying you're wrong but I'm just curious how you got only 44k btu thru 5' csst? The way we size gas piping here is always a debate between installers, inspector and even the gas company. If I imstalled this in a new house I would use 1/2" csst. I've always thought gas piping is gemerally oversized. In several years I've not once been called back saying there wasn't enough gas to an appliance.

 

When sizing the longest length method you must stay in that column on the gas chart for all other calculations... ( This being 50ft) Thats 44kbtu on the chart for csst... Its 72 k btu for hard pipe 1/2"

 

Right... Maybe... But most people dont have all appliances on at same time. so it will not rear its ugly head.. But code dictates the piping must be able to supply with all appliances on..

Or you get low flames possibly, carbon issues in the burner, then possible CO issues from lack of draft...

Ive been doing longest length method for 35 years... This is the easiest what to do gas calculations...

Longest length video...

https://www.youtube.com/watch?v=rSuRxQSrHCg


**** Remember for all calculations you must stay in the column for what the longest length is.... Period........

 

Im sry wrong chart... csst table one @ 50 ft is 32kbtu...

Most pressures I know in US are .5" wc.. meters...

But my trac pipe app states 45 k btu..... I dont have time to get my charts out...

 

I definitely agree that the longest length method is the safest way to size the system. I just can't totally grasp having to stay in that same 90' column for all runs of pipe. With that said I guess you can't ever run too big of line. Always better to oversize than undersize!

The way I typically pipe the house is install black pipe from the meter to a mechanical room. Build a manifold and pipe csst to each fixture. Csst fittings must be accessible here. If total btu is say 275k and the length of pipe from the meter to that manifold is only 15'. The farthest fixture from the manifold is 45'. I'm not looking at a chart but if 1" black pipe will provide 400k in the 15' column to me that says at the point if the manifold 400k btu is availabe. If you size the black pipe for 60' then you must run 1 1/4". According to the longest length method it doesn't matter if the farthest fixture is a 16k btu fireplace or a 120k btu furnace. Why can't you size each individual csst run on it's own length on the chart and the black pipe on its actual length? Like I said the longest length method is no chance of undersizing but seems to me adds extra cost and hassle. I hope this makes some sense. Im typing from an iphone and it sucks

 

no SD.. Even when running a manifold system you must stay in the charts longest length method.. 60 ft blk pipe @ 275kbtu = 1 1/4 black pipe to manifold.. ( even though its only 15 ft of blk pipe.) Like any gas plumbing equation its the total developed length from meter to farthest appliance...

Then from manifold you stay in 60 ft column on the csst charts... Then its easy as you size to load of each csst run..

60ft csst= 1/2 41kbtu 3/4 = 102kbtu 1" = 174 k btu..

I think you can go to trac pipes website and confirm what I say...

 

Counter strike application guide.. ( And dont forget to bond it)

http://www.tracpipe.com/Customer-Con...AutoSnapdf.pdf

But aside from the longest run from the manifold yes you can size each individual appliance on length from meter in the charts..

example

So if there is an appliance that is say 15ft of your black pipe then another 15 ft from the manifold thats 30ft. So use the trac pipe 30ft column on the chart..

But like I said one of those csst runs will be piped on your longest length of 60ft as you descibe..

I mis quoted somewhat below..

 

Also to perform your job better I urge everyone to down load the trac pipe app..

I only use trac pipe as it supplys more volume over other types of csst..

http://www.tracpipe.com/Customer-Con...mobile_app.pdf

 

I see what you are saying now lawrosa. I've never heard of the trac pipe brand. I doubt any if our area suppliers carry it. We primarily use wardflex.

 

Not sure how the ward flex seals.. Looks like some type compression fittings..

http://1nud9a2j8wrb2t7d2f2s9k98.wpen...2015_FINAL.pdf

Trac pipe is a self flaring with a split ring. The nut pulls the last corrugated rind to a flare nose end to self flare..

Your brand piping is piped longest length method the same as my brand.. See page 25 in the above link...

Its confusing because they show all the appliances at the same distance, but the HWH.. But piped the same as I descibed in previous post