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Natural gas pipe sizing

1120 ratings | 292259 views
This one covers wrought iron pipe sizing for natural gas systems. This method is the branch length method (402.4.2) and conforms to the IFGC 2009 code book. The charts are the same in the 2012 code book, just different page numbers.
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Text Comments (223)
Kelly Anderson (2 days ago)
Question on gas pressure. Probably not the most appropriate video to comment on. I had an issue with about a 40 year old furnace (NG). The property originally had this one furnace and a gas meter set at 7"WC. About 15' of 1" pipe to the Mechanical area and the Tee'd a d reduced to 1/2" to go to the 77,000 btu furnace and 30,000 btu water heater. An additional added a new kitchen with gas stove. Followed by a third addition which added a second 60,000 btu furnace. I was called to look at the original furnace because at beginning of this heating season the owner found it to light but then would shut off moments later. I determined the controls to all be working correctly and checked the inlet gas pressure and found it to have about 7-8"WC without the furnace running and would drop to about 6 while it was in operation. Within 30 seconds of flame you could visually notice the flame fizzle out and then the gas valve would shut off at a flame fail. The furnace spec indicated a minimum of 4.5"wc and max of 10.5. Manifold spec was 3.5. My testing of gas pressure always showed gas pressure within range on inlet and manifold sides. I checked the orifice and burners yet come to the conclusion that the gas valve must be faulty. Instead of replacing the gas valve the owner just wanted to replace the furnace being it was as old as it was and this being a rental property. I put new furnace in and found it to do the exact same thing as the original one.. gas pressures all read within spec. Manometer was zeroed out numerous times as I did when checking the original to be absolute certain I was getting the most accurate reading of gas pressure. I went as far as turning the gas off to the other furnace and water heater..But each time the gas pressure was and remained in range yet still the furnace flame would fizzle out and the go out on flame fail. I'm using a new UEI two port manometer. Is it possible that this just isn't picking up a drop in gas pressure fast enough? All I can figure is that there simply isn't enough pressure being the meter is only set to 7"WC and there just simply isn't the volume available. Even though I don't have the readings of too low of gas pressure at the furnace to support that.... ????? ... plus doesn't explain why there hasn't been any issues up until now.. the 2nd furnace operates just fine. Right now the plan is to have the gas company replace the meter with a 2 psi and we step it down right at the furnaces and water heater as well as replacing some of the old blue pipe. Curious if you have ever encountered this?
Tony Bruno (11 days ago)
Been plumbing for 20 years. This is how we were taught in our Union. Great Job!
A R (24 days ago)
This is way too broken down. If you figure out 65 feet instead of 70 you’re good to go. Then you can just branch off. 1 1/4” for 65 feet then 1/2”, 1/2” and 3/4”. 1” on the other leg with 1/2” and 1/2” branches. This was waaaaaay too drawn out.
grayfurnaceman (24 days ago)
This is a video backed up by the IFGC. We do it this way because it is code. You could or could not be right, but I am not going to do it that way and then have to explain how I did not follow policy. GFM
Matt Ridzon (1 month ago)
The IFGC table lists "Capacity in Cubic Feet of Gas Per Hour." It doesn't say, "BTU/hr." Is it inferred that 1000 BTU/hr = 1 cubic foot gas per hour? Is that how you correlate BTUs to Cubic Feet of Gas?
Armando Najarro (15 days ago)
Here is the heat content for Natural Gas: https://www.eia.gov/dnav/ng/ng_cons_heat_a_EPG0_VGTH_btucf_a.htm If gets below 1000 they have other combustible gases.
grayfurnaceman (1 month ago)
Unless your local gas suppliers gives you different numbers, yes. GFM
Matt Ridzon (1 month ago)
+grayfurnaceman My apologies, but it's still not clear to me. As an example, look at 30' length for 1/2" pipe. The chart publishes 95 Cubic Feet Capacity of Gas Per Hour. Using the logic in your demonstration, that correlates to 95000 BTU's. It's not clear to me how you are making that correlation. Is it standard convention that 1 cubic foot of gas per hour equals 1000 BTU?
grayfurnaceman (1 month ago)
I am correlating to 100 BTU. If your numbers are different, you must adjust. GFM
MNicehole (1 month ago)
One hell of a teacher, got it. thank you very much..
grayfurnaceman (1 month ago)
Welcome GFM
Lawrence Tang (1 month ago)
Great Video! Thank you for sharing. So easy to understand.
grayfurnaceman (1 month ago)
Welcome GFM
RAHUL GOSWAMI (1 month ago)
Thank you very much sir 💐🙏🏻
Muzzio Tallini (2 months ago)
Is there a chart for plastic gas main?
Johnson videos (2 months ago)
when the end of times comes and theres no more teachers or school and cavemen must learn again this video is how they will do it
SendEveryone (1 month ago)
At the end of times, the Aliens will come back and take care of everything. http://wanna-joke.com/wp-content/uploads/2013/07/funny-gif-dogs-aliens.gif
David Williams (2 months ago)
Is it the input btu’s you use? Does every appliance need a drip leg?
grayfurnaceman (2 months ago)
Yes on both. GFM
christopher scola (2 months ago)
so great. thanks much. saved the day. 15 years as a general contractor and i finally learned how to do it with confidence.
Steven Shelton (3 months ago)
Great job i passed
Wisam Rabeea (4 months ago)
Thank you, Sir. It is the best explanation I ever see.
grayfurnaceman (4 months ago)
Welcome GFM
Avery Alexander (4 months ago)
I have a question- What happens if you size the pipes incorrectly? I presume that if the pipes are too small the appliances won't work correctly, but too big is okay. Am I correct? Thanks.
mad as hell canadian (1 month ago)
No thats not right bigger is not better, appliance will run inefficient
Avery Alexander (4 months ago)
That's what I thought. Thanks for confirming.
grayfurnaceman (4 months ago)
This is a minimum sizing system. Bigger is better. GFM
Manuel Manjarrez (9 months ago)
Great video! Could you make a video of combustion air sizing as well? Thanks
grayfurnaceman (9 months ago)
That one is in the works. GFM
Justin Crediblename (10 months ago)
slow AF but gets the job done. much appreciated for the tutorial. I'll feel much better now.
grayfurnaceman (10 months ago)
Thanks for the support. GFM
scseagle (11 months ago)
This is a great video! Do the specs define the requirements when you have 2 appliances on a single drop on a branch line?
grayfurnaceman (11 months ago)
2 appliances on a single drop are considered as one appliance using the total BTU of both appliances. GFM
After sizing that first 5' pipe at 1-1/4", could I just use that 1-1/4" pipe everywhere else including all the drops? I'm sure the material would cost more, but is there any other reason not to do that?
grayfurnaceman (1 year ago)
No.  You could do that. GFM
Ahmad Faour (1 year ago)
I would stay you have to stick with 70 FT!! but also, what about the fittings?? you should add equivalent length for fittings as part of your total full length to the longest run! sorry but this is not the way it should done
grayfurnaceman (1 year ago)
This method is the accepted method by the IFGC and I taught it for 9 years.  Branches are sized separately.  Consider if you had one branch that was 10 feet long and the other is 150.  It would be a massive oversize on the short branch.  Fittings are accounted for in the method.  This way of sizing is designed for installers that are not engineers.  So it is simplified, and the size is larger than if an engineer sized a system. An engineered plan would include fittings and would probably be sized smaller.   GFM
Ahmad Faour (1 year ago)
I would stay you have to stick with 70 FT!! but also, what about the fittings?? you should add equivalent length for fittings as part of your total full length to the longest run! sorry but this is not the way it should done
venom pen (1 year ago)
gray...I gotta say, the calculations are wrong! after establishing the 70 foot LMR(longest measured run)all pipe sizing, including main and branch lines are based on that LMR. The LMR could potentially change if the table requires you to add fitting loss due to Tees, valves, 90s etc. But from my knowledge, that LMR is king! essentially doing it the way you did, establishes, different LMRs within the actual longest measured run, which is absolutely wrong...sorry Gray!
Steven Shelton (3 months ago)
Stfu
Steven Shelton (3 months ago)
+Daniel Mendoza did you get it
Daniel Mendoza (9 months ago)
Thank you for this reply. I'm reading the coding book right now, and this was actually getting me confused. It's how you just mentioned.
Jack T (1 year ago)
Question: I went to use the tables for .5 in icc.ifgc.2012.pdf and that got me to wonder if the losses for normal Schedule 40 fittings are factored into those tables.
Jack T (1 year ago)
Perfect! Thanks tons!
Jack T (1 year ago)
Perfect! Thank you!
grayfurnaceman (1 year ago)
Yes they are. GFM
Jack T (1 year ago)
Fabulous! You were clear and methodical. The sites I visited prior to this didn't make sense. Now I know the sizes I need to feed my generator.
grayfurnaceman (1 year ago)
Thanks for the support. GFM
Omega Plumbing (1 year ago)
That last drop to the 150,000 is basically (a branch or a drop) you could get away with 3/4inch. Its only 26' thats 30' at 199 CFH. Its technically not traveling 70' Staying in the row of 70 feet technically doesn't make sense. It is the easy method and all your doing is actually up-szing the pipe. Really all you need to do is adequately size the main all the way to the branches or drops. I typically size the main and just use developed length of the drops below its capacity. If a pipe can carry what the chart says regardless if its at the end of a run or close to the meter thats what it can carry. Most important is the main. Also the problem with this method is when your sizing a 2 to 3 million btu project you end up with giant branches that really are are not needed.
Ken Duong (1 year ago)
Thanks ! Long Run Method and Branch Run Method
Ken Duong (1 year ago)
grayfurnaceman Thanks, you are right . There are 2 methods to size the gas pipe. Longest Run Method and Branches Run Method. I got it. But the Branches Run Method use smaller size of pipe
grayfurnaceman (1 year ago)
This method follows the IFGC. It is the longest pipe method. When you have 2 branches, you use the longest pipe in the branch. GFM
Beloved One (1 year ago)
Great, you took 20 minutes to do a couple math problems but GAVE NO REASONING! If you already know how to add, subtract, multiply, and divide this video will only waste your time.
grayfurnaceman (1 year ago)
I am curious about vacuum. The gas pressure is positive pressure. Residential runs 1/4# . The piping size does determine flow at a fixed pressure drop. The pressure drop is usually 1/2# water column. Let me know if I can help further. GFM
Beloved One (1 year ago)
Actually, I was eluding to the REASON for the code. I'm guessing there is a code in place so there isn't too much of a vacuum created. Are there any other factors you know of that might contribute to the reason different pipe sizes are needed? I apologize for the harsh criticism. I spent a lot of time looking for the reason on the internet. Thanks for the reply.
grayfurnaceman (1 year ago)
Ours is not to reason why, ours is to follow the code. We are not engineers. GFM
simple arithmetic (1 year ago)
first off convert BTUs to cubic ft demand per each fixture now size your c f demand by the developed length any questions
Jason bullprey (1 year ago)
In Canada we use the LMR to size both branch and drops. do you know why that is ?
Tripnotyst (1 year ago)
Because Canada's code is superior. There is a reason the Red Seal is internationally recognized.
Fredis Amaya (1 year ago)
because table read cubic feet of gas consumption by hour and you are calculating by btu...
Fredis Amaya (1 year ago)
hi...cubic feet of gas per hour is the same a btu???
grayfurnaceman (1 year ago)
We use 1000BTU to be equal to 1 cu ft in this sizing chart. GFM
MewCat100 (1 year ago)
More than one foot makes it feet.
maynardr6 (1 year ago)
Hand me that 6 feet ladder?
james fields (1 year ago)
Page 36 of the 2015 IFGC
Design4Building (1 year ago)
I did not watch the entire video, but he is doing this wrong. He is reading off a CFH chart not a BTU chart. In order to use this chart, get the total number of btu's and divide by 1100. That will give you CFH So in this case 350,000 / 1100 = 318 cfh
grayfurnaceman (1 year ago)
The video is based on 1000 BTU per cu ft. Your local utility may have different capacities. If you have 1100 BTU per cu ft, you will have to adjust. If you have 900 BTU you will have to adjust. GFM
Romppai's Outdoors (1 year ago)
its like hydro, if you install under ground cable for 200 amp they want 4/0 aluminum, but if hydro do the same work they only install 1/0,, now with gas, the gas company only supply's a 1/2 line from a 2 inch line on the street, 1/2 inch to your home, yet the want you to have an 1-1/2 from your meter into your home, the supply to the home is far from what it can supply to that 1-1/2
lbj6979 (5 months ago)
Depending on your gas utility company! Locally we have some gas mains with 50+ psig and some old systems with 14" WC in the main... our typical house meters supply 7" WC at the meter regulator.
Romppai's Outdoors (1 year ago)
thanks,
grayfurnaceman (1 year ago)
Actually it is not. The gas supplier uses a pressure of about 20#, and you are supplied after the meter 1/4#. GFM
hvac01453 (2 years ago)
Great class, informative too. What is code as far as unions go? Can they be inside the cabinet, or must they be outside the cabinet? I had someone tell me, drip legs, are no longer required, because the gas is so clean, compared to yesteryear. Lets say I’m at the unit and want to drop the pipe size. Does it matter what side I install the gas ball valve on. I mean the smaller size will do just as well as a large one, and be cheaper to boot! What is code about painting and color. What about pipe support distances… I heard high pressure gas pipe was painted “Red” (25PSI) I need DATA!!!!!!!!! FEED ME!!!!!!
grayfurnaceman (2 years ago)
Drip legs are part of the IFGC regs as far as I know. However, the only thing I have ever found in a drip leg was cutting oil and threading chips, so they could do away with them. Use the smaller valve as long as it is not smaller than the input pipe to the appliance. The only color I have seen for gas is yellow. I will be doing more on gas codes. I have just started a series on passing gas codes tests. Hope this helps. GFM
Brian G (2 years ago)
Ignoring material cost for a moment, couldn't you just use 2" everywhere? is there any harm in oversizing?
grayfurnaceman (2 years ago)
You certainly could. No problem. GFM
jude 22 (2 years ago)
GFM you are the man ! I can get my gas masters today thanks to your help sir. I couldn't learn this by just reading the IFGC I tried . Thank you sir !
Mike Vida (2 years ago)
I understand all the different methods you've applied for sizing each pipe. My question is when you go from the iron pipe to the actual applicance, since it's such a short distance do do you drop down to 1/2 that point? For example the furnace I'm installing has a 1/2 inlet.
grayfurnaceman (2 years ago)
You got it. GFM
Mike Vida (2 years ago)
Sorry that was a bad example on my part, lets say the drop leg requires a 3/4" pipe to feed a gas range that is 80k but the range accepts 1/2" pipe. Do i take the 3/4" pipe all the way to the range and then reduce to 1/2"?
grayfurnaceman (2 years ago)
The piping plan should be followed. The drops are calculated in the video. Do not just assume. Just because the inlet is 1/2" does not mean the drop is 1/2" GFM
Htube78 (2 years ago)
Does this method of calculation work also for propane? I know the chart will have to be different ,but just the way u do the calculation for pipe sizing.
Randy Seib (2 years ago)
Htube78
grayfurnaceman (2 years ago)
The calculations are the same GFM
Jesse (2 years ago)
Good pipe sizing tutorial, but what's up with wrought iron pipe? I though it was black steel pipe.
grayfurnaceman (2 years ago)
You got it. GFM
Jesse (2 years ago)
Thanks, so on this wrought iron pipe sizing chart, this would apply to IPS-threaded black galvanized steel, like that of the type commonly found at home depot?
grayfurnaceman (2 years ago)
The black steel pipe you mention is made from wrought iron. Note the is no seam. Hope this helps. GFM
yao (2 years ago)
even go to 1080P, I still can't read the chart. wish you could have enlarge the chart so I can read. but anyhow, it is a good video.
Manuel Smith Jr (2 years ago)
yao ddd
grayfurnaceman (2 years ago)
That was a problem when the video was done. I used the best camera I could get. Using 4K now. GFM
Fred Green (2 years ago)
Well at least I understand this now before my midterm tomorrow. XD
Jose Aguilar (2 years ago)
whats the website called?
grayfurnaceman (2 years ago)
If you mean my website, grayfurnaceman.com GFM
BoomerHQ & BlynKv2 (2 years ago)
When or do you add the fittings to the longest runs? (fittings as in elbows and such)
Fahim Jamadar (2 years ago)
nice video. please give more details on design and fitting used in gas pipeline
grayfurnaceman (2 years ago)
The piping is wrought iron schedule 40 as are the fittings. You can also use copper. The specifications are in the IFGC code book. GFM
N vacaville (2 years ago)
ok
flippowill (2 years ago)
great video. you couldn't have explained it better!
grayfurnaceman (2 years ago)
Thanks for the support. GFM
sam111880 (2 years ago)
Though this is really good to have a chart to calculate pipe sizes for gas if your doing alot construction. I am wondering if there is seperate charts for each type of gas supplied. Though natural gas is probably the only one uses distributively normally
sam111880 (2 years ago)
Nice i wonder if they have a BTU to length of run chart for gas lines for nonresidential building like from natural gas supply company to house appliances or distributing compressors each... These charts seem to work with just buildings and home based piping not the pipelines starting at the natural gas company
grayfurnaceman (2 years ago)
+sam111880 Utility calculations for gas sizing are controlled by the utilities. I have no idea what they use. GFM
Rabai Mokrani (2 years ago)
you have to include the fittings size, the chart for the fitting is available for down load on internet
grayfurnaceman (2 years ago)
+Rabai Mokrani The charts used are from the IFGC and fittings do not need to be included. GFM
Ante Pavelić (2 years ago)
Also what if there is a branch off of a branch?
Ante Pavelić (2 years ago)
So you dont need to account for number of fittings with this method, just the length of pipe? Or did you already factor that into the "length"?
Emily Houle (6 months ago)
In New Brunswick Canada we use the b149-1 code book charts for sizing pipe.. and for low pressure systems anything under 2 PSI they calculate fittings for restriction for up to 20% of your LMR... so the charts have already calculated in low pressure systems for that 20% of restriction of flow.. but if you have an unusual large amount of fittings on low pressure system it’s safe to do your calculations and if they add up to more than 20% of the length of your LMR then you have to start adding in fittings equivalent lengths on low pressure systems.. but on high-pressure systems anything to 2 psi and over you have to do fitting calculations automatically...and the System would be all calculated using the 70 ft code zone to calculate pipe size for the whole system in this video
grayfurnaceman (2 years ago)
+bc454irocz89 I can't say I know. GFM
Ante Pavelić (2 years ago)
+grayfurnaceman how? do they just estimate the avg no. of fittings? wouldn't the fittings effect flow?
grayfurnaceman (2 years ago)
+bc454irocz89 The charts compensate for fittings. GFM
Erin (2 years ago)
How do you find high pressure piping diagram?
Tripnotyst (1 year ago)
lol if you are talking about the G2 as in the Ontario Gasfitter lvl 2 ticket then this is the entirely wrong code book. In Canada the code book used is the B149.1 natural gas and propane installation code and we size using total furthest distance, not the way he demonstrates with this code.
Erin (2 years ago)
Thanks so much.  My boyfriend needs to study it for his G2 exam.  He was having a difficult time with it.
grayfurnaceman (2 years ago)
+Erin Try the IFGC code book. GFM
Scott Rosenkrantz (2 years ago)
Sorry, meant .919
Scott Rosenkrantz (2 years ago)
You forgot one very important step. You are using the cubic foot chart for your capacity. btu/h are always different than cfh. Check with your local gas supplier to find your btu/h per cubic foot of gas. Your sizing is based on 1000 BTUs/hr per cfh. Wouldn't work in any town in my state. No go.
grayfurnaceman (2 years ago)
+Scott Rosenkrantz Thanks for the thoughts. GFM
Scott Rosenkrantz (2 years ago)
+grayfurnaceman In my town it is 919 BTUs per cfh. which is 100,000 BTUs=109 cfh. Your sizing is correct based on ifgc, but you just didn't convert BTUs/h to cfh/h. British thermal units to cubic feet/hour. Other than that you were spot on.
grayfurnaceman (2 years ago)
+Scott Rosenkrantz What is your gas rated? GFM
Chad Jones (2 years ago)
I used the exact same chart you used , I am a master plumber in texas and I was taught a different way , and it works great and easy for me . I am dyslexic . I get the total developed length then go to the furthest fixture and go backwards to the meter . I noticed I up sized every pipe compared to yours . I understand your method completely but I think here in texas they want you to be on the safe side I don't know. I used your method with great ease but came up with smaller pipe sizes . I do think my way is easier to learn and do you just go backwards . instead of forwards .
Angel de la torre coll (2 years ago)
I have applied this method of calculation for other purposes , many years ago : sizing of ducts for exhaust gas smoke for electrical generators , sizing of ducts for ventilation , sizing of pipes for water. But I have a question , According to this code is NOT necessary to include the loss flow generate by accesories , like elbows , valves or tee ? Is that related whit doing the calculation are made by using the BTU ?
grayfurnaceman (2 years ago)
+Angel de la torre coll The plan assumes an average number of 90s. GFM
Carlos Saad (2 years ago)
how do I get this table ??
grayfurnaceman (2 years ago)
+Carlos Saad Check my website grayfurnaceman.com In the piping chapter there is a copy of the IFGC. GFM
WALID ALHADDI (2 years ago)
Love this video
grayfurnaceman (2 years ago)
+DILAW IDDAHLA Welcome GFM
JulianTheOwl (2 years ago)
Why didn't you add more length for turns?
Robert Travaline (3 years ago)
how did you arrive at the .5 Iwc pressure drop ?
Carlos Saad (2 years ago)
+Carlos Saad considered LOSS load average?
Carlos Saad (2 years ago)
+Robert Travaline good question
Syed Ahmed (3 years ago)
Very Nice and Thorough.I am preparing for my gas technician 3 Test in Ontario.I think it will be the same code here. Which other videos I can use for this exam?
Syed Ahmed (1 year ago)
crephotos thanks. yes I did.
Tripnotyst (1 year ago)
Syed I know your comment is 2 years old but this is not the code book used in Canada. Did you get your G3?
grayfurnaceman (3 years ago)
+Syed Ahmed I don't have any right now. GFM
M.C. A. (3 years ago)
Nice video.  How is sizing copper gas pipe different? 
Carlos Saad (2 years ago)
+M.C. A. metals pipe,,,,what kind of metals??? cooper is a metal?
Gemini2Two (3 years ago)
Great instruction. My memory has been refreshed. You explained this better than most journeymen plumbers I have worked with. Thank you!
E. M. Torres (3 years ago)
I have a 2 # system, I have 1" coming out of the meter, then goes in to the 1" manifold, then, 1= 1/2 to gas logs, 1= 1/2 to future use 60' away, 1= 1" for tankless water heater 58' away, 1= 3/4" for generac 15' away, 1= 3/4" for the hydronic system.4' away, 1= 3/4" another tankless water heater 2' away,                            Does my manifold and my main line coming out of the meter does it have to be bigger or not?
E. M. Torres (3 years ago)
Thank you, Yes I have 2#, am looking for a 6 port manifold, thank you again
grayfurnaceman (3 years ago)
+E. M. Torres Are you sure you have 2# gas?  This pressure is reserved for large commercial applications.  If you do have 2# gas you could run all residential appliances you have on 1/2" pipe.  When sizing pipe, you need to know the BTU input of all appliances served.  The type of appliance does not help.  You can find a link to the IFGC under "gas piping" on the grayfurnaceman website.  It gives all the pipe sizing charts. GFM
Thomas Jones (3 years ago)
Thoroughly  represented on PowerPoint and explained.  Helped me comprehend and apply the 2012 IFGC methodology to calculate a rough-in we had to do on a New Orleans, multi-unit structure.  Tom Jones, ColdAirNOW!. Thank you for the time take to prepare this excellent presentation.
Volusia-ev (3 years ago)
A quick question: From the above video, would the pipe coming directly out of the meter need to be at least 1 !4'?  Some videos I've see may have shown a 3/4' pipe exiting the meter for a couple feet and then feeding a larger load pipe. To me this seems wrong.  Thanks in advance.  -Eric
grayfurnaceman (3 years ago)
+Volusia-ev Yes GFM
Volusia-ev (3 years ago)
+grayfurnaceman So from your example in the above video, you would want to see a 1 1/4 meter exit pipe? Just trying to wrap my head around this.  Thanks
grayfurnaceman (3 years ago)
+Volusia-ev Sometimes the meter exit pipe supplied by the gas supplier is smaller that what the piping requires, but that is not something you need to worry about because that is the supplier's problem.   GFM
pop stream (3 years ago)
 Do you know witch chart to use for propane?
grayfurnaceman (3 years ago)
+pop stream The grayfurnaceman site has the IFGC under gas code training.  Propane is on page 54
Ashrafe H (3 years ago)
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Rick Giunta (4 years ago)
I would stay in the 70' column/row for all pipe size calculation. End up with the same the same result. The way I was taught. Using your video to teach a few apprentices.  Thank you for posting this video.
Nic Walton (4 days ago)
I was taught the same thing, 48 years ago. You stay in the 70 foot column for all your sizing.
whommee (4 years ago)
re-read the code,,, the 5 ft pipe off of the meter must be 1 1/2". period, case closed, finished.
grayfurnaceman (4 years ago)
+whommee This piping calculation is done using the 2012 IFGC.  It is also only for wrought iron pipe.  Sometimes local codes will be added but I can't consider that.  The general guidelines for piping are on page 29 and 30 of the IFGC.  Thanks for the thoughts. GFM
frank smith (4 years ago)
@grayfurnaceman hello good sir, I was just wondering do you add 5 foot to your length for each fitting? like a 90 or tee. is that a rule, or is that with propane, or is it for both, or not a rule at all. thank you for your time.. great video
frank smith (4 years ago)
@grayfurnaceman thanks for your quick response good man
grayfurnaceman (4 years ago)
+frank smith The figures are from the the IFGC and they do not include fittings. GFM
james poole (4 years ago)
I live in lapeer mi they recently pipe gas to my house  I have a 1 1/4 service coming in and the pipe to the house is 1 1/4 does it have to remain this or can I down size to 1'' to feed everything..???????????
grayfurnaceman (4 years ago)
+james poole  It depends on the length of pipe and the BTU input of the appliances.  That is why I did the video. GFM
Matt Rodriguez (4 years ago)
Taking my unlimited mechanical journeyman test tomorrow, needed this for a refresher....THANK YOU!
Christopher Willson (4 years ago)
Do you show water sizing?
Christopher Willson (4 years ago)
Yea gas seems easy, but its the sizing of water, especially when looking at the chart,  but I went through the class and received my plumbing license , and it will come back to me, so thanks for your reply.
grayfurnaceman (4 years ago)
+Christopher Willson No, I only have the charts for fuel gas. GFM
Robert Easley (4 years ago)
Great the 2 lb system is popular in our area, We will be watching for your next video to come out this winter. Thanks Again Your Expertise Makes it Easy for Us Dummies
Robert Easley (4 years ago)
Great demo this will definitely help our apprentice who are trying to pass there journeyman test and help the guys in the field in the sizing of small to large size gas systems. Have you ever thought about doing a video of installing and sizing of a 2-lb gas system with regulators to reduce the sizing of black pipe used in large residential homes using several million BTU's. Thanks Your Help is Appreciated
grayfurnaceman (4 years ago)
+Robert Easley I will be considering that one for the winter. GFM
highrider57 (4 years ago)
Good video! Good tutorial ! I needed to have a refresher and this was it! I have several co-workers who can understand how to do it now!
blueice999uk (4 years ago)
Its done differently in Canada as someone else previously explained. Does your calculations change above a certain gas pressure as in Canada. Up to 2 psig fittings such as tees, elbows valves are included in the tables. Above this pressure we have to take in account of the  fittings because it creates resistance. We use tables for equivalent length of a fitting and then prove it against the selected table that it does not go over the longest measured run of the code length. If it does we go to the next longest run in the table.
grayfurnaceman (4 years ago)
The different methods usually end up using mostly the same size of pipe when all is said and done.  The method used here is international code which is not adopted in all jurisdictions. GFM
John Tavares (4 years ago)
How would you find the pressure drop, if it is not already showing?
Robert Kennedy (4 years ago)
Luc Dumouchel (4 years ago)
I really appreciate your explanation.Would it be possible to download the chart? That would be helpful.  Thanks
grayfurnaceman (4 years ago)
The chart comes from the International Fuel Gas Code.  I would get the book. GFM
Joe Meza (4 years ago)
This is all wrong. You do not change total developed lengths when sizing the drops. You stay in the column/row of the total developed length of the furthest gas fixture always. Remember you are sizing the system to be running all the gas fixtures at one time, not individually. if you have a water heater with a 50k btu demand - 1/2" pipe can only feed it up to 100'. If you have a BBQ stub at 125' feet the water heater will need 3/4" pipe because 1/2" pipe can only supply 44k btu's at 125' total developed length.   
Diehard (3 months ago)
He didn't write the code. You should try reading it.
Scott Henderson (8 months ago)
grayfurnaceman , what do I KNOW,just a elementary school kid. Thanks for the video, & channel.
Scott Henderson (8 months ago)
grayfurnaceman , You LACK common sense.
grayfurnaceman (4 years ago)
The method used here is the IFGC "Branch length method".  The sections are sized using the most remote outlet from the point of delivery method.  However, the branch piping (normally called drops) is sized using the most remote outlet of that branch from the point of delivery.  Both ways will pass this code. GFM
Frank A (4 years ago)
I assume if the main exiting the meter will be 1-1/4", then the main entering the meter should be 1-1/4" or larger?
Frank A (4 years ago)
Ok thanks gfm.
grayfurnaceman (4 years ago)
No.  The gas pressure into the meter is higher.  As a service tech, our responsibility ends at the outlet of the meter. GFM
bodybuildingking (4 years ago)
This is a good example and makes perfectly logical sense to me, but up here in Canada we calculate it slightly differently. We still go by the longest measurement and total BTU. But we must then use the longest branch line measurement to size every other branch line appliance coming off that system, and we're not allowed to count those 2 subsections as separate unless they're tied in within 2' of the meter. I think it all boils down to maintaining a proper pressure drop that doesn't exceed 2' w.c. It's amazing how complicated something that seems so simple has gas guys arguing and scratching their heads. Good video.
bodybuildingking (4 years ago)
Our normal chart is 7-14" w.c. with an allowable drop of 1". But we do have another chart for a system under 7" which then demands a pressure drop not any greater then .5. It's kind of tricky since most residential places are pretty well bang on at 7".
grayfurnaceman (4 years ago)
+bodybuildingking I think sometimes you see "regulation creep" in these charts.  Each reviewer ups the the restrictions.  Our pressure drop is .5 in wc. GFM
bodybuildingking (4 years ago)
+grayfurnaceman Whoops. I meant a pressure drop not exceeding 1"w.c., not 2"w.c.. We use the B149 CSA code books up here... Yeah it really can be annoying. For example, we could have a LMR of 70' and have a branch line for a small BTU appliance within 3 feet of the meter and only 2 feet of a branch and STILL have to calculate that appliance by the LMR of 70", which is nuts when we're so close to the regulator.. The majority of guys don't follow these rules to the letter when it really sometimes seems like overkill.
grayfurnaceman (4 years ago)
The text I used is the IFGC.  As is normal, not all jurisdictions use the same source.  And yes, we do seem to argue about this a lot.  Thanks for the thoughts. GFM
Mike Tanguay (4 years ago)
Great vid. There is one thing I can,t seem to understand. When you refer to the chart to look up the BTU, the chart column label is cubic feet per hour. Is btu equal to cubic feet per hour? Thanks
Leon Archer (4 years ago)
The chart is designed for volume of gas. The appliances is calling for so much volume of gas inside of the pipe per length. Get chart is laid out for distance and btus the appliance is calling for. I hope that helped.
grayfurnaceman (4 years ago)
The chart actually calculates cu ft per hr.  If you have a local BTU per cu ft of 1000 BTU as most areas do, its an easy conversion.  If your local BTU are different, you must adjust.
Sean Cohen (4 years ago)
nice video
1WaySafe (4 years ago)
I would like you to  mention things that are not on the chart .  just to point out there are times when this chart  is not able to  be used  and the method  that must be used before it does become useful . Thanks   nice  vid.
Harvey Pool (5 years ago)
Wow grayfurnanceman this is a cool video  and added as favorite where i can refer back for information.
sanjiv rai (5 years ago)
thank you so much giving us vip lesson. Could you do vedio about combi boiler instllaion and maintenace
grayfurnaceman (5 years ago)
Thanks for thoughts. GFM
Robert Weeks (5 years ago)
Thanks for the piping info. You would be shocked at what I've seen under some houses. Who ever installed some of this stuff should be shot, half of it doesn't even pass gas code.Some would take 1/2 inch from the main branch, and that would be it. Makes you wonder how any of their gas appliances work. Thanks again for the info, this always helps especially green horns like me coming up in the trade.
grayfurnaceman (5 years ago)
This one is part of the gas code test prep that I am putting together. It won't cover all codes tests for every area, but will a good general prep. Thanks for the support. GFM
Steven Berry (5 years ago)
Very good video.Thanks for posting.
grayfurnaceman (5 years ago)
It should not. Big is good. However, 4" is a bit big. GFM
mechanicwarrior20 (5 years ago)
I got a question for you, if you really oversized the runs going into a furnace, will this effect the input BTU firing rate or will it make no change? Lets say for example you had a 4 inch pipe reduced down to a 1/2 pipe going into a 88,000 BTU furnace? and the furnace manifold pressure is set at factory specs. And assuming 7" WC going into the furnace.
grayfurnaceman (5 years ago)
Glad it helped GFM
cmalinoski (5 years ago)
Great tutorial,easy to follow. Your video's have helped me thru a lot of topics of concern.Awesome & Thanks !!
grayfurnaceman (5 years ago)
Thanks for the support. GFM
grayfurnaceman (5 years ago)
Yeah, it probably is a bit oversized. Glad I could help. GFM

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