Natural gas pipe sizing

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.

[@theonlybuster]

7yrs later and this is STILL extremely helpful and so very easy to understand. This is the best instructional video I've seen in YT thus far. It just sucks that I had to watch 8 before, finding this. FYI table 402.4(2) in the 2018 book.

[@grayfurnaceman]

Thanks for the support. GFM

[@madcowusa4277]

Just a homeowner redoing my gas pipes to accommodate adding a tankless water heater and high output gas fireplace, but found this really helpful. Oversized everything to 1" and reduced right before appliances. Gas company came out to hook up at meter and said I could have just had them bump up the pressure instead. Whatever, I sleep well at night and no more rusty 40 year old gas pipe hanging from coat hanger wire under the house and which some idiot thought needed insulated with rolled newspapers.

[@madmatt2024]

Thank you so much for this. I had suspected that the builder had drastically undersized the gas piping in my new home and this proves it. There is no way that a system with a 6-8" WC regulator using 1/2" piping with 1/2" drops is suitable for an 85K BTU furnace, water heater, stove, and gas dryer. It's also worth noting that the 2018 edition of NFPA 54 also has foot equivalents for fittings like 90's 45's and T's.

[@diegodelolmo3701]

Old video...but for all of you checking this out. On table the numbers displayed is for CF/hr not BTU's... 1100 BTU equals 1 CF/hr. You must divide the 350,000 BTU's for 1100 to find the CF/hr to use the table. He missed that step and therefore had a size or two larger pipes that he needed. Good luck!

[@jonsaulmon]

Thank you Brother 🙏

[@rwm5518]

Muchas gracias, amigo!

[@josezabanal1073]

You are correct sir

[@Gemini2Two]

Great instruction. My memory has been refreshed. You explained this better than most journeymen plumbers I have worked with. Thank you!

[@00ABBITT00]

My teacher spent roughly 6 minutes trying to explain this process to a room full of 1st year apprentices in preparation for an exam the following day. If it wasn’t for channels like this, I’d never pass a test. Thank you.

[@grayfurnaceman]

Welcome GFM

[@andrewmalone3635]

Thank you!! First time I took my Master Gas fitter exam I failed, it shows you what you got wrong and I got 11/12 on gas pipe sizing because I watched this video a few times!! I appreciate you making this! I passed the Master Gas fitter exam the 2 time I took it!

[@grayfurnaceman]

Congrats GFM

[@nestummutsen5251]

I passed my gas fitter test. Thank you very much this helped me 100 percent to learn pipe sizing

[@grayfurnaceman]

Congrats. GFM

[@hodgknob3545]

This video is more helpful than the time I spent in class, and hopefully it'll help me pass my certification test.

[@grayfurnaceman]

Good luck. GFM

[@jude2242]

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 !

[@rickgiunta5959]

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.

[@nicwalton000]

I was taught the same thing, 48 years ago. You stay in the 70 foot column for all your sizing.

[@generationless6942]

I was taught the same thing 30+ years ago to get my license in Phoenix. Stay with the 70'.

[@tracker1ify]

​@@ozm8642are you talking about for the drops? Or you talking about both branches staying in 70 ft??

[@ozm8642]

@@tracker1ify u measure main run from the meter to the furthest appliance. Then u look in your book and you stay in that column forever. And you go off of those btus to select pipesizes

[@tracker1ify]

@@ozm8642 ya That's what I was talking about

[@christopherscola6790]

so great. thanks much. saved the day. 15 years as a general contractor and i finally learned how to do it with confidence.

[@Elchingon-0710]

Great class, easy to understand and very well and clearly explained, I highly recommend it.

[@jackt6112]

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]

Thanks for the support. GFM

[@ralphwaters8905]

That methodology is a clever and simplified way to get a consistent pressure drop per foot of pipe throughout the system. Once you understand that, it all makes perfect sense.

[@ronpossick]

Probably the best explanation. My instructor 54 yrs ago was not as good.

[@A1luisss_]

10 years later and this is still helpful, thanks.

[@trevorburgess2643]

Thank you so much for your videos! Ive just finished school and am a apprentice now going for my journeyman gas license in a few weeks. Your videos have really helped simplify gas piping compared to school. Thanks again!

[@grayfurnaceman]

Welcome GFM

[@tonybruno9897]

Been plumbing for 20 years. This is how we were taught in our Union. Great Job!

[@chrismorse2096]

Absolutely simplistic and effective overview. Thanks for your advice expertise!

[@alanalvarez5964]

Correct me if I'm wrong, but the sizing chart goes off CFH so for example on the 2nd section where you had 250k btu and you convert to CFH it comes to 228 CFH you could actually use 1".

[@steveowens7966]

Great job explaining in such an easy to understand way 🤜🤛

[@tenzin9563]

one of the best demonstrated and explained

[@grayfurnaceman]

Thanks GFM

[@TheProletariat.]

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?

[@nsboost]

Good stuff. Passed my plumbing masters w/gas a few weeks back. Don’t forget them damn 90s technically add length

[@bnmarshall]

I'm studying for my mechanical license exam. Great video!

[@90FF1]

Was directed to this video by a comment under another on the same topic. "Grayfurnaceman IS the man!" Learned a lot here and found that pipe sizing isn't a guessing game. Does temperature effect flow through an above ground natural gas pipe to an outdoor grill, and is ambient temperature taken into consideration, along with all the other factors, when determining pipe size. Thanks for posting all the educational videos. No telling how much mony you have save folks - not to mention possibly lives too.

[@grayfurnaceman]

This method is a simplified one used by gas fitters and oversizes the pipe size to account for fittings and temp losses. GFM

[@glynnethomas51]

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.

[@mrplumbob]

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

[@mrod72785]

Taking my unlimited mechanical journeyman test tomorrow, needed this for a refresher....THANK YOU!

[@harrismohammad5009]

Thank you for taking time to post such a great video.

[@markywi6098]

Excellent & simplistic instructional! Thank you! Also thank you for not pandering for thumbs up, subscribing, & "hitting the bell notification so the KZbin algorithm can..." make you more $$$$! You got my thumbs up, now to investigate home owner permit requirements (ain't no dummy!).

[@grayfurnaceman]

I understand why some KZbinrs do that, some even doing endorsements during the video. That is just not my way. Thanks for the support. GFM

[@lonestar6821]

Very informative, nicely explained in plain simple language. Thanks 🙏

[@danielallred780]

I have my track pipe cert already, but forgot. Going in to test for my C-21. Thank you very much!

[@duaneroberson7447]

Very thorough explanation on sizing gas piping. Thank you 😊

[@grayfurnaceman]

Welcome GFM

[@yohad81]

Thank you for taking the time to explain how the gas pipe sizing works. I really appreciate it Sir

[@grayfurnaceman]

Merry Christmas GFM

[@mrplumbob]

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]

Robert Easley I will be considering that one for the winter. GFM

[@highrider57]

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!

[@tedk9144]

Thank you for this awesome tutorial. It helped me to calculate my pipe size for an additional pool heater to my existing gas appliances. I calculated that I have sufficient pipe size in my grey pipe to just add PE gas pipe to the end of one of my existing branches, vs. adding a new branch directly at the meter. One question that I am still stuck on is total gas supply being enough for all my appliances. Can anyone lend their expertise in this area? It would be much appreciated. Meter is an American Meter AC-250 that supplies 250k btu total. So American Meter AC-250 (250,000) - Gas Luxaire Furnace (100,000) - Water Tank (45,000) - gas dryer (25,000) - Gas Range (50,000) - New Gas Pool Heater (125,000) puts me well over the 250,000 supplied by the meter (a total of 345,000) in appliances. A couple of things I considered whether I need to have a new meter swapped in for more capacity: When the pool heater is running in warmer months, I won't be simultaneously running the gas furnace, so I'd be "exchanging" the 100,000 furnace use, for a 125000 pool heater and then my meter will allow this delivery (245,000) total when furnace is out. My stove calculation came right from the stoves manual for the burners and they didn't include the oven part of the stove, just the 5 burners at max. Our outdoor grill is propane, so not a factor. Sorry for the long post...wanted to cover every factor. Thanks all.

[@grayfurnaceman]

This issue is one that is best solved by contacting the utility. The meter is their responsibility. GFM

[@joelanzetta9358]

Excellent video, extremely well put together. He made it very easy to understand.

[@bodybuildingking]

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.

[@grayfurnaceman]

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

[@bodybuildingking]

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]

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]

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".

[@adamr8628]

great video.... I'm looking to ADD pipe to the existing system in order to add a garage heater and a manifold for future appliances. So that must be a whole extra calculation. I'm guessing that I could look at each of the calculations for the existing system and look for any surplus BTU's that the existing pipes are capable of moving that are currently being used? And if the existing pipes are close to their maximum BTU carrying capacity, would I need to add my new manifold directly off of the gas meter area?

[@MrPaley-fq7eo]

Boy I needed this!! Many Thanks!!!!!!! You made it so simple even I can understand!!

[@grayfurnaceman]

Welcome GFM

[@adammichalowski5336]

Dussosdksussut

[@fredwild190]

This is clear and concise, but what happens when a drop supplies more than one appliance, for example, a stove and a fireplace burner? How do you calculate the pipe size between the stove and the fireplace? And what happens when it's time to add a drop to an existing system? Would this require a complete recalculation? Thank you.

[@grayfurnaceman]

A single drop for 2 appliances requires the total BTU input of the 2 appliances as if they are one (unless one is A/C and one is a heating appliance), for sizing the common branch size. The branch for the fireplace is sized using the total length of the drop and farthest appliance. GFM

[@awsom70]

Thanks gray furnace man! I guess i have been doing it wrong and actually oversizing since i have been useing the longest length for the sizing of the branches and the drops as well. Thanks for your help.

[@b_rad5678]

Best explanation / detail I've heard.

[@ignaciovasquez3638]

Great video !

[@mikekimble9151]

I was tought this the wrong way and failed my test over it I will get it passed now me and my family thanks you

[@cmalinoski]

Great tutorial,easy to follow. Your video's have helped me thru a lot of topics of concern.Awesome & Thanks !!

[@robertweeks1171]

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.

[@pauldautriel]

How would I find out of what chart to use? The Gas company would know the inlet pressure, pressure drop, and specific gravity ?

[@grayfurnaceman]

I would contact the gas supplier. GFM

[@wisamrabeea4026]

Thank you, Sir. It is the best explanation I ever see.

[@grayfurnaceman]

Welcome GFM

[@walterjohnson1157]

This really helped me understand. Thank you.

[@-stealthy-cricket8209]

Thanks for the info. Greatly appreciated.

[@CliffordEasileyIV]

Broken down so well! Thank you.

[@MrChipBryant]

Thank very much for these videos!!!

[@grayfurnaceman]

Its hard to get across the piping, and I hope this will help. Thanks for the support GFM

[@johngriffith8999]

Will this help me draw a riser diagram for my diy gas line?

[@grayfurnaceman]

@@johngriffith8999 It is meant for determining the correct size piping in accordance with the IFGC. You can use a screen shot for your diagram if this is for code issues. GFM

[@johngriffith8999]

@@grayfurnaceman I'm adding a gas line for a stove, and I hope if I follow this video I can draw my own riser and submit for permit

[@grayfurnaceman]

@@johngriffith8999 You should be able to, if the local code uses the IFGC. GFM

[@grayfurnaceman]

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

[@mikesuml6361]

Can you do one for the Maryland IFGC test

[@grayfurnaceman]

@@mikesuml6361 If the local codes follow the IFGC, this will work. But as I don't know the local codes I can't help. GFM

[@andrewpopescu4485]

Thanks man keep up the great work !

[@mattmas8640]

Question for you. I have 70’ for my furthest distance. However, I want to install a 199,000 tankless water heater. The tankless water heater only has 3/4” connections. Using the chart, 3/4 is not supposed to be utilized even in a branch off of a 1-1/4 just to supply the water heater. The chart would state that I would need a 1” connection to the water heater. How do you get around this to meet code? Do you just reduce down to 3/4” close to the water heater?

[@grayfurnaceman]

You have the answer. The piping you are responsible for does not include the equipment itself. The manufacturer decides for the equipment. GFM

[@Doobie2100]

Excellent video as always!!!

[@barher8930]

It would be necessary to calculate the vent pipe considering the regulators inside the building.

[@PowerFitness84]

You are very good teacher, my teacher is giving me hard time to understand this now I get it well

[@MNicehole]

One hell of a teacher, got it. thank you very much..

[@grayfurnaceman]

Welcome GFM

[@jahjr1989]

Perfect explanation

[@ramchillarege1658]

Very nice. Thank you.

[@chrisgrompson762]

Fyi for better or worse those of you taking the TSSA exam in Ontario, the answers are based on the longest run. You keep the longest run code zone when calculating the shorter run.

[@grayfurnaceman]

Thanks for the support GFM

[@hvac01453]

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]

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

[@stevejazzband]

You made this so simple to understand... Thank you.

[@grayfurnaceman]

Welcome GFM

[@Nudnik1]

In engineering if one doubles inside diameter of a pipe one multiplies exponetially . In some cases 27 times or more gpm when you double the diameter of the flow rate at same psig for non turbulent flow of fluids.

[@Oto_Travel]

Excellent explanation!

[@shaneboyd5766]

Great video helped a lot!!!

[@law626]

Great Video! Thank you for sharing. So easy to understand.

[@grayfurnaceman]

Welcome GFM

[@om4444]

Excellent..I actually got it all.

[@ceecee212]

You can do step by step with him using IRC 2018 Table G2413.4(1) [402.4(2)]

[@flippowill]

great video. you couldn't have explained it better!

[@grayfurnaceman]

Thanks for the support. GFM

[@grayfurnaceman]

Thanks for the support. GFM

[@zombiemason9866]

Thanks man! Now I understand :)

[@DhaSrma]

Very nice 👌 easy to understand Thank you sir

[@grayfurnaceman]

Welcome GFM

[@sam111880]

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]

+sam111880 Utility calculations for gas sizing are controlled by the utilities. I have no idea what they use. GFM

[@harrysack9164]

Hello Great Video. I also have a question asked by my plumbing teacher. It says How many hangers are needed if all pipe is suspended from floor joists. LIST sizes as well. Just wondering if you knew how to figure this out as well. Thanks again

[@1WaySafe]

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.

[@jackpestaner6925]

Excellent, thanks!

[@odhiamboogutu1872]

great thanks for sharing. subscribing to you channel right away.

[@grayfurnaceman]

Welcome GFM

[@rabaimokrani2745]

you have to include the fittings size, the chart for the fitting is available for down load on internet

[@grayfurnaceman]

+Rabai Mokrani The charts used are from the IFGC and fittings do not need to be included. GFM

[@peterv2306]

I believe you have to convert to CFH by dividing your BTU by 1100 before using table.

[@grayfurnaceman]

This video makes the assumption that the BTU value of the gas is 1000BTU per cu ft. GFM

[@joebrewer5885]

Can you explain "Pressure Drop"? Is that something the gas supplier can give you?

[@davekauffman8727]

Just like with plumbing, the goal is to have the same amount of pressure available to every appliance in the event of all of the appliances being used at the same time. The appliances that require more gas draw more pressure, and require larger piping, so that they will not rob other appliances of gas.

[@Talentman18]

Thank you for this!

[@mrdeafman]

Wow grayfurnanceman this is a cool video and added as favorite where i can refer back for information.

[@danny4982]

Great work 👍

[@Captainkleen]

I mainly have 1” pipe from the nipple to the back of the house is 3/4” to outside w shut off valve. If I go to my 13hp 420cc Generator 8’750/7,000 running watts can I run 40 ft of 1/2” hose and run my generator smoothly? I explained this to a NG guy on KZbin and he said from the 1” solid pipe to 18ft of 3/4” pipe to 50 ft of 1/2” pipe I would be giving 34,800 BTU and my generator is 13hp 420cc it would need 28,400 BTU and told me it would work fine. I’m just looking for other options so I don’t waste time and money on wrong sizes. Thanks and if he is right let me know.

[@stevieb031969]

Very good video.Thanks for posting.

[@MrPlumber27]

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 .

[@fahimjamadar2093]

nice video. please give more details on design and fitting used in gas pipeline

[@grayfurnaceman]

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

[@sergioganoza6070]

Thanks for your help Sir!!!

[@grayfurnaceman]

Welcome GFM

[@MJ-iy4fb]

Nice video. Good step by step direction. One question, what does FAG mean?

[@grayfurnaceman]

Forced Air Gas GFM

[@MJ-iy4fb]

@@grayfurnaceman thank you for replying

[@JustinCrediblename]

slow AF but gets the job done. much appreciated for the tutorial. I'll feel much better now.

[@grayfurnaceman]

Thanks for the support. GFM

[@wildoutrudeboy]

Great presentation. Thx.

[@grayfurnaceman]

Welcome GFM

[@elmermt]

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?

[@grayfurnaceman]

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

[@elmermt]

Thank you, Yes I have 2#, am looking for a 6 port manifold, thank you again