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.

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!

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 !

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

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.

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

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

10 years later and this is still helpful, thanks.

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!

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

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

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

Best explanation / detail I've heard.

Thanks for the support GFM

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

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

Thanks for the support. GFM

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.

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

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

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.

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.

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

one of the best demonstrated and explained

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

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!

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

Very thorough explanation on sizing gas piping. Thank you 😊

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.

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

Thanks for thoughts. GFM

Thanks for the info. Greatly appreciated.

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.

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

Broken down so well! Thank you.

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

Excellent video as always!!!

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

Thank very much for these videos!!!

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!

Thanks for your help Sir!!!

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

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

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

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

This really helped me understand. Thank you.

Thank you for making this easy!

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

Excellent explanation!

Very good video.Thanks for posting.

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.

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

Thank you very much sir 💐🙏🏻

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

Glad it helped GFM

Perfect explanation

Thanks man keep up the great work !

Excellent..I actually got it all.

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

Great video helped a lot!!!

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?

Great video !

Thank you for this!

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

Very nice. Thank you.

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

excellent instruction

This is very helpful! 🙂

Excellent, thanks!

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.

Great work 👍

That was great. Thanks!!

great video, thank you very much

Great presentation. Thx.

Thank you, great help

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

Page 36 of the 2015 IFGC

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

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.

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

Great Video Thank You!

Very nice 👌 easy to understand Thank you sir

Thanks man! Now I understand :)

Great video

Thank you very much sir

Thanks. GFM

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.

Thanks, Sr.

you rock mang

Love this video

Excellent

outstanding. thank you.

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".

Excellent thanks …. !

Well at least I understand this now before my midterm tomorrow. XD

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.

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.

When or do you add the fittings to the longest runs? (fittings as in elbows and such)

Thank you

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