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.
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.
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.
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!
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!! 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!
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.
@@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
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
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!
@@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
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.
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".
Not sure were I went wrong but at 8:37 I keep getting 1" for that branch not 1-1/4" like the grayfurnaceman. Can someone explain where i went wrong? I used the Unit of conversion of BTU's to CU/Hr of 1100. Thank you. All the other branches and drops check out except for the branch at 8:37. Thank you!
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
Excellent & simplistic instructional! Thank you! Also thank you for not pandering for thumbs up, subscribing, & "hitting the bell notification so the RUclips algorithm can..." make you more $$$$! You got my thumbs up, now to investigate home owner permit requirements (ain't no dummy!).
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?
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?
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.
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?
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 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.
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.
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.
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
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.
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
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".
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
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 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
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.
What about the small 5” on the right side that come off of the LMR are those the same pipe size? That are measured with the 7”& 26”? I have a test tomorrow to get into a trade. 😮💨
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.
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
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
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.
I have a situation where I need some advice, my fire pit is 240k btu and 60 ft away from gas meter . My plumber installed 1/2” pipe all the way and fire pit is not getting sufficient gas due to smaller gas pipe size and recommend size is 1” for 60ft long . My patio is already built so it’s not possible to replace the pipe all the way and only option is to replace 50’ pipe with 1”and keep rest of the 10’ as 1/2” drop out.Is it going to work provide enough gas for fire pit?
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
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
hi, can i use the existing 1/2" gas line of my water heater for a new tankless? the new tankless requires 3/4" gas line. so can i use a 1/2" to 3/4" reducing coupler on the old 1/2" gas line? will this affect flow to the new tankless going from 1/2" line to 3/4" line? or is it better to take it directly from another gas line that is 3/4". thank you.
With a tankless, you may have to replace the entire piping system depending on the max draw of the heater. Definitely no on the 1/2 to 3/4 reducer. You will need to to do a piping plan using the video referenced. GFM
Question here! My dryer and oven range require 3/4 inch pipe based on the calculations in the video, however they come from the manufacturer with 1/2 inch connector, should I just install 3/4 inch up to the manual shut off then half inch after the shut off to the appliance?
@@grayfurnaceman Thank you sir! Great video and thanks for the response so it sounds like using this method up to the manual shut off valves should be good and just have adapters after the shut off to fit the appliance!
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 RUclips 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.
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.
I have a situation, my new firepit requires 240k and it is 60’ away from meter. The current pipe line is as follows-from gas meter 1” pipe size for 50’ distance and then branch out for 1/2” size for next 10’ distance to fire pit.Does this current pipe system would be good enough for 240k btu firepit?
There is no length of 1/2" pipe that can accommodate 240K in black pipe at 7" wc pressure with .5" pressure drop. The maximum is 172BTU. Even the 1" pipe is at its maximum rating for that appliance alone. As a practical matter, will it work? Maybe, if no other appliance is operating at the time. GFM
grayfurnaceman the poly gas pipe is used and there is only one more appliance is connected that’s of 60k btu and that’s branch out again from 1” to 1/2”
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.
I've got a 300 kBTU gas generator on the exact opposite side my house from the regulator. I'm planning on running a second dedicated line just to the generator tee'd off from right after the regulator. Is there a way to get around using the longest line? I hate for that one appliance 100' away to make me use the 100' column for all my other appliances that are even on an entirely independent branch.
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!!!!!!
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
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
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.
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.
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.
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
This method is designed to account for ells. When this plan is used, the piping is somewhat oversized. Piping plans can be engineered using proper engineering principles including all changes in direction of flow, and the pipe will be generally smaller. This method is for us dummies. GFM
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 ?
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
GFM,drops are sized using the distance from the meter to the gas appliance at the end of the drop ( is this still in the National Fuel Code today ?). The reason why I asked is most of the demonstrations out there today continue to use the longest run to size drops ( your thoughts please ?). I've always use your method which I thought was still the current National Fuel Code method.
I believe my method is the current accepted one. I have heard of the longest run method, but to me it makes no sense. I think those that use it are misinterpreting the instructions. You would be oversizing drops on piping systems that have one very long run for a single appliance. GFM
@@grayfurnaceman , thank you for getting back to me. I came up with the same conclusion as you " they must be interpreting the instructions wrong." The longest run makes perfect sense for the main line ( trunk line), but to use total length to size branch lines makes no sense. Hopefully all is well and the new Tesla is running good. Regards Bob
Great class!...question: All of this is based on minimum size?...I can always go bigger? for instance: if all my branch lines were 1.5" and my drop lines go down in size to feed the appliance it will still be OK?...
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?
@@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?
Here is the heat content for Natural Gas: www.eia.gov/dnav/ng/ng_cons_heat_a_EPG0_VGTH_btucf_a.htm If gets below 1000 they have other combustible gases.
Good video GFM. I'm a homeowner doing a project and looking at the International Code table 402.4(2) which you used in your video. Question I can read the pressure at my gas stubout, but How do I know that mine is "Pressure Drop 0.5 in. w.e. & Specific Gravity 0.60" and not something else which would lead me to use a different table? Thanks GFM.
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.
Thanks for the support.
GFM
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.
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.
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!
Thank you Brother 🙏
Muchas gracias, amigo!
You are correct sir
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.
Welcome
GFM
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!
Congrats
GFM
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 !
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.
I was taught the same thing, 48 years ago. You stay in the 70 foot column for all your sizing.
I was taught the same thing 30+ years ago to get my license in Phoenix. Stay with the 70'.
@@ozm8642are you talking about for the drops? Or you talking about both branches staying in 70 ft??
@@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
@@ozm8642 ya That's what I was talking about
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
Can you do one for the Maryland IFGC test
@@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
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!
Welcome
GFM
I passed my gas fitter test. Thank you very much this helped me 100 percent to learn pipe sizing
Congrats. GFM
This video is more helpful than the time I spent in class, and hopefully it'll help me pass my certification test.
Good luck.
GFM
Great class, easy to understand and very well and clearly explained, I highly recommend it.
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.
Thanks for the support.
GFM
so great. thanks much. saved the day. 15 years as a general contractor and i finally learned how to do it with confidence.
Probably the best explanation. My instructor 54 yrs ago was not as good.
10 years later and this is still helpful, thanks.
Its hard to get across the piping, and I hope this will help. Thanks for the support
GFM
Will this help me draw a riser diagram for my diy gas line?
@@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
@@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
@@johngriffith8999 You should be able to, if the local code uses the IFGC.
GFM
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.
Been plumbing for 20 years. This is how we were taught in our Union. Great Job!
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".
Absolutely simplistic and effective overview. Thanks for your advice expertise!
Not sure were I went wrong but at 8:37 I keep getting 1" for that branch not 1-1/4" like the grayfurnaceman. Can someone explain where i went wrong? I used the Unit of conversion of BTU's to CU/Hr of 1100. Thank you. All the other branches and drops check out except for the branch at 8:37. Thank you!
Great job explaining in such an easy to understand way 🤜🤛
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
Excellent & simplistic instructional! Thank you! Also thank you for not pandering for thumbs up, subscribing, & "hitting the bell notification so the RUclips algorithm can..." make you more $$$$! You got my thumbs up, now to investigate home owner permit requirements (ain't no dummy!).
I understand why some RUclipsrs do that, some even doing endorsements during the video. That is just not my way. Thanks for the support.
GFM
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?
You have the answer. The piping you are responsible for does not include the equipment itself. The manufacturer decides for the equipment.
GFM
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?
How would I find out of what chart to use? The Gas company would know the inlet pressure, pressure drop, and specific gravity ?
I would contact the gas supplier.
GFM
I'm studying for my mechanical license exam. Great video!
Thank you for taking time to post such a great video.
one of the best demonstrated and explained
Thanks
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.
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?
Excellent video, extremely well put together. He made it very easy to understand.
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!
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.
This method is a simplified one used by gas fitters and oversizes the pipe size to account for fittings and temp losses.
GFM
Taking my unlimited mechanical journeyman test tomorrow, needed this for a refresher....THANK YOU!
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 tutorial,easy to follow. Your video's have helped me thru a lot of topics of concern.Awesome & Thanks !!
Very informative, nicely explained in plain simple language. Thanks 🙏
Thank you for taking the time to explain how the gas pipe sizing works. I really appreciate it Sir
Merry Christmas
GFM
Good stuff. Passed my plumbing masters w/gas a few weeks back. Don’t forget them damn 90s technically add length
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.
Boy I needed this!! Many Thanks!!!!!!! You made it so simple even I can understand!!
Welcome
GFM
Dussosdksussut
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.
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
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.
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
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".
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
Robert Easley I will be considering that one for the winter.
GFM
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 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
Thank you, Yes I have 2#, am looking for a 6 port manifold, thank you again
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.
This issue is one that is best solved by contacting the utility. The meter is their responsibility.
GFM
I have my track pipe cert already, but forgot. Going in to test for my C-21. Thank you very much!
What about the small 5” on the right side that come off of the LMR are those the same pipe size? That are measured with the 7”& 26”? I have a test tomorrow to get into a trade. 😮💨
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.
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
Best explanation / detail I've heard.
Very thorough explanation on sizing gas piping. Thank you 😊
Welcome
GFM
Thanks for the support
GFM
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
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
Thank you, Sir. It is the best explanation I ever see.
Welcome
GFM
Can you explain "Pressure Drop"? Is that something the gas supplier can give you?
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.
I have a situation where I need some advice, my fire pit is 240k btu and 60 ft away from gas meter . My plumber installed 1/2” pipe all the way and fire pit is not getting sufficient gas due to smaller gas pipe size and recommend size is 1” for 60ft long . My patio is already built so it’s not possible to replace the pipe all the way and only option is to replace 50’ pipe with 1”and keep rest of the 10’ as 1/2” drop out.Is it going to work provide enough gas for fire pit?
I'm in a similar situation. Did that work for you?
Thanks for the support.
GFM
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
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
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
Volusia-ev Yes
GFM
hi, can i use the existing 1/2" gas line of my water heater for a new tankless? the new tankless requires 3/4" gas line. so can i use a 1/2" to 3/4" reducing coupler on the old 1/2" gas line? will this affect flow to the new tankless going from 1/2" line to 3/4" line? or is it better to take it directly from another gas line that is 3/4". thank you.
With a tankless, you may have to replace the entire piping system depending on the max draw of the heater. Definitely no on the 1/2 to 3/4 reducer. You will need to to do a piping plan using the video referenced.
GFM
You have to size everything again to add the btus a tankless draws
Question here!
My dryer and oven range require 3/4 inch pipe based on the calculations in the video, however they come from the manufacturer with 1/2 inch connector, should I just install 3/4 inch up to the manual shut off then half inch after the shut off to the appliance?
When sizing pipe, you only size up to the appliance. The appliance sizing is done by the manufacturer.
GFM
@@grayfurnaceman Thank you sir! Great video and thanks for the response so it sounds like using this method up to the manual shut off valves should be good and just have adapters after the shut off to fit the appliance!
I do have a question, how I could add the static head of pipe , in multi story building?
There is no static head. It is a sealed system.
GFM
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 RUclips 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.
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.
Thank you! one question, where do I get the pressure drop. the gas co. could not get it to me. Just got 7 w.c. from them.
That would come from the authority having jurisdiction. City or county. If you can't find it, use .5 WC drop.
GFM
In Canada we use the LMR to size both branch and drops. do you know why that is ?
Because Canada's code is superior. There is a reason the Red Seal is internationally recognized.
@@TRUE_GR1T It's been clubbed?
I have a situation, my new firepit requires 240k and it is 60’ away from meter.
The current pipe line is as follows-from gas meter 1” pipe size for 50’ distance and then branch out for 1/2” size for next 10’ distance to fire pit.Does this current pipe system would be good enough for 240k btu firepit?
There is no length of 1/2" pipe that can accommodate 240K in black pipe at 7" wc pressure with .5" pressure drop. The maximum is 172BTU. Even the 1"
pipe is at its maximum rating for that appliance alone. As a practical matter, will it work? Maybe, if no other appliance is operating at the time.
GFM
grayfurnaceman the poly gas pipe is used and there is only one more appliance is connected that’s of 60k btu and that’s branch out again from 1” to 1/2”
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.
This is a minimum sizing system. Bigger is better.
GFM
That's what I thought. Thanks for confirming.
No thats not right bigger is not better, appliance will run inefficient
@@Jeff-hg7nw You are saying that if the gas pipe is bigger than needed, the appliance will run inefficiently? That makes no sense
You mentioned some exercises on your web site but I am not able to find them.
Try this: ruclips.net/video/YiDOn7-NU44/видео.html
GFM
I've got a 300 kBTU gas generator on the exact opposite side my house from the regulator. I'm planning on running a second dedicated line just to the generator tee'd off from right after the regulator. Is there a way to get around using the longest line? I hate for that one appliance 100' away to make me use the 100' column for all my other appliances that are even on an entirely independent branch.
Ah, you answered my question at 12:30. Yes you can. In fact, this reinforces my reasoning for running the generator on its own branch.
Great video !
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!!!!!!
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
Can you make an updated video over polyethylene gas pipe that conforms to the latest IFGC Code book??
I will put it on the list.
GFM
Thanks man!! Awesome video btw
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
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.
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.
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.
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
So the only difference between this method and the longest length method is that he used the different branch lengths?
Hello there, Thanks for sharing! Sir, do you have that table on pdf to download?
No, you will need to screenshot it or you can find the entire code book online.
GFM
How much does an elbows and tees cause the pressure to drop or do I need to worry about them in calculating pipe size?
This sizing system is simplified for technician use, and includes fittings.
GFM
@@grayfurnaceman thank you I figured that was the case.
how are the fittings (bends, elbows, etc..) incorporated in branch length method and longest length method, while sizing the gas pipes?
This method is designed to account for ells.
When this plan is used, the piping is somewhat oversized. Piping plans can be engineered using proper engineering principles including all changes in direction of flow, and the pipe will be generally smaller.
This method is for us dummies.
GFM
How would you find the pressure drop, if it is not already showing?
Where can I find out the inlet pressure pressure drop and specific gravity?
Pressure drop is usually determined by the Authority having jurisdiction (city, county). Specific gravity from gas supplier.
GFM
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 ?
+Angel de la torre coll The plan assumes an average number of 90s.
GFM
It doesn't appear that you converted total BTU to cubic feet of gas which is what the chart is based off of? Any reasons why?
The base is 1000 BTU per cu ft.
GFM
It would be necessary to calculate the vent pipe considering the regulators inside the building.
This really helped me understand. Thank you.
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
+sam111880 Utility calculations for gas sizing are controlled by the utilities. I have no idea what they use.
GFM
GFM,drops are sized using the distance from the meter to the gas appliance at the end of the drop ( is this still in the National Fuel Code today ?). The reason why I asked is most of the demonstrations out there today continue to use the longest run to size drops ( your thoughts please ?). I've always use your method which I thought was still the current National Fuel Code method.
I believe my method is the current accepted one.
I have heard of the longest run method, but to me it makes no sense. I think those that use it are misinterpreting the instructions. You would be oversizing drops on piping systems that have one very long run for a single appliance.
GFM
@@grayfurnaceman , thank you for getting back to me. I came up with the same conclusion as you " they must be interpreting the instructions wrong." The longest run makes perfect sense for the main line ( trunk line), but to use total length to size branch lines makes no sense.
Hopefully all is well and the new Tesla is running good.
Regards Bob
@@boby115 It is, great fun.
GFM
Broken down so well! Thank you.
Thanks for the info.
Greatly appreciated.
How do you find out inlet pressure, pressure drop, and specific gravity?
Its all in IFGC code book which is referenced in this video.
GFM
Thank very much for these videos!!!
Great class!...question: All of this is based on minimum size?...I can always go bigger? for instance: if all my branch lines were 1.5" and my drop lines go down in size to feed the appliance it will still be OK?...
Bigger is always better.
GFM
@@grayfurnaceman thanks!
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?
I am correlating to 100 BTU. If your numbers are different, you must adjust.
GFM
@@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?
Unless your local gas suppliers gives you different numbers, yes.
GFM
Here is the heat content for Natural Gas: www.eia.gov/dnav/ng/ng_cons_heat_a_EPG0_VGTH_btucf_a.htm
If gets below 1000 they have other combustible gases.
Good video GFM. I'm a homeowner doing a project and looking at the International Code table 402.4(2) which you used in your video.
Question
I can read the pressure at my gas stubout, but How do I know that mine is "Pressure Drop 0.5 in. w.e. &
Specific Gravity 0.60" and not something else which would lead me to use a different table?
Thanks GFM.
The pressure drop is local code. The specific gravity is for all natural gas.
GFM
You are very good teacher, my teacher is giving me hard time to understand this now I get it well
Excellent video as always!!!