Gas Orifice Sizing and Interpolation

[@richarda.valdes1197]

If the oriface is too large you can roll the hole smaller using a steel ball bearing. Also use a expoxy to close the hole to the needed size . Insert the right size drill , coat with oil and allow the drill to stay in the hole as the expoy sets. I live in an area when there are no services available to do this

[@AbdulDanmalan]

Very informative. I've been working on a school project aimed at designing a gas burner. I really would like to know how the orifice size relate to the gas injector size. Any help would be appreciated.

[@tpcevolution1789]

Why do you change two orifice sizes when drilling out the orifice? You didn't explain that in your video? Is it because of the inaccuracy of hand drilling vs machine?

[@MathematicPlumber]

4:39 Drill wobble can ream out the orifice to a larger diameter

[@safa111]

All of good information for someone with no Gas experience, But it was all really organized

[@speedtuff]

Great video. I wish you added the calculation for 1000's of feet over sea level.

[@robertwardi358]

Thank you sir

[@jefforr1362]

Hi.I bought a fire table from Costco the table can be converted to NG but not sure where to buy the orifice. In the manual it says i need a 3.66mm orifice..i would like to just drill it out. What size of bit would i have to use? Thanks

[@MathematicPlumber]

3.25 mm or 1/8" It's not a perfect match, but very close. I recommend reaching out to the manufacturer to see if they have an official kit. Then it will be precise.

[@jefforr1362]

@@MathematicPlumber thank you very much..unfortunately i called the company and after 3 hours on hold and it was my turn yup cut off...if its that close i will just do the 1/8... Thanks again

[@hurricanepowerwash]

I’m trying to convert my outdoor fire place from propane to natural gas. No one seems to be able to help. It’s a single burner 30,000 Btuh fire pit. What combination Regular/Orfic would work?

[@MathematicPlumber]

Orifice gauge# 38 at 3.5 inches water column. As for getting the appropriate orifice and gas regulator, no idea how I can direct you there.

[@martinwoods6716]

Are the orifices equipment specific, or universal..???

[@MathematicPlumber]

In today's appliances, they are very equipment specific. The new burners run with extreme precision, therefore the orifice needs to be exact. In old appliances, (30+ years old) they are very generic and/or universal. But there are still different types. (Mainly to due with the type of treads on it and the internal angle of the orifice hole)

[@joco4488]

How do you apply this to build a grill?

[@MathematicPlumber]

Two part answer: Scenario one, you plan to build the entire grill including building the burners. There is a fair bit of engineering here for the burners alone, so this would take me far beyond my expertise. Scenario two, you plan to install orifices into an existing burner design. At that point you need to find out how many BTUs the burners are rated for (found on the rating plate of the BBQ/Grill) And then you would follow the system as laid out in this video.

[@joco4488]

@@MathematicPlumber thanks for the reply. I'm planning to do it the hard way... LOL, build my own. I considered purchasing one then modify it. But that would limit the size of grill and flat-top surface. Thanks, if I come across numbers I'll pass them along.

[@davequesnel8740]

is gas oricace sizing in the B149 code book? just did my test & there were a few oriface questions, just couldnt find in provided code book, assume I'm not to memorize every oriface size?

[@MathematicPlumber]

Right near the back of the code is table I.3, there she be!

[@davequesnel8740]

excellent thanks, don't think i did well on it, need 70/100, knew about 50% biggest challenge was navigating the code book! i now just about every answer is in there & the index appears not always intuitive, i need to study off an actual code book to get efficient at finding info

[@davequesnel8740]

what's of concern to me while studying, is this table(s) IS NOT listed in the contents, nor does the book have a index at the back,i would have to flip pages forever to find that table without being told where it is! @@MathematicPlumber

[@MathematicPlumber]

@@davequesnel8740 2 years ago I wrote my A-gas Red Seal exam. I found stuff in the code that I have never seen before, and I have spent major time in the code. It's a journey.

[@davequesnel8740]

thanks for everything! serious question: on the "Navigating code book"video, you reference a "Index" i just opened out of plastic the B149,1:20 and there IS NO INDEX (alphabetical directory at the back) is it missing? weirdest thing @@MathematicPlumber