I have a propane meter question

[Cy4ka]

I have a question about the propane meter pipe everyone is using for their combustion cannons. I am making my first advanced type cannon and would like to meter propane. I am already familiar with the process and the math but from what I've seen at that burtlatke sight, they calculate your meter pipe for you and I need to know if they use measurements from the actual nominal diamter of the meter pipe or if they are speaking in usual/general terms... because a 3/8" pipe is actually 1/2" inner diameter and a 1/2" pipe is actually about 5/8" diameter.

If I calucate using their tool and I use what they call a 3/8" pipe for my meter, I would actually be using a 1/2" for volume.

Do you all know what I'm saying?

[mark.f]

They use actual inner diameters for those calculations. So if you chose, say, 1/2" SCH-40, the calculator would be using 0.625" for inner diameter (or thereabouts).

[Cy4ka]

No not sch40 PVC I mean for the meter pipes. The gas pipe nipples and appropriate fittings. A 1/2" gas pipe or galvanized steel pipe is actually 5/8" about. Allot of people I've seen using 3/8" gas pipe nipples and fittings those have an actual nominal diameter of 1/2" though. So the calculator is either adjusting for that or they want you to use the actual inner diamters, I don't know.

[jrrdw]

No not sch40 PVC I mean for the meter pipes.

You can build your meter from any type pipe. It should be pressure rated. All ways use inside diameter for sizing pipe. There are good 'how to's' here at Spudfiles on meter building that use PVC.

[mark.f]

No not sch40 PVC I mean for the meter pipes. The gas pipe nipples and appropriate fittings. A 1/2" gas pipe or galvanized steel pipe is actually 5/8" about. Allot of people I've seen using 3/8" gas pipe nipples and fittings those have an actual nominal diameter of 1/2" though. So the calculator is either adjusting for that or they want you to use the actual inner diamters, I don't know.

Steel pipes are still measured by schedule. Galvanized or black nipples bought at most hardware stores are SCH-40. So 'gas' pipes have the same inner diameter of SCH-40 PVC pipes with the same nominal size.

(By the way, 'nominal' size refers to the marked size, 1/4", 3/8", 1/2", 3/4", etc. The actual inside and outer diameters aren't the nominal size.)

Take a look here for pipe sizes.

[Cy4ka]

Ok. So if I used 3/8 pipe I should use the calculator for 1/2" pipe.

[mark.f]

If you used 3/8" pipe, choose 3/8" pipe in the calculator (on burntlatke).

That simple.

[Cy4ka]

Lol, ok thanks.