Compressor Regulator Sizing ???

[Gore]

I just purchased a 5hp Speedaire/CH and need to get it set up. The outlet size is 3/4npt, and the compressor has a max psi of 140 (150 safety valve).

I already own a 3/8 regulator that works up to 155psi.

Would this work (well) for a single user garage with mixed duty? (I would run a ball valve and adapt it to match sizing)

 

[jallyn]

Yes, it will safely work because of the pressure rating. That should be fine for one small or medium air tool.

The cross-sectional area of a 3/8" pipe is 1/4th of the cross-sectional area of a 3/4" pipe. So the rated air-flow is also 1/4th. When you ever want to use a large air tool or multiple tools the upgrade to 3/4" will be needed.

 

[Gore]

Ok, thanks. I think it said the regulator could flow something like 30cfm at 90psi...which is more than enough for me right now.

 

[md21722]

It would probably work "ok". Personally I went with a 100 SCFM regulator with 1/2" NPT fittings because some air tools I have like impacts, air ratchets, etc. are rated at 32-37 SCFM.

 

[Gore]

Damn...those are some air hogs.

Isn't silly to justify it by saying that since my compressor only produces 16cfm at 90 that this regulator is sufficient?

 

[md21722]

You may still be starving your tools a little. When the tank is full, the limit to air delivery from the tank is as big as the tank outlet and the piping. For example, 1/2" hose/pipe is generally good for nearly 100 SCFM. So that 100 SCFM potential delivery is cut down to 30 SCFM by the regulator. When the tank runs down and all you're getting is compressor output, you are limited to the 16 SCFM of your compressor pump.

 

[Gore]

I see, thanks.

The regulator is still new in the box, so I may look around for a larger one first.

 

[jallyn]

Another option is installing a 3/4" tee on your compressor, install your 3/8" regulator now, and plug the other port in the 3/4" tee. Use your 3/8" regulator for now. If it always powers your tools fine then you are golden. If down the road you need two tools at a time you could remove the plug from the 3/4" tee and install another 3/8" regulator for a second line with the bonus of being able to regulate the lines at different pressures for different tools. Or you could upgrade to a larger regulator at that time.