New air lines from compressor

[Aram]

Looks like I am getting an 80 gallon, 2-stage big old air compressor with my new shop. It is outside the shop in its own enclosure. Not hooked up to anything at the moment.

Couple questions I have failed to find answers to after searching. What size lines? Is 3/4" sufficient? The shop is 40' across in the long dimension, and the longest run I envision is maybe 30'. 

What do you think of the RapidAir Fastpipe products? I used to be good at sweating copper (years ago though!) but I'm looking at other, easier options as well.

Any recommendations for brands (regulators, filters, hose, etc.) also welcome.

Thanks!

[fixtureman]

We used 3/4 pipe for a shop of 25 people with no problems.  We run DA sanders air guns and blow guns off it

[JosephP]

fixtureman hinted towards the big question:  what are you running off of the compressor.  3/4" will get you a LOT of air.  I use 1" flexible hose to get 185CFM at 125psi from the towable compressor...and I  know some use 3/4" to run a jackhammer.  You won't be getting that much out of an 80 gallon shop compressor.

I'm no engineer, but I'd bet that 38/" - certainly 1/2" will get more than a 1 or 2 person shop will use even for heavy use tools like sanders or grinders.

[Robert Adams]

I like to do a 1/2" pipe loop around the building. Then do your drops off of it. Even flow everywhere due to the loop and its available everywhere. Make slopes to drain pipes that feed off the bottom of the main line. Your hose drops will come off the top of the line then loop straight down to a drain valve. Then pit tees in that to hook your hoses to. 


             This is the best method for high volume and dry air. More fittings and work but if you run high demand airtools its worth it. As i assume you do with that size compressor.

[TDKPE]

Line size depends on required air flow and the pressure in the line.  If it's running 150-175 psi in that trunk line (tank pressure) with regulators at or near the tools, you can use smaller air lines.  A smaller line in a ring, as the previous poster suggested, will also make for reduced flow resistance.

Just like high/low voltage and the corresponding low/high current for a given power delivery.  And British 'ring mains'.  

[pprobus]

If you can afford to go 3/4", go for it, even if you don't need the flow capacity of 3/4" pipe.  The reason is that since air is compressible, unlike water, so its like adding tank capacity to your system which helps reduce the cycling of your compressor.  Granted you are starting out with a nice rig, assuming this is for hobby use and not production, but as mentioned, a loop of 3/4" pipe around the perimeter of the shop and, assuming you don't need the flow capacity of the 3/4" pipe at the outlet, you can make your takeoff's 1/2" and still have good flow capacity at each takeoff.

[EricU]

I am an engineer, but I'm really lazy, so I didn't bother figuring out the head loss when I ran piping.  We use a lot of air, and there was a point in the system where someone had put 1/2" copper. I didn't bother going any bigger.

We have something like the rapid air going to our backup compressor.  It's pretty nice if you can afford it. I saw recently that you can bend it like conduit, that would save some money. The fittings are expensive

[LarryK]

Friend of mine ran Pex 3/4". I worry about that stuff in shops and barns with mice. I'd love to see a video of a mouse getting blasted across a room.

[daddo]

1/2" pipe for a 30'- 40' run is more than sufficient.

[Aram]

Thanks everyone. The shop has been cleared out by the seller, and I finally got to see the lines coming in (I didn't think there were any). A short 1/2" run of copper along one of the walls. I'll have to extend it, but it's a good start.

I don't plan on any major draw or high pressure, but ya never know. I think I can use 1/2" everywhere, but I'll run some numbers (I used to know how to calculate conductance!) to get a rough idea of whether that will choke the system. I doubt it will and hopefully can go 1/2".

If anyone has experience with Fastpipe or Maxline, I'd love to get your feedback.