Compressed Air Network

[Glen Blanchard]

Currently I have a hose running from my air compressor closet into the shop. I'd like to have 4 or 5 air line drops throughout the shop and am looking at the system below. My primary purpose will be to run a brad nailer and just to blow dust off of an object or work surface.

Has anyone tried the RapidAir system? It looks very easy to install and is quite inexpensive. I don't know if it could supply enough air to run pneumatic sanders and such, but my needs are much less demanding than that.

http://www.woodcraft.com/product/208...aster-kit.aspx

[glenn bradley]

Recently picked it up on sale at Rockler. My intended use is the same as yours but, I am no real help as I will not put it in till this weekend. Their site has plenty of info on capacity and air delivery which states (according to the math) that it should more than meet our needs.

[Fred Belknap]

I have the system and give it 4 stars. I got the 3/4" version because I wanted to have enough air to do couple things at ounce. The only problem I had was one of the fittings leaking a little, my fault as the aluminum boxes are easy to mess up the threads. I had to make a tap out of a mpe nipple to clean the threads. I consider it a good investment and in hindsite would go with the smaller version.

edit: Try Amazon for price check as it was cheaper for me.

[John Coloccia]

If ALL you want to do is run a nailer and blow off some dust, then you're fine. I find the theoretical CFM calculator on their site a bit misleading. What you need to know is this, though. If you plug in .375 ID line at 1', you get 195 CFM. At 50' you get 27 CFM. That's what adding line does to your total capacity. Their calculating a theoretical max flow, but when you're running tools or spraying that doesn't tell the entire story. It doesn't show you the dynamics of what happens when you pull the trigger, and then you get a large pressure drop and a slow recovery because of the small diameter line, and that could cause major problems trying to spray, and poor performance with air tools. None of this is an issue with nailers and blow guns.

For example, to get good performance in my paint booth, I usually run about 150 PSI to the booth, and then have other regulators that step down to about 40 or so. I need the pressure to overcome my small air hose because I don't have my shop plumbed with a 5HP compressor like I used to back in California. It's a dramatic difference in performance to go through 50' of tiny air line as opposed to 50' of big pipe.

[Peter Kelly]

You could also run everything out Type L copper plumbing pipe using coil hose where the drops are. Would almost certainly cost less too.

[David Kumm]

although not cheap, if you plan on painting or sanding in the future- and sanding with air is great- look at the tranair AL piping with removable fittings. Makes for a forever installation that can be changed as your needs or plans change. Dave

[Stan Krupowies]

edit: Try Amazon for price check as it was cheaper for me.

Amazon is $99.99 for the same kit

[Bill Petersen]

That seems like a great system but really a lot of overkill just to run some air. Copper would be wonderful but I've worked in several automotive shops that just used schedule 40 PVC and it lasted for years. The trick is to use lots of support and don't have long unsupported runs. It also has the advantage of exceptionally low cost and easy change and repair.

Bill

[John Coloccia]

I'm sorry Bill, but I really have to disagree with running PVC for air pipe. I know people do it for years with no problem, but other people have had it blow up on them with tremendous damage done. Regular PVC is never OK for air. It has nothing to do with supporting it or the pressure involved, and everything to do with cyclic stress causing cracks and catastrophic failure. It's never safe. There is a kind of pipe made from PVC that is OK for air, I believe, but schedule 40 is definitely not it. I just really can't stress enough how dangerous this is, and I'm not talking about theoretical dust collector explosion from static discharge dangerous (i.e. something that has never happened as far as I can tell). I'm talking about happens and is well documented kind of dangerous.

[Peter Kelly]

Agreed. Schedule 40 PVC becomes very brittle over time and in freezing weather. Not a terribly safe option for compressed air.

[Mike Cutler]

It looks like nice stuff. Flexible, adaptable,and removable. Having installed similar products I will tell you that the cutter looks a little cheesy. You may want to consider precutting with something else and trimming with the cutter. Those tube ends will need to be square and deburred for best performance.
John kinda touched on the CFM calculator being a little misleading, and to add to that I would tell you that the internal orifice restrictions of the fittings will be a limiting factor for CFM. Too many and you may drop it way down. A short run with straight fittings at each end would be able to supply most tools. Realize that the tool itself has 1/4" or 3/8" npt pipe fitting, and the internal diameter of that will less than then internal diameter of the tubing.
Flow is equal to the square root of the delta pressure across an orifice restriction. The more fittings the more pressure drops. Limit the fittings, or up size the piping.
Everybody gets hung up on PVC not being suitable for compressed gas systems. Nothing is further from the truth. The PVC used for low pressure DWV in a house system, or electrical conduit, is unsuitable for compressed gasses, but there are many products and systems out there marketed as "PVC" that are entirely suitable, and pressure rated for compressed gasses. The same incomplete info is associated with "black pipe". There is pipe that is black and there is black pipe and CI pipe. They're all different. Once again it is the material spec that needs to be consulted, not the color of the pipe.
Piping schedule is also misleading. Schedule 40 and 80 are just that. Piping schedules. The material composition however will dictate the use, and rating.

You would also be a little hard pressed to install 100' of ASTM B-88, L or K Copper tubing and brass transition adapter fittings for < than the price of that system by the time the first tool got air.

It's a nice system. The manufacturer has done the engineering work for you and designed a product/system with an intrinsic safety limit.

Addy Protocol;
I've been installing and repairing compressed gas system, air, inert and explosive, for almost thirty years in industrial applications.

[Michael W. Clark]

At one time OSHA had only allowed PVC to be used for compressed gasses at an operating pressure at or below 100 psig. Some of our home shop air compressors can go well above this and are certainly at the cusp of this pressure. In addition, OSHA required that any above ground PVC used for compreseed gasses be "encased" such that personnel and property were protected in case of a rupture. Maybe OSHA has revised this, but most of the time I have seen PVC used in industrial applications is for liquids or fume ventilation lines.

Mike, you are correct about the pipe schedules and even flange schedules. They are only schedules, not pressure ratings. I'm not sure cast iron is available in the size range we are discussing. Most pipe you buy from the BORG is SCH 40 threaded steel pipe. Both black and galvanized will work. Galvanized may a little prettier, but they are both the same on the inside. If you go to a plumbing supplier, you may get the steel pipe cheaper. A combination of steel pipe and the RapidAir system may be advantageous to reduce fittings and losses.

Mike

[Larry Edgerton]

I'm sorry Bill, but I really have to disagree with running PVC for air pipe. I know people do it for years with no problem, but other people have had it blow up on them with tremendous damage done. Regular PVC is never OK for air. It has nothing to do with supporting it or the pressure involved, and everything to do with cyclic stress causing cracks and catastrophic failure. It's never safe. There is a kind of pipe made from PVC that is OK for air, I believe, but schedule 40 is definitely not it. I just really can't stress enough how dangerous this is, and I'm not talking about theoretical dust collector explosion from static discharge dangerous (i.e. something that has never happened as far as I can tell). I'm talking about happens and is well documented kind of dangerous.

100% in agreement with this.

Smash a piece of schedule 40 and take a look at what the pieces look like. They look like little knives. Not what I want flying around. Compressed air kills people, it needs to be respected.

Larry