Why not to use PVC for the shop

[Ed HD]

So my dad was talking to someone the other day who had run PVC in their shop for their air-lines, and he was trying to talk me into it. I'm vehemently against it, because I don't trust either of us to be able to put it together and not have it explode. Can you guys back me up on this so I can show it to him as to why NOT to use it? I want to go Garage Pak, due to the easy assembly and ability to easily re-configure it as systems and needs change.

 

[bison]

I would use steel piping too,much safer me thinks.

 

[Ed HD]

Well the Garage Pak is actually aluminum pipe with plastic fittings, but it's rated for high-pressure air use, unlike any grade of PVC pipe. My concern with PVC pipe is something (or someone) hitting it whether as a joke, on accident or just unknowingly and causing a big mess and possible injury. There will be more than us in our shop at times, and I don't want anyone getting hurt.

 

[NVW]

I wouldn't use pvc either. I know some do and it may work but as plastic ages it won't just leak, it'll explode. It will also be much closer to it's max pressure than steel pipe.

When we test vessels with air it's usually at 2 1/2 psi to a max of 5 psi (max allowed). Air is like a bomb.

 

[ak diesel driver]

got a friend who used it (pvc) in his industrial shop buildings in southern Utah the heat didn't do it any good at all. I helped him put in black iron. Leo doesn't the pressure depend alot on the volume /size of the vessel?

 

[trouttrooper]

3/4 inch Schedule 80 pvc has a max working pressure of about 480 psi with a burst pressure at about 2200 psi according to one chart I've seen. I certainly wouldn't use schedule 40 from an accidental damage concern. The biggest concern I would have is making sure all connections were "glued" thoroughly.

Having said that I'd still use metal just for peace of mind with threaded connections. Plus like you said, once you've connected pvc you're done. No unscrewing and reusing parts.

 

[NVW]

No Les, with air 5 psi is max, unless things have changed which I doubt. Anything higher and water and or water/glycol is used depending on temps.

I was air testing a 400 bbl tank and had the inspection hatch sealed with a plate and rtv and vise grips. I released the last clamp and wedged a screw driver beneath the plate just after the shop brown noser walked by. The plate dented the overhead metal door and the woosh of air scared the crap out of the guy.:hihi::hihi: Never seen anyone move so fast.

 

[Turbine Doc]

PVC is fine as stated if glued properly, go to the web look up the tables, not generally recommmended as it is fragile in shop environment may burst of hit indavertantly, I use it but don't leave it pressurized when I'm not using air, also if really concerned you could put pipe in pipe making it double walled in event of burst of primary, 2nd wall would protect. Black Iron would be best set & forget option,

 

[chevyCowboy]

iv heard of people using copper, but that seems very expensive. i thought i saw on horsepower tv on time they used some type of plastic that was designed and rated for air use, cant remember any the name of it thought.

 

[88gmctruck]

We have Schedule 40 PVC in dad's garage ran in the ceiling and walls, never had a problem with any of it.

 

[schiker]

http://www.smokstak.com/forum/showthread.php?t=27734

For home use < 125 psi its probably ok within reason but use a ton of common sense and pay attention to all the little things like joints, support, and exposure to sunlight, chemicals, vibration, heat etc.

I don't like that it could get brittle and shatter its really intended for water not air. Air tends to be much more dangerous and stores more potential energy than non compressible fluids. I would use it in walls and ceiling then run drops and transitions to avoid it at eye level or where danger of impact / puncture /stress etc.

 

[btfarm]

I know you would be shut down in a hurry if OSHA walked in and you had employees. I do, however, have it in my shop. Next one will be iron though.

 

[Ed HD]

I've seen what water freezing can do to PVC, and it scares the shit out of me to think that that could happen with 150 PSI plus behind it. We finally got a compressor that can handle air-tools (88 gallon horizontal tank with 2 cyl 2 stage compressor), and I want this to last.

chevyCowboy, From what I've seen the guys on all the powerblock shows use Garage Pak: http://www.garage-pak.com/

 

[schiker]

This is one hard thing about the forums all the details of applications is hard to convey. After I posted to watch out for heat I looked and you are in Collegeville, Minnesota. So yeah freezing is probably just as bad or worse. Then the temp swing from cold to hot is probably fairly rough on a shop air system (more so than plumbing that could only swing to 32F -115-120F ??? ).

 

[Pepperidge]

what about this stuff?

http://www.rapidairproducts.com/store/shopexd.asp?id=323

$249 for 100' kit with 3 outlets


Kit Includes

• 100 Feet Tubing
• 3 Outlet Kits
• 2 Tees
• 1 Male 3/4" NPT Fitting
• 20 Clips
• Bevel and Cutter Tool

• Operating Pressure:
  175psi at 70ºF
  140psi at 140ºF
• - Meets OSHA guidelines
• - Temperature range: -40ºF to 140ºF
• - Compatible with common compressor oils
• - 100 ft and 300 ft rolls
• ½" and ¾" sizes

 

[WarWagon]

'Dad, work in that dangerous PVC air line shop alone and at your own risk. I ain't gonna set foot in it!'

Worked in a small engine shop with the s#it PCV air lines. It was "entertaining" and "exciting" when on mechanic got a lawnmower caught on 'his' PVC air line. We never did find the part of the air line and metal air hose hook up that broke off. The bang and hiss prevented any verbal communication. The shop air was cloudy afterwards. The grass and dirt from his bench was everywhere like a dust storm. Many of his tools were scattered off the bench. And no air power till it was fixed.

Only thing worse is a rubber air line failure.

 

[saratoga]

I've got a lot of respect for compressed air, while I don't think the PVC itself is dangerous, hitting it with something hard while it's pressurized would be.

Saw the aftermath of a DA mechanic who used compressed air to push the piston rod out of a bucket cylinder from a big Hitachi excavator instead of using the hydraulic test stand back when I worked for an industrial seal distributor. The approx 2-3/4" dia 4' long hardened chrome steel rod and 4" dia piston went through two concrete block walls and stopped when it hit a steel door frame inside the adjoining business. Hate to think what would have happened if anyone would have been in the way.

 

[dmaxx3500]

we plumbed a 20,000 sq ft bout building shop in ''sch 80'' pvc and never had a problem in 10 years

 

[llewis7249]

Water is not compressible and therefore cannot store energy. Failures may create small flying pieces but they will not travel far. Air/gasses ARE compressible and will store energy. Pipe failure will release the stored energy and can launch deadly shards. OSHA does no allow PVC for pressurized air/gas.

 

[L98TPI]

Water is not compressible and therefore cannot store energy. Failures may create small flying pieces but they will not travel far. Air/gasses ARE compressible and will store energy. Pipe failure will release the stored energy and can launch deadly shards. OSHA does no allow PVC for pressurized air/gas.

The points as I see it.
The issue is the energy stored in the air.
There is no difference in liquid or air as far as causing a burst pipe (other than freezing, air cant).
Plastic shards are light and cant store much energy. (bad outcomes for a failure is limited)
OSHA wont let you use plastic for air but that doesn't apply for most of us.
OSHA is anal about potential issues, likes to make things idiot proof.
Physical damage is the cause of burst plastic air lines, assuming its glued up properly.
Using Schedule 80 instead of the more readily available 40 is strongly suggested as it it very resistant to physical damage.

Using plastic over head for its cost and ease of install with metal drops to the outlets may be a good compromise.