PVC Airline Safety.........

1FATGMC · February 08, 2009, 12:50:44 AM

Anytime this topic comes up there is a lot of debate over the use of them. I'm tired and need to get to bed, but here.........

........ is what I've done about the safety issue.

There are more pictures and a description here........

http://purplesagetradingpost.com/sumner/techinfo/air-line-safety.html

c ya,

Sum

Crosley.In.AZ · February 08, 2009, 11:35:29 AM

This is always a hot topic.

I use PVC for air lines for many years. I have galvanized pipe where air fittings hook up. I use the PVC for the bulk run of the system.

Some folks will say with all the effort you went to with wood covering , the stronger pipe would have saved time and money

Jbird · February 08, 2009, 02:28:39 PM

The only problem I'd have with that setup is, in my advancing age I'd forget there was an airline behind that OSB and then I'd try to screw a hanging hook to it with a one inch screw. Pssssst. I always run my airlines "out of harms way" but sometimes you just can't. I like your idea, there's a couple of spots in my shop that I'll be using it on real soon.
I've only seen one PVC failure and it was caused by the installer pressurizing the system immediately after adding an extension to it. The air pressure pushed apart the glue joint.

enjenjo · February 08, 2009, 04:27:10 PM

Here in the north country, the ones that fail are usually in an unheated building, and they fail when the air is turned on while the pipes are still cold.

1FATGMC · February 08, 2009, 10:27:25 PM

Quote from: "Crosley"This is always a hot topic. .......Some folks will say with all the effort you went to with wood covering , the stronger pipe would have saved time and money

Hey Tony, I'd tell them that "hey I'm retired and that only took about an hour to do and I had the scrap wafer board taking up valuable space in the shop anyway"

c ya,

Sum

wayne petty · February 08, 2009, 10:59:02 PM

decades ago.... back in the late 80s... the shop i worked in down in south central los angeles..(figueroa st south of vernon ave) on a monday morning.. the compressor started... but would not build any pressure... i checked it.. running fine... suction at the air filter ... no pressure.. i turned off the tank outlet valve.. pressure started to build up.. open it... all gone.. must be a huge leak... over on the brick wall of the radiator repair area... the plastic line was not just broken .. but shattered... sitting next to it was a smashed bullet.. a stray shot had shattered the plastic.. drive by shootings were an everyday thing in that area...

did you use schedule 40 or 80 abs

slocrow · February 09, 2009, 08:11:37 AM

Just a thought; With air hose so cheap at the large box discounters, why not just string it around the shop. Inexpensive and easy to replace if a blow out happens. What am I missing?

?? Frank

sirstude · February 09, 2009, 08:58:27 AM

Quote from: "slocrow"Just a thought; With air hose so cheap at the large box discounters, why not just string it around the shop. Inexpensive and easy to replace if a blow out happens. What am I missing??? Frank

Neatness

enjenjo · February 09, 2009, 09:47:31 AM

Quote from: "sirstude"
Quote from: "slocrow"Just a thought; With air hose so cheap at the large box discounters, why not just string it around the shop. Inexpensive and easy to replace if a blow out happens. What am I missing??? Frank

Neatness

And the fact that rubber hose is an insulator and holds the heat in the air. This keeps water vapor in the air, until it comes out the end of the hose, where it condenses as crud in your fresh paint.

Mac · February 09, 2009, 10:56:33 AM

Quote from: "enjenjo"
Quote from: "sirstude"
Quote from: "slocrow"Just a thought; With air hose so cheap at the large box discounters, why not just string it around the shop. Inexpensive and easy to replace if a blow out happens. What am I missing??? Frank

Neatness

And the fact that rubber hose is an insulator and holds the heat in the air. This keeps water vapor in the air, until it comes out the end of the hose, where it condenses as crud in your fresh paint.

...and, might I add, the pressure drop with 3/8 hose compared to 3/4 pipe.

Okiedokie · February 09, 2009, 11:23:44 AM

Slocrow, I get where you are coming from. I use my air for tools and tires, not paint. I usually have the hose ran across my shop floor. I have also thought about just running a hose down the back wall to a reel that I could access without having the hose on the floor. Still may do that. Joe

Ohio Blue Tip · February 09, 2009, 11:43:54 AM

Couple of years back my friend Jerry from nothern Michigan had a PVC line explode and it took out windows in the garage door and tore holes in the steel walls. The lines have now been replaced with black pipe. The line that failed was about shoulder height and would have killed, if any one was there at the time. Don't take the chance, spend a little and keep safe. Ex OSHA safety inspector says so!

slocrow · February 09, 2009, 03:15:42 PM

Ken said; "The lines have now been replaced with black pipe."
Well you probably know more about black pipe then I do but isn't that a low pressure deal? You know, 20#s or less. I can't imagine 100#s or so at my house.

Okiedokie said; "tools and tires"
Me too..........but I'm learning here for the future. It appears PVC may be out.

Mac said; "...and, might I add, the pressure drop with 3/8 hose compared to 3/4 pipe."
Without going back to 3/4 size would there be a pressure drop at all?

Enjenjo said; "rubber hose is an insulator and holds the heat in the air. This keeps water vapor in the air, until it comes out the end of the hose"
I'm assuming that the water vapor condenses on the sides of the pipe and is filtered out eventually. Is metal better then PVC at this condensing process? It would seem so but I don't know for sure so I'm asking. And, couldn't I filter the air from a rubber hose if I processed it through a condenser first, if there is such a thing applicable?

sirstude said; Neatness

Neatness counts :b-d:

enjenjo · February 09, 2009, 03:36:55 PM

Black pipe is black iron pipe, good to about 200 psi. or more depending on the size.

As long as the air is hot, the water vapor won't condense, until it comes out of the air line, and the pressure is reduced. So even with a filter, it will get through there. Metal is better than plastic for cooling, plastic is better than rubber. Even with metal pipe it is recommended to have 20 ft before your use point. most big commercial systems have an air chiller to remove the moisture before it gets into the lines. A properly set up air system has a down leg with a drain under each use point.

I have a buddy that had a compressor tank blow up in his shop. 30 by 30 shop. It blew out all the walls, just some of the studs supporting the roof. a 500 lb freezer was thrown clear across the shop, and hit one of his employees, breaking his pelvis, and cripling him permanently.

wayne petty · February 09, 2009, 04:39:52 PM

ok.. lets change this thread a bit... to what to do to not blow up the shop and hurt people... or cars...

here in los angeles the building and safety comes around every year or two and inspects the compressor tanks... and installation... in commercial installations... the have a wire brush... and some shop towels ... they clean and check the welds on the tank for cracks.. not just on the ends... but where the mount for the motor and compressor is... they also check the tags on the pressure relief valves.. make sure they have not been modified.

they examine the outlet pipes.. and verify that it is bolted down solid.. bolting the compressor down is probably a great thing to do... even without it being a requirement in your area..

flexable sections of pipe are available. to separate the compressor from the rigid pipe on the wall... if you are not sand blasting with it.. installing a globe valve will save the air you have for weeks without running the compressor... gate valves and ball valves leak tiny amounts over time.

having enough pressure relief valves on larger compressors is also needed.. i have seen the pressure switch fail... the compressor build up more and more till the 2 relief valves were at full flow and the tank was coming up on max pressure..

at the restoration shop we got a deal on a fire special 5 hp IR.. the shop it came out of had burned down... after i replaced the new motor??? burned out... everything worked just fine... until one day.. when we were using the air a bunch... when the compressor tried to restart it stalled... the centrifical unloader had failed.. so the compressor was trying to start against a full head of pressure.. NOT... it was humming so loud i could hear it across the yard... i ran at full speed to shut it off.. the IR guy came out and replaced the unloader valve that screws into the crank case end cover.. but... it still did it... after i took out the copper sealing gasket.. it worked fine... build up of tolerances is what i figured.. but i bet that compressor burned down the other shop...

water drains and careful alignment of any horizontal runs of pipe so they drain.. away from the compressor... and into the individual runs.. so any time you are going to go vertical after a straight run.. put a tee in with a drain at the bottom... globe valve... bell reducer to go bigger... a nipple that fits that.. another bell reducer that goes to a really small size.. like 1/4" stuff the nipple full of stainless steel choirboy... or roll up some old scotch brite and stuff it in and put the small ended bell reducer on to hold the stuffing in... this makes a muffler so you can drain the shop air without loosing your hearing... leaving the valves open once in a while over night on hot nights... like there will be warm nights soon.. and the system will dry out...