[bluesman2333]

I just noticed the plastic pipe.

[trees]

There has been a lot of discussion on plumbing air lines with Schedule 40 PVC and the consensus is the PVC is not the best way to go. Obviously, I would like nothing better than to put in copper lines, but not at today's prices. Black iron would be good, but I just don't like the stuff. Moist air and black iron equal rust that you can't see. PEC is very popular and easy to use. Pricey, but not as bad as copper. But I don't see a lot of advantage of PEC over Sched 40. I have operated out of a shop with Sched 40 air lines for 16 years with out any failure and it had 175 PSI all the time (except when the compressor could not keep up.

Trees

[oldred]

Trees I respect you very much and I would not want to say anything to hurt your feelings but based on what I know for a fact and have seen personally I would feel I would be doing a dis-service to not speak up on this. If you are running 175 PSI on PVC, regardless of the rating, which means little when dealing with gas pressures, then you are working in an extremely dangerous environment. The fact it has managed to go 16 years without an incident actually increases the dangers and in no way means it has simply proven itself to be adequate. PVC, especially with that much pressure, is very dangerous from the very first day but as time goes by it gets even worse since the plastic gets more brittle and weaker with age. Being a plastic it will degrade over time as the plasticizers evaporate (it is actually a slow evaporation process that leaves the PVC very brittle) and the chemical structure undergoes change the pipe will fail, it is truly not a matter of IF but WHEN. I strongly urge you to replace that piping as soon as possible and because the Copper is too expensive black iron or galvanized is a very good choice. I know there are concerns about rusting, flaking, etc but in all honesty in all the years I have worked with this stuff I have never seen that to be a problem. Please do yourself and those working around you a big favor and consider the very real dangers that are so close at hand.

[trees]

Thanks for the concern, Red. The 15 years was in another shop. My shop is new and if I remember correctly, the PVC is rated for 450 PSI. As a Chemical Engineer (by degree only), I fully understand the continuous chemical reaction taking place in Polymers. I also am aware of the dangers of gas (air) expansion with increased heat. I do bleed down my in line pressure at quitting time and turn the power off before going home. This way I start the day with fairly warm air and don't have it sitting there building pressure as the ambient temp rises. Last, all my lines are in the walls. The regulators are the only thing in the open in the shop area. They could become missles if the PVC threads failed.

Out of all of this, I am aware of the potential risks of PVC, but my informal risk assessment lets me sleep pretty good at night.

Trees

[cobalt327]

OT- I make fireworks and it's a often repeated "fact" that shards of PCV pipe won't show up very well on an X-ray unless the tech is either experienced or at least made aware of it. Newbies always want to make rocket tubes, etc. from PVC pipe, and this is always given as a reason not to use it, and to use cardboard tubing instead.

I don't really buy the whole "won't show up" deal- my thinking is, as long as the densities are different, it should show up fine.

I just hope no one ever has to find out due to an accident w/a compressor line.

[boatbob2]

Hi,you got a helluva deal on that compressor,spend some of the money you saved,and get rid of the pvc airlines,(as EVERYONE) here has said.if you cant afford to go first class,you cant afford to go,and the money you save,will be used in the emergency room (if youre lucky) DUMP THE PVC.

[schnitz]

Guys, can we please steer this thread back onto the topic originally posted? trees is well respected, and has made his decision to use PVC. His shop is built, and he is a big boy. Myself, I do side with NOT using it for the reasons given., but its usage in his shop is ultimately his choice. So, please, no more beating a dead horse.


In a while, Chet.

[bluesman2333]

I understand what you are saying Chet, but I think people genuinely like trees and fear for his safety. THAT is why all the chiming in.

I have seen industrial accidents, one guy killed, none of it pleasant. For me anyway, when I finally noticed the PVC, I felt I had to at least say something.

BACK ON TOPIC:

In another thread, I saw a comment about energy usage vs. cut-out pressure. I suppose a home shop would benefit from turning down the pressure to 110 pounds or so.

[oldred]

Originally Posted by bluesman2333

I suppose a home shop would benefit from turning down the pressure to 110 pounds or so.

Not really, although the compressor would work slightly less to reach cut-off it would store fewer cubic feet of air at the lower pressure which would have the same effect as reducing the size of the tank. This would lead to more start cycles because of the reduced storage and off course extra start-ups will add more wear&tear than the compressor building a bit higher pressure. Actually it is best to just leave everything as it was designed because it should be a fairly close balance for the components that make up the compressor as it came from the factory. In the case of the compressor that is the subject here reducing the cut-off pressure from 135 to 125 will, as already stated, reduce the amount of air stored in the tank causing more run cycles in any given work period but slightly less effort to reach shut-off pressure. In this case the differences will be slight and should be about a trade off.

[deadbodyman]

I've seen pvc in many shops and I've been around when theve let loose,heres my low buck solution: use 3/4 pvc to run the lines,then use 2" pvc split in half with a bandsaw,use these halfs as covers to keep shrapnel at bay "WHEN" (not if) let loose.My lines blow around three times ayear and the shields do work,I use drywall screws and straps to remove the shields easily,for me its the way to go,no time to lay pipe,pvc's quick,ez,cheap,now safe

[oldred]

Why on Earth would you use PVC in the first place? This has been discussed to death and PVC is a loser any way you look at it. When you say "let loose" are you talking rupture? That stuff will throw razor sharp shards that can maim or kill you (they will not show up on an X-ray!) and depending on home made guards for protection is a little like playing Russian roulette. If you are having problems with the pipe bursting then there simply is no excuse at all for using it not even for economical reasons if you are having to replace it periodically. Even if you don't get hurt the stuff is total crap from a practical use standpoint because of the fact it will contribute greatly to moisture in the air lines because of it's inability to efficiently transfer heat thus keeping the moisture from the compressor in a vapor state until it reaches the hose/tools. PVC should NEVER even be considered for air lines because it is very dangerous and probably about the worst choice you could make for dry air, in fact it is the worst choice period for many reasons.

[bluesman2333]

In my mind, anything that has the potential to fail at the least opportune time when I am counting on it to work right the most, it has no place in my life. I absolutely have to have reliability.

[deadbodyman]

Originally Posted by oldred

Why on Earth would you use PVC in the first place? This has been discussed to death and PVC is a loser any way you look at it. When you say "let loose" are you talking rupture? That stuff will throw razor sharp shards that can maim or kill you (they will not show up on an X-ray!) and depending on home made guards for protection is a little like playing Russian roulette. If you are having problems with the pipe bursting then there simply is no excuse at all for using it not even for economical reasons if you are having to replace it periodically. Even if you don't get hurt the stuff is total crap from a practical use standpoint because of the fact it will contribute greatly to moisture in the air lines because of it's inability to efficiently transfer heat thus keeping the moisture from the compressor in a vapor state until it reaches the hose/tools. PVC should NEVER even be considered for air lines because it is very dangerous and probably about the worst choice you could make for dry air, in fact it is the worst choice period for many reasons.

like I said cheap quick ,ez to fix,it would take days to run pipe and take speciaized tools,very expensive,All the shops Ive worked in had it too,covers make it pretty safe too. How much would It cost to run pipe and how long would it take? Just curious....
,,

[timothale]

Have you been to the emergency room lately,? $ 1000 for 2 hours. We did a commercial remodel, and revised the Air system. I got about 500 ft of copper pipe fron 2 inch down to 1/2 inch from the boss for half of what he would have got from recycling it. He didn' have to hassle taking it in and spend 2 hours driving, unloading, etc. and a lot of air fitting and valves included. If you can find a commercial plumber friend and can wait for a while it can be cheaply done. I got paid $ 50 to take out a 4 ft X 4 ft southworth lift table , and paid the guy with a forklift in the next building $ 10 to load it on my trailer. Pvc is ok underground when it is covered with 18 inches of dirt. but not when exposed. We ran metal risers up out of the ground.

[oldred]

Originally Posted by deadbodyman

like I said cheap quick ,ez to fix,it would take days to run pipe and take speciaized tools,very expensive,All the shops Ive worked in had it too,covers make it pretty safe too. How much would It cost to run pipe and how long would it take? Just curious....
,,

PVC is not all THAT much cheaper that iron, you are talking just a few dollars here, and certainly not at all if you have to re-do it periodically, neither cheaper nor quicker. Besides it still has the moisture problem in addition to being dangerous so there is no real reason to use PVC and a heck of a lot of good reasons not to! I am not sure what it costs these days since I have been out of the business for a few years now but I have seen (and replaced) enough PVC and it's associated problems to know it is a bad deal any way you look at it. The few dollars you save now will cost you in the near future and if you are not careful it could cost you dearly!