Most shops I have seen use iron pipe for air, but I was just looking at a
couple on-line specs sheets on PVC and it looks like if I were to distribute
air at 125 PSI in my shop using 1" Schedule 40 PVC I would have about a 30%
safety margin at the worst case scenario. That's based on 120F operating
temperature. While yes it does hit 120F here in the desert once in a great
while I don't think its ever gotten above 105 in the shop building. Better
safe than sorry though.

Wadda ya think?

P.S. I have seen other shops use PVC also, and they said they never had any
problems.

The only real issue I see is that "wish this hose was 2 inches longer"
factor. I could probably mitigate that by using brass fittings at the ends
and securing them properly at the wall, and of course the fact that there
would be air all over the shop instead of in one corner would help quite a
lot.

On Mar 10, 12:30*pm, "Bob La Londe" wrote:
Most shops I have seen use iron pipe for air, but I was just looking at a
couple on-line specs sheets on PVC and it looks like if I were to distribute
air at 125 PSI in my shop using 1" Schedule 40 PVC I would have about a 30%
safety margin at the worst case scenario. *That's based on 120F operating
temperature. *While yes it does hit 120F here in the desert once in a great
while I don't think its ever gotten above 105 in the shop building. *Better
safe than sorry though.

Wadda ya think?

P.S. *I have seen other shops use PVC also, and they said they never had any
problems.

The only real issue I see is that "wish this hose was 2 inches longer"
factor. *I could probably mitigate that by using brass fittings at the ends
and securing them properly at the wall, and of course the fact that there
would be air all over the shop instead of in one corner would help quite a
lot.

Not regarded as a good idea.

http://www.osha.gov/dts/hib/hib_data/hib19880520.html

http://www.hotrodders.com/forum/pvc-...es-108824.html

Gets brittle, fractures, plenty of sharp high-velocity shards.


Dave

You cannot use regular Sch. 40 PVC pipe for compressed air, as it is
known to explode. The cracks in it run faster than the speed of sound
in compressed air, therefore the appearance is that your entire pipe
exploded at once.

http://www.google.com/search?q=pvc+p...+air+explosion

i

On 2009-03-10, Bob La Londe wrote:
Most shops I have seen use iron pipe for air, but I was just looking at a
couple on-line specs sheets on PVC and it looks like if I were to distribute
air at 125 PSI in my shop using 1" Schedule 40 PVC I would have about a 30%
safety margin at the worst case scenario. That's based on 120F operating
temperature. While yes it does hit 120F here in the desert once in a great
while I don't think its ever gotten above 105 in the shop building. Better
safe than sorry though.

Wadda ya think?

P.S. I have seen other shops use PVC also, and they said they never had any
problems.

The only real issue I see is that "wish this hose was 2 inches longer"
factor. I could probably mitigate that by using brass fittings at the ends
and securing them properly at the wall, and of course the fact that there
would be air all over the shop instead of in one corner would help quite a
lot.



--
Due to extreme spam originating from Google Groups, and their inattention
to spammers, I and many others block all articles originating
from Google Groups. If you want your postings to be seen by
more readers you will need to find a different means of
posting on Usenet.
http://improve-usenet.org/

"Bob La Londe" wrote in message
...
Most shops I have seen use iron pipe for air, but I was just looking at a
couple on-line specs sheets on PVC and it looks like if I were to
distribute air at 125 PSI in my shop using 1" Schedule 40 PVC I would have
about a 30% safety margin at the worst case scenario. That's based on
120F operating temperature. While yes it does hit 120F here in the desert
once in a great while I don't think its ever gotten above 105 in the shop
building. Better safe than sorry though.

Wadda ya think?

P.S. I have seen other shops use PVC also, and they said they never had
any problems.

I was told this is not safe. So, I used copper tubing. Very easy to add a
drop, just cut and sweat in a "T". Its worked well for 20 years now.

Karl

"Bob La Londe" wrote in message
...
Most shops I have seen use iron pipe for air, but I was just looking at a
couple on-line specs sheets on PVC and it looks like if I were to
distribute air at 125 PSI in my shop using 1" Schedule 40 PVC I would have
about a 30% safety margin at the worst case scenario. That's based on
120F operating temperature. While yes it does hit 120F here in the desert
once in a great while I don't think its ever gotten above 105 in the shop
building. Better safe than sorry though.

Wadda ya think?

P.S. I have seen other shops use PVC also, and they said they never had
any problems.

The only real issue I see is that "wish this hose was 2 inches longer"
factor. I could probably mitigate that by using brass fittings at the
ends and securing them properly at the wall, and of course the fact that
there would be air all over the shop instead of in one corner would help
quite a lot.



it'll work fine...as long as you run the PVC inside steel pipe.

On Mar 10, 12:30*pm, "Bob La Londe" wrote:

P.S. *I have seen other shops use PVC also, and they said they never had any
problems.

I had PVC air pipes for years until the warnings first appeared here.
Then I replaced them with iron near the wood stove and copper
elsewhere, just before the price skyrocketed. Some of the old PVC
pipes fragmented like glass when I tried bending them, others crinkled.

On Tue, 10 Mar 2009 09:30:09 -0700, "Bob La Londe"
wrote:

Most shops I have seen use iron pipe for air, but I was just looking at a
couple on-line specs sheets on PVC and it looks like if I were to distribute
air at 125 PSI in my shop using 1" Schedule 40 PVC I would have about a 30%
safety margin at the worst case scenario. That's based on 120F operating
temperature. While yes it does hit 120F here in the desert once in a great
while I don't think its ever gotten above 105 in the shop building. Better
safe than sorry though.

Wadda ya think?

P.S. I have seen other shops use PVC also, and they said they never had any
problems.

The only real issue I see is that "wish this hose was 2 inches longer"
factor. I could probably mitigate that by using brass fittings at the ends
and securing them properly at the wall, and of course the fact that there
would be air all over the shop instead of in one corner would help quite a
lot.

DO NOT use PVC for compressed air. It is fine untill it fails - and
then it is EXTREMELY DANGEROUS. There is a reason it is NOT ALLOWED by
OSHA etc. It turns into high velocity shrapnel on failure.

On Tue, 10 Mar 2009 09:30:09 -0700, "Bob La Londe"
wrote:

Most shops I have seen use iron pipe for air, but I was just looking at a
couple on-line specs sheets on PVC and it looks like if I were to distribute
air at 125 PSI in my shop using 1" Schedule 40 PVC I would have about a 30%
safety margin at the worst case scenario. That's based on 120F operating
temperature. While yes it does hit 120F here in the desert once in a great
while I don't think its ever gotten above 105 in the shop building. Better
safe than sorry though.

Wadda ya think?

P.S. I have seen other shops use PVC also, and they said they never had any
problems.

The only real issue I see is that "wish this hose was 2 inches longer"
factor. I could probably mitigate that by using brass fittings at the ends
and securing them properly at the wall, and of course the fact that there
would be air all over the shop instead of in one corner would help quite a
lot.


Bob..at least once a year, I get called in to replumb a shop that had
PVC pipe that decayed due to compressor oil, heat etc etc and finally
blew out, often taking entire banks of florescent lights off the
ceiling, blowing **** everywhich way etc.

Im not telling you not to do it. Ive seen some up for as long as 10
yrs with no explosions. But each and every piece Ive taken down had
the structural composition of a grahm cracker. Drop it from 3 feet
and it shatters like glass.

If you put up PVC...every bit has to be firmly secured to something
rigid. After a couple years...putting any strain on it, thumping it,
tapping it, pulling on it..and its gonna break. With luck, no one gets
hurt.

Just my .02USD worth. My own home shop, is salvaged black pipe,
mixed with air hose all running into homemade manifolds with taps for
QDs all over the place. Only in places that I need a LOT of volume,
such as die grinders, DA sanders and so forth, do I use a lot of
pipe.

Black pipe is cheap if you buy it at a wholesale plumbing supply place
such as Ferguson Express etc. I think Im paying $11 for a 20' joint of
black. One of the tricks in doing a shop is to never ever use 90'
elbow. Only use Ts and plug off the unused side. Sooner or later, you
will need to put in another run or valve or line there.

Last year, I ran 3000+ feet of pipe air lines in (2) shops, one being
35,000 sqft, the other being about 10,000 sqft, but in 4 different
units of a "industrial strip mall", and installed 4 screw compressors
and a couple piston pumps total.

Its one of the things I do to make a living..and Im quite qood at it.
Ive turned down jobs where they wanted PVC. I dont want the liability.



Gunner

"Human nature is bad. Good is a human product*
A warped piece of wood must be steamed and forced
before it is made straight; a metal blade must be put to the whetstone
before it becomes sharp. Since the nature of people is bad, to become corrected
they must be taught by teachers and to be orderly they must acquire ritual
and moral principles."
—Sun Tzu
*

In article ,
"Bob La Londe" wrote:

Wadda ya think?

Bad idea.

P.S. I have seen other shops use PVC also, and they said they never had any
problems.


And they'll keep saying that right up until the fragmentation bomb hits.
Then they'll be "shocked, just shocked" to find that this has been a
known dumb idea for *decades*. You can get special (green?) plastic pipe
(Not PVC) rated for air service, but at last look it was more expensive
than regular pipe. Copper or iron can be had any any hardware/building
supply.

http://www.osha.gov/dts/hib/hib_data/hib19880520.html

http://www.lni.wa.gov/Safety/Basics/HazAlerts/902.asp

My personal preference is copper. Costs a fair amount, once. Relatively
clean. Easy to add on to.

The usual litany - slope the lines away from the compressor, and put
drain legs on the bottom of the line. Take air off from the top of the
line (Up over down) and provide additional drain legs at the bottom of
each drop leg, extending well below the air connector. Decouple the
compressor from the piping system with a section of flex, and decouple
the compressor from the tank to reduce one cause of tank fatigue
failure. Plumb your air intake outside.

--
Cats, coffee, chocolate...vices to live by

Bob La Londe wrote:

Wadda ya think?

P.S. I have seen other shops use PVC also, and they said they never had
any problems.

I've been using PVC, schedule 40, for a decade with no problems. I do
however, limit line pressure to 80 psi. Having said that, I am
considering replumbing everything with 3/8 nylon tubing. I'm not going
to the expense of iron or copper unless I manage to score enough to do
the job at scrap prices. Reasons for replumbing is several joints have
developed minor air leaks, as well as the ease of adding lines. My
consumption is not great enough to worry about flow restrictions.
And I happen to have a 100' roll I scored on ebay dirt cheap...

When I finally get into a permanent shop that I own, I'll use copper.

Jon

"Bob La Londe" wrote in message
...
Most shops I have seen use iron pipe for air, but I was just looking at a
couple on-line specs sheets on PVC and it looks like if I were to
distribute air at 125 PSI in my shop using 1" Schedule 40 PVC I would have
about a 30% safety margin at the worst case scenario. That's based on
120F operating temperature. While yes it does hit 120F here in the desert
once in a great while I don't think its ever gotten above 105 in the shop
building. Better safe than sorry though.

Wadda ya think?

P.S. I have seen other shops use PVC also, and they said they never had
any problems.

The only real issue I see is that "wish this hose was 2 inches longer"
factor. I could probably mitigate that by using brass fittings at the
ends and securing them properly at the wall, and of course the fact that
there would be air all over the shop instead of in one corner would help
quite a lot.


I started with PVC years ago, and never had any problem, but that doesn't me
you won't. Most building or mechanical codes forbid it because of the
possible air born chards due to impact damage.

When I added to my shop a couple of years ago, I switched to PEX. I found
that PEX will not shatter even when frozen, and can even be easier to route.
The only down side is the cost of the tool.

On Tue, 10 Mar 2009 12:03:03 -0500, Ignoramus26567
wrote:

You cannot use regular Sch. 40 PVC pipe for compressed air, as it is
known to explode. The cracks in it run faster than the speed of sound
in compressed air, therefore the appearance is that your entire pipe
exploded at once.

http://www.google.com/search?q=pvc+p...+air+explosion
========
Another problem is that in the case of fire, if the pvc pipe
becomes involved, air pressure may convert the pipe into a flame
thrower spewing molten burning plastic if it doesn't explode.

The price difference with black or galvanized iron is not *THAT*
great and most good hardware stores will cut pipe to length and
thread for you. Be sure to include "drip legs" and blow
down/drain valves at frequent intervals to avoid water in the
lines problems.

Good luck, and let the group know how you make out.
Unka' George [George McDuffee]
-------------------------------------------
He that will not apply new remedies,
must expect new evils:
for Time is the greatest innovator: and
if Time, of course, alter things to the worse,
and wisdom and counsel shall not alter them to the better,
what shall be the end?

Francis Bacon (1561-1626), English philosopher, essayist, statesman.
Essays, "Of Innovations" (1597-1625).

"Bob La Londe" wrote in message
...
Most shops I have seen use iron pipe for air, but I was just looking at a
couple on-line specs sheets on PVC and it looks like if I were to
distribute air at 125 PSI in my shop using 1" Schedule 40 PVC I would have
about a 30% safety margin at the worst case scenario. That's based on
120F operating temperature. While yes it does hit 120F here in the desert
once in a great while I don't think its ever gotten above 105 in the shop
building. Better safe than sorry though.

Wadda ya think?

P.S. I have seen other shops use PVC also, and they said they never had
any problems.



Bad idea!
I also have used PVC pipe for air lines, but after seeing the carnage that
ensues when a line fails I tore it all out of my shop. Copper, black pipe,
rubber, are fine, but no to PVC!
Greg

On Mar 10, 9:30*am, "Bob La Londe" wrote:
Most shops I have seen use iron pipe for air, but I was just looking at a
couple on-line specs sheets on PVC and it looks like if I were to distribute
air at 125 PSI in my shop using 1" Schedule 40 PVC I would have about a 30%
safety margin at the worst case scenario. *That's based on 120F operating
temperature. *While yes it does hit 120F here in the desert once in a great
while I don't think its ever gotten above 105 in the shop building. *Better
safe than sorry though.

Wadda ya think?

P.S. *I have seen other shops use PVC also, and they said they never had any
problems.

The only real issue I see is that "wish this hose was 2 inches longer"
factor. *I could probably mitigate that by using brass fittings at the ends
and securing them properly at the wall, and of course the fact that there
would be air all over the shop instead of in one corner would help quite a
lot.

If you use copper or iron pipe you will find you can run your line
pressure up to 160# or above. Even though you may not want
or need the high pressure at your nozzles (etc.) you will find
your compressor will be starting and stopping 1/2 as much or
less which will extend the life of your compressor motor and
starting/running gear.

dennis
in nca

On Tue, 10 Mar 2009 12:56:07 -0600, F. George McDuffee
wrote:

The price difference with black or galvanized iron


If you feel you MUST use galvanized pipe...remember, you are GOING to
get flakes of Galv in your tools.

Its a given. Its pretty much Verbotten to use galvanized pipe with
CNC machiney, along with teflon tape.

Use both at your own risk.

Gunner

"Human nature is bad. Good is a human product*
A warped piece of wood must be steamed and forced
before it is made straight; a metal blade must be put to the whetstone
before it becomes sharp. Since the nature of people is bad, to become corrected
they must be taught by teachers and to be orderly they must acquire ritual
and moral principles."
—Sun Tzu
*

This one gets MY vote!

One of the tricks in doing a shop is to never ever use 90°
elbow. Only use Ts and plug off the unused side. Sooner or later, you
will need to put in another run or valve or line there.


Pete Stanaitis
-----------------------

On Mar 10, 2:28*pm, F. George McDuffee gmcduf...@mcduffee-
associates.us wrote:
On Tue, 10 Mar 2009 12:34:56 -0700, Gunner wrote:

snipIf you feel you MUST use galvanized pipe...remember, you are GOING to
get flakes of Galv in your tools.

Its a given. *Its pretty much Verbotten to use galvanized pipe with
CNC machiney, along with teflon tape.

snip
---------
A good point and another reason to use a filter/regulator/oiler
immediately before your air tool or other equipment and no teflon
tape, etc. on the downstream side.

For an example see:http://www.use-enco.com/CGI/INPDFF?P...Item.do?itemid...
and many others.

Unka' George [George McDuffee]
-------------------------------------------
He that will not apply new remedies,
must expect new evils:
for Time is the greatest innovator: and
if Time, of course, alter things to the worse,
and wisdom and counsel shall not alter them to the better,
what shall be the end?

Francis Bacon (1561-1626), English philosopher, essayist, statesman.
Essays, "Of Innovations" (1597-1625).

"no teflon tape, etc. on the downstream side. "

There's nothing wrong with properly applied teflon tape. It's
when it's applied to the last and next-to-last thread on a
fitting that it becomes a problem. Before I began work-
in in the service department I applied tape to thousands
of fittiings without problem. Others, less attentive to details,
had numerous problems. We were all using the same tape
and fittings so I've concluded application is the key.

dennis
in nca

On Tue, 10 Mar 2009 09:30:09 -0700, "Bob La Londe"
wrote:

Most shops I have seen use iron pipe for air, but I was just looking at a
couple on-line specs sheets on PVC and it looks like if I were to distribute
air at 125 PSI in my shop using 1" Schedule 40 PVC I would have about a 30%
safety margin at the worst case scenario. That's based on 120F operating
temperature. While yes it does hit 120F here in the desert once in a great
while I don't think its ever gotten above 105 in the shop building. Better
safe than sorry though.

Wadda ya think?

P.S. I have seen other shops use PVC also, and they said they never had any
problems.

The only real issue I see is that "wish this hose was 2 inches longer"
factor. I could probably mitigate that by using brass fittings at the ends
and securing them properly at the wall, and of course the fact that there
would be air all over the shop instead of in one corner would help quite a
lot.


I had to replace all the PVC air plumbing in the last shop I worked in
because it started to explode. Made one hell of a mess and lots of
noise. We used a special plastic pipe for air that was really
expensive. No I wonder if maybe PEX would work well.
ERS

On 2009-03-10, rigger wrote:
"no teflon tape, etc. on the downstream side. "

There's nothing wrong with properly applied teflon tape. It's
when it's applied to the last and next-to-last thread on a
fitting that it becomes a problem. Before I began work-
in in the service department I applied tape to thousands
of fittiings without problem. Others, less attentive to details,
had numerous problems. We were all using the same tape
and fittings so I've concluded application is the key.

A sane practice is that for expensive machines that do not tolerate
various particles, to install an air filter right on them. Ergo,
that's what my plasma cutter does.

This is also what the Dumore No. 24 automatic drilling head (for sale)
does.

--
Due to extreme spam originating from Google Groups, and their inattention
to spammers, I and many others block all articles originating
from Google Groups. If you want your postings to be seen by
more readers you will need to find a different means of
posting on Usenet.
http://improve-usenet.org/

On Tue, 10 Mar 2009 12:34:56 -0700, Gunner Asch
wrote:
snip
If you feel you MUST use galvanized pipe...remember, you are GOING to
get flakes of Galv in your tools.

Its a given. Its pretty much Verbotten to use galvanized pipe with
CNC machiney, along with teflon tape.
snip
---------
A good point and another reason to use a filter/regulator/oiler
immediately before your air tool or other equipment and no teflon
tape, etc. on the downstream side.

For an example see:
http://www.use-enco.com/CGI/INPDFF?P...MITEM=801-1110
http://www.harborfreightusa.com/usa/...ateg oryName=
and many others.



Unka' George [George McDuffee]
-------------------------------------------
He that will not apply new remedies,
must expect new evils:
for Time is the greatest innovator: and
if Time, of course, alter things to the worse,
and wisdom and counsel shall not alter them to the better,
what shall be the end?

Francis Bacon (1561-1626), English philosopher, essayist, statesman.
Essays, "Of Innovations" (1597-1625).

rigger writes:

If you use copper or iron pipe you will find you can run your line
pressure up to 160# or above. Even though you may not want
or need the high pressure at your nozzles (etc.) you will find
your compressor will be starting and stopping 1/2 as much or
less which will extend the life of your compressor motor and
starting/running gear.

This is an utter waste of power. Use the minimum tank and line pressure
needed to achieve the pressure, volume, and regulation needed at the
tool(s).

Regulating 160 to 90 at the tool turns (160-90)/160 = 44 percent of the
compressor's power into waste heat.

The cost of a compressor is mostly in the electric power input, not the
capital cost of the unit, so this "extending the life" with higher tank and
line pressures is false economy.

On Mar 10, 2:57*pm, Richard J Kinch wrote:
rigger writes:
If you use copper or iron pipe you will find you can run your line
pressure up to 160# or above. *Even though you may not want
or need the high pressure at your nozzles (etc.) you will find
your compressor will be starting and stopping 1/2 as much or
less which will extend the life of your compressor motor and
starting/running gear.

This is an utter waste of power. *Use the minimum tank and line pressure
needed to achieve the pressure, volume, and regulation needed at the
tool(s).

Regulating 160 to 90 at the tool turns (160-90)/160 = 44 percent of the
compressor's power into waste heat.

The cost of a compressor is mostly in the electric power input, not the
capital cost of the unit, so this "extending the life" with higher tank and
line pressures is false economy.

Think of your air system as a battery. When it pumps up to (a charge)
of 160# and turns off nothing is lost.

When you use part of the charge for air motors, etc. you only use
the portion going through your device. Nothing is lost.

Perhaps you're thinking of a system that pumps to a reservior past
a pressure relief valve to a hydraulic tank; an air system doesn't
work this way.

dennis
in nca

On Mar 10, 2:20*pm, Ignoramus26567 ignoramus26...@NOSPAM.
26567.invalid wrote:
On 2009-03-10, rigger wrote:

"no teflon tape, etc. on the downstream side. "

There's nothing wrong with properly applied teflon tape. *It's
when it's applied to the last and next-to-last thread on a
fitting that it becomes a problem. *Before I began work-
in in the service department I applied tape to thousands
of fittiings without problem. *Others, less attentive to details,
had numerous problems. *We were all using the same tape
and fittings so I've concluded application is the key.

A sane practice is that for expensive machines that do not tolerate
various particles, to install an air filter right on them. Ergo,
that's what my plasma cutter does.

This is also what the Dumore No. 24 automatic drilling head (for sale)
does.

--
* *Due to extreme spam originating from Google Groups, and their inattention
* * * to spammers, I and many others block all articles originating
* * * *from Google Groups. If you want your postings to be seen by
* * * * *more readers you will need to find a different means of
* * * * * * * * * * * *posting on Usenet.
* * * * * * * * * *http://improve-usenet.org/

"A sane practice is that for expensive machines that do not tolerate
various particles, to install an air filter right on them. Ergo,
that's what my plasma cutter does."

It would be difficult to add a filter after every junction. But
careful
attention to detail works as well.

dennis
in nca

On 2009-03-10, rigger wrote:
Think of your air system as a battery. When it pumps up to (a charge)
of 160# and turns off nothing is lost.

Rigger, this is untrue and Richard Kinch is correct within his set of
assumptions (which probably do not apply to your home shop).

If you use a given amount of energy (such as 1 kilowatt-hour) to
compress air to 120 PSI, you can then use that air to power your air
tools and get back some good fraction of that energy.

If you use the same 1 kilowatt-hour to compress air to higher
pressure, such as 175 PSI, you will get less energy out of your tools.

This is because compressing air to higher pressure heats air more than
compressing air to lower pressure, and that heat is completely wasted
(unless you are also heating your shop in winter, for example).

So it is indeed true that compressing air to more than the required
pressure wastes energy. And it is partly a reason for rotary screw
compressors.

However, many "home shop" owners do not particularly care about the
cost of energy, as they use their compressors very little, say an hour
per week. A more important issue for them could be availability of a
lot of air for short bursts of air use. And under these circumstances,
maintaining a higher pressure makes sense.

When you use part of the charge for air motors, etc. you only use
the portion going through your device. Nothing is lost.

Energy is lost when compressing and heating.

i

Perhaps you're thinking of a system that pumps to a reservior past
a pressure relief valve to a hydraulic tank; an air system doesn't
work this way.

dennis
in nca

--
Due to extreme spam originating from Google Groups, and their inattention
to spammers, I and many others block all articles originating
from Google Groups. If you want your postings to be seen by
more readers you will need to find a different means of
posting on Usenet.
http://improve-usenet.org/

spaco wrote:

This one gets MY vote!

One of the tricks in doing a shop is to never ever use 90°
elbow. Only use Ts and plug off the unused side. Sooner or later, you
will need to put in another run or valve or line there.

I use that idea for air, water, and coolant. When available, we use crossing tee's. Also
known as a cross depending on were you live.

Wes

--
"Additionally as a security officer, I carry a gun to protect
government officials but my life isn't worth protecting at home
in their eyes." Dick Anthony Heller

On Tue, 10 Mar 2009 11:47:04 -0700, Gunner Asch wrote:

On Tue, 10 Mar 2009 09:30:09 -0700, "Bob La Londe"
wrote:

Most shops I have seen use iron pipe for air, but I was just looking at
a couple on-line specs sheets on PVC and it looks like if I were to
distribute air at 125 PSI in my shop using 1" Schedule 40 PVC I would
have about a 30% safety margin at the worst case scenario. That's based
on 120F operating temperature. While yes it does hit 120F here in the
desert once in a great while I don't think its ever gotten above 105 in
the shop building. Better safe than sorry though.

(snip)

Its one of the things I do to make a living..and Im quite qood at it.
Ive turned down jobs where they wanted PVC. I dont want the liability.

I kinda think of this as "if the customer wants to kill themselves on a
piece of equipment, _they_ can build it".

"Human nature is bad. Good is a human product A warped piece of wood
must be steamed and forced before it is made straight; a metal blade
must be put to the whetstone before it becomes sharp. Since the nature
of people is bad, to become corrected they must be taught by teachers
and to be orderly they must acquire ritual and moral principles."
—Sun Tzu

Orderliness as a virtue? If that's not a mistranslation, I'm doomed!

--
http://www.wescottdesign.com

"Ignoramus26567" wrote: (clip) This is because compressing air to higher
pressure heats air more than
compressing air to lower pressure, and that heat is completely wasted
(clip)
^^^^^^^^^^^^^^^^^^^^^^
Dropping the pressure to a lower value through a throttling valve or
regulator wastes the energy that could have been obtained by running it
through an air motor to lower the pressure. So you lose on the way up and
you lose on the way down.

On Tue, 10 Mar 2009 12:34:56 -0700, Gunner Asch
wrote:

On Tue, 10 Mar 2009 12:56:07 -0600, F. George McDuffee
wrote:

The price difference with black or galvanized iron


If you feel you MUST use galvanized pipe...remember, you are GOING to
get flakes of Galv in your tools.

Its a given. Its pretty much Verbotten to use galvanized pipe with
CNC machiney, along with teflon tape.

Use both at your own risk.

Gunner

"Human nature is bad. Good is a human productÂ*
A warped piece of wood must be steamed and forced
before it is made straight; a metal blade must be put to the whetstone
before it becomes sharp. Since the nature of people is bad, to become corrected
they must be taught by teachers and to be orderly they must acquire ritual
and moral principles."
€”Sun Tzu
Â*
Use galvanized to an air filter, with brass or copper from there to
the QD. Put air filters on the "important" stuff.

On 2009-03-11, Leo Lichtman wrote:

"Ignoramus26567" wrote: (clip) This is because compressing air to higher
pressure heats air more than
compressing air to lower pressure, and that heat is completely wasted
(clip)
^^^^^^^^^^^^^^^^^^^^^^
Dropping the pressure to a lower value through a throttling valve or
regulator wastes the energy that could have been obtained by running it
through an air motor to lower the pressure. So you lose on the way up and
you lose on the way down.

Great point.
--
Due to extreme spam originating from Google Groups, and their inattention
to spammers, I and many others block all articles originating
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Bob La Londe wrote:
Most shops I have seen use iron pipe for air, but I was just looking at
a couple on-line specs sheets on PVC and it looks like if I were to
distribute air at 125 PSI in my shop using 1" Schedule 40 PVC I would
have about a 30% safety margin at the worst case scenario. That's based
on 120F operating temperature. While yes it does hit 120F here in the
desert once in a great while I don't think its ever gotten above 105 in
the shop building. Better safe than sorry though.

Wadda ya think?

P.S. I have seen other shops use PVC also, and they said they never had
any problems.

The only real issue I see is that "wish this hose was 2 inches longer"
factor. I could probably mitigate that by using brass fittings at the
ends and securing them properly at the wall, and of course the fact that
there would be air all over the shop instead of in one corner would help
quite a lot.



As others have already said, very bad idea, the pressure listed on the
pipe is liquid pressure, which is a very different animal, (thus the
reason hydro testing uses water for pressure testing) a very small
amount of non-compressible water has to leak before the pressure falls
to zero, not so with gases.

If you feel compelled to use plastic, ABS is rated for gas pressure.

Stuart

Let the Record show that Gunner Asch on
or about Tue, 10 Mar 2009 11:47:04 -0700 did write/type or cause to
appear in rec.crafts.metalworking the following:

Bob..at least once a year, I get called in to replumb a shop that had
PVC pipe that decayed due to compressor oil, heat etc etc and finally
blew out, often taking entire banks of florescent lights off the
ceiling, blowing **** everywhich way etc.

Im not telling you not to do it. Ive seen some up for as long as 10
yrs with no explosions. But each and every piece Ive taken down had
the structural composition of a grahm cracker. Drop it from 3 feet
and it shatters like glass.

Sounds like a shop which was plumbed for air with PVC pipe is like
the guy who was told smoking cigarettes was bad for his health. "I
don't know, they haven't killed me yet."

tschus
pyotr

-
pyotr filipivich
We will drink no whiskey before its nine.
It's eight fifty eight. Close enough!

"pyotr filipivich" wrote in message
...
Let the Record show that Gunner Asch on
or about Tue, 10 Mar 2009 11:47:04 -0700 did write/type or cause to
appear in rec.crafts.metalworking the following:

Bob..at least once a year, I get called in to replumb a shop that had
PVC pipe that decayed due to compressor oil, heat etc etc and finally
blew out, often taking entire banks of florescent lights off the
ceiling, blowing **** everywhich way etc.

Im not telling you not to do it. Ive seen some up for as long as 10
yrs with no explosions. But each and every piece Ive taken down had
the structural composition of a grahm cracker. Drop it from 3 feet
and it shatters like glass.

Sounds like a shop which was plumbed for air with PVC pipe is like
the guy who was told smoking cigarettes was bad for his health. "I
don't know, they haven't killed me yet."


I don't recommend it, I have switched to PEX for impact resilience, but I
have at least 100' of 1/2 and 3/4 white PVC that is at least 25 years old,
without issue.

All this discussion got me curious about the relative strength of copper
vs. black steel pipe. As I suspected, the black pipe is stronger. 1/2"
black schedule 40 is rated at 10,380 psi bursting pressure, while 1/2"
Type L copper (hard) is rated for 4,600 psi bursting pressure.

--
Jedd Haas - Artist - New Orleans, LA
http://www.gallerytungsten.com

"Ignoramus26567" wrote in message
...
On 2009-03-11, Leo Lichtman wrote:

"Ignoramus26567" wrote: (clip) This is because compressing air to higher
pressure heats air more than
compressing air to lower pressure, and that heat is completely wasted
(clip)
^^^^^^^^^^^^^^^^^^^^^^
Dropping the pressure to a lower value through a throttling valve or
regulator wastes the energy that could have been obtained by running it
through an air motor to lower the pressure. So you lose on the way up
and
you lose on the way down.

Great point.

Uh, actually, not. Throttling doesn't affect the pressure-volume product. No
energy is lost by throttling. However, expansion of the air to a
lower-pressure downstream value does give up heat upon expansion. Whether
that "loses" energy depends on what the temperature of the air was before it
was throttled, and what it is just before you actually use it to perform
some work. It can regain that energy from the ambient heat in the room, if
the expansion dropped the temperature of the air below room temperature when
it expanded, and then the air re-heated by running through the copper pipe
in a relatively warmer room.

Running that same air through a motor results in a greater PV loss -- lower
pressure or less volume -- than it would through a throttle that produced
either the same downstream pressure, OR the same downstream volume. The
difference is the work performed by the motor.

Most of the energy loss is from what you suggested in the first place:
losing the heat of compression. That's why those compressed-air cars they've
been experimenting with in France are so inherently inefficient. You can, in
theory, recover all of that heat. But it's like recovering lost heat in a
steam engine or turbine: exceedingly complicated, with multiple heat
exchangers.

--
Ed Huntress

Ed Huntress writes:

No energy is lost by throttling.

Not sure what you mean by "throttling".

Energy is certainly lost in dropping pressure via a regulator. The entire
pressure drop (times volume) is wasted. It has nothing to do with the heat
contained in the compressed air itself. This should be obvious from
conservation of energy. But shop air users can be quite stubbornly
ignorant of physics.

On Tue, 10 Mar 2009 09:30:09 -0700, "Bob La Londe"
wrote:

Most shops I have seen use iron pipe for air, but I was just looking at a
couple on-line specs sheets on PVC and it looks like if I were to distribute
air at 125 PSI in my shop using 1" Schedule 40 PVC I would have about a 30%
safety margin at the worst case scenario. That's based on 120F operating
temperature. While yes it does hit 120F here in the desert once in a great
while I don't think its ever gotten above 105 in the shop building. Better
safe than sorry though.

Wadda ya think?

P.S. I have seen other shops use PVC also, and they said they never had any
problems.

The only real issue I see is that "wish this hose was 2 inches longer"
factor. I could probably mitigate that by using brass fittings at the ends
and securing them properly at the wall, and of course the fact that there
would be air all over the shop instead of in one corner would help quite a
lot.



Aside from safety issues, my use of the PVC's was some years ago when
it was "new", and with a specific electric conduit called "Septre",
and to run control wires in a hoistway.. Worked nice, easy to use and
bend. But two months later we had to back in and triple up on the
number of wall clips to stop the sagging in any of the horizontal runs
over 3 feet. It was in a fairly warm area in a meat packing plant.

I would also like to congratulate the RCM community for over 30
straight emails that didn't wander off topic!!! PLEASE...NO REPLY TO
THAT COMMENT!!!

Brian Lawson,
Bothwell, Ontario.

On Tue, 10 Mar 2009 14:47:36 -0400, Ecnerwal
wrote:

In article ,
"Bob La Londe" wrote:

Wadda ya think?

Bad idea.

P.S. I have seen other shops use PVC also, and they said they never had any
problems.


And they'll keep saying that right up until the fragmentation bomb hits.
Then they'll be "shocked, just shocked" to find that this has been a
known dumb idea for *decades*. You can get special (green?) plastic pipe
(Not PVC) rated for air service, but at last look it was more expensive
than regular pipe. Copper or iron can be had any any hardware/building
supply.

http://www.osha.gov/dts/hib/hib_data/hib19880520.html

http://www.lni.wa.gov/Safety/Basics/HazAlerts/902.asp

My personal preference is copper. Costs a fair amount, once. Relatively
clean. Easy to add on to.

The usual litany - slope the lines away from the compressor, and put
drain legs on the bottom of the line. Take air off from the top of the
line (Up over down) and provide additional drain legs at the bottom of
each drop leg, extending well below the air connector. Decouple the
compressor from the piping system with a section of flex, and decouple
the compressor from the tank to reduce one cause of tank fatigue
failure. Plumb your air intake outside.

My shop is all galv steel. 3/4" main with 3/4 x3/4 x 1/2 tee's all
pointing straight up, two 90 deg street ells to turn it down the wall
90 deg ell out from wall then a ball valve and a QC coupler. no drip
legs anywhere, never had water anywhere except in the compressor tank.

All Milton type "A" QC's, you can just push to connect without pulling
back the collar. Very nice feature.

CNC machine has a built in filter/oiler/regulator. And I have a
filter/oiler that I plug in where needed.

Champion compressor 5hp 80 gal., 175 PSI. Located on other side of
wall in the unheated warehouse side of my building.

I held the pipe in my lathe and used a Ridgid pipe theader head to
thread it. ( model 00-R)

If you do use copper, you might want to use a few steel nipples and
ell's at the end of each leg. My uncle did his garage in copper,
tripped over a hose and bent the hell out of the copper tubing.

Thank You,
Randy

Remove 333 from email address to reply.

"Bob La Londe" wrote in message
...
snip

P.S. I have seen other shops use PVC also, and they said they never had
any problems.

Maybe that's because the ones that did have a problem are now 6 feet under.

On Wed, 11 Mar 2009 09:03:18 -0500, the infamous "Mike Henry"
scrawled the following:


"Bob La Londe" wrote in message
...
snip

P.S. I have seen other shops use PVC also, and they said they never had
any problems.

Maybe that's because the ones that did have a problem are now 6 feet under.

Whadda maroon! I've worked in shops (new, inspected/stamped-off in
'83) with PVC air-lines and have seen the fittings and lines break
from damage when a chain pull let loose or when someone drove off with
a hose in the door. Nobody was ever hurt from the "horrible shrapnel"
of the "exploding PVC" you guys seem to worry about. Can you cite a
death report, Mikey? OSHA only shows one lacerated hand.
http://www.osha.gov/dts/hib/hib_data/hib19880520.html

BUT, I've read the OSHA warnings and I wouldn't use Sch 40 in a new
shop. HF has 100' PVC-jacketed hose for ten bucks. Why use hard lines
at all, unless you have multiple taps going balls-out at the same
time? ABS is approved if one wants to save money. Just don't hit it
with anything while it's pressured up...

....or you'll be SIX FEET UNDER, right, Mikey?

--
I predict future happiness for Americans if they can prevent the government
from wasting the labors of the people under the pretense of taking care of them.
--Thomas Jefferson

On 2009-03-11, Larry Jaques novalidaddress@di wrote:
BUT, I've read the OSHA warnings and I wouldn't use Sch 40 in a new
shop. HF has 100' PVC-jacketed hose for ten bucks. Why use hard lines
at all, unless you have multiple taps going balls-out at the same
time? ABS is approved if one wants to save money. Just don't hit it
with anything while it's pressured up...

I use flexible hose as well for my "shop air".

It is safe, easy to work with, and cheap. Very easy to splice when
necessary.

If it ever ruptures because or something, all I will get is a loud
PSSSSS6666SSSSSSSST.

--
Due to extreme spam originating from Google Groups, and their inattention
to spammers, I and many others block all articles originating
from Google Groups. If you want your postings to be seen by
more readers you will need to find a different means of
posting on Usenet.
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