Mike Marlow wrote:

Wasn't the original post referring to 1/2" air hose?


I didn't think so. My original mention of flexible hose simply stated
"air hose". The stuff in the bike shop is a product that I think comes
from the commercial beverage dispensing industry. FWIW, this is a big
bike shop, with lots of repair / build stations in multiple rooms, not
what you'd typically see. Their usual use of compressed air is blow
guns, so the demand can be pretty good during peak tune / clean season.

I'm with you all the way if the line is driving die grinders, air
routers, and sanders all day long. I'd probably just run a pipe to that
work area. For the average one or two person shop we talk about here,
even 1/2" hose should be fine.

"B A R R Y" wrote in message
t...
Mike Marlow wrote:

Wasn't the original post referring to 1/2" air hose?


I didn't think so. My original mention of flexible hose simply stated
"air hose".

Ok - assumption on my part.

The stuff in the bike shop is a product that I think comes
from the commercial beverage dispensing industry. FWIW, this is a big
bike shop, with lots of repair / build stations in multiple rooms, not
what you'd typically see. Their usual use of compressed air is blow
guns, so the demand can be pretty good during peak tune / clean season.


Pretty low demand by air compressor/delivery system standards.

I'm with you all the way if the line is driving die grinders, air
routers, and sanders all day long. I'd probably just run a pipe to that
work area. For the average one or two person shop we talk about here,
even 1/2" hose should be fine.

Lots of guys want to do spray painting and that kind of delivery capacity,
especially with smaller compressors, will hurt their efforts. For a small
operation like most folks here have, and some simple blow gun, air nailer,
etc., low air volume operations, I agree it could be suitable. If they
envision larger air volume requirements though, I'd suggest some pipe - and
these days that pipe would be copper. Mine is a black pipe system, and if I
had it to do over again, I'd go copper.

--

-Mike-

Robatoy wrote:
Find me one report/link to an accident that didn't involve air
pressures greater than 150 psig or an explosive (oil) mixture.

One!


The very first listing from googling "shop air explosion" revealed one occasion
where 140psi of air was accidentally put in a truck tire which then exploded,
killing the worker. No explosive mixture... just air pressure less than 150
psi.

http://www.state.nj.us/health/eoh/survweb/01nj108.pdf .

Compressed air is nothing to play with.



--
Mortimer Schnerd, RN
mschnerdatcarolina.rr.com

I've heard of shops using PEX for air lines. It's really easy to work
with. Not rated for air or areas exposed to sun light, but if it
explodes it won't turn into shrapnel like PVC does.

Max wrote:
Is there any consensus on whether or not to use PVC or CPVC for air lines?
My compressor is capable of 150psi.
I already have copper for most of my distribution system but I need to add a
branch and the copper prices are profanity inducing.

Max

On Dec 6, 8:40 am, "Mortimer Schnerd, RN" mschnerdatcarolina.rr.com
wrote:
Robatoy wrote:
Find me one report/link to an accident that didn't involve air
pressures greater than 150 psig or an explosive (oil) mixture.

One!The very first listing from googling "shop air explosion" revealed one occasion
where 140psi of air was accidentally put in a truck tire which then exploded,
killing the worker. No explosive mixture... just air pressure less than 150
psi.

That's not a shop-air explosion. That is an idiot overinflating a tire.
Using that barometer (I made a funny), I am sure there are many
air-related accidents.
Put 30 psi in your ears, and you'll get hurt. 5 psig through an
intravenous needle into your bloodstream and you're toast. How many
accidents have been reported where somebody has blown dirt into their
eyes? That happens all the time.

Compressed air can hurt you.

I want to see a report where it states that an air distribution line
exploded, pvc, copper. rubber... anything. My old shop has a large 3/4"
PVC airline distribution system. A dozen drops. Never had an issue for
20 years. Had a crimp come off a cheap airline once.. chased one of the
guys around the paintbooth real good.. he had some welts on the back of
his legs and a bruised ego..we had a huge laugh...(Could have been more
serious, we were lucky.. but you need full-tilt air to blow off dirt
particles)

With all due respect,

r

On Wed, 06 Dec 2006 08:40:18 -0500, Mortimer Schnerd, RN wrote:

Robatoy wrote:
Find me one report/link to an accident that didn't involve air
pressures greater than 150 psig or an explosive (oil) mixture.

One!


The very first listing from googling "shop air explosion" revealed one occasion
where 140psi of air was accidentally put in a truck tire which then exploded,
killing the worker. No explosive mixture... just air pressure less than 150
psi.

http://www.state.nj.us/health/eoh/survweb/01nj108.pdf .

Compressed air is nothing to play with.

Truck tire "explosions" are common--it's not the tire that explodes but an
improperly assembled rim that separates, and if one of the pieces hits
someone he generally gets hurt--truck wheels are rather large and the rims
are rather heavy.




--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)

In article om, "Robatoy" wrote:

I want to see a report where it states that an air distribution line
exploded, pvc, copper. rubber... anything.

If you hadn't found any such reports... it's because you didn't look. This is
the very *first* hit turned up by a Google search on
"compressed air" pvc explosion

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

Here's another:
http://www.woodworkersjournal.com/ez...59/readers.cfm

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

So, does this mean that my potato cannon constructed out of schedule 40
PVC is now to be considered "unsafe"? I wrapped a few layers of duct
tape around the combustion chamber, just in case of a blow out - no
problems yet.

BTW, I've got a great book on the subject called "Backyard
Ballistics". All kinds of fun projects involving PVC.

Robatoy wrote:


That's not a shop-air explosion.

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

Mike Marlow wrote:

Lots of guys want to do spray painting and that kind of delivery capacity,
especially with smaller compressors, will hurt their efforts.

Mike, I have spray painted with that setup. G

"Lew Hodgett" wrote in message
ink.net...
Robatoy wrote:

Only if you fill the cavity with an explosive mixture.
Air pressure alone will not have that catastrophic an effect.
At worst, the 'shrapnel' will fall at your feet.

BULL ****! !

Lew

Oh yeah!! That stuff can serve as shrapnel too. Ever heard the expression,
"When the **** hit the fan".

Max

"Lew Hodgett" wrote in message
ink.net...
Robatoy wrote:

Find me one report/link to an accident that didn't involve air
pressures greater than 150 psig or an explosive (oil) mixture.

Why would you expect to find reports of something that isn't done?

Lew

I would like to see a *reliable* report of schedule 40 PVC exploding at an
air pressure of 150 psi. Note the "reliable".

Max (who is satisfied that it just might be possible)

Robatoy wrote:
Robatoy wrote:
Find me one report/link to an accident that didn't involve air
pressures greater than 150 psig or an explosive (oil) mixture.

One!The very first listing from googling "shop air explosion" revealed one
occasion
where 140psi of air was accidentally put in a truck tire which then exploded,
killing the worker. No explosive mixture... just air pressure less than 150
psi.

That's not a shop-air explosion. That is an idiot overinflating a tire.
Using that barometer (I made a funny), I am sure there are many
air-related accidents.


Look at the first line you wrote above: I met every criteria you asked for.
Now you're adding conditions?



--
Mortimer Schnerd, RN
mschnerdatcarolina.rr.com

Doug Miller wrote:
In article om, "Robatoy"
wrote:

I want to see a report where it states that an air distribution line
exploded, pvc, copper. rubber... anything.

If you hadn't found any such reports... it's because you didn't look. This is
the very *first* hit turned up by a Google search on
"compressed air" pvc explosion

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

Here's another:
http://www.woodworkersjournal.com/ez...59/readers.cfm


Of course he didn't look. He was hoping you wouldn't, either. Now he's
probably going to claim these don't count because the ambient temperature was
beyond parameters, or it was the wrong phase of the moon, or whatever.

You can rub this one all day but you can't put a polish on a turd. PVC line for
compressed gases is a dangerous game. Just because he's gotten away with it for
a lengthy period of time doesn't mean it's not ready to fail later today... or
tomorrow... with disasterous results.



--
Mortimer Schnerd, RN
mschnerdatcarolina.rr.com

Robatoy wrote:
On Dec 6, 12:35 am, Lew Hodgett wrote:
Robatoy wrote: Only if you fill the cavity with an explosive mixture.
Air pressure alone will not have that catastrophic an effect.
At worst, the 'shrapnel' will fall at your feet.

BULL ****! !

Find me one report/link to an accident that didn't involve air
pressures greater than 150 psig or an explosive (oil) mixture.


Anecdotal only. My boss at my old job had a neighbor
who tired to inflate a space-saver spare tire to 32 psig
or so instead of the rated maximum.

It separated from the rim and the blast of air blew his
face off of his skull.

That's not a terribly good analog to the present discussion.

What size pipe is pretty important in this context.

IIRC, plastic soda-pop bottles are rated for about 150 psig.
So you could take a small one, put some vinegar in it and
then drop in some baking soda wrapped in wax paper,
screw on the cap and put it somewhere safe to see how
big a bang it makes.

Please note, this may be illegal in your locale. If that is
the case, don't do it.

--

FF

Mortimer Schnerd, RN wrote:
Frank Stutzman wrote:
Anybody wager a guess if an exploding 1 inch PVC pipe could go through 1/2
inch plywood? The pipes couldn't be hit by anything, but summer heat
might soften the PVC to the point it would burst


Summer heat will do a lot more than soften PVC; it will raise the pressure of
the compressed gas.


If you've kept the same gas compressed in the same pipe since
winter....

--

FF

Mortimer Schnerd, RN wrote:
Robatoy wrote:
Robatoy wrote:
Find me one report/link to an accident that didn't involve air
pressures greater than 150 psig or an explosive (oil) mixture.

One!The very first listing from googling "shop air explosion" revealed one
occasion
where 140psi of air was accidentally put in a truck tire which then exploded,
killing the worker. No explosive mixture... just air pressure less than 150
psi.

That's not a shop-air explosion. That is an idiot overinflating a tire.
Using that barometer (I made a funny), I am sure there are many
air-related accidents.


Look at the first line you wrote above: I met every criteria you asked for.
Now you're adding conditions?

You did not meet the criteria. You did not point to a situation where
the PVC pipe had exploded... it was a truck tire. The topic here is PVC
piping.

Having said that, I have discovered one of the errors of mine and that
is the air plumbing in the old shop is in fact ABS. My apologies.
I also read the other links that kind Wreckers have posted. I would
never even think of PVC in an industrial application. Service air
systems in my history have been driven by 100 HP rotary vane
compressors at pressures of 300 PSIG and higher. 4" lines are not
uncommon in power generation.
To be blowing craters of the dimensions stated in some of the reports,
one needs a whole lot more than a basic wood-workers' compressor.
Therefore the parallels are ridiculous.

Even though, in one of the reports it states "Gas Transmission and
Distribution Piping Systems Standard, limit the operating pressure of
plastic piping distribution systems to 100 pounds per inch (psi)",
which makes me think that PVC isn't as fragile as some think it is, it
obviously isn't worth taking a chance on PVC. I hereby retract my
careless endorsement of PVC and suggest we stick to copper, ABS or
other stuff I have never heard of before.

Lesson learned, ABS isn't PVC and you can't get anything past this
alert crew of wreckers.

Thanks for the corrections.

r

wrote:

IIRC, plastic soda-pop bottles are rated for about 150 psig.
So you could take a small one, put some vinegar in it and
then drop in some baking soda wrapped in wax paper,
screw on the cap and put it somewhere safe to see how
big a bang it makes.

When I was a kid, would use a glass Mason jar, put in a rock for
weight, some carbide and water, then screw on lid and toss in the creek.

The carbide and water combined to produce acetylene gas which would
expand and cause the glass jar to burst while under water.

Any fish would float to the surface for easy pickings.

Lew

"Robatoy" wrote in news:1165417304.856433.40150
@l12g2000cwl.googlegroups.com:


Robatoy wrote:
Had a crimp come off a cheap airline once.. chased one of the
guys around the paint-booth real good..

which reminded me....


Same guy took a full swing with a #1 wood at a golf-ball in his tiled
bathroom.
33 cuts, 112 contusions and 44 lacerations.
Good thing his roommate heard the commotion and opened the door to let
the ball out.



Bright fellow, no?

Patriarch

"B A R R Y" wrote in message
. net...
Mike Marlow wrote:

Lots of guys want to do spray painting and that kind of delivery
capacity,
especially with smaller compressors, will hurt their efforts.

Mike, I have spray painted with that setup. G

How much? I have to admit that I tend to think in bigger terms than
woodworking, owing to the type of painting I do, so that's my shortcoming in
a discussion like this. I suppose for typical small scale painting it could
be ok.

How much small diameter hose do you have in your delivery system? Do you so
small scale spraying? Are you getting good atomization and patterning? I
guess if you're getting good results, that's all that really matters for
your application.

--

-Mike-

Mike Marlow wrote:
"B A R R Y" wrote in message

Mike, I have spray painted with that setup. G

How much? I have to admit that I tend to think in bigger terms than
woodworking, owing to the type of painting I do, so that's my shortcoming in
a discussion like this. I suppose for typical small scale painting it could
be ok.

How much small diameter hose do you have in your delivery system? Do you so
small scale spraying? Are you getting good atomization and patterning? I
guess if you're getting good results, that's all that really matters for
your application.


The main delivery tubing is some sort of 1/2" to 5/8" ID plastic hose,
tee'd off with barbed and clamped fittings. The main line is 100 to 125
feet long, with 8 or 9 20-30' 3/8" air hose drops terminated with Milton
quick connects. The whole rig is run by an Ingersoll Rand 80 gallon
220v compressor. I don't know the HP rating of the compressor, but the
airline is typically charged to 125 PSI.

I connected a standard, 50' x 3/8" hose to the final connector so I
could spray in the parking lot behind the building. Several large
items were sprayed this way. Spray results were as good as I get with
my Fuji 4 stage HVLP rig. However, nobody else was using air. I don't
believe this setup would have worked if others were using air, nor would
I install it in a professional finishing shop or auto paint shop.

"B A R R Y" wrote in message
. net...


The main delivery tubing is some sort of 1/2" to 5/8" ID plastic hose,
tee'd off with barbed and clamped fittings. The main line is 100 to 125
feet long, with 8 or 9 20-30' 3/8" air hose drops terminated with Milton
quick connects. The whole rig is run by an Ingersoll Rand 80 gallon
220v compressor. I don't know the HP rating of the compressor, but the
airline is typically charged to 125 PSI.

I connected a standard, 50' x 3/8" hose to the final connector so I
could spray in the parking lot behind the building. Several large
items were sprayed this way. Spray results were as good as I get with
my Fuji 4 stage HVLP rig. However, nobody else was using air. I don't
believe this setup would have worked if others were using air, nor would
I install it in a professional finishing shop or auto paint shop.

Pretty interesting Barry. You've got the pressure and likely, the delivery
capacity in the compressor to somewhat compensate for the friction
loss/restriction in the hose so you're probably ok - or so I would guess. I
really don't stay up late at night calculating these things...

--

-Mike-

"J. Clarke" wrote in message
...
On Wed, 06 Dec 2006 08:40:18 -0500, Mortimer Schnerd, RN wrote:



Truck tire "explosions" are common--it's not the tire that explodes but an
improperly assembled rim that separates, and if one of the pieces hits
someone he generally gets hurt--truck wheels are rather large and the rims
are rather heavy.


If you are actually mounting a tire on a split rim you have the very real
possibility of the ring coming off and causing damage. Additionally it is
becoming less common to see split rim wheels and tires do explode when being
seated on regular one piece wheels.

wrote in message
ups.com...

Anecdotal only. My boss at my old job had a neighbor
who tired to inflate a space-saver spare tire to 32 psig
or so instead of the rated maximum.

Moden day space saver tires are usually inflated in excess of 50lbs. I
suspect his spave saver tire was old and rottten.

Leon wrote:
wrote in message
ups.com...

Anecdotal only. My boss at my old job had a neighbor
who tired to inflate a space-saver spare tire to 32 psig
or so instead of the rated maximum.

Moden day space saver tires are usually inflated in excess of 50lbs. I
suspect his spave saver tire was old and rottten.

Old yes. Not rotten. The original ones were only to be inflated
to 12 psig or something like that. Accidents of the sort described
are why those are no longer available.

Memory dims but I think they were collapsible with the tire folded
into the rim.

--

FF

wrote in message
ups.com...

Leon wrote:
wrote in message
ups.com...

Anecdotal only. My boss at my old job had a neighbor
who tired to inflate a space-saver spare tire to 32 psig
or so instead of the rated maximum.

Moden day space saver tires are usually inflated in excess of 50lbs. I
suspect his spave saver tire was old and rottten.

Old yes. Not rotten. The original ones were only to be inflated
to 12 psig or something like that. Accidents of the sort described
are why those are no longer available.

Memory dims but I think they were collapsible with the tire folded
into the rim.

Yes those were the original space savers with a canister of air for filling.

Leon wrote:


Yes those were the original space savers with a canister of air for filling.

The 2006 Porsche Carrera GT comes with a can of puncture fix. No spare.
Reason being, that there is no room for a spare..even a small temporary
one, but most of all there certainly isn't any room to put any of the
wheel/tires that would come off the car... even when flat. HUGE rear
wheels. (335/30 ZR20 got to get them 600 ponies to the street somehow,
eh?)

Don't need no steeenking spares....

Robatoy wrote:

Leon wrote:


Yes those were the original space savers with a canister of air for filling.


The 2006 Porsche Carrera GT comes with a can of puncture fix. No spare.
Reason being, that there is no room for a spare..even a small temporary
one, but most of all there certainly isn't any room to put any of the
wheel/tires that would come off the car... even when flat. HUGE rear
wheels. (335/30 ZR20 got to get them 600 ponies to the street somehow,
eh?)

Don't need no steeenking spares....


If you can afford the car you don't need a spare. Two phone calls, one
to your limo drive to pick you up and one to "Estate Maintenance" to
came and get the car.

--
Jack Novak
Buffalo, NY - USA

On Tue, 5 Dec 2006 19:32:17 +0000 (UTC), Frank Stutzman
wrote:

True. But I spent better than a week cutting, threading and cursing that
black pipe. I could have done the PVC thing in a few hours. Could have
made a lot of sawdust in that week. If the heat caused a failure once in
10 years then maybe the trade off might be worth it.

A week! How big is your shop anyway? I've plumbed an entire house with
galvanized in less than a week.

--
"We need to make a sacrifice to the gods, find me a young virgin... oh, and bring something to kill"

Tim Douglass

http://www.DouglassClan.com

Nova wrote:
Robatoy wrote:

If you can afford the car you don't need a spare. Two phone calls, one
to your limo drive to pick you up and one to "Estate Maintenance" to
came and get the car.

lol.. I guess so. So few of us have a gardener who is also a factory
trained mechanic.

r

Tim Douglass wrote:
On Tue, 5 Dec 2006 19:32:17 +0000 (UTC), Frank Stutzman
wrote:

True. But I spent better than a week cutting, threading and cursing that
black pipe. I could have done the PVC thing in a few hours. Could have
made a lot of sawdust in that week. If the heat caused a failure once in
10 years then maybe the trade off might be worth it.

A week! How big is your shop anyway? I've plumbed an entire house with
galvanized in less than a week.

1,400 sq ft.

In my defense, I had never worked with black pipe before and I was probably
not so effecient with the cutting and threading. Also didn't help that
I changed by design once or twice while doing it.

--
Frank Stutzman

On Fri, 8 Dec 2006 00:31:28 +0000 (UTC), Frank Stutzman
wrote:

Tim Douglass wrote:
On Tue, 5 Dec 2006 19:32:17 +0000 (UTC), Frank Stutzman
wrote:

True. But I spent better than a week cutting, threading and cursing that
black pipe. I could have done the PVC thing in a few hours. Could have
made a lot of sawdust in that week. If the heat caused a failure once in
10 years then maybe the trade off might be worth it.

A week! How big is your shop anyway? I've plumbed an entire house with
galvanized in less than a week.

1,400 sq ft.

Huh! That's bigger than my house.

In my defense, I had never worked with black pipe before and I was probably
not so effecient with the cutting and threading. Also didn't help that
I changed by design once or twice while doing it.

We'll go with the changing design excuse. That one always seems to
work well for me. ;-)
--
"We need to make a sacrifice to the gods, find me a young virgin... oh, and bring something to kill"

Tim Douglass

http://www.DouglassClan.com

Tim Douglass wrote:

[snip]


brilliant segue.

B A R R Y wrote:
Robatoy wrote:


That's not a shop-air explosion.

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

With all due deference, the operating pressure of the exploded line was
not given. However, there is no reason for presuming that it exceeded
the pressure under discussion, either. Moreover, further down in the
page a restriction of 100 psi was imposed ... well below your postulated
150 psi.

One of the additional links DID relate specifically to shop-level
pressure and a couple of clearly dangerous failures.

ABS, apparently, ruptures. PVC, just as apparently, shatters rather
dramatically.

Under the banner of erring on the side of caution, would it not make
sense to eschew pvc in favor of one of the other, commonly used, materials?

Your pvc has flexed each time the pressure has changed. That's a lot of
cycles over the lifetime you told us about. The course of prudence would
be to at least shield it.

Bill

Mike wrote:
So, does this mean that my potato cannon constructed out of schedule 40
PVC is now to be considered "unsafe"? I wrapped a few layers of duct
tape around the combustion chamber, just in case of a blow out - no
problems yet.

BTW, I've got a great book on the subject called "Backyard
Ballistics". All kinds of fun projects involving PVC.


When I worked for the railroad the car knockers would drop a lit fusee
into a pipe they had rigged up to a glad-hand and kick the valve on the
ground air open.

Probably got a good 100 ft or so altitude ... maybe twice that
horizontally.

;-)

I think that they used them to signal each other. The fusee goes out
when it strikes anything hard (a gentle sideways tap is sufficient to
extinguish them) so they are actually pretty safe for that use.

Bill