I agree with Dan. In our shop we have a commercial type plastic pipe that
we use for our air supply. We ran a galvanized pipe from the compressor
into the shop to the regulator. We then regulate our air to about 120 psi.
then we have commercial grade pipe run the rest fo our airline. Ask the
hardware guy about commercial plastic pipe.
Kevin
----------
> From: DANMAS@aol.com
> To: vafred@erols.com; triumphs@autox.team.net
> Cc: spitfires@autox.team.net
> Subject: Re: air compressor
> Date: Friday, January 01, 1999 11:09 PM
>
>
> In a message dated 1/1/99 6:23:33 PM Eastern Standard Time,
vafred@erols.com
> writes:
>
> > Listers, just finished wiring my new work shed, my question is for the
> > piping for the air compressor, is plastic pipe O/K or do I need metal,
if
> > so, should it be galvanized or the black pipe ?? The run is going to
be
> > rather long for attempting to keep all the water out, 1 in line filter
&
> > 1 filter/regulator, total up & down configuration is about 20 feet. As
> > usual you advice is valued.
>
> Fred,
>
> There are two types of plastic pipe available -- one for water and one
for
> compressed air. The compressed air type is a bit more expensive than the
water
> pipe, but well worth the extra. You get the ease of installation of
plastic,
> and the safety of iron or copper pipe. In the quantity you are going to
be
> using, the extra cost is not significant. Do NOT use the ordinary PVC
water
> pipe, as it can shatter when used for air.
>
> Ordinary PVC, designed for water usage, can also shatter under certain
> conditions when used for water as well, but there are two factors which
> prevent this potential shattering from being a problem; one, the pipes
are
> almost always behind walls, and, most important, the nature of water as
> compared to air. Water is non-compressible, so if you get a rupture, you
get a
> small squirt of water and the pressure is gone. With air, which is highly
> compressible, when you get a rupture, a tremendous volume of compressed
air is
> released, which can be quite deadly. In our nuclear plants, we test low
> pressure piping with water at pressures up to 2000 psi, with no danger
> whatever, even when testing unknown systems. As I said, if there is a
leak,
> only a small squirt of water is released before the pressure drops to
> atmospheric. It's an eerie feeling, standing next to a small pipeline,
knowing
> it is pressurized to 2000 psi, but it's perfectly safe. Using water, you
can
> pressurize a tank to 2000 psi and then drill a hole in it with no danger
-
> don't try that with air!
>
> There are lots of folks who have been using plastic water pipes for
compressed
> air for years with no problems, but there are also adults who played in
> traffic as a child without being run over by a car. Nevertheless, it's
> dangerous to be playing in traffic, and it's dangerous to use plastic
water
> pipe for air.
>
> Plastic is the easiest to install, with copper being the next easiest.
Iron
> pipe is the cheapest to buy, but is impossible to install without special
> tools -- pipe cutter, threader, etc. If you have to rent these tools, or
pay
> someone else to do it, the cost of iron pipe goes way up. Iron pipe will
rust
> with time and have to be replaced, but with air usage instead of water,
the
> time to replacement will be quite a bit longer (the air will have water
in it,
> which will settle in the pipe). Compared to our life span, copper is
forever.
> I don't know the life expectancy of plastic.
>
> When the air leaves your compressor, it will be hot and have a lot of
moisture
> in it. As the air cools, the moisture will separate out and condense in
the
> pipes. For this reason, you want the pipes to be long enough for the air
to
> cool and for all the moisture to separate before the air gets to your
tools,
> and you want the moisture separator to be at the end of the air line --
you
> don't want any more moisture separating out after the moisture separator.
You
> want to arrange the air lines so the moisture that condenses inside
drains
> away from the outlet, and provide a place to drain the line occasionally.
When
> you tap off the main line for your tool outlet, run the tap line
vertically
> for a couple of inches or so, then turn it down to the tool outlet. This
> lessons the amount of water that gets to the tool. Air turns corners
pretty
> well, but water doesn't.
>
> The few pipeline fittings you buy will cost more than the rest of the
pipe put
> together, but I recommend adding a few quick disconnects at various
places in
> the line, if your installation and tool usage locations allow it. My
> compressor is in the garage, and I have a workshop just off the garage.
In the
> garage (two car), I have three outlets, and one in the workshop. I used
the
> special air service plastic pipe, btw. (Being an electrical type, I have
two
> control switches for my compressor -- one in the garage and one in the
shop. I
> have it arranged so that if I leave either one of the switches in the on
> position, the compressor runs as usual, but if I turn the switch on and
then
> back off, the compressor will run just long enough to fill the tank. When
the
> tank is full, the pressure switch cuts off the compressor, and it won't
start
> again till I turn one of the switches back on. I have found that I often
need
> just a little bit of air for a project in the shop, and I got tired of
> forgetting to turn off the compressor when I was finished, only to have
it
> cycle on and off for days as air leaks brought the pressure down while I
> wasn't working in the garage. With four quick disconnects and two drain
taps,
> there is a bit of leakage.)
>
> That's about all I know about it, hope it is of some help to you.
>
> Dan Masters,
> Alcoa, TN
>
> '71 TR6---------3000mile/year driver, fully restored
> '71 TR6---------undergoing full restoration and Ford 5.0 V8 insertion -
see:
> http://www.sky.net/~boballen/mg/Masters/index.html
> '74 MGBGT---3000mile/year driver, original condition - slated for a V8
soon
> '68 MGBGT---organ donor for the '74
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