"Tim Wescott" wrote in message
...
On Wed, 10 May 2017 14:00:52 -0400, Carl Ijames wrote:

"rangerssuck" wrote in message
...

The refrigerant pipes in a typical rink are about 10 or 11 miles
long
(seriously), and are (sometimes) 5/8 OD thinwall steel, but that's
a
variable.

================================================== ==================================================

Just as a sanity check when you do the pressurize with nitrogen
test, I
get a volume of 72 cu ft or 2039 L for 10 miles of 1/2" ID tubing.
At
STP, 0 C and 101 kPa nitrogen has a density of 1.25 g/L so at STP
72 cu
ft would weigh 5.62 lbs (I'm ignoring the difference between room
temperature and STP for this estimate :-)). If you start at
atmospheric
pressure you would need 3x72 cu ft = 216 cu ft to reach 44.1 psig
which
should be completely safe since the vapor pressure of R22 at 75 F
is 132
psig. So you will need at least a couple of tanks of nitrogen on
hand
to be safe, and a refrigeration scale that can do 0.1 lbs at the
weight
of a full tank of nitrogen with regulator should let you get an
answer
in the 5-10% range. Have fun.

Man, I just know that if I tried this I'd be lucky to be off by a
factor
of two, and not 10 or something.

Good luck, and have fun.
Tim Wescott

=========================
Yes, I tend to practice an experiment cheaply to find issues with my
equipment and technique, before making careful measurements. I no
longer have access to recently calibrated lab instruments and the
motley assortment of surplus I have at home doesn't all agree too
well.

However my flea-market 1970's Fluke 4-1/2 and 5-1/2 digit bench meters
are still within spec when measuring a 10V calibration standard.
-jsw