Reference the ASTM B88 Copper Tubes which sound like what I have.
Why would they have Nominal and Actual sizes for all pipe/tube? I'm using
the word interchangeably. Is it because it was originally metric and it's
been changed to all inches or is there another reason? It just seems plain
dumb to be calling something one size when it's actually a different size. I
notice in the specifications everything is in inches only, If I have time
I'll see what they all are in millimeters.
It's very frustrating as a homeowner who can do some of this work
themselves, drives down to the hardware store with measurement in hand only
to find there is no correlation. I've found the only way to get anything
that fits is to take the old one to the store for comparison. Buying wood
falls has the same problem, Newer wood products made in the last 20 years
are smaller but called by the same name (measurement). I hate to think of
the time and fuel wasted annually in just the United States on this sort of
thing.
Mike Payne
----- Original Message -----
From: "James Frysinger" <[email protected]>
To: "U.S. Metric Association" <[email protected]>
Sent: Friday, 30 January 2009 18:54
Subject: [USMA:42629] Re: Copper Pipe Sizes
There is tubing and then there is pipe. They have different standards.
Even those two categories subdivide by application and standard.
Copper tubing (ASTM B88)
http://www.astm.org/Standards/B88.htm
http://www.engineeringtoolbox.com/astm-copper-tubes-d_779.html
Copper pipe (ASTM B42)
http://www.astm.org/Standards/B42.htm
Summary of standards:
http://www.indpipe.com/images/PDF/copper_tube_federal_and_astm_specifications.pdf
Jim
Michael Payne wrote:
I promised to measure the copper pipes I have in my home, done with a
micrometer at 20 C.
3/4" pipe is 22,2 mm OD. 19,9 mm ID.
1/2" pipe is 16,0 mm OD. 13,8 mm ID.
1/4" pipe is 9,7 mm OD. 7,9 mm ID.
Seems like the wall thickness on this pipe is very close to 1 mm. None
of the inch sizes have any correlation to the actual "nominal" size.
Allowing for manufacturing tolerances, these pipes are as near to whole
millimeter sizes as is possible.
When you go into a hardware store and try to find fitting that are
labeled 1/2"or 3/4", etc. The actual size bears no relationship to actual
size which can be very frustrating if you measured something at home and
expect this to match what they have in the store. A 3/4" fitting from one
manufacturer will fit the 1/2" fitting from another manufacturer, so each
company is choosing any definition they want for the named size.
Mike Payne
--
James R. Frysinger
632 Stony Point Mountain Road
Doyle, TN 38559-3030
(C) 931.212.0267
(H) 931.657.3107
(F) 931.657.3108
