I'm talking about threaded fittings and what they call them here Don. Next time
I'm in your area I'll have to come over and take you to the hardware store.
It's a very frustrating experience with hundreds of different bits to connect
one piece with another. Connecting a dishwasher is one example I remember well.
Mike Payne
----- Original Message -----
From: Stan Jakuba
To: U.S. Metric Association
Cc: U.S. Metric Association
Sent: Friday, 30 January 2009 20:26
Subject: [USMA:42631] Re: Copper Pipe Sizes
Don:
I'd rather not. This subject is very specific and full of exceptions, trade
names, and new developments. To help, here is an attachment, presented on this
forum before, that hints at the complexity of the issue. Working with
experienced plumbers in my house projects I was amazed talking to them how
little they new about the pipe/tube product they had in their hands.
There used to be a respectable trade - called the pipe fitters - that hardly
exists today. At least I do not know of any parent that would have their child
training for that formally. The existence of the many nominal inches blurs the
picture, as is the fact that the metric world uses some of them also. Parallel
with their hard metric sizes, that is. Some are inch, or nominal inch, soft
converted sizes designated in mm or in symbols like "G", or in the name of the
company that brought it to the market. With "fittings" fitting, there is no
need to know the dimensions. One justification for the mess.
I, or anyone, can look up the ANSI (ASTM, ASME, SAE,...), DIN, ISO, CEN, ....
standards if they are free on line (many are not free), and get the details. I
guarantee, a most boring task for the uninitiated.
Stan
----- Original Message -----
From: Hillger, Don
To: [email protected]
Sent: 09 Jan 30, Friday 13:53
Subject: FW: [USMA:42628] Copper Pipe Sizes
Stan,
Seems like you should know the answer to this? Certainly there are
standards for copper pipe in inch sizes, so that one company does not call it
1/2 inch and another 3/4 inch??? I understand that those sizes are only names,
but certainly those names are standardized. I believe, however, that 1/2 inch
may mean different things for different kinds of pipe, steel vs. copper.
Hoping you might clarify, since I think Mike's last statement is wrong.
Don
From: [email protected] [mailto:[email protected]] On Behalf
Of Michael Payne
Sent: Friday, 2009 January 30 10:50
To: U.S. Metric Association
Subject: [USMA:42628] Copper Pipe Sizes
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
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