James, I thought Mike's figures looked small. My house is fitted with 1/2" copper pipe and the outer diameter is 18 mm. I have no idea what the ID is. But if the wall thickness is close to 1 mm, then the ID would be 16 mm or so.
Jerry ________________________________ From: James Frysinger <[email protected]> To: U.S. Metric Association <[email protected]> Sent: Friday, January 30, 2009 1:54:20 PM 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
