Remember that the pipe sizes are really nominal pipe sizes and the actual inside diameter is probably not exactly either of the dimensions shown. It’s more of a label to ensure similar pipes fit together. When we converted to metric we just changed our pip labels to NPS since US industry was not going to manufacture metric pips for highway and utility use and we have millions of meters of legacy pips. So for example a 12” water pipe became a 12 NPS pipe. Where it didn’t matter too much, say for drainage pipes that don’t have fittings, we use a substitution (vs. a conversion), i.e. we called it a 300 mm pipe but in reality it was still the same pipe that manufactures called 12”.
Howard R. Ressel Project Design Engineer New York State Department of Transportation From: owner-u...@colostate.edu [mailto:owner-u...@colostate.edu] On Behalf Of Michael Payne Sent: Wednesday, March 11, 2015 6:58 AM To: U.S. Metric Association Subject: [USMA:54632] Parker pipes This American company sells their equipment in France, looking thru their US website I see the pipes (page 8) are nominally inch but exact metric. i.e. the ½ inch is 16,5 mm, the 7/8 inch is 25 mm, etc. Most of the document does not list other SI units, they obviously assume everyone knows what Fahrenheit and inches of mercury are. I did email them asking to include SI but no reply. I’m aware the inch sizes do not correspond to the actual size, I’m not sure why? http://www.parker.com/literature/Brass%20Products/Advanced%20Air%20Pipe%20System%20Cat.%200110TRN.pdf When I called the main number in Michigan they gave me a number in Arizona that has been busy every time I’ve tried to call it. They appear to have a very good product but have a hard time selling it from my difficulty in getting information. I’m interested in using this piping to install compressed air outlets in my workshop and garage, aka a barn over here which is 25 m long. Mike Payne
