What is the metric name or designation for nominal ½″ copper pipe in the various English dialects where metric dimensions are used?

Question

I hope this question is as on-topic as this question about distances.

I need to know what people call nominal ½″ copper pipe (the stiff unbendable kind used in domestic plumbing) in English dialects where such things are stated in metric units rather than in nominal imperial units.

It's 15 mm piping. It can be bent with a pipe bending tool. The 3/4" size is now 22 mm. — Weather Vane, Feb 24 '24 at 18:47
For what purpose? https://www.engineeringtoolbox.com/cts-copper-tubing-sizes-d_2112.html — Lambie, Feb 24 '24 at 19:01
@WeatherVane I meant for other purposes: like literary translation or telling a French person our size of pipe, etc. In those cases, it might be different. I don't know if he wants the exact meaning or not. The EU measurements are not the same...Generally, one's country has its own measurements for what they actually use. So unless they are importing American piples, one has to look to that English-speaking country that uses the same exact size but in millimeters. — Lambie, Feb 24 '24 at 19:17
https://en.wikipedia.org/wiki/Copper_tubing round the world! — Lambie, Feb 24 '24 at 19:22
Americans do ɴᴏᴛ use the term ‘ɪᴍᴘᴇʀɪᴀʟ ᴜɴɪᴛꜱ’ for these: “The two systems used for specifying units of measure are the English and metric systems. …The basic units for length or distance measurements in the English system* are the inch, foot, yard, and mile. Other units of length also include the rod, furlong, and chain. survey foot definition. In the English system, areas are typically given in square feet or square yards.”* — tchrist, Feb 24 '24 at 19:49

Terry Barnes · Accepted Answer · 2024-02-24T18:34:25.300

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15mm copper pipe is also known as Type L copper pipe. That is probably what you are looking for, but some less commonly used names: copper rounds, blue stamp, and for the imperialists 1/2 inch copper pipe (even though it’s not 1/2 and is 15mm).

edited Feb 24 '24 at 18:34

answered Feb 24 '24 at 18:33

Terry Barnes

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The apparent difference (15 mm not the exact 12.7 mm) is because with the change to metric, the nominal outside diameter is used instead of the internal diameter. – Weather Vane Feb 24 '24 at 18:46
Sed nunc nullum imperium Romanum est. :) – tchrist Feb 24 '24 at 19:48
Type L is the thickness. K, L, and M being the common weights. – Phil Sweet Feb 25 '24 at 16:41
Blue stamp also refers to the type specification. Not sure if the color coding is standardized across countries. – Phil Sweet Feb 25 '24 at 16:42

What is the metric name or designation for nominal ½″ copper pipe in the various English dialects where metric dimensions are used?

1 Answers1