Question: what are metric pipe sizes?
Answer: Pipe Size. 16mm. 20mm. 25mm. 32mm. 40mm. 50mm. 63mm. 75mm. 90mm. 110mm. 125mm. 140mm. ... 
Outside Diameter (mm) 110. 125. 140. 160. 200.
Wall Thickness 10 bar (mm) - 1.0. 1.25. 1.8. 1.9. 2.4. 2.4. 2.9. 3.5. 4.2. 4.8. 5.4. ... 
Wall Thickness 16 bar (mm) 1.5. 1.5. 1.9. 2.4. 3.0. 3.7. 4.7. 5.6. 6.7. 6.6. 7.4. 8.3.