Copper Round Tube Sizes and Standards
Copper round tubes are supplied in sizes from 4 mm to 150 mm, or 1/8 inch to 8-1/8 inch outer diameter, to standards including ASTM B42, B88, B111, B280, JIS H3300, and IS2501. Common grades include C10200, C11000, C12200, and C21000, in seamless and welded forms, with plumbing types DWV, K, L, and M.
Nominal Bore to Outer Diameter
Copper pipe is specified by nominal bore with a standard outer diameter: 1/8 inch NB has a 1/4 inch OD, 3/8 inch NB a 1/2 inch OD, 1/2 inch NB a 5/8 inch OD, 3/4 inch NB a 7/8 inch OD, 1 inch NB a 1-1/8 inch OD, 2 inch NB a 2-1/8 inch OD, and 4 inch NB a 4-1/8 inch OD.
Wall Thickness by Type
Copper tube is classified into Type K, L, and M by wall thickness, with the outside diameter identical at a given nominal size and the wall determining the inside diameter. For half-inch tube, Type M has a wall of 0.028 inches, Type L 0.040 inches, and Type K 0.049 inches. For 1 inch tube, Type M is 0.035 inches, Type L 0.050 inches, and Type K 0.065 inches. Type K is the thickest and strongest for underground and high-pressure service, Type L is the standard for residential and commercial plumbing, and Type M suits low-pressure residential lines.
Working Pressures
Working pressures at 150 degrees F vary with tube size and wall thickness. For example, a 1/2 inch tube with 0.065 inch wall has a working pressure of about 1600 psi, a 1 inch tube with 0.083 inch wall about 900 psi, and a 1-1/8 inch tube with 0.120 inch wall about 1300 psi. Typical residential water pressure of 40 to 80 psi is well within safe limits for all standard copper tubes.
Thermal Expansion
Copper expands with temperature change: a 10-meter length expands approximately 17 mm with a 100 degree F increase, and 34 mm with a 200 degree F increase. Long runs of copper pipe require expansion loops or slip joints to prevent stress and buckling.
Mechanical Properties by Standard
Per ASTM B88, annealed C11000 tube has a tensile strength of 200 MPa with grain size 0.025 to 0.040 mm, and hard C12200 tube provides 250 MPa. Per EN 1057, R220 provides 220 MPa with 40 percent elongation, R250 provides 250 MPa, and R290 provides 290 MPa. Per JIS H3300, hard C1220 provides 255 MPa, and annealed OL provides 205 MPa with 40 percent elongation.
Frequently Asked Questions
Q: What is the difference between Type K, L, and M?
A: Type K has the thickest wall, Type L medium, and Type M the thinnest.
Q: What is the working pressure of 1/2 inch Type L?
A: Approximately 1300 to 1600 psi at 150 degrees F.
Q: How much does copper pipe expand with 100 degrees F?
A: About 17 mm for a 10-meter length.
Q: What is the difference between C12200 and C11000?
A: C12200 is phosphorus-deoxidized and weldable; C11000 contains oxygen.
Q: What tests are performed on copper pipes?
A: Flattening, hardness, PMI, and intergranular corrosion tests, plus eddy current or hydrostatic testing.
Q: What color codes identify the types?
A: Green for Type K, blue for Type L, red for Type M.
Contact us for copper round tubes with certified dimensions, tempers, and test reports.
