Copper Tubing
(1) Copper tube in a plumbing system shall,
(a) be certified to ASTM B88, “Seamless Copper Water Tube”, or
(b) comply with ASTM B306, “Copper Drainage Tube (DWV)”.
(2) The use of copper tube shall conform to Table 7.2.7.4.
Table 7.2.7.4.
Permitted Use of Copper Tube and Pipe
Forming Part of Sentence 7.2.7.4.(2)

Notes to Table 7.2.7.4.:
P — Permitted
N — Not Permitted
(3) Copper tube used in a plumbing appliance shall conform to,
(a) ASTM B88, “Seamless Copper Water Tube”, or
(b) ASTM B68 / B68M, “Seamless Copper Tube, Bright Annealed”.
(4) Type K or L copper tube shall be used for the potable water side of a heat exchanger in a pre-engineered wastewater heat recovery system.
(5) Copper tubing shall not be used for the fixture drain or the portion of the vent pipe below the flood level rim of manually flushing or waterless urinals.
Article and table 7.2.7.4. Ontario Regulation 332/12 Building Code, O. Reg. 332/12: BUILDING CODE (ontario.ca) © Queen’s Printer for Ontario, 2021.
Note : At your local hardware store you might find Type L and Type M copper pipes on the shelf. The copper pipe diameters differ based on the thickness of their walls and, consequently, the amount of pressure they can withstand. Since the external measurements are the same, the same copper fittings are also used. You cut and sweat them using the same equipment, supplies, and methods. The larger Type L is frequently used for gas lines, hot water heating systems, commercial plumbing, and underground applications (where permitted).