IS 427 covers copper and copper alloy tubes for plumbing, HVAC refrigerant lines, heat exchangers, medical gas, and general engineering. DHP copper (deoxidized, high phosphorus) is the standard for plumbing and refrigeration. Copper tubes are naturally antimicrobial and corrosion resistant.
Specification for seamless and welded copper and copper alloy tubes for general engineering, plumbing, and heat exchanger applications.
Key Values
DHP copper (C12200) OD range6mm to 159mm
Annealed copper tensileMin 220 MPa
Standard AC tubing OD6.35mm (1/4"), 9.52mm (3/8"), 12.7mm (1/2")
Practical Notes
! Copper tubes for refrigeration MUST be Type ACR (clean, capped, dehydrated) — contamination causes compressor failure.
! DHP copper (phosphorus deoxidized) is mandatory for brazing/soldering — ETP copper becomes brittle when brazed.
! Soft (annealed) tubes are used in rolls for refrigeration/AC. Hard-drawn tubes for plumbing supply lines.
! Copper plumbing is more expensive than CPVC but lasts 50+ years and is naturally antibacterial.
! For medical gas systems, copper tubes per IS 427 with Type L wall thickness are the standard worldwide.