Introduction — Three Grades, One Metal
Pure copper is the backbone of electrical engineering, HVAC, plumbing, refrigeration, heat exchange and marine systems worldwide. Yet "pure copper" is not a single material — it encompasses several commercially important grades that differ in oxygen content, trace alloying elements and the impurities intentionally left in or driven out during refining. The three most widely specified and commercially available copper grades globally are:
- C10200 — Oxygen-Free Copper (OF/OFE): 99.95% min Cu, produced in oxygen-free atmosphere
- C11000 — Electrolytic Tough Pitch Copper (ETP): 99.90% min Cu, contains controlled oxygen as Cu₂O
- C12200 — Phosphorus Deoxidised, High Residual Phosphorus Copper (DHP): 99.90% min Cu, deoxidised with phosphorus
Understanding which of these grades is correct for your application is not a minor technical detail — it can mean the difference between a system that runs reliably for 30 years and one that fails within months. This article provides a definitive comparison of all three grades across composition, conductivity, mechanical properties, corrosion resistance and the full matrix of international standards.
C11000 ETP is the world's most widely produced copper — best for electrical conductors and bus bars. C12200 DHP is the standard for plumbing, HVAC, refrigeration and fluid systems — joinable by all methods without risk. C10200 OF is specified for high-frequency electronics, vacuum electronics and applications where even trace oxygen causes failure.
C10200 — Oxygen-Free Copper (OF)
C10200, designated Oxygen-Free Copper (OF), is produced by melting and casting cathode copper in a controlled reducing or inert atmosphere — eliminating dissolved oxygen to below 0.0010% (10 ppm). The result is the highest-purity commercially available copper, with a minimum copper content of 99.95% (Cu+Ag).
C10200 Key Data
- Cu+Ag min: 99.95%
- Oxygen max: 0.0010% (10 ppm)
- Phosphorus: None added
- Electrical conductivity: ≥101% IACS
- Thermal conductivity: 391 W/m·K
- Hydrogen embrittlement: Immune
- Key standard: ASTM B170
- Use: Electronics, vacuum, RF
European / Int'l Equivalents
- EN designation: Cu-OF (CW008A)
- BS 6017: OF Cu
- DIN 17670: E-Cu 57F
- JIS H3100: C1020
- ISO 1337: Cu-OF
- IS 191: Grade ETP-OFR
C10200 Applications
- Electron tubes & klystrons
- Waveguides & RF components
- Vacuum electronic devices
- Coaxial cable inner conductors
- Semiconductor equipment
- Cryogenic applications
C11000 — Electrolytic Tough Pitch Copper (ETP)
C11000 is the most widely produced and commercially dominant form of copper in the world. Produced by electrolytic refining of blister copper, it achieves a minimum copper content of 99.90% (Cu+Ag) and contains a small, controlled amount of oxygen — typically 0.02–0.04% — in the form of cuprous oxide (Cu₂O) particles distributed throughout the grain boundaries.
C11000 Key Data
- Cu+Ag min: 99.90%
- Oxygen: 0.02–0.04% (Cu₂O)
- Phosphorus: None
- Electrical conductivity: ≥100% IACS
- Thermal conductivity: 388 W/m·K
- Hydrogen embrittlement: Susceptible
- Key standard: ASTM B152 (sheet), B187 (bus bar)
- Use: Electrical, bus bars, wire
European / Int'l Equivalents
- EN designation: Cu-ETP (CW004A)
- BS 2870: C101 ETP
- DIN 1787: E-Cu 58
- JIS H3100: C1100
- IS 191: Grade ETP
- ISO 197: Cu-ETP
C11000 Applications
- Bus bars & electrical conductors
- Transformer windings
- Motor windings & generators
- Commutator segments
- Electrical flat bars & sheets
- Power cables & earthing strips
Never braze, weld or anneal C11000 ETP copper in a reducing (hydrogen-containing) atmosphere. The oxygen in C11000 reacts with hydrogen to form water vapour at grain boundaries, causing catastrophic embrittlement — known as "hydrogen disease" — that leaves the copper with near-zero ductility. Use C12200 DHP or C10200 OF copper in any joining process involving hydrogen-bearing atmospheres.
C12200 — Phosphorus Deoxidised Copper (DHP)
C12200 is the go-to copper for the global plumbing, HVAC, refrigeration and fluid handling industries. Produced by adding a controlled amount of phosphorus (0.015–0.040%) to deoxidise the molten copper during casting, DHP copper is completely free of dissolved oxygen — making it fully immune to hydrogen embrittlement and weldable by all conventional methods.
C12200 Key Data
- Cu min: 99.90%
- Phosphorus: 0.015–0.040%
- Oxygen: <0.001% (effectively zero)
- Electrical conductivity: ≥85% IACS
- Thermal conductivity: 339 W/m·K
- Hydrogen embrittlement: Immune
- Key standard: ASTM B88 (plumbing)
- Use: Plumbing, HVAC, ACR, medical
European / Int'l Equivalents
- EN designation: Cu-DHP (CW024A)
- EN 1057: Type R / Type Y tube
- BS 2871: C106 (DHP)
- DIN 1787: SW-Cu
- JIS H3300: C1220
- IS 407 / IS 1545: C12200
- ISO 274: Cu-DHP tube
C12200 Applications
- Domestic plumbing (hot & cold water)
- HVAC refrigerant lines
- ACR (Air Conditioning & Refrigeration)
- Medical gas piping systems
- Heat exchanger tubes
- Solar thermal panels
Chemical Composition & Conductivity Comparison
| Property | C10200 (OF) | C11000 (ETP) | C12200 (DHP) |
|---|---|---|---|
| Cu+Ag min (%) | 99.95 | 99.90 | 99.90 |
| Oxygen (%) | <0.001 (10 ppm) | 0.02–0.04 | <0.001 (deoxidised) |
| Phosphorus (%) | None | None | 0.015–0.040 |
| Electrical Conductivity | ≥101% IACS | ≥100% IACS | ≥85% IACS |
| Thermal Conductivity | 391 W/m·K | 388 W/m·K | 339 W/m·K |
| H₂ Embrittlement Risk | None — immune | High — susceptible | None — immune |
| Weldability | Excellent | Poor in H₂ atmosphere | Excellent (all methods) |
| Brazeability | Excellent | Avoid reducing flame | Excellent |
| Cost (relative) | Premium (+10–15%) | Standard baseline | Near standard (+3–5%) |
| Primary ASTM Standard | ASTM B170 | ASTM B152, B187 | ASTM B88, B280, B75 |
Phosphorus atoms dissolve in the copper lattice and act as scattering centres for conduction electrons, reducing electrical conductivity from ~100% IACS (C11000) to ~85% IACS (C12200). This is why C12200 DHP should never be used as an electrical conductor in high-current applications — always specify C11000 ETP or C10200 OF for bus bars, windings and earthing systems.
Mechanical Properties
| Property | C10200 (OF) | C11000 (ETP) | C12200 (DHP) |
|---|---|---|---|
| UTS — Annealed | 220–260 MPa | 220–260 MPa | 215–260 MPa |
| UTS — Hard Drawn | 380–430 MPa | 380–430 MPa | 360–420 MPa |
| Yield Strength (0.2%) | 70–380 MPa (varies) | 70–380 MPa | 70–350 MPa |
| Elongation (annealed) | 40–55% | 40–55% | 40–55% |
| Hardness (Rockwell F) | 40–90 HRF | 40–90 HRF | 40–85 HRF |
| Density | 8.94 g/cm³ | 8.94 g/cm³ | 8.94 g/cm³ |
| Cold Work Response | Excellent | Excellent | Excellent |
Corrosion Behaviour
All three grades exhibit the outstanding natural corrosion resistance characteristic of pure copper — resistance to neutral water, seawater (at moderate velocities), atmospheric exposure, organic acids and many chemicals. The key differentiator is behaviour under specific process conditions:
- C10200 and C12200 resist attack in all standard service environments including reducing atmospheres during joining — no oxygen present to cause hydrogen disease.
- C11000 ETP performs identically to C10200 and C12200 in all normal service environments. The hydrogen embrittlement risk arises exclusively during high-temperature processing (annealing, welding, brazing) in hydrogen-containing atmospheres — not in end-use service.
- All three grades are susceptible to erosion-corrosion at high velocity (above ~1.5 m/s in seawater) and to stress corrosion cracking in the presence of ammonia and amines.
- For high-velocity seawater applications above 1.5 m/s, specify 90/10 Cupro-Nickel (C70600) or 70/30 Cupro-Nickel (C71500) instead of pure copper.
International Standards — ASTM, EN, DIN, BS, JIS, IS, ISO
| Standard | Product | Grades Covered |
|---|---|---|
| ASTM B88 | Seamless Copper Water Tube (Types K, L, M, DWV) | C10200, C12200 — primary plumbing standard worldwide |
| ASTM B280 | Seamless Copper Tube — ACR | C10200, C12200 — air conditioning & refrigeration |
| ASTM B75 | Seamless Copper Tube (general purpose) | C10200, C11000, C12200 — industrial fluid service |
| ASTM B251 | General Requirements — Copper & Alloy Tube | Umbrella document for B88, B75, B280, B111, B135 |
| ASTM B111 | Condenser Tubes & Ferrule Stock | C10200, C12200 for heat exchangers |
| ASTM B152 | Copper Sheet, Strip, Plate & Rolled Bar | C10200, C11000, C12200 — all plate/sheet forms |
| ASTM B187 | Copper Bus Bar, Rod & Strip | C11000 ETP — electrical bus bar primary standard |
| ASTM B124 / ASME SB124 | Forging Rod, Bar & Shapes | C10200, C11000, C12200 — forged fittings & flanges |
| ASTM B283 | Die Forgings | C12200 — forged copper fittings (valves, flanges) |
| ASTM B170 | Oxygen-Free Electrolytic Copper | C10200 — refinery shapes and fabricated products |
| ASTM B359 | Copper & Alloy Integral-Fin Tube | C10200, C12200 — finned heat exchanger tubes |
| EN 1057 | Copper & Alloy Tubes — Sanitary & Heating | Cu-DHP (C12200) Type R/Y/X tubes — European plumbing |
| EN 12449 | Seamless Round Tubes — General Purpose | Cu-ETP (C11000), Cu-DHP (C12200), Cu-OF (C10200) |
| EN 1652 | Plate, Sheet, Strip & Circles | Cu-ETP, Cu-DHP, Cu-OF plates and sheets |
| EN 12163 | Rods — General Purposes | Cu-ETP, Cu-DHP, Cu-OF round and hex bars |
| EN 12167 | Profiles & Rectangular Bars | Cu-ETP for bus bars; Cu-DHP for flat bars |
| DIN 1787 | Copper Rods & Bars | E-Cu 58 (C11000), SW-Cu (C12200) — German standard |
| DIN 17670 | Copper Tubes | SF-Cu / SW-Cu (C12200) and E-Cu (C11000) tubes |
| BS 2870 | Rolled Copper Sheet, Strip & Foil | C101 (ETP), C106 (DHP), C103 (OF) — British sheets |
| BS 2871 | Copper Tubes — Parts 1, 2 & 3 | C106 (DHP) for sanitary; C101 (ETP) for industrial |
| BS 2874 | Copper Rods, Sections & Wire | C101 (ETP) bus bar; C106 (DHP) machining rod |
| JIS H3300 | Copper & Copper Alloy Seamless Tubes | C1020 (OF), C1100 (ETP), C1220 (DHP) |
| JIS H3100 | Copper & Alloy Sheet & Plate | C1020, C1100, C1220 — all three grades |
| JIS H3250 | Copper & Alloy Rod & Bar | C1020, C1100, C1220 rods and bars |
| IS 191 | Electrolytic Tough Pitch Copper | Indian standard for C11000 ETP copper shapes |
| IS 407 | Copper Seamless Tubes | C12200 DHP plumbing and industrial tubes — India |
| IS 1545 | Copper Condenser & Heat Exchanger Tubes | C12200 and C10200 condenser tubes for Indian market |
| IS 2501 | Wrought Copper & Alloy Forgings | C12200 die forgings — Indian standard |
| ISO 274 | Copper & Alloy Seamless Round Tubes | Cu-DHP (C12200) tubes per international ISO standard |
| ISO 431 | Copper & Alloy Rod & Bar | Cu-ETP (C11000) and Cu-DHP (C12200) rod/bar |
Product Forms & Standards Matrix
| Product | C10200 Grades & Standards | C11000 Grades & Standards | C12200 Grades & Standards |
|---|---|---|---|
| Plumbing Tubes (Types K/L/M) | ASTM B88, EN 12449 | Not recommended | ASTM B88, EN 1057, BS 2871, JIS H3300 C1220, IS 407 |
| ACR Refrigeration Tubes | ASTM B280 | Not used | ASTM B280 — primary standard |
| Industrial / General Tubes | ASTM B75, B251, EN 12449 | ASTM B75, EN 12449 | ASTM B75, B251, EN 12449, DIN 17670 |
| Condenser & HX Tubes | ASTM B111, B359 | Limited | ASTM B111, B359, EN 12449, IS 1545 |
| Plates & Sheets | ASTM B152, EN 1652, JIS H3100 | ASTM B152, B187, EN 1652, BS 2870 | ASTM B152, EN 1652, BS 2870 |
| Bus Bars & Flat Bars | ASTM B187, EN 12167 | ASTM B187, EN 12167, BS 2874, IS 191 | Not recommended (low conductivity) |
| Round Bars & Rods | ASTM B124, EN 12163, ISO 431 | ASTM B124, B187, EN 12163, ISO 431 | ASTM B124, EN 12163, BS 2874, ISO 431 |
| Die Forgings | ASTM B283, ASTM B124 | ASTM B283 | ASTM B283, IS 2501 |
| Flanges | ASME B16.5, EN 1092-1 | ASME B16.5 | ASME B16.5, ASME B16.47, EN 1092-1, JIS B2220 |
| Wrought Fittings | ASME B16.22 | ASME B16.22 | ASME B16.22, ASME B16.18, MSS SP-104, BS EN 1254, ISO 4144 |
Applications — Which Grade for Which Use?
| Application | Recommended Grade | Reason |
|---|---|---|
| Domestic water supply pipes (Type K/L) | C12200 DHP | ASTM B88 — joinable by soldering, brazing or press-fit |
| ACR refrigerant lines | C12200 DHP | ASTM B280 — internally clean & nitrogen-charged for ACR duty |
| Medical gas piping (O₂, N₂, CO₂, N₂O) | C12200 DHP | ASTM B819 — degreased and capped for medical gas service |
| Electrical bus bars & conductors | C11000 ETP | ASTM B187 — highest conductivity at lowest cost |
| Transformer & motor windings | C11000 ETP | Maximum conductivity; reduce I²R losses |
| Electron tubes, klystrons, magnetrons | C10200 OF | Zero oxygen essential; any O₂ would degrade vacuum |
| High-frequency RF components & waveguides | C10200 OF | Highest purity for skin-effect conductance |
| Solar thermal collector tubes | C12200 DHP | Brazeable in air with standard flux & phosphor-copper filler |
| Heat exchanger & condenser tubes | C12200 DHP | ASTM B111 — excellent formability and corrosion resistance |
| Copper flanges & fittings (piping systems) | C12200 DHP | ASME B16.22, B16.5 — weldable by all methods |
| Earthing & grounding systems | C11000 ETP | Maximum conductivity for fault current dissipation |
| Roofing, cladding & architectural sheet | C11000 ETP | ASTM B370 — standard for copper architectural products |
Selection Guide — One-Minute Decision
Need maximum electrical conductivity? → C11000 ETP (ASTM B187, EN 12167 Cu-ETP)
Carrying fluids, gases or refrigerants? Need to braze or solder? → C12200 DHP (ASTM B88 / ASTM B280 / EN 1057 Cu-DHP)
Electronics, vacuum tubes, high-frequency RF, cryogenics? → C10200 OF (ASTM B170 / EN 12449 Cu-OF)
Forming heat exchanger tubes? → C12200 DHP (ASTM B111 / ASTM B359)
Hot forging fittings or flanges? → C12200 DHP (ASTM B283 / ASME B16.22 / ASME B16.5)
Frequently Asked Questions
Can I substitute C12200 for C11000 in an electrical application?
Only if conductivity loss is acceptable. C12200 carries approximately 85% IACS vs 100% IACS for C11000 — a 15% reduction in conductivity which means higher I²R losses and need for larger cross-sectional area for the same current capacity. For bus bars, motor windings and earthing, always use C11000 ETP.
Can I braze C11000 ETP copper pipe with a standard torch?
Yes, using an air-propane or air-acetylene torch with standard flux — this does not involve a reducing hydrogen atmosphere, so hydrogen embrittlement is not a concern. The risk arises only in furnace brazing or bright annealing in hydrogen or forming gas atmospheres.
What is ASTM B88 Type K, L and M?
ASTM B88 specifies three wall thickness types for C12200 DHP copper water tube: Type K (heaviest wall — underground and high-pressure service), Type L (medium wall — the most common for residential plumbing) and Type M (lightest wall — low-pressure interior systems). All three meet the same ASTM B88 chemical specification for C12200 DHP.
Does Melta Alloys supply all three copper grades?
Yes — Melta Alloys supplies C10200, C11000 and C12200 in pipes & tubes (ASTM B88, B75, B280, B111, EN 1057, EN 12449), plates & sheets (ASTM B152, EN 1652), bars & rods (ASTM B124, EN 12163), flanges (ASME B16.5, EN 1092-1) and fittings (ASME B16.22, MSS SP-104) — all with full Mill Test Certificates and export documentation.
