Copper
Copper is a distinctive reddish-brown metal prized for its exceptional thermal and electrical conductivity, natural antimicrobial properties, and ability to develop a protective patina that evolves from its initial bright finish to a rich green over decades.
Composition
Primarily pure copper (Cu) with a minimum purity of 99.9% for most architectural applications. Architectural copper is typically supplied as commercially pure copper (C11000), also known as Electrolytic Tough Pitch (ETP) copper. For specialized applications, copper may be alloyed with small amounts of other elements to enhance specific properties.
Properties
Density
559 lbs/ft³ (8,960 kg/m³)
Relatively high density, approximately 1.14 times that of steel.
Tensile Strength
32,000-50,000 psi (220-345 MPa)
Varies based on temper, with annealed copper at the lower end and cold-worked copper at the higher end.
Thermal Conductivity
231 BTU/hr·ft·°F (400 W/m·K)
Exceptional thermal conductor, second only to silver among metals.
Electrical Conductivity
100% IACS
The standard against which other electrical conductors are measured (International Annealed Copper Standard).
Corrosion Resistance
Excellent
Forms a protective patina that prevents further corrosion, providing exceptional durability in various environments including coastal areas.
Antimicrobial Properties
99.9% bacterial reduction
Naturally kills bacteria, viruses, and fungi on contact, typically eliminating >99.9% of bacteria within two hours.
Applications
Roofing and Flashing
Used for roofing systems, flashing, gutters, and downspouts due to exceptional durability and weather resistance. Copper roofing can last 100+ years with minimal maintenance, developing a distinctive patina that evolves from bright copper to brown to the characteristic green verdigris.
Architectural Cladding
Applied as wall cladding, fascia, and decorative elements to provide distinctive aesthetic appeal that changes over time. Available in various forms including sheets, panels, shingles, and tiles with different finishes and patination options.
Plumbing Systems
Widely used for water supply piping due to its corrosion resistance, natural antimicrobial properties, and reliability. Copper plumbing typically lasts 50+ years and is recyclable at end of life.
Electrical Systems
The standard material for electrical wiring and components due to superior conductivity, reliability, and fire resistance. Copper wiring minimizes energy losses and heat generation compared to alternatives.
Decorative Elements
Employed for architectural details, hardware, fixtures, and sculptures, offering both aesthetic appeal and durability. Can be finished in various ways including polishing, antiquing, and pre-patination.
Solar Thermal Systems
Used in solar collectors and heat exchangers due to exceptional thermal conductivity, corrosion resistance, and compatibility with various heat transfer fluids.
Advantages
- Exceptional longevity, with copper roofing often lasting 100+ years
- Self-healing protective patina that prevents further corrosion
- Natural antimicrobial properties that kill bacteria and viruses on contact
- Distinctive aesthetic that evolves over time, adding character
- Virtually maintenance-free in most applications
- Excellent thermal and electrical conductivity
- Fully recyclable with no degradation in properties
- Compatible with many architectural styles from traditional to contemporary
Limitations
- High initial cost compared to many alternative materials
- Runoff can stain adjacent materials if not properly detailed
- Relatively soft and susceptible to mechanical damage
- Natural patination process takes years and may develop unevenly
- Potential for theft due to high material value
- Requires skilled installation for best results
- Thermal expansion must be accommodated in design
- Not suitable for direct contact with certain other metals due to galvanic corrosion
Sustainability Profile
Copper offers excellent sustainability credentials primarily due to its exceptional longevity and complete recyclability. While primary copper production is energy-intensive, requiring approximately 30-40 MJ/kg, copper's indefinite recyclability with no loss of performance significantly reduces lifecycle impacts. Currently, about 35% of global copper demand is met through recycling, with this percentage continuing to increase. Copper's durability is remarkable, with roofing applications often lasting 100+ years and plumbing systems 50+ years, spreading embodied carbon impacts over an exceptionally long service life. The metal's high thermal conductivity can contribute to energy efficiency in appropriate applications. Copper mining and production have historically had significant environmental impacts, though modern operations have substantially improved practices. The metal's antimicrobial properties can reduce the need for chemical cleaners and disinfectants in certain applications, further enhancing its environmental profile.