and ETP copper that can meet or exceed 101% of this standard. (Ultra-pure copper has a conductivity of S/m, 102.75% IACS.) Note that OF and ETP coppers have identical conductivity requirements. Oxygen plays a beneficial role for improving copper conductivity. During the copper smelting process, oxygen is deliberately injected into the melt to scavenge impurities that would otherwise degrade conductivity. There are advanced refining processes such as the Czochralski process than can achieve impurity levels below the C10100 specification by reducing copper grain density. At this time, there are currently no UNS/ASTM classifications for these specialty coppers and the IACS conductivity of these coppers is not readily available. Industrial applications For industrial applications, oxygen-free copper is valued more for its chemical purity than its electrical conductivity. OF/OFE-grade copper is used in plasma deposition (sputtering) processes, including the manufacture of semiconductors and superconductor components, as well as in other ultra-high vacuum devices such as particle accelerators. In any of these applications, the release of oxygen or other impurities can cause undesirable chemical reactions with other materials in the local environment. Use in home audio The high-end speaker wire industry markets oxygen-free copper as having enhanced conductivity or other electrical properties that are supposedly advantageous to audio signal transmission. In fact, conductivity specifications for common C11000 (ETP) and higher-cost C10200 oxygen-free (OF) coppers are identical; and even the much more expensive C10100 has only a one-percent higher conductivity—insignificant in audio applications. OFC is nevertheless sold for both audio and video signals in audio playback systems and home cinema. Oxygen-free phosphorus-containing copper High-electrical-conductivity coppers are distinct from coppers deoxidized by the addition of phosphorus in the smelting process. Oxygen-free phosphorus-containing copper (CuOFP) is typically used for structural and thermal applications where the copper material will be subject to temperatures high enough to cause hydrogen embrittlement or more exactly steam embrittlement. Examples include welding/brazing rods and heat exchanger tubing. Copper alloys containing oxygen as an impurity (in the form of residual oxides present in the metal matrix) can be embrittled if exposed to hot hydrogen. The hydrogen diffuses through the copper and reacts with inclusions of Cu2O, forming H2O (water), which then forms pressurized water steam bubbles at the grain boundaries. This process can cause the grains to be forced away from each other and is known as steam embrittlement (because steam is produced, not because exposure to steam causes the problem). CuOFP has