Metals and Materials Processing

Industrial gases, such as nitrogen, hydrogen, and argon, for furnace atmospheres are characterized by their very high purity (>99.995% and above). For example, impurity levels for cryogenic nitrogen are 10 parts per million by volume (ppmv) oxygen or less, and 3 ppmv or less moisture (< – 90° F dew point). This purity is typically adequate for many processes involving a wide array of materials. Some materials, due to their high reactivity, may require gases with even lower levels of impurity, especially those supplied via bulk or tube trailer supply modes. Some facilities install in-line purifiers as an added precaution against impurities picked up from the houseline. In-line purification typically involves the removal of oxygen and moisture. Sometimes with argon supply, it is necessary to remove trace nitrogen impurities. The choice of purifier is dependent on the gas and the type and amount of impurities to be removed. If you are having a process issue that you think may be related to gas purity, please call Air Products at 800-654-4567.