Purpose This specification provides a standard for the manufacture@ performance@ inspection@ reliability and procurement of a series of manual gas tungsten arc welding equipment. This standard lists minimum requirements and is not to limit design advances. Classification The machines shall be of the following types@ sizes and classes. Type I Direct Current II Alternating Current III Combination AC/DC IV Pulsed DC Size Power source and accessory size shall be rated in terms of current rating (amperes) at 60% duty cycle for each current type. Class Commercial Hardware - stock item Modified Commercial Hardware Custom Hardware