The purpose of this document is to specify the recommended method for measuring alpha emissivity in materials utilized in the manufacturing of semiconductors. The method specifically applies to gas proportional instruments and designates recommended instrument settings. In addition, the method discusses operation of ionization counters. The document also recommends methods for determining sample size and for evaluating instrument background accurately. Treatment of data is also outlined, including identification and elimination of systematic errors. The calculation of results and detection limits is detailed with examples in the annexes. A standard format for reporting results is specified.