To monitor production of carbon fibers, each manufacturer has their own inhouse test procedures. The primary aim of these procedures is to ensure the uniformity of products, with all measured properties within the stipulated manufacturing range. In the developmental stages, only a few ASTM standards but no SACMA test procedures were available. So, Courtaulds developed and published their Grafil Test Methods , which were regularly updated. Major carbon fiber users and government agencies, however, had their own buying specifications, which in many instances incorporated their own test procedures. There was consequently a great demand for unified national specifications but, unfortunately, each country tended to write their own specifications e.g. U.S.A. (ASTM), Great Britain (BSI), Japan (JIS) and Germany (DIN), which led to great confusion.