ASTM D578-00 pdf free.Standard Specification for Glass Fiber Strands.
For yarns made from discontinuousfilaments and described in SI units, the parts of Segment oneare respectively the symbol for the glass family as directed inSection 4; the symbol for fiber form,”D”for discontinuous;and a numeric symbol for filament diameter as directed inTable 1.For yarns made from discontinuousfilaments and described in SI units, the second segment of thedescription of discontinuous filament yarns specifies the yarnnumber of the single yarn in tex.For yarns made from discontinuousfilaments and described in SI units, the third segment of thedescription of discontinuous filament yarns specifies the num-ber of single yarns in the complete yarn. The descriptionconsists of the following with no intervening spaces: (1) acount of the singles yarns twisted together， (2) a lower casemultiplication sign or x, (3) a count of the twisted yarns pliedtogether to form the final yarn, and (4) a symbol R when yarnis reinforced by a single continuous filament yarn (Note 3).For yarns made from discontinuousfilaments and described in Sl units, the fourth segment of thedescription of discontinuous filament yarns specifies the twistlevel and direction.The description consists of an S or Z toshow direction of twist immediately followed by the twist levelin turns per metre (tpm) to the nearest 1 tpm (Note 4).For yarns made from staple fila-ments and described in inch-pound units, the second segmentof the description of staple filament yarns specifies the numberof singles yarn in the complete yarn.The description consistsof the following with no intervening spaces: ( 1) the nominalyarn number of the single yarns in hundreds of yards perpound; that is, yards per pound divided by 100, (2) the divisorsign or”3, (3) a count of the twisted yarns plied together inthe final yarn, and (4) a symbol R when yarn is reinforced bya single continuous filament yarn. (Note 3)For yarns made from staple fila-ments and described in inch-pound units, the third segment ofthe description of staple filament yarns specifies the twist leveland direction. The description consists of the twist level inturns per inch (tpi) to the nearest 0.1 tpi immediately followedby an S or Z to show direction of twist.ASTM D578 pdf download.