This specification provides complete evaluation procedures for two types of laboratory filter papers used in chemical analysis. The filter papers covered in this specification are grouped into two types according to which type of analysis each is used for, and seven classes according to flow rate and the type of precipitate it filters. The products should be made of materials and manufactured by methods which will ensure that each product would conform to the required values of ash content, wet bursting strength, maximum water flow rate, and precipitate retention.