ASTM D646-13

4.1 Most paper is bought and sold in accordance with its mass per unit area, and therefore has great significance both to the consumer and the producer in defining price. Also, the values of many physical properties such as bursting strength, thickness, and bulk are interpreted and specified with regard to the particular mass per unit area involved.

1.1 This test method covers the determination of the mass per unit area of paper and paperboard.

1.2 In the SI metric units system, the mass per unit area of paper and paperboard is expressed in grams per square meter (g/m²).

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.