DIN EN ISO 1133-1 specifies two procedures for the determination of the melt mass-flow rate (MFR) and the melt volume-flow rate (MVR) of thermoplastic materials under specified conditions of temperature and load. Procedure A is a mass-measurement method. Procedure B is a displacement-measurement method. Normally, the test conditions for measurement of the melt volume-flow rate and melt mass-flow rate are specified in the material standard with a reference to this part of ISO 1133. The test conditions normally used for thermoplastics are listed in Annex A. The melt volume-flow rate (MVR) is particularly useful when comparing materials of different filler content and when comparing filled with unfilled thermoplastics. The melt mass-flow rate (MFR) can be determined from MVR measurements, or vice versa, provided the melt density at the test temperature and test pressure is known. DIN EN ISO 1133-2 specifies a procedure for the determination of the melt volume-flow rate (MVR) and melt mass-flow rate (MFR) of thermoplastic materials that exhibit a high rheological sensitivity to the time-temperature history experienced by the sample during the test and/or to moisture. The International Standards ISO 1133-1:2011 and ISO 1133-2:2011 have been prepared by ISO/TC 61/SC 5 "Physical-chemical properties" (secretariat: DIN, Germany). CEN/TC 249 "Plastics", the secretariat of which is held by NBN (Belgium), is responsible for the European Standard. On the national level, Working Committee NA 054-01-03 AA "Physikalische, rheologische und analytische Prüfungen" ("Physical, rheological and analytical tests") of FNK is responsible for the standard.