This part of the standard gives a general test method for the determination of the temperature of deflection under load (flexural stress under three-point loading) of plastics. Different types of test specimen and different constant loads are defined to suit different types of material. The methods specified are suitable for assessing the relative behaviour of different types of material at elevated temperature under load at a specified rate of temperature increase. The results obtained do not necessarily represent maximum applicable temperatures because in practice essential factors, such as time, loading conditions and nominal surface stress, can differ from the test conditions. True comparability of data can only be achieved for materials having the same room-temperature flexural modulus. The methods specify preferred dimensions for the test specimens. This standard differs from DIN EN ISO 75-1:2004-09 as follows: a) a fluidized bed or an air oven may also be used as heating equipment; b) the edgewise test position has been deleted; c) the standard has been editorially revised. The International Standard ISO 75-1:2013 has been prepared by ISO/TC 61/SC 2 "Mechanical properties" (secretariat: AENOR, Spain). 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 054-01-02 AA "Mechanische Eigenschaften und Probekörperherstellung" ("Mechanical properties and preparation of test specimens") of the Plastics Standards Committee (FNK) at DIN is responsible for the standard.