ISO 844-2014 pdf free.Rigid cellular plastics —  Determination of compression properties. ISO 844 specifies a method of determining: a) the compressive strength and corresponding relative deformation, b) the compressive stress at 10 % relative deformation, and c) when desired, the compressive modulus of rigid cellular plastics. There are two procedures: — Procedure A employs crosshead motion for determination of compressive properties. Procedure A is intended to be used when compressive stress at 10 % relative deformation has to be determined. — Procedure B employs strain measuring devices mounted on the specimen (contact extensometer) or similar device which measures directly sample deformation. Procedure B is intended to be used when compressive modulus has to be determined. NOTE Compressive strength (at maximum load) can he determined either with Procedure A and B. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 1923, Cellular plastics and rubbers — Determination of linear dimensions 3 Terms and definitions For the purposes ol this document, the lollowing terms and…

DIN EN ISO 844:2014 pdf free.Rigid cellular plastics -Determination of compression properties (ISO 844:2014); ;English version EN ISO 844:2014,English translation of DIN EN ISo 844:2014-11. A force sensor shall be fixed to one of the machine plates in order to measure the force F produced by the reaction of the test specimen upon the plates during the test. This sensor shall be such that its own deformation during the course of the measurement operation is negligible compared with that being measured and, in addition, it shall allow the continuous measurement of the force at any point in time with an accuracy of ± 1 %. Itis recommended that a device he used for the simultaneous recording of the force Fand the displacement x that allows, by obtaining a curve of F = 1(x), the graphical determination of the pair of values F; x required In Clause 9 with the accuracy laid down in 6.2.1 and this subclause, and provides additional information on the behaviour of the product. 6.2.3 Calibration Devices for measuring and, if applicable, recording graphically the force and displacement produced by the test machine shall he checked periodically. The devices shall he checked by using a series of…