BS ISO 18898:2016 pdf download

BS ISO 18898:2016 pdf download.Rubber — Calibration and verification of hardness testers
1 Scope
This International Standard specifies procedures for the calibration and verification of durometers of types A, D, AO and AM (see ISO 7619-1), IRHD pocket meters (see ISO 7619-2), IRHD dead-load instruments (see ISO 48) and dead-load instruments using the very low rubber hardness scale (see ISO 27588).
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 48, Rubber, vulcanized or thermoplastic — Determination of hardness (hardness between 10 IRHD and 100 IRHD)
ISO 7619-1, Rubber, vulcanized or thermoplastic — Determination of indentation hardness — Part 1:Durometer method (Shore hardness)
ISO 7619-2, Rubber, vulcanized or thermoplastic — Determination of indentation hardness — Part 2: IRHD pocket meter method
ISO 18899, Rubber — Guide to the calibration of test equipment
ISO 27588, Rubber, vulcanized or thermoplastic — Determination of dead-load hardness using the very low rubber hardness (VLRH) scale
ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 48 and ISO 18899 apply.
4 Measurands and metrological requirements for calibration and verification
4.1 Environmental conditions
The ambient temperature of the measurement room in which the calibration or verification is carried out shall be 18 °C to 25 °C.
4.2 Metrological requirements
The measurands of indentor and pressure foot for the instrument to be calibrated are depicted in Figures 1 to 7 and requirements are specified in Tables 1 to 10.
5.2.3 Depth of indentation
5.2.3.1 Type A durometer
The durometer is mounted in an indentation-depth measuring device comprising a length-measuring system with a measuring range from 0 mm to 2,5 mm and a displacement device. A digital micrometer, for example, can be used as the length-measuring system. The measuring axes of the length-measuring system and of the hardness tester to be calibrated shall be in alignment and disposed vertically. Displace the indentor of the hardness tester in accordance with its scale indication from 100 Shore A to 0 Shore A in steps. Alternatively, displace the indentor a known distance in steps and read the Shore value. Measure the indentation depth at a minimum of four points, including 0 Shore A and 100 Shore A. The values of the indentation depth and the permitted tolerance are given in Table 11.