ISO 11631 pdf download

ISO 11631 pdf download.Measurement of fluid flow — Methods of specifying flowmeter performance 1 Scope This International Standard applies to technical specifications and descriptions issued by manufacturers of flowmeters. It specifies methods of describing the performance of any flowmeter, for use in either closed conduits or open channels. It indicates how flowmeters may be classified according to their traceability group, and specifies how manufacturer’s statements on traceability, quality assurance and conditions of use should be expressed, although further statements may be required for other conditions of use. NOTE The terms and definitions given in clause 3 include a large number of associated terms to encourage common usage of these terms in technical specifications. 2 Normative reference The following normative document contains provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, this publication do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent edition of the normative document indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO/TR 51 68, Measurement of fluid flow — Estimation of uncertainty of a flowrate measurement. 3 Terms and definitions For the purposes of this International Standard, the terms and definitions given in ISO 51 68 apply, adapted where appropriate to refer specifically to flowmeters and to describe the characteristics of flowmeters. 3.1 accuracy (deprecated) ^of a flowmeter& ability of a flowmeter to give responses close to a true value NOTE Accuracy is a commonly used term and can include the effects of systematic and random errors, hysteresis, deadband, etc. Although it is convenient to combine all these errors under the heading of “accuracy”, it is a qualitative term: no numerical value is attached to it, and it is not used in the performance specification of a flowmeter. 3.2 accuracy class class of flowmeters which meets certain metrological requirements that are intended to keep errors within specified limits NOTE An accuracy class is usually denoted by a number or symbol which is adopted by convention and is called the class index.3.3 bias ^of a flowmeter& systematic error of the indication of a flowmeter 3.4 calibration set of operations which establish, under specified conditions, the relationship between values of quantities indicated by...