BS ISO 27893:2011 BSl Standards Publication Vacuum technology Vacuum gauges Evaluation of the uncertainties of results of calibrations by direct comparison with a reference gauge bsi. ..making excellence a habit.. BS ISO 27893:2011 BRITISH STANDARD National foreword This British Standard is the UK implementation of IS 27893:2011. The UK participation in its preparation was entrusted to Technical Committee MCE/8/-/4, Vacuum technology. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. @BSI 2011 ISBN 9780 580743917 ICS 23.160 Compliance with a British Standard cannot confer immunity from legal obligations. This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31August 2011. Amendments issued since publication Date Text affected BS ISO 27893:2011 ISO INTERNATIONAL STANDARD 27893 First edition 2011-08-15 Vacuum technology Vacuum gauges - Evaluation of the uncertainties ofresultsofcalibrationsbydirect comparison with a reference gauge Technique du vide-Manometres a vide-Evaluation de I'incertitude desresultats des étalonnagesparcomparaison directeavec un manometrede reference Referencenumber ISO 27893:2011(E) @ ISO 2011 BS ISO 27893:2011 ISO27893:2011(E) COPYRIGHTPROTECTEDDOCUMENT ISO2011 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or IsO's member body in the country of the requester. ISO copyright office Case postale 56.CH-1211Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail [email protected] Web www.iso.org Published in Switzerland ii @ ISO 2011 All rights reserved BS ISO27893:2011 ISO27893:2011(E) Contents Page Foreword .iv 1 Scope 2 Normative references 3 Terms and definitions 4 Symbolsandabbreviatedterms. 3 5 Basic conceptand model 5.1 General 5.2 Sum model. 5.3 Quotientmodel. 5.4 Combination ofthetwomodels. 6 Calculation of uncertainty in the sum model .. 6.1 Total uncertaintySum model .. 6.2 Uncertainty contributions due to reference standard .6 6.3 Uncertainty contributions due to unit under calibration. 6.4 Uncertainty contributionsdueto calibrationmethod orcalibrationconditions 6.5 Coverage factor.. 7 Calculation of uncertainty in the quotient model.. .9 7.1 Total uncertainty- -Quotientmodel.... 9 7.2 Uncertainty contributions due to reference standard.. .9 7.3 Uncertainty contributionsduetotheunit undercalibration. 10 7.4 Uncertaintycontributionsduetocalibrationmethodorcalibrationconditions 11 7.5 Coverage factor.......... 8 Combination of the sumand quotient modelforerrorof reading... 9 Reporting uncertainties.... 9.1 Uncertainty budget... 9.2 Calibration certificate... 14 Bibliography. 15 @ ISO 2011 All rights reserved ili BS ISO 27893:2011 ISO27893:2011(E) Foreword IsO (the International Organization for Standardization) is a worldwide federation of national standards bodies (isO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been InternationalElectrotechnicalCommission(lEC)onallmattersofelectrotechnicalstandardization International Standards are drafted in accordance with the rules given in the ISO/lEC Directives, Part 2. adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such p