Intercomparison of measurements on ear protectors by subjective and objective test methods

European Commission Directorate-General For The Information Society And Media Directorate-General For Research And Innovation

Description

Final report on the 1982 EEC intercomparison
Industrial research and development

Sujets

• Metrology
• Naoise

Informations

• Publié par: EUROPEAN-COMMISSION-DIRECTORATE-GENERAL-FOR-THE-INFORMATION-SOCIETY-AND-MEDIA-DI
• Nombre de lectures: 10
• Langue: English
• Poids de l'ouvrage: 3 Mo

Extrait

Commission of the European Communities
ber information
APPLIED METROLOGY
Intercomparison of measurements
on ear protectors
by subjective and objective test methods
Final report
on the 1982 EEC intercomparison Commission of the European Communities
m m g*
ber information
APPLIED METROLOGY
Intercomparison of measurements
on ear protectors
by subjective and objective test methods
Final report
on the 1982 EEC intercomparison
M.S. Shipton
National Physical Laboratory
Teddington, Middlesex
United Kingdom
Contract No 778/1 /000/057/82/4-BCR-UK (30)
Directorate-General
^f^^|?<^:#v''·' Science, Research and Development
1986 EUR 10575 EN Published by the
COMMISSION OF THE EUROPEAN COMMUNITIES
Directorate-General
Telecommunications, Information Industries and Innovation
Bâtiment Jean Monnet
LUXEMBOURG
LEGAL NOTICE
Neither the Commission of the European Communities nor any person acting on
behalf of then is responsible for the use which might be made of the
following information
Cataloguing data can be found at the end of this publication
Luxembourg: Office for Official Publications of the European Communities, 1986
ISBN 92-825-6362-6 Catalogue number^
© ECSC-EEC-EAEC, Brussels · Luxembourg, 1986
Printed in Belgium RE SUITE
Des serre-tête et des bouchons en mousse plastique utilisés pour la
protection individuelle contre le bruit ont fait l'objet de mesures dans
cinq laboratoires en vue de déterminer leur pouvoir d'atténuation. Les la­
boratoires ont utilisé la méthode dite subjective décrite dans la norme
ISO 4869 et pour les serre-tête, ils ont également utilisé la méthode objec­
tive suivant le projet de norme ISO/DIS 6290. L'un des laboratoires a éga­
lement suivi la méthode AFNOR (NF S31—062—1982) à titre de comparaison.
La méthode subjective conduit à une répétabilité (dans un laboratoire)
de +/- 2dB, mais les différences entre laboratoires s'étalent sur 5dB. Pour
la méthode objective, les résultats entres varient de +/- 6dB;
de plus, des résonances ont été détectées à basse fréquence (100-250Hz).
Enfin, pour les mesures d'atténuation produite par les bouchons en matière
plastique, les différences entre laboratoires sont également de +/- 6dB.
Les résultats obtenus à partir de la méthode ISO sont généralement de
2dB inférieurs à ceux obtenus par la méthode AFNOR.
Des recommandations sont formulées pour l'amélioration de la méthode
ISO.
- Ill CONTENTS
Page
SUMMARY VII
1. INTRODUCTION 1
2. PRE-CIRCULATION MEASUREMENTS 2
2.1 Non-acoustical tests
2.2 Objective tests 3
2.3 Muff selection for subjective testing
2.4 Muffn for objectiveg
2.5 Subjective tests
2.6 Distribution of muffs 4
3. POST-CIRCULATION MEASUREMENTS
3.1 Objective tests
3.2 Subjective tests 5
4. SUMMARY OF PROCEDURES USED
4.1 DTH (Denmark)
4.1.1 Objective test facilities
4.1.2 Subjective test facilities 6
4.1.3 Headband application force
4.2 INRS (France) 7
4.2.1 Objective test facilities
4.2.2 Subjective tests
4.2.3 Headband application force
4.3 NPL (United Kingdom) 8
4.3.1 Objective test facilities
4.3.2 Subjective tests
4.3-3 Headband application force
4.4 PTB (Germany) 9
4.4.1 Objective test facilities
4.4.2 Subjective tests
4.4.3 Headband application force
4.5 TNO (Netherlands) 10
4.5.1 Objective test facilities
4.5.2 Subjective tests
4.5.3 Headband application force
- V 5. COMPARISON OF RESULTS 11
5.1 Objective results
5.1.1 Values of insertion loss obtained by each
of the participating laboratories 1
5.1.2 Difference in insertion loss between
repeated tests on the same muff2
5.1.3 Central laboratory pre- and post-
circulation results 13
5.2 Subjective results
5.2.1 Mean values of attenuation
5.2.2 Central laboratory pre- and post-
circulation results4
5.3 Non-acoustical results
6. DISCUSSION 1
6.1 Comparison of pre- and post-circulation objective
measurements
6.2 Comparison of pre- and post circulation subjective
results5
6.3 Comparison of subjective results for NPL
reference muffs 16
6.4 Comparison of objective results from all laboratories 1
6.5n of subjectives from alls8
6.6 Comparison of ISO and AFNOR test results 22
6.7n of headband application force measurements 2
7. SUMMARY OF RESULTS AND CONCLUSIONS 23
7.1 Comments on ISO/DIS 6290
7.2s on ISO 4869:19837
8. RECOMMENDATIONS 28
9. ACKNOWLEDGEMENTS
10. BIBLIOGRAPHY9
FIGURES 31
PLATE 7 6
TABLES7
APPENDICES 12
VI SUMMARY
An intercomparison involving five laboratories has been carried out,
with NPL acting as the central coordinating laboratory. Detailed results
of measurements made on five hearing protector types using both the
objective and subjective methods are presented. Insertion loss
measurements made prior to despatch of twenty muffs to each
participating country are compared with those made following their
return to NPL. Results of repeated attenuation measurements at NPL and
in the participating laboratories are compared both against NPL values
and against the mean values over all laboratories.
VII