Testing of high flow rate respirable samplers to …

1 Prepared by the Health and Safety Laboratory for the Health and Safety Executive 2010 Health and Safety ExecutiveTesting of high flow rate respirable samplers to assess the technical feasibility of measuring respirable crystalline silica RR825 Research ReportPeter Stacey and Andrew Thorpe Health and Safety LaboratoryHarpur HillBuxton DerbyshireSK17 9 JNTesting of high flow rate samplers to assess the technical feasibility of measuring respirable crystalline report describes Testing of five personal respirable dust samplers operating with flow rates of 4 l/min or greater, available in 2008. Three were commercially available, one a prototype and one adapted at HSL to operate at a higher flow rate.

2 Testing compared these samplers with a reference sampler , operating at l/min, to ascertain if an increase in the mass of dust sampled could improve the reliability of measurements of respirable crystalline silica (RCS). None of the samplers satisfied all of the success criteria for the project, which included, the ability to maintain the specified flow rate over 4-hours, ease of use in the workplace, and an improvement in the measurement precision without additional complications caused by the increased mass of sampled dust. Infrared analysis is not recommended for samples with dust mixtures, because it was difficult to obtain a reliable result when the loading exceeds 1 mg.

3 The samplers with the best performance were the PGP10 and the modified samplers . The other samplers tested either under-sampled or there was lost sample during transfer onto the analysis filter. When field tests were conducted, air sampling pumps operating with the modified samplers failed to maintain a consistent flow rate, and the PGP 10 samplers were heavy and caused discomfort for the workers The report recommends the use of the PGP 10 and samplers after further work to resolve the minor issues and changes in the sampling and measurement strategies to accommodate new procedures for use of higher flow rate report and the work it describes were funded by the Health and Safety Executive (HSE).

4 Its contents, including any opinions and/or conclusions expressed, are those of the authors alone and do not necessarily reflect HSE of high flow rate respirable samplers to assess the technical feasibility of measuring respirable crystalline silica HSE BooksHealth and Safety Executive Crown copyright 2010 First published 2010 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording or otherwise) without the prior written permission of the copyright for reproduction should be made in writing to:Licensing Division, Her Majesty s Stationery Office,St Clements House, 2-16 Colegate, Norwich NR3 1 BQor by e-mail to CONTENTS 1 1 Background.

5 1 Principles of the analysis techniques .. 1 2 STAGE 1: SELECTION OF EQUIPMENT INCLUDED IN THE 4 Selection of 4 Selection of filters .. 4 Selection of sampling 4 3 CALIBRATIONS .. 10 Calibrations for x-ray diffraction .. 10 Calibrations for infrared analysis .. 10 Discussion .. 10 4 STAGE 2B: ABSORPTION AND DEPTH 12 Evaluation of absorption and depth effects in x-ray diffraction analysis. 12 Evaluation of the effect of absorption on FTIR 20 5 STAGE 3: ASSESSMENT OF THE BIAS OF 23 Sampling tests with Arizona road 23 Gravimetric Analysis .. 24 RCS Analysis by X-ray Diffraction .. 25 RCS Analysis by Direct on Filter Infrared Analysis.

6 26 Recovery for the PGP 10 cyclone using cellulose nitrate 27 6 STAGE 4: ASSESSMENT OF BIAS OF ANALYTICAL TECHNIQUES .. 29 Workplace tasks examined .. 29 Particle SIZE distribution of the generated 30 Gravimetric 30 X-ray Diffraction analysis .. 33 7 FIELD TRIALS .. 36 Approach .. 36 Analytical Results .. 36 Practical experience .. 39 Comments recorded from the 39 8 OVERALL PERFORMANCE OF samplers .. 44 Modified GK 44 IOM sampler with foam IPP Impactor .. 44 PGP 10 45 CIP 10 sampler .. 459 PRECISION OF XRD MEASUREMENTS AT 46 iii 10 PROJECT SUCCESS 49 11 REFERENCES.

7 5212 APPENDIX 1: PRESSURE DROP WITH FLOW RATE ACROSS AN MIXED CELLULOSE ESTER FILTER .. 54 13 APPENDIX 2: INSTRUMENTAL PARAMETERS .. 56 X-ray Diffraction .. 56 56 14 APPENDIX 3: CALIBRATIONS FOR X-RAY DIFFRACTION .. 57 SIMPEDS GK cyclone Calibrations .. 57 IOM sampler wih foam 58 15 APPENDIX 4: CALIBRATION FOR THE INDIRECT ANALYSIS PROCEDURE ..59 16 APPENDIX 5: CALIBRATIONS FOR INFRARED DIRECT ON-FILTER 60 SIMPEDS .. 60 GK 60 IOM sampler with foam 61 17 APPENDIX 6: CALIBRATIONS FOR INFRARED INDIRECT 62 18 APPENDIX 7: XRD SCANS OF ABSORPTION TEST MATERIALS.

8 64 19 APPENDIX 8: INFRA RED 67 20 APPENDIX 9: PARTICLE SIZE DISTRIBUTIONS FROM SIMULATED WORK 69 21 APPENDIX 10: GRAVIMETRIC ANALYSIS WITH SIMULATED WORK 71 22 APPENDIX 11. DUST LOSSES FROM PVC 72 23 APPENDIX 12: STAGE 4 XRD COMPARISON WITH SIMPEDS .. 75 24 APPENDIX 13 STAGE 4: COMPARISON WITH PGP 10 CYCLONES 77 25 SITE 1: FOUNDRY 7926 SITE 2: POT/BRICK MANUFACTURE .. 94 27 SITE 3: CERAMICS 105 28 SITE 4 115ivii 29 SITE 5: QUARRY VISIT.

9 123 v EXECUTIVE SUMMARY Objectives This project investigated the technical feasibility of using high volume personal respirable dust samplers (> 4 l/min) to improve the reliability of measurements of respirable crystalline silica (RCS) using x-ray diffraction (XRD) and Fourier Transform Infra Red (FTIR) analysis in order to support further reductions in the United Kingdom s (UK) Workplace Exposure Limit (WEL). The objective was to evaluate the samplers against the following criteria: Can the nominal flow rate of the sampler be maintained over typical sampling periods (within 5%)?

10 Does the sampler have a performance comparable with the SIMPEDS respirable dust sampler recommended in the Health and Safety Executive (HSE) method MDHS 14 for dust sampling (HSE 2000)? Is the sampler be comfortable to wear without interfering with the activity of the worker and is it applicable for use in UK workplaces? Does the increased mass of dust collected with the sampler affect RCS measurement by XRD and FTIR? Does the increased mass of dust collected with the sampler increase interferences? Would the precision of measurement at the proposed WEL of be equal to or better than the precision of 12% (2 ) at the current WEL of Five high flow rate (> 4 l/min) personal samplers were evaluated in this project: a GK cyclone, modified to use 25 mm rather than 37 mm diameter filters, operating at 4 l/min; the PGP 10 cyclone, operating at 10 l/min; a prototype IPP impactor, operating at 8 l/min; an IOM sampler with a foam separator selected to operate at 4 l/min; and the CIP 10 sampler , operating at 10 l/min.