1、BSI Standards Publication Impact of changes in ISO fluid power particle counting Contamination control and filter test standards PD ISO/TR 16386:2014National foreword This Published Document is the UK implementation of ISO/TR 16386:2014. It supersedes BS ISO/TR 16386:1999 which is withdrawn. The UK
2、participation in its preparation was entrusted by Technical Committee MCE/18, Fluid power systems and components, to Panel MCE/18/-/6, Contamination control. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to includ
3、e all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2014. Published by BSI Standards Limited 2014 ISBN 978 0 580 78544 3 ICS 23.100.60 Compliance with a British Standard cannot confer immunity from legal obligations. This
4、 Published Document was published under the authority of the Standards Policy and Strategy Committee on 30 November 2014. Amendments/corrigenda issued since publication Date Text affected PUBLISHED DOCUMENT PD ISO/TR 16386:2014 ISO 2014 Impact of changes in ISO fluid power particle counting Contamin
5、ation control and filter test standards Consquences des changements survenus dans les normes ISO relatives au comptage des particules Contrle de la contamination et essais de filtres TECHNICAL REPORT ISO/TR 16386 Reference number ISO/TR 16386:2014(E) Second edition 2014-11-15 PD ISO/TR 16386:2014 IS
6、O/TR 16386:2014(E)ii ISO 2014 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2014 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on th
7、e internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.o
8、rg Web www.iso.org Published in Switzerland PD ISO/TR 16386:2014 ISO/TR 16386:2014(E)Contents Page Foreword iv Introduction v 1 Scope . 1 2 Historical background 1 2.1 What is ACFTD? 1 2.2 Calibrating particle counters using ACFTD 1 2.3 The original multi-pass filter test . 2 3 New test dusts 2 4 Ne
9、w APC calibration procedure 2 5 Why changes were necessary 5 6 Impact on particle sizes and contamination measurements . 5 6.1 Redefinition of particle sizes . 5 6.2 Apparent particle concentrations . 6 6.3 Contamination code reporting 8 7 Impact on filter test results . 8 7.1 Filter retained contam
10、inant capacity 8 7.2 Filtration ratio and filter efficiency . 9 8 Conclusion 11 Bibliography .12 ISO 2014 All rights reserved iii PD ISO/TR 16386:2014 ISO/TR 16386:2014(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO me
11、mber 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 established has the right to be represented on that committee. International organizations, governme
12、ntal and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. The procedures used to develop this document and those intended for its further maintenanc
13、e are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives). Attention
14、 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 patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and
15、/or on the ISO list of patent declarations received (see www.iso.org/patents). Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement. For an explanation on the meaning of ISO specific terms and expressions related to conformity
16、assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT), see the following URL: Foreword Supplementary information. The committee responsible for this document is ISO/TC 131, Fluid power systems, Subcommittee SC 6, Contamination control.
17、 This second edition cancels and replaces the first edition (ISO/TR 16386:1999) which has been technically revised.iv ISO 2014 All rights reserved PD ISO/TR 16386:2014 ISO/TR 16386:2014(E) Introduction This Technical Report has been prepared as an information document to give users an understanding
18、into the background and implications of a number of new and revised contamination control standards, namely ISO 11171, ISO 11943, ISO 16889 and ISO 4406. The adoption of four revised and updated contamination control standards, ISO 11171, ISO 11943, ISO 16889, and ISO 4406:1999, has produced signifi
19、cant changes in terms of how solid contamination levels and filter performance are reported. With ISO 11171, the method of calibrating automatic particle counters (APCs) using AC Fine Test Dust (ACFTD) used since the early 1970s has been replaced by a new method traceable to the USAs National Instit
20、ute of Standards and Technology. As a result, contaminant particle sizes previously referred to as 2 m, 5 m, 10 m, and 15 m became 4 m(c), 6 m(c), 10 m(c), and 14 m(c), respectively, where (c) refers to particle sizing and counting done with an APC calibrated in accordance with ISO 11171. ISO 11943
21、is a new standard for calibrating online particle counting systems that are primarily used to evaluate filter performance. With the ISO 16889 filter multi-pass test, which replaces the original ISO 4572 method, ISO Medium Test Dust (ISO MTD) replaces ACFTD as the test dust and the new ISO 11171 trac
22、eable particle counter calibration method is used. In ISO 4406:1999, the new calibration method is used, and a new 4 m(c) size class has been added to the solid contamination code for particle counts made with an automatic particle counter. These improvements in particle counting and filter testing
23、have a significant impact on contamination control activities. However, it is important to note that there has been no change in the actual contamination levels or in the performance of filters, or their effectiveness in protecting the reliability of components. This Technical Report discusses what
24、the changes are, why they were made, how they impact contamination levels and filter ratings, and how they benefit the industry. ISO 2014 All rights reserved v PD ISO/TR 16386:2014 Impact of changes in ISO fluid power particle counting Contamination control and filter test standards 1 Scope This Tec
25、hnical Report discusses the impact of changes in International Standards for particle counting, contamination control, and filter testing. Liquid automatic particle counters (APCs) are used in monitoring contamination levels in hydraulic fluids, to establish component and assembly cleanliness level
26、specifications, and in determining filter efficiencies and particle size ratings. As a result of the replacement of ISO 4402 with ISO 11171 (APC calibration), the replacement of ISO 4572 with ISO 16889 (multi-pass filter test), and the publication of ISO 11943 (online particle counter calibration),
27、the quality and reliability of particle count and filter test data have improved, increasing their usefulness to industry. However, the resultant redefinition of particle sizes and the use of a new test dust affect how contamination levels and filter performance are reported and interpreted. NOTE Th
28、e first editions of ISO 11171, ISO 16889 and ISO 11943 were published in 1999; all three of these International Standards either have been, or are in the process of being, revised. 2 Historical background 2.1 What is ACFTD? ACFTD was a test dust that was originally produced in batches by the AC Spar
29、k Plug Division of General Motors Corporation. ACFTD was manufactured by collecting dust from a certain location in Arizona (USA), then ball milling and classifying it into a consistent particle size distribution, including particle sizes from roughly 0 m to 100 m. The manufacturer supplied the aver
30、age volumetric particle size distribution of each batch of ACFTD, as determined by either the roller analyser of laser diffraction technique. In 1992, the production of ACFTD ceased. Because of its relatively consistent particle size distribution, ACFTD had been used to calibrate APCs in ISO 4402 an
31、d to evaluate filter performance in ISO 4572 for hydraulic and other applications. With its irregular shape and siliceous nature, ACFTD was believed to be representative of contaminants found in typical hydraulic systems. In ISO 4402, a particle size distribution for ACFTD is given which is based on
32、 optical microscopy work done in the late 1960s. At that time, there was no statistical analysis of batch- to-batch variations in ACFTD. Later, it was discovered that differences exist between the published particle size distribution and actual particle size distributions of subsequent batches of AC
33、FTD. These differences are a significant source of variability in particle count results. 2.2 Calibrating particle counters using ACFTD Though often taken for granted, particle counting is the mainstay of contamination control programs. APCs are used to monitor contamination levels in the hydraulic
34、fluid of operating equipment, to establish component and assembly cleanliness level specifications, and to provide a basis for determining filtration ratios (beta ratios), efficiencies, and particle size ratings of hydraulic filters. Calibration consists of establishing the relationship between APCs
35、 threshold voltage setting and particle size. This was done by comparing observed particle contamination levels at known threshold settings to the published ACFTD particle size distribution. Because of this, calibration accuracy depends on the accuracy of the published particle size distribution. In
36、 the absence of a more controlled contaminant, ACFTD had been used for APC calibration for hydraulic and other applications. The ACFTD particle size distribution used for calibration in ISO 4402 is based TECHNICAL REPORT ISO/TR 16386:2014(E) ISO 2014 All rights reserved 1 PD ISO/TR 16386:2014 ISO/TR
37、 16386:2014(E) on the longest chord dimension of particles as measured by optical microscopy in the late 1960s. At the time, optical microscopy was the most common method used to size and count particles. The goal of the APC calibration procedure was to ensure that particle counts obtained with an A
38、PC agreed as closely as possible with counts obtained by optical microscopy. The accuracy of the published ACFTD particle size distribution and the corresponding APC particle counter calibration has been questioned since the late 1970s. Because the original microscopy work was done on specific batch
39、es of ACFTD, the effects of batch-to-batch variability on the particle size distribution and APC calibration were not considered. Despite this, ISO 4402:1991 required laboratories to calibrate to the original published size distribution, even though the particular batch of ACFTD used likely had a di
40、fferent distribution. 2.3 The original multi-pass filter test While the ACFTD method of APC calibration was being developed, the hydraulic filter multi-pass test method was developed to measure filter performance, primarily efficiency and contaminant capacity. In 1981, the multi-pass test was publis
41、hed as ISO 4572:1981 and is still widely used. The characteristics of ACFTD that made it valuable for APC calibration also make it ideal for filter testing. In a multi-pass test, hydraulic fluid is recirculated through the filter under test while a slurry of ACFTD in hydraulic fluid is continually a
42、dded to a reservoir located upstream of the filter under test. Particle counts are taken both upstream and downstream of the filter under test throughout the test. These counts are used to calculate particle removal efficiency as a function of particle size. The results, expressed as a filtration ra
43、tio (beta ratio) depend not only on the APC calibration but also the particle size distribution of the test dust. The retained contaminant capacity of the filter under test is also reported as the amount of ACFTD needed to cause the filter to reach its terminal differential pressure. The particle si
44、ze distribution and morphology of the test dust also have a significant impact on filter efficiency and retained contaminant capacity. 3 New test dusts In 1992, efforts to revise particle counter calibration and filter test standards took on new urgency when the AC Rochester (formerly AC Spark Plug)
45、 Division of General Motors Corporation discontinued production of ACFTD. ISO Technical Committee 22 responded by developing ISO 12103-1, a filter test dust standard that specifies the physical, chemical, and particle size distribution characteristics of four silica test dusts. The new test dusts ar
46、e manufactured by jet milling instead of the ball milling process used for ACFTD. As a result, their particle size distribution and the shape of individual particles differ from ACFTD. Further, ISO 12103-1 specifies electrozone techniques, instead of the roller analyser or laser diffraction methods
47、used in the production of ACFTD, to specify the particle size distribution of the new test dusts. Because of ISO 12103-1, the new test dusts are better controlled, and batch-to-batch variability is less than that of ACFTD. One of the test dust specified in ISO 12103-1, ISO medium test dust (ISO MTD)
48、 (ISO 12103-1 grade A3) was chosen by ISO/TC 131/SC 6 to replace ACFTD for particle counter calibration and multi-pass filter testing. ISO MTD is chemically identical to ACFTD but contains fewer particles smaller than 5 m and is easier to disperse in hydraulic fluid. The high concentration of fine p
49、articles in ACFTD can result in coincidence errors during particle counting. Thus, the use of ISO MTD reduces the potential for error while retaining the desirable characteristics of ACFTD. 4 New APC calibration procedure Due to concerns about the accuracy of the ACFTD particle size distribution, the National Fluid Power Association (NFPA) in the USA began a project in 1980 to develop a traceable APC calibration method. The first attempt at a traceable method resulted in the American National Standard ANSI/(NFPA) T2.9.6 R1-1990, which
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