JIS-B-9920-2002-ENG.pdf

J IS JAPANESE I NDUSTRIAL STANDARD Translated and Published by Japanese Standards Association (JACA/ JSA) Classif kat ion of air cleanliness for cleanrooms ICs 13.040.35 Reference number : JIS B 9920 : 2002 (E) PROTECTED BY COPYRIGHT 14 S B 9920 : 2002 Foreword This translation has been made based on the original Japanese Industrial Standard revised by the Minister of Economy, Trade and Industry through deliberations at the Japanese Industrial Standards Committee, as the result of proposal for revision of Japanese Industrial Standard submitted by the Japan Air Cleaning Association (JACA)/the Japanese Standards Association (JSA) with the draft being attached, based on the provision of Article 12 Clause 1 of the Industrial Standardization Law applicable to the case of revision by the provision of Article 14. Consequently JIS B 9920 : 1989 is replaced with this Standard. This revision has been made based on IS0 14644-1 : 1999 Cleanrooms and associated controlled environments-Part 1 : Classification of air cleanliness for the purposes of making easy to compare this Standard with International Standard; to prepare Japanese Industrial Standard conforming with Inter- national Standard; and to propose a draft of International Standard which is based on Japanese Industrial Standard. Attention is drawn to the possibility that some parts of this Standard may conflict with a patent right, application for a patent after opening to the public, utility model right or application for registration of utility model after opening to the public which have technical properties. The relevant Minister and the Japanese Industrial Standards Committee are not responsible for identifying the patent right, application for a patent after opening to the public, utility model right or application for registration of utility model after opening to the public which have the said technical properties. Date of Establishment: 1975-05-01 Date of Revision: 2002-09-20 Date of Public Notice in Official Gazette: 2002-09-20 Investigated by: Japanese Industrial Standards Committee Standards Board Technical Committee on Industrial Machinery JIS B 9920 : 2002, First English edition published in 2003-05 Translated and published by: Japanese Standards Association 4-1 -24, Akasaka, Minato-ku, Tokyo, 107-8440 JAPAN In the event of any doubts arising as to the contents, the original JIS is to be the final authority. O JSA 2003 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 the publisher. Printed in Japan PROTECTED BY COPYRIGHT -,-,- B 9920 : 2002 Contents Page Introduction . 1 Scope 2 Normative references 3 Definitions 3.1 General 3.2 Airborne particle 3.3 Descriptors 3.4 Occupancy states . 3.5 Others 4 4.1 4.2 4.3 5 5.1 5.2 5.3 5.4 6 Classification of air cleanliness Occupancy statets) . Classification number . Designation of specification regarding air cleanliness . Demonstration of compliance with air cleanliness Principle Testing . Maximum permitted concentration of airborne particles . Test report Particle measuring test and test frequency . Annex A (informative) Graphical illustration of the classes of Table 1 . Annex B (normative) Determination of particulate cleanliness classification using a discrete.partic1e.counting. light-scattering instrument Annex C (normative) Statistical treatment of particle concentration data . 4 4 4 5 5 5 5 5 6 6 7 8 12 (i) PROTECTED BY COPYRIGHT B 9920 : 2002 Annex D (informative) Considerations for the counting and sizing of particles outside the size range applicable for classification 14 Annex E (normative) Sequential sampling air cleanliness evaluation method 16 Annex 1 (informative) Comparison table between JIS and corresponding International Standard . 18 (ii) PROTECTED BY COPYRIGHT JAPANESE INDUSTRIAL STANDARD JIS B 9920 : 2002 Classification of air cleanliness for cleanrooms Introduction This Japanese Industrial Standard has been prepared based on IS0 14644-1 Cleanrooms and associated controlled environments-Part 1 : Classification of air cleanliness published in 1999 as the first edition with modification in techni- cal contents. In addition, portions underlined with dots are the matters which are modified the corresponding International Standard. A list of modification with its explana- tion is shown in Annex 1. 1 Scope This Standard specifies the classification of air cleanliness in cleanrooms and associated controlled environments (hereafter referred to as “cleanroom facili- ties”) exclusively in terms of concentration of airborne particles, and its evaluation method. Only particle populations having cumulative distributions based on threshold (lower limit) sizes ranging from 0.1 ym to 5 pm are considered for classification purposes. However, concentrations of ultrafine particles (particles smaller than O. 1 pm) and macroparticles (particles larger than 5 pm) may be used to quantify these popula- tions in terms of U descriptors and M descriptors, respectively. This classification shall not be used in order to characterize a physical and chemical nature of airborne particles. Furthermore, the relation between the particle size and maximum permitted concentration specified in this Standard are intended for classifying, and do not express the actual particle size distribution. Remarks : The corresponding International Standard of this Standard shall be as follows: In addition, symbols which denote the degree of correspondence in the contents between the relevant International Standard and JIS are IDT (identical), MOD (modified), and NEQ (not equivalent) ac- cording to ISODEC Guide 21. IS0 14644-1 : 1999 Cleanrooms and associated controlled environ- ments-Part 1 : Classification of air cleanliness (MOD) 2 Normative references The following standards contain provisions which, through reference in this Standard, constitute provisions of this Standard. The most recent editions of the standards (including amendments) shall be applied. . _ _._ . JIS B 9921 Light scattering automatic particle counter JIS Z 8101-1 Statistics-Voeabulary and symbols-Part 1 :Probability and gen- eral statistical terms . 3 Definitions 8122, JIS B 9921 and JIS Z 8101-1, and the following definitions apply. For the purposes of this Standard, the definitions given in JIS 2 . PROTECTED BY COPYRIGHT 2 B 9920 : 2002 3.1 General 3.1.1 classification of air cleanliness Level of airborne particulate cleanliness applicable to a cleanroom expressed in terms of Class N, which represents maxi- mum allowable concentrations (in particles per 1 m3 of air) for considered sizes of particles. Remarks 1 Level of airborne particulate cleanliness shall be designated by N according to the formula (1) of 4.2, and shall be expressed by Class N. 2 Classification in accordance with this Standard is limited to the range extending from Class 1 through Class 9. 3 Intermediate class may be used as the level of airborne particulate cleanliness with 0.1 the smallest permitted increment; i.e. the range of intermediate classes extends from Class 1.1 through Class 8.9. 4 Classification may be specified in any of three occupancy states of cleanrooms, as-built, at-rest and operational (see 3.4). 3.2 Airborne particle 3.2.1 particle size Diameter of a sphere that produces a response, by a given par- ticle-sizing instrument, that is equivalent to the response produced by the particle being measured. Remarks : For discrete-particle-counting, light-scattering instruments, the equivalent optical diameter is used. 3.2.2 particle size distribution Cumulative distribution of particle concentra- tion as a function of particle size. 3.2.3 ultrafine particle Particle with an equivalent diameter less than 0.1 pm. 3.2.4 macroparticle Particle with an equivalent diameter greater than 5 pm. 3.2.5 fibre Particle having an aspect (length-to-width) ratio of 10 or more. 3.3 Descriptors 3.3.1 U descriptor Measured or specified concentration, of particles per 1 m3 of air, including the ultrafine particles. 3.3.2 M descriptor Measured or specified concentration of macroparticles per 1 m3 of air. 3.4 Occupancy states 3.4.1 as-built Condition where the installation is complete with all services con- nected and cleanroom facilities operated but with no production equipment, instru- ments, or personnel present. PROTECTED BY COPYRIGHT 3 B 9920 : 2002 3.4.2 at-rest Condition where the installation is complete with cleanroom facili- ties operated, equipment for production installed and operating in a manner agreed upon by the customer and supplier, but with no personnel present. 3.4.3 operational Condition where the installation is functioning in the specified manner, with the specified number of personnel present and working in the manner agreed upon. 3.5 Others 3.5.1 95 % upper confidence limit (UCL) Concentration values obtained by es- timating the concentration of a population by 5 % of significance level using Students t distribution from the average and standard deviation of the measuring particle con- centration in the space of cleanroom facility. It is used for the case of sampling locations from 2 to 9. . 3.5.2 average particle concentration at location Average particle concentra- tion for a certain period of time at a sampling location. 3.5.3 over all mean of average particle concentration at location Av a space verage particle concentration for a certain period of time at a s location. . 3.5.4 sequential sampling air cleanliness evaluation method Method for de- termining classification of air cleanliness if it is suitable or not by comparing with the reference value exDected from the observed cumulative Darticle number and the - sample volume by the continuous instrumentation at each sampling location. It is applicable to the space which is Class 4 of air cleanliness or cleaner. . 3.5.5 reference value for upper limit Particle number shown in the formula (E.l) which is used in the sequential sampling air cleanliness evaluation method. It is used for determination of non-acceptance. . 3.5.6 reference value for lower limit Particle number shown in the formula (E.2) which is used in the sequential sampling air cleanliness evaluation method. It is used for determination of acceptance. . 3.5.7 expected cumulative particle count The expected value of particle count calculated from the maximum permitted concentration, the cumulative sample vol- ume shown in the formula (E.31, which are used in the sequential sampling air clean- liness evaluation method. . 3.5.8 observed cumulative particle count Cumulative particle count of mea- sured values, which is used in the sequential sampling air cleanliness evaluation method. PROTECTED BY COPYRIGHT -,-,- 4 B 9920 : 2002 Class 3 Class 4 Class 5 Class 6 Class 7 Class 8 4 Classification of air cleanliness 1 O00 237 102 35 8 10 O00 2 370 1020 352 83 100 O00 23 700 10 200 3 520 832 29 1 O00 O00 237 O00 102 000 35 200 8 320 293 352 O00 83 200 2 930 3 520 O00 832 O00 29 300 4.1 Occupancy state(s) The particulate cleanliness of air in a cleanroom shall be defined in one or more of three occupancy states, viz. “as-built”, “at-rest”, or “op- erational” (see 3.4). 4.2 Classification number Airborne particulate cleanliness shall be designated by a classification number, N. The maximum permitted concentration of particles, C, for each considered particle size, D, is determined from the formula: (1) . cn = loN x ( D ) 0.1 m8 where, C n : the maximum permitted concentration (in particles per 1 m3 of air) of airborne particles that are equal to or larger than the considered particle size, D. C n is rounded to the nearest whole number, using no more than three significant figures. N : the classification number, which shall be a value from 1 to 4. Intermediate classification numbers may be a value from 1.1 to 8.9. D : the considered particle size (pm) 0.1 : a constant (pm) Table 1 presents classification of air cleanliness and the maximum permitted con- centration for each measuring particle size. Fig. A.l provides a representation of Table 1 in graphical form. In the case of intermediate class and measuring particle size, the maximum permitted concentration, C, shall be according to the formula (i). Table 1 Classification of air cleanliness I Classifica- I Maximum permitted concentration (particles/m3) tion of air cleanliness Measuring particle size I (N I 0 . 1 pn I 0.2pm 1 0.3 pm I 0.5 pm I 1 pm I 5 Fm I Class i I 2 1 1 Class 9 I 1 I 1 35 200000 I 8320 000 I 293 000 Remarks : Uncertainties related to the measurement process require that concen- tration data with no more than three significant figures be used in determining the classification level. PROTECTED BY COPYRIGHT -,-,- 5 B 9920 : 2002 4.3 Designation of specification regarding air cleanliness The designation of airborne particulate cleanliness for cleanrooms shall include: a) b) the occupancy state; c) the classification number, expressed as “Class IV; the considered particle size(s), and its maximum permitted concentration. Example : Class 4; operational state; 0.2 pm (2 370 particles/m3), 1 pm (83 par- t icl e s/m3) The considered particle size(s) shall be agreed upon by the customer and the supplier. If measurements are to be made at more than one considered particle size, each larger particle diameter shall be at least 1.5 times the next smaller particle diam- eter. Example : DZ 2 1.5 x D l where, DI, D z : considered particle size 5 Demonstration of compliance with air cleanliness 5.1 Principle Compliance with air cleanliness (classification of air cleanliness) requirements specified by the customer is verified by performing specified testing procedures and by providing specified documentation of the results and conditions of testing, as agreed upon by the customer and the supplier. 5.2 Testing The evaluation method for demonstrating compliance shall be as given in Annex B. An alternative method having comparable accuracy may be specified, although if no method is specified or agreed upon, the reference test method shall be used. However, for the evaluation of classification of air cleanliness which is cleaner from Class 4, the sequential sampling shown in Annex E may be applicable. Tests performed to demonstrate compliance shall be conducted using calibrated instruments. . . .-.-.- - -.-.-_._._*-.-.- _._._ 5.3 Maximum permitted concentration of airborne particles Upon comple- tion of testing in accordance with the method of Annex B, average particle concen- trations and the 95 % upper confidence limit (when applicable) shall be calculate