1、 IEC 60721-2-3 Edition 2.0 2013-06 INTERNATIONAL STANDARD NORME INTERNATIONALE Classification of environmental conditions Part 2-3: Environmental conditions appearing in nature Air pressure Classification des conditions denvironnement Partie 2-3: Conditions denvironnement prsentes dans la nature Pre
2、ssion atmosphrique IEC 60721-2-3:2013 THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2013 IEC, Geneva, Switzerland 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 photocopyi
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16、ion 2.0 2013-06 INTERNATIONAL STANDARD NORME INTERNATIONALE Classification of environmental conditions Part 2-3: Environmental conditions appearing in nature Air pressure Classification des conditions denvironnement Partie 2-3: Conditions denvironnement prsentes dans la nature Pression atmosphrique
17、INTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION ELECTROTECHNIQUE INTERNATIONALE H ICS 19.040 PRICE CODE CODE PRIX ISBN 978-2-83220-875-5 Registered trademark of the International Electrotechnical Commission Marque dpose de la Commission Electrotechnique Internationale Warning! Make sure that yo
18、u obtained this publication from an authorized distributor. Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agr. 2 60721-2-3 IEC:2013 CONTENTS FOREWORD . 3 1 Scope . 5 2 Normative references . 5 3 Terms and definitions . 5 4 Air pressure effects 5 4.1 Gene
19、ral . 5 4.2 Air pressure lower than normal 5 4.3 Air pressure higher than normal 6 5 Values of air pressure 6 Bibliography 8 Table 1 Normal air pressure related to altitudes above and below sea-level . 6 60721-2-3 IEC:2013 3 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ CLASSIFICATION OF ENVIRONMENTAL
20、 CONDITIONS Part 2-3: Environmental conditions appearing in nature Air pressure FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promo
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28、s publication. 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and members of its technical committees and IEC National Committees for any personal injury, property damage or other damage of any nature whatsoever, whether direct or ind
29、irect, or for costs (including legal fees) and expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications. 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable for t
30、he correct application of this publication. 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 60721-2-3 has been p
31、repared by IEC technical committee 104: Environmental conditions, classification and methods of test. This second edition cancels and replaces the first edition, published in 1987, and constitutes a technical revision. The main changes with regard to the previous edition are as follows: removal of f
32、igures for decreasing cooling efficiency for altitude; simplification of Table 1; additional formula for calculating air pressure from altitude. 4 60721-2-3 IEC:2013 The text of this standard is based on the following documents: FDIS Report on voting 104/611/FDIS 104/615/RVD Full information on the
33、voting for the approval of this standard can be found in the report on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. A list of all parts in the IEC 60068 series, under the general title Classification of environmental condit
34、ions, can be found on the IEC website. The committee has decided that the contents of this publication will remain unchanged until the stability date indicated on the IEC web site under “http:/webstore.iec.ch“ in the data related to the specific publication. At this date, the publication will be rec
35、onfirmed, withdrawn, replaced by a revised edition, or amended. 60721-2-3 IEC:2013 5 CLASSIFICATION OF ENVIRONMENTAL CONDITIONS Part 2-3: Environmental conditions appearing in nature Air pressure 1 Scope This part of IEC 60721 presents a selection of different values of air pressure appearing in nat
36、ure. It is intended to be used as part of the background material when selecting appropriate severities of air pressure for product applications, which products are liable to be exposed during storage, transportation and use. 2 Normative references The following documents, in whole or in part, are n
37、ormatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60721-1, Classification of environmental conditions Pa
38、rt 1: Environmental parameters and their severities 3 Terms and definitions Terms and definitions are defined, in context, throughout the present standard. 4 Air pressure effects 4.1 General When selecting severities of the parameter air pressure for product application, the values given in IEC 6072
39、1-1 should be applied. Air pressure can affect products in various ways, the most important of which are as follows: 4.2 Air pressure lower than normal Low air pressure occurring at altitudes above sea-level can affect products as follows: leakage of gases or fluids from gasket-sealed containers; ru
40、pture of pressurized containers; change of physical and chemical properties of low density materials; erratic operation or malfunction of equipment from arcing or corona as the breakdown voltage between two electrodes in air decreases with pressure (the breakdown voltage of air in a uniform electric
41、 field depends on the product of the gas pressure and the electrode spacing for a given electrode shape and material (Paschens law); decreased efficiency of heat dissipation by convection and conduction in air; acceleration of effects due essentially to temperature, for example volatilization of pla
42、sticizers, evaporation of lubricants, etc. 6 60721-2-3 IEC:2013 4.3 Air pressure higher than normal High air pressure occurring in natural depressions and mines can have a mechanical effect on sealed containers. 5 Values of air pressure The normal value of air pressure at mean sea level is 101,325 k
43、Pa. Depending on meteo- rological conditions, air pressure at sea level may vary. Similar variation occurs at altitudes above and below sea-level. In areas above sea-level, air pressure is lower than at sea level; in areas below sea level (natural depressions and mines) it is higher than at sea-leve
44、l. Table 1 gives standard values of air pressure, in round figures, for different altitudes. Table 1 Normal air pressure related to altitudes above and below sea-level Altitude m Air pressure kPa 15 000 12,0 10 000 26,6 8 000 35,6 6 000 47,2 5 000 54,0 4 000 61,6 3 000 70,1 2 000 79,5 1 000 89,9 0 S
45、ea level 101,3 400 106,2 NOTE 1 Values corresponding to the highest altitudes are given to take into account meteorological observation units and transportation by air. NOTE 2 The altitude 400 m corresponds to the deepest natural depression in the world. NOTE 3 For further information, see 1. 60721-
46、2-3 IEC:2013 7 According to 1, the formula for calculating the relation between altitude and air pressure is: p = p 0 (1 (L h) / T 0 ) g / (R L) ) (for altitude below 11 000 m); and p = p 1 e ( g (h h 1 ) / (R T 1 )(for altitude between 11 000 m and 20 000 m); where p is the air pressure (kPa); p 0=
47、 101,325 kPa (standard pressure at sea level); p 1= 22,632 kPa (standard pressure at 11 000 m); h is the altitude above sea level (m) ( 20 000 m); h 1= 11 000 m (altitude at 11 000 m); L = 0,006 5 K/m (temperature lapse rate); T 0= 288,15 K (standard temperature at sea level); T 1= 216,65 K (standar
48、d temperature at 11 000 m); g = 9,806 65 m/s 2(earth-surface gravitational acceleration); R = 287,053 J/(kg.K) (universal gas constant). 8 60721-2-3 IEC:2013 Bibliography 1 ISO 2533, Standard Atmosphere _ 10 60721-2-3 CEI:2013 SOMMAIRE AVANT-PROPOS 11 1 Domaine dapplication 13 2 Rfrences normatives
49、. 13 3 Termes et dfinitions 13 4 Effets de la pression atmosphrique . 13 4.1 Gnralits 13 4.2 Pression atmosphrique infrieure la normale 13 4.3 Pression atmosphrique suprieure la normale 14 5 Valeurs de la pression atmosphrique 14 Bibliographie . 16 Tableau 1 Pression atmosphrique normale aux altitudes suprieures et infrieures au niveau de
