1、SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirelyvoluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefro
2、m, is the sole responsibility of the user.”SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions.QUESTIONS REGARDING THIS DOCUMENT: (724) 772-8512 FAX: (724) 776-0243TO PLACE A DOCUMENT
3、 ORDER; (724) 776-4970 FAX: (724) 776-0790SAE WEB ADDRESS http:/www.sae.orgCopyright 1998 Society of Automotive Engineers, Inc.All rights reserved. Printed in U.S.A.TECHNICALSTANDARDS400 Commonwealth Drive, Warrendale, PA 15096-0001BOARDSTANDARDSubmitted for recognition as an American National Stand
4、ardTSB 003REV.MAY1999Issued 1965-06Revised 1999-05Superseding TSB 003 JUN92Rules for SAE Use of SI (Metric) UnitsForewordSI denotes The International System of Units (Le Systme International dUnits). SI was established in1960, under the Treaty of the Meter, by Resolutions and Recommendations of the
5、General Conference onWeights and Measures (Confrence Gnrale des Poids et Mesures, CGPM) and the International Committee forWeights and Measures (Comit International des Poids et Mesures, CIPM) on The International System of Units.The abbreviation “SI“ is used in all languages.In 1969, the SAE Board
6、of Directors issued a directive that “SAE will include SI units in SAE Standards and othertechnical reports.“ During the ensuing several decades, SAE metric policy evolved and implementationprogressed. The SAEs current metric policy is, “Operating Boards shall not use any weights and measuressystem
7、other than metric (SI), except when conversion is not practical, or where a conflicting world industrypractice exists.“Principal driving forces for SAE metrication were: worldwide movement to metric units; enactment of UnitedStates Federal metric legislation and the resultant national metrication ac
8、tivity; the international trend in industryand business throughout the world, and the growing international scope of SAE. Currently, the widespread, strongsupport for international standards harmonization is another key motivating factor in the global metricationmovement.TSB 003 (formerly SAE J916)
9、has been updated periodically, to reflect SAE metric policy evolutionas well asdevelopments in the specific, formal content of SI; and in the correct, consistent usage and application ofSI.which sometimes is referred to as “the modern version of the metric measurement system.“The content of TSB 003
10、is consistent with international and U.S. national authoritative resource documents forSIsuch as: NIST SP 330; IEEE/ASTM/ANSI SI 10; the U.S. Federal Register Notice, “Metric System ofMeasurement“; and ISO 1000. For additional information on SI, see Section 2 of this document.Throughout this documen
11、t, SI is intended to include recognized SI units, as established by CGPM, and a limitednumber of other units that, formally, are not SI units. The reason is that: SI forms the foundation of internationalstandardization; but it is recognized worldwide that certain exceptions are required. For example
12、, the degree (ofplane angle), the minute, and the hour, are non-SI units. It is the purpose of this document to provide guidanceand further references on SI metric practice for SAE use; and, also, to give guidance concerning acceptable use ofnon-SI units in SAE practice.SAE TSB 003 Revised MAY1999-2
13、-TABLE OF CONTENTS1. Scope22. References .32.1 Applicable Publications.32.2 Related Publications .33. Definitions .44. SAE Metric Policy .45. Measurement Units Approved for SAE Use .46. Units Not Approved for Use 57. Rules for Use of SI Units 58. Notes 10APPENDIX A Methods for Applying SI in Tables
14、and Graphs . 11APPENDIX B Application of SI Units . 16APPENDIX C Federal Register Notice, July 28, 1998Metric System of Measurement: Interpretationof the International System of Units for the United States. 281. Scope1.1 This SAE Standard provides information on the International System of Units (ab
15、breviated SI in all languages),and its application in measurement unit usage.1.2 The purpose is to provide information on SI and guidance on SIs correct, uniform usage in application to land,sea, and aerospace design, engineering, and manufacturing practices and technical communications.1.3 This doc
16、ument and the referenced IEEE/ASTM/ANSI SI 10 Standard, establish rules for the use of SI units inSAE technical reports, including Standards, Recommended Practices, and Information Reports, as well astechnical papers, publications, etc. This TSB 003 document is designated as applicable for goverance
17、 of SImetric practice in all SAE operations, internal and external communications, products, and services.1.4 Throughout this document, SI is intended to include recognized SI units, as established by the GeneralConference on Weights and Measures (CGPM), and a limited number of other units that, for
18、mally, are not SIunits.SI forms the foundation of international metric standardization. But it is recognized, worldwide, that certainexceptions are required. For example: the degree (of plane angle), the minute, and the hour, are non-SI units.The decibel is another example.This document provides gui
19、dance and authoritative references for acceptable use of certain non-SI units withinthe SAEs operations, practices, services, and products.SAE TSB 003 Revised MAY1999-3-2. References2.1 Applicable PublicationsThe following publications form a part of the specification to the extent specifiedherein.
20、Unless otherwise indicated, the latest revision of SAE publications shall apply.2.1.1 SAE PUBLICATIONAvailable from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.In the SAE Strategic Plan, January 1, 1997, under the Technical Standards Boards implementation of theVision “To provide world-cl
21、ass standards-related products and services to the global mobility industry,“ theSAE Vision/Ends Strategies include “H. Encourage and promote the use of metric weights and measuresby adopting the system of SI Metrics.“2.1.2 ANSI PUBLICATIONSAvailable from ANSI, 11 West 42nd Street, New York, NY 1003
22、6-8002.The SAE Metric Advisory Committee adopted (Feb. 1997) the ANSI (American National StandardsInstitute) American National Standard; IEEE/ASTM SI 10-1997 “Standard for Use of the InternationalSystem of Units (SI): The Modern Metric System“as the SAEs primary reference for SI. The SI 10document i
23、s the formally designated primary American National Standard for use of the InternationalSystem of Units.2.1.3 U.S. GOVERNMENT PUBLICATIONSAvailable from U.S. Government Printing Office, Washington, DC 20402.NIST Special Publication 330The International System of Units (SI)1991U.S. Federal Register
24、Notice, Metric System of Measurement; Interpretation of the International System ofUnits for the United States, July 28, 1998 (see Appendix C) 2.1.4 ISO PUBLICATIONAvailable from ANSI, 11 West 42nd Street, New York, NY 10036-8002.ISO 1000SI Units and Recommendations for the use of their multiples an
25、d of certain other units, 19922.2 Related PublicationsThe following publications are provided for information purposes only and are not arequired part of this document.2.2.1 SAE PUBLICATIONSAvailable from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.SAE Paper No. 850218SI Metric for the Pr
26、acticing Mechanical Engineer, S. R. JakubaSAE BookMetric (SI) in Everyday Science and Engineering, Stan Jakuba, 1993SAE authoritatively) in such documents as: the U.S. Federal Register, SI Notice; NIST SP330;IEEE/ASTM SI 10; ISO 1000.SAE TSB 003 Revised MAY1999-5-3.11 Units for Mass, Weight, and For
27、ceMass units, such as kilogram, pound, and ounce, have often been usedfor units of both mass and force. This has led to serious confusion. In SI this confusion is eliminated becausethe unit of mass is the kilogram, and the unit of force is the newton. The kilogram-force (from which the suffix“force“
28、 in practice has often been erroneously dropped) is not used. Derived units that include force areformed using the newton.3.12 WeightThe weight of a body in a particular reference frame is defined as the force that provides the body anacceleration equal to the local acceleration of free fall in that
29、 reference frame. Thus the SI unit of weight is thenewton (N).In commercial and everyday use, the term “weight“ is often used as a synonym for mass, for which the SI unitis the kilogram. The verb “to weigh“ means “to determine the mass of“ or “to have a mass of.“ Nevertheless,in scientific and techn
30、ical practice, the term “weight“ should not be used to mean mass.3.13 Work, Heat, EnergyThe joule (Nm) is work done when the point of application of a force of one newton isdisplaced a distance of one meter in the direction of the force. The SI unit of energy is the joule, which is equalto newton me
31、ter or watt second. The kilowatt hour is accepted as a unit of electrical energy only.4. SAE Metric Policy4.1 StatementThe following statement of Metric Policy was approved by the SAE Board of Directors on March4, 1993:4.1.1 SAE METRIC POLICYOperating Boards shall not use any weights and measures sy
32、stem other than metric(SI), except when conversion is not practical, or where a conflicting world industry practice exists.“5. Measurement Units Approved for SAE Use5.1 As noted above, SAE has endorsed and adopted as its primary SI Reference, theANSI/IEEE/ASTM SI 10-1997 document, which is the prima
33、ry American National Standard for SI. SAEReports and other documents must utilize, as applicable, the metric units of SI and other allowable units givenin the SI 10-1997 Standard and in Appendix C.5.2 The liter, which the General Conference established as a special name for the cubic decimeter, is a
34、pproved forSAE use. The only prefixed use allowed is mL. SAE preference should be to use cubic centimeter (cm3),rather than milliliter (mL); and cubic decimeter (dm3) rather than liter (L).5.3 In regard to time, committees should use the second and its multiples, except where minutes or hours units
35、arewarranted.EXAMPLEkm/h for velocity.5.4 Additional examples of approved non-SI units.5.4.1 The unit metric ton (exactly 1 Mg) is in wide use, but should be limited to commercial description of vehiclemass, or freight mass; and no prefix is permitted.5.4.2 The unit hectare (exactly 1 h m2) is restr
36、icted to land and water area measurement.5.4.3 In acoustics, the bel is retained as a unit for measuring the loudness of sounds, in its prefixed form, decibel(dB).SAE TSB 003 Revised MAY1999-6-5.5 Some expressions for derived SI units are valid. For example: The SI unit for electric field strength i
37、s V/m;however, field strength also is expressed in terms of base units as kgm/(s3A) or kgms3A1. Likewise,torque and bending moment (Nm) may also be expressed as kgm2/s2 or kgm2s-26. Units Not Approved for Use6.1 Gravimetric units such as kilogram-force for force and kilogram-force per square millime
38、ter or centimeter forpressure or stress, which have been commonly used in some countries, must not be used in SAE metricpractice. Similarly: calorie, bar, angstrom, and dyne are not SI units, and are not approved for general use.Numerous examples of units that are not to be used, are listed in Table
39、 8, pp.10-11, of the primary referencedStandard, IEEE/ASTM SI 10.7. Rules for Use of SI Units7.1 Requirements of this document establish the use of SI units in SAE practice, in one of the following manners:7.1.1 Exclusively as regular (primary) units.7.1.2 As regular units followed by other units in
40、 parentheses.7.1.3 Under special circumstances it is permissible to deviate from these rules. See Appendix A.7.2 SI units must be those shown in Appendices B and C, or their decimal multiples or units derived from approvedunits. For example: use kg/s for mass per unit time. In case of need for other
41、 units, the Metric AdvisoryCommittee of the SAE Technical Standards Board should be consulted. If units for quantities not included inAppendix B are required, the above committee should be contacted for guidance.An apparent anomaly exists in the use of the joule for work (J = Nm) and the use of Nm f
42、or torque or bendingmoment. These are, however, entirely different units. In the former, the unit of work results from unit forcemoving through unit distance. In the latter, there is no implication of movement, and unit force acts at rightangles to the lever arm of unit length. This would be readily
43、 seen if vectors were incorporated in the unitsymbols. For these reasons, it is important to express work and other energy in joules. Moment of force,torque and bending moment are expressed in newton meters, not joules.7.3 Symbols and Abbreviations7.3.1 DISTINCTIONThe distinction between unit symbol
44、s and unit abbreviations is not always recognized,particularly with certain U.S. inch-pound units of measure. There are, however, several distinctions betweenunit symbols and conventional abbreviations. Unit symbols are standardized forms, the same in alllanguages. They have the same form in singula
45、r and plural; they may be handled mathematically (forexample, ft/s, cm3); they are not followed by periods. Conventional abbreviations and acronyms arelanguage-dependent (for example, cfm for cubic foot per minute), shortened presentations of words ornames in a particular language. The symbols for s
46、ome U.S. units are also abbreviations (ft, in, yd). In manycases the unit symbol and the abbreviation are not the same (such as unit symbol ft3/min and abbreviationcfm; unit symbol A and abbreviation amp; unit symbol in3 and abbreviation cu in); see Table 1.7.3.2 USAGEUse symbols and technical abbre
47、viations only where necessary to save time and space and onlywhere their meaning is unquestionably clear to the intended reader. Unit symbols are to be used in place ofconventional abbreviations for units. Units used with specific numbers (for example, 3.7 m) are abbreviatedor designated by symbol,
48、except where a potential exists for misinterpretation; in which case the units shouldbe spelled out, such as unit symbol “in“ should be spelled out as “inch“ or “inches.“SAE TSB 003 Revised MAY1999-7-7.3.3 UNIT SYMBOL COMPOSITIONUnit symbols are letters or groups of letters predominantly from the La
49、tinalphabet representing the units in which physical quantities are measured (m for meter, Wh for watt hour).Non-English alphabet unit symbols are () for ohm, () for the plane angle degree or used with the Celsius( C) temperature scale, and () for the prefix micro. All unit symbols are printed in Roman (upright) type.The symbol C for degree Celsius is treated as an entity; the two components and C are not to beseparated.7.3.4 UNIT SYMBOL STYLE1Unit symbols, in general, use lower case letters. If, however, the symbol is derivedfrom a
