1、BRITISH STANDARD BS 350:2004 Conversion factors for units ICS 01.060; 17.020 BS 350:2004 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 25 May 2004 BSI 25 May 2004 First published June 1930 Second edition July 1944 Third edition, as BS 350-1
2、, February 1959 Fourth edition, as BS 350-1, March 1974 Fifth edition, as BS 350, May 2004 The following BSI references relate to the work on this British Standard: Committee reference SS/7 Draft for comment 03/659657 DC ISBN 0 580 43516 4 Committees responsible for this British Standard The prepara
3、tion of this British Standard was entrusted to Technical Committee SS/7, General metrology, quantities and units, upon which the following bodies were represented: British Measurement and Testing Association City University Department of Trade and Industry, National Weights and Measures Laboratory F
4、ederation of Small Businesses Institute of Measurement and Control Institution of Electrical Engineers National Physical Laboratory Royal Society of Chemistry Society of Chemical Industry Trading Standards Institute Coopted members Amendments issued since publication Amd. No. Date CommentsBS 350:200
5、4 BSI 25 May 2004 i Contents Page Committees responsible Inside front cover Foreword iv 1S c o p e 1 2N u m b e r 1 3L e n g t h 2 4 Area (length squared) 6 5 Volume and capacity (length cubed) 9 6 Modulus of section, first moment of area 12 7 Second moment of area, or geometrical moment of inertia
6、12 8P l a n e a n g l e 1 7 9S o l i d a n g l e 1 8 10 Time 18 11 Linear velocity (speed) (length/time) 19 12 Angular velocity (angle/time) 20 13 Frequency (number/time) 22 14 Acceleration (length/time squared) 23 15 Mass 24 16 Mass per unit length (or lineic mass) (formerly linear density) (mass/l
7、ength) 29 17 Mass per unit area (areic mass) (mass/length squared) 31 18 Specific surface, or area per unit mass 31 19 Area per unit capacity 34 20 Density (volumic mass), (mass/volume) 34 21 Mass concentration (mass/volume) 36 22 Specific volume (volume/mass) 38 23 Mass rate of flow (mass/time) 38
8、24 Volume rate of flow (volume/time) 40 25 Traffic factors 42 26 Moment of inertia (mass length squared) 43 27 Momentum (linear) (mass velocity) 43 28 Angular momentum (mass velocity length) 43 29 Force (mass acceleration) 44 30 Weight 46 31 Moment of force, or torque (force length) 46 32 Force per
9、unit length (force/length) 49 33 Pressure (force/area) 49 34 Stress (force/area) 52 35 Viscosity, dynamic (stress/velocity gradient) 56 36 Viscosity, kinematic (length squared/time) 58 37 Energy (work, heat, etc.) 60 38 Power (energy/time) 62 39 Temperature, including temperature difference or inter
10、val 66 40 Specific energy (energy or heat)/mass 67 41 Heat content, volume basis (heat/volume) 68 42 Specific heat capacity heat/(mass temperature interval) 72 43 Specific entropy heat/(mass thermodynamic temperature) 73 44 Heat capacity, volume basis heat/(volume temperature interval) 73BS 350:2004
11、 ii BSI 25 May 2004 Page 45 Heat flux density heat/(area time) 74 46 Thermal conductance (heat transfer coefficient) 77 47 Thermal conductivity heat length/(area time temperature difference) 78 48 Thermal resistivity area time temperature difference/(heat length) 79 49 Heat release rate (e.g. as use
12、d in connection with furnaces)heat/(volume time), or (power/volume) 80 50 Thermal diffusivity (area/time) 80 Annex A (informative) Commentary on imperial and metric systems of measurement and units 81 Index of symbols and abbreviations 84 Index of terms 89 Bibliography 105 Table 1 Prefixes denoting
13、decimal multiples or submultiples 1 Table 2 Meaning of million, billion, trillion, etc. 2 Table 3 Length 5 Table 4 Area 8 Table 5 Area of section of wire 9 Table 6 Volume and capacity 13 Table 7 Volume and capacity (continued) 14 Table 8 Volume and capacity (continued) 15 Table 9 Relationship betwee
14、n UK (imperial) and US units of capacity 16 Table 10 Second moment of area 16 Table 11 Plane angle 18 Table 12 Linear velocity 21 Table 13 Angular velocity and velocity of rotation 22 Table 14 Acceleration 23 Table 15 Mass 26 Table 16 Mass (continued) 27 Table 17 Mass (continued) 28 Table 18 Mass pe
15、r unit length (lineic mass) 30 Table 19 Mass per unit area (areic mass) 32 Table 20 Specific surface, or area per unit mass 33 Table 21 Area per unit capacity 34 Table 22 Density (volumic mass) (mass/volume) 35 Table 23 Mass concentration 37 Table 24 Specific volume 39 Table 25 Mass rate of flow 40
16、Table 26 Volume rate of flow 41 Table 27 Fuel consumption (volume/distance) 42 Table 28 Fuel consumption (distance/volume) 42 Table 29 Moment of inertia 43 Table 30 Force 45 Table 31 Moment of force (torque) 48 Table 32 Pressure 53 Table 33 Pressure (continued) 54 Table 34 Pressure (continued) 55BS
17、350:2004 BSI 25 May 2004 iii Page Table 35 Viscosity (dynamic) 57 Table 36 Viscosity (kinematic) 59 Table 37 Energy 63 Table 38 Energy (continued) 64 Table 39 Power 65 Table 40 Equivalent values on four temperature scales 67 Table 41 Specific energy 69 Table 42 Calorific value, volume basis 70 Table
18、 43 Calorific value of gases, volume basis (with differing reference conditions) 71 Table 44 Conversion factors previously used by the UK Gas Industry 72 Table 45 Specific heat, mass basis 75 Table 46 Heat capacity, volume basis 76 Table 47 Heat flux density, intensity of heat flow rate 76 Table 48
19、Thermal conductance 77 Table 49 Thermal conductivity 78 Table 50 Thermal resistivity 79 Table 51 Heat release rate 80 Table A.1 Other metric systems 82 Table A.2 Base and supplementary quantities, units and symbols in the SI system 82BS 350:2004 iv BSI 25 May 2004 Foreword This British Standard has
20、been prepared by Technical Committee SS/7. It supersedes BS 350-1:1974 which is withdrawn. BS 350 was first published in 1930, and has been revised on a number of occasions since. It was split into two parts in 1959, Part 1 dealing with the basis of tables and conversion factors, and Part 2, which f
21、irst appeared in 1962, giving detailed conversion tables for the more frequently used conversions. In 1967 a Supplement (PD 6203) was issued to Part 2, giving additional detailed tables for SI conversions. BS 350-2 was withdrawn in 1981 since many of the tables included in it had become inconsistent
22、 with the International System of Units (SI) and the increasing use of pocket calculators was considered to have made such tables, which often required interpolation, obsolete. PD 6203 was withdrawn in 1998. This revision provides a comprehensive list of conversion factors and notes on their use. Th
23、e units in about fifty quantities of measurement are given, together with such definitions and information on the derivation of conversion factors as are considered necessary for the purpose. However, as it is now the only part of the standard, it has been returned to its original numbering, BS 350.
24、 In this revision, while interconversion factors between all the important units treated are given, the standpoint from which the various units and conversion factors are discussed is the SI. Very few imperial units remain in official use in the UK. Furthermore, the SI, under the custody of the Gene
25、ral Conference of Weights and Measures (CGPM), forms the precise and natural basis for conversion information on units, and offers firm prospects of an international harmonization in unit practice, after which conversion factors will no longer be required. However, it is recognized that many older d
26、ocuments refer to units which are not recommended now, so conversion factors have been retained for many of these. The standardization function of this standard lies in the provision of conversion factors reliable to a stated accuracy. Other important information is included to help the user to make
27、 conversions. BS 350 does not purport to define quantities or units, or to standardize the letter symbols or abbreviations used for units. These matters are dealt with elsewhere, but their mention is necessary here and has been updated with the latest international and national decisions. Where conv
28、ersion factors are given in bold type it is to show that they are exact; in general, factors have been rounded to include six significant figures, thus permitting accuracies satisfactory for most practical purposes. The computation of each factor has as far as possible been made from first principle
29、s, using eight or more significant figures to minimize the possibilities of errors in rounding. Six-figure factors are unnecessarily precise for many practical purposes, and may be rounded to fewer significant figures as appropriate. The Department of Trade and Industry has asked that users of these
30、 conversion factors be reminded that conversions for trade purposes have to be based on the statutory definitions of units in the Weights and Measures Act, 1985 1. Submission of additional units for inclusion in a future edition of the standard will be welcomed. These should be sent to the secretary
31、 of Technical Committee SS/7 at BSI, 389 Chiswick High Road, London W4 4AL. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obl
32、igations. In particular, attention is drawn to the Weights and Measures Act 1985 1 and associated Orders and Amendments. Summary of pages This document comprises a front cover, an inside front cover, pages i to iv, pages 1 to 105 and a back cover. The BSI copyright notice displayed in this document
33、indicates when the document was last issued.BS 350:2004 BSI 25 May 2004 1 1 Scope This standard provides conversion factors for units of measurement for a number of quantities, which are, or have been, in general use in engineering, industry and trade. The subjects covered are, broadly, metrology, m
34、echanics and heat; the standard does not deal with purely electrical units. NOTE 1 SI units are normally recommended. However, in certain circumstances use of particular units is required by legislation. NOTE 2 Electrical and light units are given in BS 5775-5 and in BS 5775-6, respectively. NOTE 3
35、A commentary on imperial and metric systems of measurement and units is given in Annex A. 2 Number 2.1 The following prefixes, with meaning, name and symbol as shown in Table 1, are used to denote decimal multiples or submultiples of (metric) units. These prefixes developed in conjunction with the m
36、etric system, and are authorized as “SI prefixes”. Table 1 Prefixes denoting decimal multiples or submultiples Meaning Name Symbol To indicate multiples 10 24 yotta Y 10 21 zetta Z 10 18 exa E 10 15 peta P 10 12 tera T 10 9 giga G 10 6 mega M 10 3 kilo k 10 2 hecto h 10 1 deca da To indicate submult
37、iples 10 p1 deci d 10 p2 centi c 10 p3 milli m 10 p6 micro 4 10 p9 nano n 10 p12 pico p 10 p15 femto f 10 p18 atto a 10 p21 zepto z 10 p24 yocto yBS 350:2004 2 BSI 25 May 2004 2.2 The scientific convention is now to use the system shown in Table 2. Table 2 Meaning of million, billion, trillion, etc.
38、 2.3 The former convention in the UK was that one billion was 10 12 , one trillion 10 18 , one quadrillion 10 24 etc. Some people still use this convention. In view of the differences between the former and the current practice, ambiguities can easily arise with the words “billion”, “trillion” and “
39、quadrillion”, etc., therefore their use should be avoided. 3 Length 3.1 The SI unit of length is the metre (symbol m). It is one of the base units of the SI and is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second. 3.2 Multiples and submultiples
40、of the metre are formed by using any of the SI prefixes given in 2.1; kilometre (km), decimetre (dm), centimetre (cm), millimetre (mm) and micrometre ( 4m) are common examples. An alternative term for the micrometre, abrogated by the CGPM but still in common use, is “micron”. The symbol 4, associate
41、d in the past with the micron, is incorrect; 4m should be used. 3.3 Some units of length having associations with the metric system but not forming part of the SI are: 3.4 The definitive UK (or imperial) and US unit of length is the yard, legally defined (since 1959 in the USA and since 1963 in the
42、UK) as follows: 1 yard = 0.914 4 m 3.5 The connection between multiples and submultiples of the yard is indicated in the following table of named UK and US units of length. Term Meaning Corresponding decimal factor million thousand thousand 10 6 billion thousand million 10 9 trillion million million
43、 10 12 quadrillion million billion 10 15 Refer to note 1 ngstrm () =1 0 p10m 1 fermi (f, fm) =1 0 p15m 1 nautical mile (international) (n mile) = 1 852 m 1 astronomical unit (AU) = 1.496 00 10 11m 1 1 parsec (pc) = = 3.085 68 10 16m 3.262 l.y. 2 1 light year (l.y.) = 9.460 528 10 15m 3 Refer to note
44、 (1 in = 0.025 4 m) 1 foot (ft) = 12 inches (in) (1 ft = 0.304 8 m) 4 1 yard (yd) = 3 feet (ft) (1 yd = 0.914 4 m) 1 chain = 22 yards (yd) (1 chain = 20.116 8 m) 5 1 furlong = 10 chains (1 furlong = 201.168 m) 1 mile = 8 furlongs (1 mile = 1 609.344 m) 6BS 350:2004 BSI 25 May 2004 3 3.6 Some less us
45、ual, or more specialized, UK and US named units of length, which are not recommended, are: Notes on Clause 3 NOTE 1 Approximately the mean distance between the Sun and the Earth. NOTE 2 The distance at which 1 AU subtends an angle of 1 second (1). NOTE 3 Approximate distance travelled by light in 1
46、year. NOTE 4 An exception is the US survey foot, shown in 3.6. NOTE 5 Commonly called Gunters chain in the USA. NOTE 6 Also known as a statute mile. There is no recognized abbreviation for mile and the complete word “mile” is used as the unit symbol. NOTE 7 Colloquial, for one-thousandth of an inch.
47、 NOTE 8 Colloquial, for one-thousandth of an inch. For other meanings of mil see 4.5, 5.5 and Clause 8, Note 2. NOTE 9 Printing trade. (Originally defined by 83 picas = 83 12 points = 35 cm.) Refer to note 1 micro-inch ( 4in) = 10 p6in = 0.025 4 4m = 25.4 10 p9m 1 thou = 10 p3in = 25.4 4m = 25.4 10
48、p6m 7 1 mil = 10 p3in = 25.4 4m = 25.4 10 p6m 8 1 point = = 0.351 mm (approx.) 9 1 iron = = 0.529 167 mm 10 1 line = = 0.635 mm 11 1 line or ligne = = 2.116 67 mm 12 1 em = = 4.233 33 mm 13 1 hand = 4 in = 10.16 cm 14 1 link = = 0.66 ft = 0.201 168m 1 US survey foot = = = 0.304 801 m 1 fathom = 6 ft = 1.828 8m 1 rod, pole, or perch =5 y d = 5.029 2m1 5 1 engineers chain = 100 ft = 30.48 m 1 cable-length 16 1 nautical mile (UK) = 6 080 ft = 1 853.18 m 17 1 telegraph nautical mile = 6 087 ft = 1 855.32 m
