Reference data: CIBSE guide C

277 Pages·2001·3.168 MB·English

by  Ken Butcher (editor)

Reference data
CIBSE Guide C
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A division of Reed Educational and Professional Publishing Ltd
First published 2001
© The Chartered Institution of Building Services Engineers London 2001
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date of going to press, neither the Chartered Institution of Building Services Engineers nor
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Note from the Publisher
This publication is primarily intended to provide guidance to those responsible for the design,
installation, commissioning, operationandmaintenanceofbuildings.Itisnotintendedto be
exhaustive or definitive and it will be necessary for users of the guidance given to exercise
their own professional judgement whendecidingwhethertoabidebyordepartfromit.
British Library Cataloguing in Publication Data
Reference data : CIBSE guide C
1. Buildings — Environmental engineering
I. Butcher, Ken II. Chartered Institution of Building Services Engineers
696
ISBN 0 7506 5360 4
Typeset in Great Britain by J&L Composition Ltd, Filey, North Yorkshire
Printed and Bound in Great Britain by MPG Books, Bodmin, Cornwall
Foreword
This2001editionofCIBSEGuideCcontainssignificantchangesfromtheprevious1986
edition.Althoughbasicphysicaldatadoesnotchangewithtime,therefinementofmeas-
urementandcalculationtechniquesmeansthateventhisbasicdataneedstobereviewedat
intervals.Additionally,revisionstopracticeincalculationmethods,productselectionand
usageledtoarequirementforchangesinthe presentationof thedata.Muchofthedatain
the1986editionactuallydatesfrom1970andwasthereforeripeforreview.
The changes made for the 2001 edition are summarised below:
Section 1: Properties of humid air. The data tables remain unchanged but the intro-
duction has been updated. A critique of the data has been published in Building Services
Engineering Research and Technology, to which interested readers are referred (reference 11
to section 1).
Section 2: Properties of water and steam. This section has been reviewed and found to
need no amendment.
Section 3: Heat transfer. This section has been completely rewritten. The theoretical
basishasbeenreviewedinthelightofcurrentknowledgeandthecalculationprocedures
updated.Referencetableshavebeenupdatedtoreflectcurrentpracticeandneeds.
Section 4: Flow of fluids in pipes and ducts. This section has been completely rewrit-
ten. Both calculation methods and reference tables have been updated. In particular, the
opportunity has been taken to replace the limited and oversimplified tables of resistance
coefficients with a more comprehensive and rigorous treatment.
Section 5: Fuels and combustion. This section has been reviewed and comprehensively
updated to take account of changes to fuels and fuel characteristics.
Section 6: Units, standard and mathematical data. This section has been reviewed and
updated. Some obsolete data has been deleted and some extra data added.
These changes have taken a significant amount of time and effort to complete and I would
like to express my thanks to the volunteer authors, contributors, reviewers and CIBSE
staff for their valuable contributions.
Finally, we hope that all users will find this Guide a useful and authoritative source of ref-
erence and guidance.
Paul Compton
Chairman, CIBSE Guide C
Guide C Steering Committee
P D Compton (Chairman) (Colt International Ltd)
W P Jones (consultant)
P Koch (Université Joseph Fourier, Grenoble; Coventry University)
D L Loveday (Loughborough University)
M R I Purvis (University of Portsmouth)
A CWatson (secretary)
Section task groups, principal authors, contributors
and acknowledgements
Section 1: Properties of humid air
Principal author
W P Jones (consultant)
The tables of data are reprinted from the previous edition of Guide Cand were prepared
by a task group, see below.
Task group members
W P Jones (Chairman) (consultant)
J FArmour
B G Lawrence
Section 2: Properties of water and steam
The tables of data are reprinted from the previous edition of Guide C.
Section 3: Heat transfer
Principal authors
D L Loveday (Loughborough University)
A H Taki (De Montford University)
Contributors
H B Awbi (University of Reading)
P DCompton (Colt International Ltd)
RMHarris (Centre for Window and Cladding Technology)
M JHolmes (Ove Arup & Partners International Ltd)
B P Holownia (Loughborough University)
J Moss (Ove Arup & Partners International Ltd)
T Muneer (Napier University)
H KVersteeg (Loughborough University)
Acknowledgements
American Society of Heating, Refrigerating and Air-Conditioning Engineers Inc
International Standards Organisation
The McGraw-Hill Companies
Pearson Education Ltd
Section 4: Flow of fluids in pipes and ducts
Principal author
P Koch (Université Joseph Fourier, Grenoble; Coventry University)
Contributor
F Sprenger (Coventry University)
Acknowledgements
American Society of Heating, Refrigerating and Air-Conditioning Engineers Inc
Centre Technique des Industries Aérauliques et Thermiques
Coventry University, School of Science and the Environment
CRC Press Inc
Sheet Metal and Air Conditioning Contractors’ National Association
Section 5: Fuels and combustion
Task group members/Principal authors
M RIPurvis (Chairman) (University of Portsmouth)
R Dando (Coal Research Establishment)
M Drew (BP Amoco plc)
R JHarris (Advantica Technologies Ltd)
K Mildren (University of Portsmouth)
Acknowledgements
BP Amoco plc
Section 6: Units, standard and mathematical data
Principal author
P DCompton (Chairman) (Colt International Ltd)
Co-ordinating editors
K JButcher (CIBSE)
A CWatson (CIBSE)
CIBSE Director of Information and Policy
J Balian
Contents
1 Properties of humid air 1-1
1.1 Psychrometric data 1-1
1.2 CIBSE psychrometric chart ((cid:1)10 to (cid:2)60(cid:3)C) 1-4
1.3 CIBSE psychrometric chart (10 to 120(cid:3)C) 1-4
References 1-4
Tables of psychrometric data 1-7
2 Properties of water and steam 2-1
2.1 Introduction 2-1
References 2-1
Tables of data 2-2
3 Heat transfer 3-1
3.1 Introduction 3-1
3.2 Heat transfer principles 3-3
3.3 Heat transfer practice 3-12
References 3-36
4 Flow of fluids in pipes and ducts 4-1
4.1 Introduction 4-1
4.2 Notation 4-1
4.3 Fluid flow in straight pipes and ducts 4-2
4.4 Water flow in pipes 4-6
4.5 Air flow in ducts 4-77
4.6 Steam in pipes 4-82
4.7 Natural gas in pipes 4-86
4.8 Pressure loss factors 4-90
4.9 Pressure loss factors for pipework components 4-91
4.10 Pressure loss factors for ductwork 4-96
References 4-116
Appendix 4.A1 Properties of various fluids 4-118
Appendix 4.A2 Mathematical basis for tables of pressure drop 4-120
Appendix 4.A3 Equivalent length 4-121
Appendix 4.A4 Compressible flow 4-122
Appendix 4.A5 Capacity K, and complex networks 4-123
5 Fuels and combustion 5-1
5.1 Introduction 5-1
5.2 Classification of fuels 5-1
5.3 Primary fuels 5-1
5.4 Secondary fuels 5-2
5.5 Specification of fuels 5-2
5.6 Combustion data 5-9
5.7 Stack losses 5-10
Bibliography 5-12
6 Units, standard and mathematical data 6-1
6.1 Introduction 6-1
6.2 The International System of Units (SI) 6-1
6.3 Quantities, units and numbers 6-4
6.4 Metrication in the European Union 6-5
6.5 Conversion factors 6-6
Bibliography 6-14
Index I-1
1-1
1 Properties of humid air
1.1 Psychrometric data
1.2 CIBSE psychrometric chart ((cid:1)10 to (cid:2)60(cid:3)C)
1.3 CIBSE psychrometric chart (10 to 120(cid:3)C)
Psychrometric tables
1.1 Psychrometric data v (cid:4) specific volume of moist air (m3.kg(cid:1)1dry
air)
1.1.1 Basis of calculation
v (cid:4) specific volume of dry air (m3.kg(cid:1)1)
a
The method of formulation suggested by Goff and v (cid:4) specific volume of saturated moist air
s
Gratch(1,2), based on the ideal gas laws with a modification (m3.kg(cid:1)1dry air)
to take account of intermolecular forces, has been adopted
for calculating the thermodynamic properties of moist air. The relevant specific property of moist, unsaturated air is
This approach remains in line with current practice(3,4). determined by adding a proportion of the property of sat-
urated water vapour to the same property of dry air, on a
The thermodymamic properties of dry air and saturated mass basis.
water vapour are well established and, although more
recent research work(4,5,6)has been done, the results are not A consequence of this is that the humidity of moist air is
significantly different from those obtained in earlier expressed as percentage saturation (defined in terms of the
work(7,8). Hence the thermodynamic properties of dry air mass of water vapour present), rather than relative humid-
and water vapour, determined by the National Bureau of ity (defined in terms of vapour pressure). The details of
Standards(7) and the National Engineering Laboratory(8), the psychrometric calculations are given in references 9, 10
have been retained for the evaluation of the thermody- and 11.
namic properties of moist air.
Since the properties of dry air and saturated water vapour 1.1.2 Standards adopted
are accurately known, the properties of a mixture of the
two can be established for the saturated case. For the All data are tabulated for an internationally agreed stan-
enthalpy and specific volume of moist air, at a condition dard atmospheric pressure(12)of 101.325 kPa.
other than saturated, the method is exemplified by the fol-
lowing equations: The zero datum adopted by the National Engineering
Laboratory(8) for the expression of the thermodynamic
h (cid:4) h (cid:2) l(h (cid:1) h )/100 (1.1) properties of steam is the triple point of water, (cid:2)0.01(cid:3)C.
a s a
v (cid:4) v (cid:2) l(v − v )/100 (1.2)
a s a The zero datum for the specific enthalpies of both dry air
where and liquid water has been taken here as 273.15K (0(cid:3)C).
h (cid:4) specificenthalpyofmoistair(kJ.kg(cid:1)1dry
air) 1.1.3 Formulae used for calculations
h (cid:4) specific enthalpy of dry air (kJ.kg(cid:1)1)
a Saturated vapour pressure over water(8):
l (cid:4) percentage saturation (%)
logp (cid:4) 30.59051 (cid:1) 8.2 log (t (cid:2) 273.16)
s
h (cid:4) specific enthalpy of saturated moist air (cid:2) 2.4804 (cid:5) 10(cid:1)3(t (cid:2) 273.16)
s
(kJ.kg(cid:1)1dry air) (cid:1) [3142.31/(t (cid:2) 273.16)] (1.3)
1-2 Reference data
where t (cid:4) dry-bulb temperature ((cid:3)C)
p (cid:4) saturated vapour pressure over water at t(cid:6) (cid:4) sling or mechanically aspirated wet-bulb
s s1
temperaturet(kPa) temperature ((cid:3)C)
or
t (cid:4) temperature, greater than or equal to 0(cid:3)C
((cid:3)C) p (cid:4) p (cid:1) 101.325B(t (cid:1) t(cid:6) ) (1.10)
v sc sc
Saturated vapour pressure over ice(7): where
logp (cid:4) 12.5380997 (cid:1) [266391/(t (cid:2) 273.15)] p (cid:4) saturated vapour pressure at temperature
s sc
(1.4) t (kPa)
sc
where t(cid:6) (cid:4) screen wet-bulb temperature ((cid:3)C)
sc
ps (cid:4) saturated vapour pressure over ice at tem- B (cid:4) 7.99 (cid:5) 10(cid:1)4K(cid:1)1whent (cid:7) 0(cid:3)C
peraturet, less than 0(cid:3)C (kPa) sc
B (cid:4) 7.20 (cid:5) 10(cid:1)4K(cid:1)1whent (cid:8) 0(cid:3)C
sc
Moisture content:
Adiabatic saturation temperature:
0.62197f p
gs (cid:4) 101.325 −sfssps (1.5) t* (cid:4) t (cid:1) (hcfg(gs(cid:2)a (cid:1)gcg)) (1.11)
pa ps
where
where
g (cid:4) moisture content of saturated moist air
s (kg.kg(cid:1)1dry air) t* (cid:4) adiabatic saturation temperature ((cid:3)C)
f (cid:4) dimensionlessenhancementfactor(1,2,3,4,11) hfg (cid:4) latent heat of evaporation of water at tem-
s peraturet (kJ.kg(cid:1)1)
a
Percentage saturation: g (cid:4) moisture content of saturated air at tem-
sa
100g peraturet (kg.kg(cid:1)1dry air)
l (cid:4) (1.6) a
g g (cid:4) moisture content of moist air at the partic-
s
ular psychrometric state (kg.kg(cid:1)1dry air)
where
c (cid:4) mean specific heat capacity of dry air
l (cid:4) percentage saturation (%) pa betweentandt (kJ.kg(cid:1)1.K(cid:1)1)
a
g (cid:4) moisture content of unsaturated moist air c (cid:4) mean specific heat capacity of water
(kg.kg(cid:1)1dry air) ps vapour between tandt (kJ.kg(cid:1)1.K(cid:1)1)
a
Vapour pressure of water vapour in unsaturated moist air:
In the case of the adiabatic saturation temperature above
p g ice,h is replaced by h , the latent heat of fusion of water
p (cid:4) a (1.7) at a tefgmperature t . ig
v f(0.62197 (cid:2) g) a
s
Dew-point:
where
p (cid:4) vapour pressure of superheated water Foraparticularpsychrometricstate,equation(1.7)isused
v to calculate the vapour pressure. An iterative technique is
vapour in unsaturated moist air (kPa)
then used with equation (1.3) or (1.4) to determine the
p (cid:4) atmospheric (barometric) pressure (kPa) temperature for which the calculated vapour pressure is a
a
saturated vapour pressure.
Relative humidity:
Specific volume:
100p
φ (cid:4) v (1.8) [ 82.0567(273.15 (cid:2) t) ]
ps v (cid:4)
28.966(101.325 (cid:1) p )/101.325
where v
(cid:1)[A x 2(cid:2)2A x (1(cid:1)x )(cid:2)A (1(cid:1)x )2]
φ (cid:4) relative humidity (%) aa a aw a a ww a
(1.12)
where
Wet-bulb temperature:
v (cid:4) specific volume (m3.kg(cid:1)1dry air)
Knowing the value of the vapour pressure, p , from equa-
v t (cid:4) dry-bulb temperature ((cid:3)C)
tion (1.7) the wet-bulb temperature is derived from the
following equations by an iterative technique: A (cid:4) second virial coefficient for dry air4
aa
(m3.kg(cid:1)1)
p (cid:4) p (cid:1) 101.325A(t (cid:1) t(cid:6) ) (1.9)
v s1 s1
A (cid:4) interaction coefficient for moist air4
where aw
(m3.kg(cid:1)1)
ps1 (cid:4) saturatedvapourpressureattemperature ts1 A (cid:4) second virial coefficient for water vapour
(kPa) ww
(m3.kg(cid:1)1)
A (cid:4) 6.66 (cid:5) 10(cid:1)4K(cid:1)1whent(cid:6) (cid:7) 0(cid:3)C
s1 0.62197
x (cid:4) (1.13)
A (cid:4) 5.94 (cid:5) 10(cid:1)4K(cid:1)1whent(cid:6)s1(cid:8) 0(cid:3)C a 0.62197 (cid:2) g
Properties of humid air 1-3
where 1.1.4 Psychrometric properties at
x (cid:4)mole fraction of dry air non-standard barometric
a pressures
In the original work(1,2) and in more recent research(4), a
third virial coefficient for water vapour, A , appears in
equation (1.12) but it is complicated to cawlwcwulate and its The tabulated psychrometric data are accurate within the
influence is insignificant. It is ignored here, without any range of barometric pressure from 95 kPa to 105 kPa and
loss of accuracy. hence are suitable for the whole of the United Kingdom.
For pressures outside these limits an application of the
Equation (1.2) yields answers of adequate precision and is ideal gas laws will give answers of a little less accuracy.
easier to use than equation (1.12). Better answers may be obtained by the use of equations
(1.15) and (1.16):
Specific enthalpy:
0.624p
h (cid:4) ha(cid:2)g hg (1.14) gs (cid:4) (p (cid:1) 1.00s4p) (1.15)
a s
where (0.287 (cid:2) 0.461g) (273.15 (cid:2) t)
(cid:1) (cid:4) (1.16)
h (cid:4) specific enthalpy of moist air (kJ.kg(cid:1)1dry p
a
air)
h (cid:4) specific enthalpy of dry air7(kJ.kg(cid:1)1) Corrections to specific enthalpy may be taken from
a
g (cid:4) moisture content (kg.kg(cid:1)1dry air) Table 1.1.
h (cid:4) specific enthalpy of water vapour at the Figure 1.1, which gives the relationship between height
g
dry-bulb temperature(8)(kJ.kg(cid:1)1dry air) above sea level and barometric pressure, is drawn from the
equation:
Equation (1.1) gives answers having the same accuracy as
p (cid:4) 101.325 exp[((cid:1)9.81(cid:2)a)/(101 325)]
those obtained from equation (1.14) and is simpler to use. a
(1.17)
Table 1.1 Corrections to specific enthalpy at non-standard pressures
Adibatic saturation Approximate additive corrections to specific enthalpy (kJ.kg(cid:1)1dry air) at various barometric pressures/kPa
temperature
°C 82.5 85.0 87.5 90.0 92.5 95.0 97.5 101.325 102.5
30 16.90 14.23 11.68 9.29 6.95 4.80 2.86 0 (cid:1)0.82
29 15.90 13.40 11.00 8.72 6.55 4.57 2.70 0 (cid:1)0.77
28 14.95 12.58 10.30 8.18 6.16 4.30 2.54 0 (cid:1)0.72
27 14.00 11.78 9.65 7.67 5.80 4.05 2.40 0 (cid:1)0.68
26 13.05 11.02 9.03 7.18 5.44 3.82 2.27 0 (cid:1)0.64
25 12.20 10.28 8.42 6.70 5.12 3.58 2.14 0 (cid:1)0.60
24 11.43 9.64 7.90 6.30 4.80 3.36 2.00 0 (cid:1)0.56
23 10.68 9.03 7.40 5.88 4.43 3.15 1.86 0 (cid:1)0.52
22 10.00 8.45 6.93 5.51 4.20 2.94 1.73 0 (cid:1)0.48
21 9.37 7.92 6.50 5.18 3.92 2.74 1.61 0 (cid:1)0.45
20 8.77 7.42 6.10 4.84 3.65 2.55 1.50 0 (cid:1)0.42
19 8.22 6.95 5.70 4.53 3.43 2.39 1.40 0 (cid:1)0.39
18 7.73 6.49 5.35 4.24 3.20 2.23 1.30 0 (cid:1)0.37
17 7.25 6.09 5.00 3.97 3.00 2.07 1.21 0 (cid:1)0.35
16 6.79 5.68 4.65 3.72 2.80 1.94 1.13 0 (cid:1)0.32
15 6.33 5.32 4.34 3.48 2.62 1.82 1.07 0 (cid:1)0.30
14 5.90 4.95 4.07 3.24 2.44 1.70 1.00 0 (cid:1)0.28
13 5.50 4.60 3.80 3.03 2.28 1.60 0.93 0 (cid:1)0.26
12 5.13 4.30 3.53 2.82 2.12 1.50 0.86 0 (cid:1)0.24
11 4.78 4.04 3.28 2.62 1.97 1.40 0.80 0 (cid:1)0.22
10 4.44 3.77 3.08 2.46 1.82 1.30 0.74 0 (cid:1)0.20
9 4.15 3.51 2.88 2.30 1.70 1.21 0.70 0 (cid:1)0.20
8 3.88 3.30 2.68 2.14 1.60 1.12 0.66 0 (cid:1)0.19
7 3.62 3.08 2.51 2.00 1.50 1.06 0.62 0 (cid:1)0.19
6 3.40 2.88 2.37 1.87 1.40 1.00 0.59 0 (cid:1)0.18
5 3.20 2.72 2.23 1.74 1.31 0.92 0.56 0 (cid:1)0.17
4 3.06 2.60 2.10 1.64 1.24 0.88 0.53 0 (cid:1)0.17
3 2.92 2.47 2.02 1.59 1.19 0.84 0.50 0 (cid:1)0.16
2 2.78 2.36 1.94 1.54 1.15 0.80 0.48 0 (cid:1)0.16
1 2.65 2.25 1.86 1.49 1.10 0.76 0.46 0 (cid:1)0.15
0 2.52 2.16 1.79 1.44 1.08 0.72 0.44 0 (cid:1)0.15
1-4 Reference data
1.0 divergingslightlyoneachsideofthe30(cid:3)Cline,andthetra-
ditionalappearanceofthechartispreserved.
0.9 The wet-bulb values shown are those read from a sling or
a mechanically aspirated psychrometer and lines of percent-
P
e/ age saturation are plotted instead of relative humidity.
r
su 0.8 Within the comfort zone, there is no practical difference
s
re between percentage saturation and relative humidity. In
p
c any case, the difference diminishes as saturated or dry con-
ri
et 0.7 ditions are approached.
m
o
ar The psychrometric data used were taken from the tables
B
0.6 of the properties of humid air in this section of CIBSE
Guide C.
0.5
0 1000 2000 3000 4000 5000
1.3 CIBSE psychrometric
Altitude / m
chart (10 to 120(cid:3)C)
Figure 1.1 Variation of barometric pressure with altitude
where
The psychrometric chart for 10 to 120(cid:3)C has been based
p (cid:4) the particular atmospheric (barometric) on the ideal gas laws. This does not give a significant dif-
a
pressure (kPa) ference when compared with a chart constructed using
more accurate data, based on the method of Goff and
(cid:2) (cid:4) density of air (kg.m(cid:1)3)
Gratch(1,2). The principles of calcuation and drawing are
a (cid:4) altitude above sea level (m) detailed elsewhere(14).
Alternatively, the standard relationship(12) for altitude,
atmospheric pressure and temperature may be used. This References
is reproduced in Table 1.2.
1 Goff, J A and Gratch, S, ‘Thermodynamic properties of moist
Table 1.2 Standard atmospheric data for altitudes to 10000 m air’, Trans. ASHVE,51, 125–164 (1945)
Altitude Temperature Pressure 2 Goff, J A, ‘Standardisation of thermodynamic properties of
(m) (°C) (kPa) moist air’, Trans. ASHVE,55, 459–484 (1949)
(cid:1)500 18.2 107.478 3 ASHRAEHandbook Fundamentals,Section6Psychrometrics
0 15.0 101.325 (1997)
500 11.8 95.461
1000 8.5 89.874 4 Hyland, R W and Wexler, A, ‘Formulations for the thermody-
2000 2.0 79.495 namic properties of dry air from 173.15 K to 473.15 K and of
saturated moist air from 173.15 K to 372.15 K at pressures to 5
MPa’, Trans. ASHRAE,89(2A), 520–535 (1982)
3000 (cid:1)4.5 70.108
4000 (cid:1)11.0 61.640 5 Hyland, R W and Wexler, A ‘Formulations for the thermody-
5000 (cid:1)17.5 54.020 namic properties of the saturated phases of H2O from 173.15 K
6000 (cid:1)24.0 47.181 to 473.15 K’, Trans. ASHRAE,89(2A), 500–519 (1983)
7000 (cid:1)30.5 41.061 6 Stimson, H F, ‘Some precise measurements of the vapour pres-
sure of water in the range from 25(cid:3)C to 100(cid:3)C’, J. Res. NBS73A
8000 (cid:1)37.0 35.600 (1969)
9000 (cid:1)43.5 30.742
7 Tables of thermal properties of gases, NBS Circular 564
10000 (cid:1)50.0 26.436
(National Bureau of Standards, November 1955)
8 National Engineering Laboratory steam tables (HMSO 1964)
1.2 CIBSE psychrometric
9 Jones,WPandLawrence,BG,‘Newpsychrometricdataforair’
chart (–10 to +60(cid:3)C)
Technicalmemorandumno.11(PolytechnicoftheSouthBank)
10 Some fundamental data used by building services engineers
(IHVE, 1973)
The chart has been designed(13) and constructed using the
11 Jones, W P, ‘A review of CIBSE psychrometry’, Building Serv.
twofundamentalpropertiesofmass(moisturecontent)and
Eng. Res. Technol.15(4), 189–198 (1994)
energy (specific enthalpy) as linear co-ordinates. Other
physical properties are not then shown as linear scales(14). 12 NACA 1955, Standard atmosphere – tables and data for alti-
The30(cid:3)Cdry-bulblinehasbeenconstructedatrightangles tudes to 65000 feet, NACA Report 1235:66, Washington DC
tolinesofconstantmoisturecontent,whicharehorizontal. 13 Jones, W P, ‘The Psychrometric Chart in SI Units’, JIHVE,38,
The scale of specific enthalpy is obliquely inclined to the 93 (1970)
verticalscaleofmoisturecontent.Inthisway,linesofcon-
14 Bull, L C, ‘Design and use of the new IHVE psychrometric
stant dry-bulb temperature are approximately vertical,
chart’,JIHVE,32, 268 (October 1964)