BS 7859:1996

Committees responsible
National foreword
Method
1 Scope
2 Definitions
3 Principle
4 Behaviour of ideal and real gases
5 Calculation of calorific value on a molar basis
6 Calculation of calorific value on a mass basis
7 Calculation of calorific value on a volumetric
      basis
8 Calculation of relative density, density and
      Wobbe index
9 Accuracy
10 Tables of recommended data
Annexes
A (normative) Symbols and units
B (normative) Values of auxiliary constants, etc
C (informative) Conversion of volume fractions to
      mole fractions
D (informative) examples of calculations
E (informative) Behaviour of ideal and real gases
F (informative) Effects of water vapour on calorific
      value
G (informative) Summary, discussion and selection
      of the calorific value of methane
H (informative) Derivation of equations relating
      to precision
J (informative) Approximate conversion factors
      between reference states
K (informative) Computer implementation of
      recommended methods
L (informative) Calorific values on a molar basis
      for 60 Deg F reference temperature
M (informative) Bibliography
Tables
1 Molar mass for components of natural gases
2 Compression factors and summation factors for
      components of natural various metering
      reference conditions
3 Calorific values for components of natural gases at
      various combustion reference conditions for the
      ideal gas on a molar basis
4 Calorific values for components of natural gases
      at various combustion reference conditions for the
      ideal gas on a mass basis
5 Calorific values for components of natural gases
      at various combustion and metering reference
      conditions for the ideal gas on a volumetric basis
B.1 Critical properties
B.2 Molar composition of dry air
D.1 Details of an example of a property calculation
D.2 Details of an example of a precision calculation
G.1 Calorific value of methane: molar basis
G.2 Calorific value of methane: mass basis
G.3 Calorific value of methane: volumetric basis
J.1 Conversion factors for calorific values
J.2 Conversion factors for densities, relative
      densities and compression factor
J.3 Conversion factors for calorific values and
      Wobbe index
K.1 Example of a retyped printout
L.1 Calorific values for components of natural gas at
      60 Deg F for the ideal gas on a molar basis
Figure
1 Calorific value on a volumetric basis - Metering
      and combustion reference conditions

Defines procedures for calculating superior and inferior calorific value, density, relative density and Wobbe index of dry natural gases, natural gas substitutes and other combustible gaseous fuels, where the composition of the gas by mole fraction is known. The procedures need values for various physical properties of the pure components, which are given in tables and their sources identified.