BS 848-1:1980

Foreword; Cooperating organizations; Methods
Section one. General
1. Scope; 2. References; 3. Definitions
4. Symbols and units
4.1 Symbols; 4.2 Subscripts; 4.3 Multiples and sub-
multiples
5. Instrumentation for measurement of pressure
5.1 Barometers; 5.2 Manometers; 5.3 Damping of
manometers; 5.4 Checking of manometers
6. Determination of average static pressure in an
      airway
6.1 Use of wall tappings; 6.2 Use of wall tappings;
6.4 Position and connections; 6.5 Checks for
compliance; 6.6 Use of pitot-static tube
7. Measurement of temperature
7.1 Thermometers; 7.2 Thermometer location;
7.3 Humidity; 7.4 Influence of air velocity
8. Determination of density
8.1 Density of the air in the test enclosure; 8.2
Average density of the air in an airway section; 8.3
Determination of vapour pressure
9. Measurement of rotational speed
9.1 Fan shaft speed; 9.2 Examples of acceptable
methods
10. Determination of power input
10.1 Measurement accuracy; 10.2 Fan shaft power;
10.3 Electrical instruments; 10.4 Impeller power;
10.5 Transmission systems
11. Measurement of dimensions and determination of
      areas
11.1 Flow measurement devices; 11.2 Tolerance on
dimensions; 11.3 Determination of cross-sectional area
12. Determination of flow rate
12.1 General; 12.2 In-line flowmeters (standard
primary devices); 12.3 Traverse methods
13. Calculation of the results of a test
13.1 General; 13.2 Units; 13.3 Temperature; 13.4
Dynamic pressure and fan dynamic pressure; 13.5 Fan
static pressure and fan total pressure; 13.6 Inlet
volume flow; 13.7 Fan efficiencies (compressible flow);
13.8 Approximation for low pressure fans
14. Conversion rules for spped, air conditions & size
14.1 Direct and indirect tests; 14.2 Conversion of
direct test; 14.3 Conversion of indirect tests; 14.4
Change of size; 14.5 Requirements for conversion
15. Fan characteristics
15.1 General; 15.2 Methods of plotting; 15.3 Constant
speed characteristic;15.4 Inherent speed characteristic
15.5 Adjustable duty fan characteristic; 15.6 Complete
fan characteristic; 15.7 Test for a specified duty
16. Uncertainty of measurement
16.1 Performance errors; 16.2 Uncertainty of measure-
ment; 16.3 Specified uncertainties; 16.4 Uncertainty
of fan performance determination; 16.5 Site tests; 16.6
Precision tests
Section two. Tests with standardized airways
17. Selection of test method
17.1 Classification; 17.2 Installation types; 17.3
Reporting of test; 17.4 User's installations; 17.5
Alternative methods; 17.6 Duct simulation
18. Installation of fan and test airways
18.1 Inlets and outlets; 18.2 Airways; 18.3 Test
enclosure; 18.4 Matching fan and airway; 18.5 Outlet
area
19. Operation of test
19.1 Working fluid; 19.2 Rotational speed; 19.3
Steady operation; 19.4 Ambient conditions; 19.5
Pressure readings; 19.6 Tests for a specified duty;
19.7 Tests for a fan characteristic; 19.8 Operating
range
20. Determination of flow rate by venturi nozzle
20.1 Geometric form; 20.2 Venturi nozzle in free inlet
condition; 20.3 Nozzle performance; 20.4 Uncertainties
21. Determination of flow rate by conical inlet
21.1 Geometric form; 21.2 Screen loading; 21.3 Inlet
zone; 21.4 Conical inlet performance; 21.5
Uncertainties
22. Determinatoin of flow rate by orifice plate
22.1 Installation; 22.2 Orifice plate; 22.3 Ducts;
22.4 Pressure tappings; 22.5 Calculation of mass flow;
22.6 In-duct orifice with D and D/2 taps; 22.7 In-duct
orifice with corner taps; 22.8 Outlet orifice with wall
tappings; 22.9 Inlet orifice with corner taps; 22.10
Expansibility factor; 22.11 Reynolds number
23. Determination of flow rate by pitot-static tube
traverse
23.1 General; 23.2 Pitot-static tube; 23.3 Limits
of air velocity; 23.4 Location of measuring points;
23.5 Determination of flow rate; 23.6 Flow coefficient
23.7 Uncertainty of measurement
24. Common airway sections for ducted fan installations
24.1 Common parts; 24.2 Common part at fan outlet;
24.3 Common part at fan inlet; 24.4 Outlet duct
simulation; 24.5 Inlet duct simulation; 24.6 Loss
allowances for standardized airways
25. Component parts of standardized airways
25.1 Symbols; 25.2 Component parts; 25.3 Flow
measurement devices; 25.4 Meaning of subscripts
26. Standardized inlet side test chambers
26.1 Test chamber; 26.2 Fan under test; 26.3 Pressure
tappings; 26.4 Flow uniformity; 26.5 Flow control;
26.6 Leakage; 26.7 Fan powered exhaust ventilators
27. Standardized test methods with inlet side test
      chambers: type A
27.1 Methods for type A installations; 27.2
Measurements taken during test; 27.3 Calculations;
27.4 Fan performance; 27.5 Use of inlet side chambers
with inlet and outlet duct simulation
28. Standardized test methods with outlet side test
      ducts: type B
28.1 Methods for type B installations; 28.1 Measure-
ments taken during test; 28.3 Calculations; 28.4 Fan
performance
29. Standardized test methods with inlet side test
      ducts: type C
29.1 Methods for type C installations; 29.2 Measure-
ments taken during test; 29.3 Calculations; 29.4 Fan
performance
30. Standardized test methods with inlet and outlet
      test ducts: type D
30.1 Methods for type D installations; 30.2 Measure-
ments taken during test; 30.3 Calculations; 30.4 Fan
performance
Section three. Site tests
31. Introduction; 32. Instructions for site testing
32.1 General conditions; 32.2 Method of varying
operating points
33. Location of measurement planes
33.1 Location of flow measurement plane; 33.2 Location
of pressure measurement plane
34. Measurement of air velocity on site
34.1 Instruments for air velocity measurement; 34.2
Pitot-static tube; 34.3 Anemometer; 34.4 Siting of
measuring points
35. Determination of flow rate on site
35.1 Pitot-static tube; 35.2 Anemometer; 35.3 Deter-
mination of cross-sectional area of airway on site;
35.4 Uncertainty of measurement
36. Determination of fan pressure on site
36.1 General; 36.2 Measurement of static pressure on
site; 36.3 Extract fans; 36.4 Blowing fans; 36.5
Booster fans
37. Determination of power input on site
37.1 Power measurement; 37.2 Transmission systems;
37.3 Other prime movers; 37.4 Special precautions for
site tests
Appendices
A. Tolerances; B. Uncertainty calculations for fan
performance; C. Conversion rules for compressible flow;
D. Friction allowance for straight, smooth ducts; E.
Conversion factors for SI units
Tables
1. Saturation vapour pressures; 2. Uncertainties of
flow rate determination; 3. Ciruclar ducts: measure-
ment positions for 6, 8 and 10 points per diameter by
the log linear rule; 4. Rectangular sections: positions
of measuring points and traverse lines by the log
Tchebycheff rule
Figures
1. Construction of wall pressure tappings; 2. Tapping
connections to obtain average static pressure; 3.
Pressure loss and pressure difference of standard
primary devices; 4. NPL modified ellipsoidal-nosed
standard pitot-static tube; 5. Chart for the deter-
mination of compressibility coefficient kp; 6. Dynamic
viscosity of atmospheric air; 7. Example of a complete,
constant-speed, fan characteristic; 8. Example of an
adjustable-duty fan characteristic; 9. Example of test
for a specified duty; 10. Uncertainty in fan total
pressure from a standardized airway test; 11. Uncertain-
ties in characteristic error and fan total efficiency
from a standardized airway test; 12. Venturi nozzle
geometry; 13. Flow metering installations; 14. Compound
flow coefficients of venturi nozzles; 15. Conical inlet
geometry; 16. Compound flow coefficient of conical
inlets; 17. Orifice plates and assemblies; 18. Flow
coefficients of in-duct orifices with D and D/2 taps;
19. Flow coefficents of in-duct or outlet orifices with
corner taps; 20. Compound flow coefficients of outlet
orifices with wall taps; 21. Flow coefficients of inlet
orifices with corner taps; 22. Expansibility factor
epsilon for orifice plates in atmospheric air; 23.
Location of positions for traverse measurements in
standardized airways; 24. Friction allowance factors for
standardized airways; 25. Inlet side test chamber; 26.
Inlet-chamber methods for type A installations; 27.
Standardized airways for free inlet, ducted outlet, type
B installations; 28. Standardized airways for ducted
inlet, free outlet, type C installations; 29. Standard-
ized airways for ducted inlet, ducted outlet, type D
installations; 30. Locations of flow measurement plane
for site testing; 31. Location of pressure measurement
planes for site testing; 32. Location of velocity
measurements in rectangular sections on site; 33.
Location of velocity measurements in a circular arched
section on site; 34. Application of modified log
Tchebycheff rule for traverse patterns in airway
sections of other than circular and rectangular form;
35. Error diagram; 36. Example of uncertainty in a fan
characteristic; 37. Duct friction allowance