84
3 Flow Rates and Pressure Measurements
0.939 A
0.765 A
0.563 A
0.437 A
0.235 A
0.061 A
A
B
0.074 B
0.288 B
0.5 B
0.712 B
0.926 B
Fig. 3.18 Location of sampling points following the log-Tchebycheff six-point rule for ducts of
rectangular section. Modified from ANSI/ASHRAE Standard 111-2008. The number of points that
must be established along each side of the duct depends on the length of that side
16 to 64 rectangles
of equal area
A
B
Fig. 3.19 Traversing a duct of rectangular section. Break-down into rectangles of equal area
3 Flow Rates and Pressure Measurements
0.939 A
0.765 A
0.563 A
0.437 A
0.235 A
0.061 A
A
B
0.074 B
0.288 B
0.5 B
0.712 B
0.926 B
Fig. 3.18 Location of sampling points following the log-Tchebycheff six-point rule for ducts of
rectangular section. Modified from ANSI/ASHRAE Standard 111-2008. The number of points that
must be established along each side of the duct depends on the length of that side
16 to 64 rectangles
of equal area
A
B
Fig. 3.19 Traversing a duct of rectangular section. Break-down into rectangles of equal area