ANNEX 11 COEFFICIENTS OF LOCAL RESISTANCE OF SOME PARTS OF AIR DUCTS

Local

resistance

Sketch

Local coefficient

resistance x

Louvre

2

Rectangular knee with beveled corner

1.0

Tee at 90 ° on the flow passage

Fn / Fc

X value with Ln / Lc

0.2

0.4

0.6

0.7

0.8

0.1

0.4

one

0.5

0.4

0.4

1.5

one

0.7

4.4

2.8

1.6

8.4

5.2

2.8

20

12.3

623

90 ° tee on the branch

Fo / Fp

X value with Ln / Lc

0.1

0.2

0.4

0.5

0.7

0.1

0.2

0.4

0.3

–1.7

–9.4

0.9

0.6

–0.6

one

one

one

one

one

one

one

one

1.1

Exhaust shaft

with umbrella

1,3