Area Of Rectangular Registers

Size of

Opening.

In.

Net Area. Sq. In.

6X 10

40

8X 10

53

8X 12

64

8X 15

80

9 X 12

72

9X 14

84

10 X 12

80

10 X 14

93

10 X 16

107

12X15

120

12 X 19

152

Size of

Opening.

In.

Net Area. Sq. In.

14x 22

205

15 X25

250

16X24

266

20X20

207

20X24

320

20X26

347

21 X29

408

27X27

488

27 X33

384

30X30

600

Area Of Round Registers

Diam. of

Opening.

In.

Net Area. Sq. In.

7

26

8

33

9

42

10

52

12

75

14

103

Diam. of Opening. In.

Net Area Sq. In.

16

134

18

169

20

209

24

301

30

471

36

679