Duct pieces | Equivalent number |
| Total | ||
| length x used | = |
| ||
1 Ft. | x ( | ) | = | Ft. | |
Rect., |
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straight |
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7” Round, | 1 Ft. | x ( | ) | = | Ft. |
straight |
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8” Round, | 1 Ft. | x ( | ) | = | Ft. |
straight |
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15 Ft. | x ( | ) | = | Ft. | |
Rect.900 |
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elbow |
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9 Ft. | x ( | ) | = | Ft. | |
Rect.450 |
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elbow |
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24 Ft. | x ( | ) | = | Ft. | |
Rect.900 |
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flat elbow |
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30 Ft. | x ( | ) | = | Ft. | |
Rect. |
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wall cap |
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with damper |
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5 Ft. | x ( | ) | = | Ft. | |
Rect.to |
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6” round |
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transition |
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20 Ft. | x ( | ) | = | Ft. | |
Rect.to |
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6” round |
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transition |
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900 elbow |
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6” Round, | 15 Ft. | x ( | ) | = | Ft. |
900 elbow |
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6” Round, | 9 Ft. | x ( | ) | = | Ft. |
450 elbow |
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| Subtotal column 1 = | Ft. |
Maximum Duct Length: For satisfactory air movement, the total duct length of a 3 1/ 4” x 10” rectangular 6” or 7” diameter round duct should not exceed 100 equivalent feet.
Duct pieces | Equivalent number | Total | |||
| length x used |
| = | ||
6”- 8”Round | 30 Ft. | x ( | ) | = | Ft. |
wall cap |
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with damper |
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6”- 8” Round, 30 Ft. | x ( | ) | = | Ft. | |
roof cap |
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6” round to | 1 Ft. | x ( | ) | = | Ft. |
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| |
rect. |
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transition |
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6” round to | 16 Ft. | x ( | ) | = | Ft. |
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| |
rect. |
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transition |
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900 elbow |
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7” or 8” | 15 Ft. | x ( | ) | = | Ft. |
Round, |
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900 elbow |
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7” or 8” | 9 Ft. | x ( | ) | = | Ft. |
Round, |
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450 elbow |
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7” or 8” | 30 Ft. | x ( | ) | = | Ft. |
Round |
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wall cap |
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with damper |
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7” or 8” | 30 Ft. | x ( | ) | = | Ft. |
Round, |
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roof cap |
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7” round to | 8 Ft. | x ( | ) | = | Ft. |
3 1/ 4” x 10” |
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rect. |
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transition |
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7” round to | 23 Ft. | x ( | ) | = | Ft. |
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| |
rect. |
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|
transition |
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|
900 elbow |
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| Subtotal column 2 = | Ft. | |||
| Subtotal column 1 = | Ft. | |||
| Total ductwork |
| = | Ft. |