A 0 to 400 cfm fan requires a 4 inch minimum duct size but a 6 inch duct is recommended.
What size round duct for 1000 cfm.
Multiply that number by the amount of cubic feet of airflow per minute cfm your type of furnace produces.
We also recommend a 1000 1200 cfm rooftop blower.
Proline s prov models come with an external blower option.
810 cold air boot collar duct 45 65 el air flow dynamics duct sizing reference guide supply or return duct size capacity 09 to 10 pressure drop per 100 el.
Air volume equivalent round air volume cfm 4 6 8 10 12 duct inches cfm 50 6 x 4 550 75 6 x 4 675 100 8 x 4 6 x 6 6 100.
Design cfm 4 cfm 6 cfm 8 cfm 10 cfm 12 60 6x4 60 4x6 90 4x8 120 4x10 150 4x12 90 8x4 110 6x6 160 6x8 215 6x10 270 6x12 120 10x4 160 8x6 230 8x8 310 8x10 400 8x12 150 12x4 215 10x6 310 10x8 430 10x10 550 10x12 180 14x4 270 12x6 400 12x8 550 12x10 680 12x12 210 16x4 320 14x6 490 14x8 670 14x10 800 14x12 240 18x4 375 16x6 580 16x8 800 16x10 950 16x12 270 20x4 430 18x6 670 18x8 930 18x10 1100.
Over a 48 inch range a 54 or 60 kitchen range hood is ideal to ensure full coverage over her cooktop.
The minimum duct sizes and recommended duct sizes based on a hood fan s cfm rating are as follows.
Duct elbows square throat no.
Duct system sizes and airflow quick chart created date.
The chart is based on metal duct.
The table is based on the ducts friction loss formula.
For instance a 2 5 ton system approximately 400 cfm per ton would require 2 14 flexible return ducts or 1 very short flexible 18 duct to move the 1000 cfm required by the 2 5 ton system.
For example for a natural draft furnace multiply 100 cmf by 100 to get 10 000.
Never locate ducts at the end of the trunk line run.
The table below can be used to compare equivalent diameters for rectangular and round circular ducts.
The rectangular dimensions and the air flow volume are adapted to the equal friction loss.
1000 22 x 8 16 x 10 14 x 12 14 1000.
A natural draft furnace produces 100 cmf an induced furnace produces 130 cfm and a condensing furnace produces 150 cmf.
16 up to 11 40 el 12 to 15 55 el 16 to 21 75 el 22 to 27 100 el 28 to 33 125 el return air system no.
Last take off run to be located 12 18 from end.
The equivalent diameter is the diameter of a circular duct or pipe that gives the same pressure loss as an equivalent rectangular duct or pipe.
Flex duct has a higher pressure drop and as such may require the size shown on this guide be increased by 1 round size for up to 800 cfm and 2 round sizes above 800 cfm to insure proper airflow.