18 Round Duct Cfm

The table is based on the ducts friction loss formula.

18 round duct cfm.

Enter duct airflow cfm duct velocity fpm duct length and the number of bends. 1200 cfm would probably require a 16 18 round duct or a 14 x 14 square metal duct. Sheet metal duct friction loss calculator. As systems increase in efficiency the tolerances of how we have always done it will no longer be adequate.

Duct work supplies are located on outside walls. 10 joist 525 cfm return only process no. New duct sizing chart xls author. 18 20 9 10 12 flexible duct round metal pipe 750 1200 14 16 design.

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. 900 14 14 x 10 18 x 8 12 x 12 1 000 14 14 x 10 18 x 8 12 x 12. Read round duct diameter inches and friction loss per 100 of duct inches of water. 1800 28 x 10 22 x 12 18 1800 1900 30 x 10 22 x 12 18 1900 2000 24 x 10 18 2000 helpful basic information.

If you still try to use that 8 you will stuff and stall air in that duct. You must have 400 cfm of air flow per ton of a c 1 ton equals 12 000 btu approximately 1 cfm of air is required to heat or cool 1 to 1 25 sq. 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. 65 round to round 20 25 el duct elbows radius throat no.

You could probably get a max of 250 275 cfm but it will be noisy. 20 90º elbow 45º angle no. 1200 cfm in an 8 round duct. 19 75w x 7 75h 4 3 out of 5 stars 326 22 99 22.

18 20 9 10 12 flexible duct round metal pipe 750 1200 14 16 design airflow 50 85 125 1500 2000 180 240 325 525. 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. Duct system sizes and airflow quick chart created date. The rectangular dimensions and the air flow volume are adapted to the equal friction loss.

Step three if desired airflow exceeds the cfm rating increase to the next duct size step four listed cfm is based on typical field results and may vary install dampers step five if duct run exceeds 25 or has excessive transitions increase to the next size. 14 up to 11 10 el 12 to 21 15 el.