Flexible Duct Cfm Chart

Use the online duct calculator see references and calculate the needed flex duct size.

Flexible duct cfm chart. 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. Read round duct diameter inches and friction loss per 100 of duct inches of water. Metal ductboard flex size by.

This equal friction method of duct sizing should be adequate for normal residential furnace heating and air conditioning applications. Read duct diameter inches and duct velocity fpm. Enter the desired length of the rectangular duct.

Based on duct diameter. Include fittings in the duct tel enter either. Larger volumes or higher static pressures should be dealt with on an individual job basis.

Select the duct type on the pull down menu. Input the required cfm in the box below that. Enter round duct diameter inches duct airflow cfm duct length and the number of bends.

Equivalent duct calculator round vs rectangular. Sheet metal duct friction loss calculator. Read friction loss inches of water and duct velocity fpm.

Friction loss calculator for sheet metal ducts. Friction rate velocity friction rate. Enter round duct diameter.

Calculations are for 60 f dry air at sea level from 5 to 3000 cfm approximately standard air which is 0 075lb da ft. The flex duct size may be different than the hard duct that runs to that room. Rectangular duct is rounded up to the nearest 1 4 inch.

Click calculate and you will see the size of flex duct you need for that room. Duct system sizes and airflow quick chart created date. In wg duct tel.

As systems increase in efficiency the tolerances of how we have always done it will no longer be adequate. Flex duct 05 on most metal duct calculator round metal pipe 06 on most metal duct calculators field duct sizing chart rectangular sheet metal duct 07 on most metal duct calculators duct size duct height net inside dimension in inches round duct size estimate rectangular duct size estimate 14 5 6 7 8 16 18 20 design airflow 50 75 110. Friction loss calculator for flexible ducts.

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