## What is oval equivalent to a 6 round duct?

The cross sectional area of a 6″ oval duct is only 75% of that of a 6″ round duct. An equivalent round duct would have a 5.1″ diameter. This means that for a 6″ oval to achieve the same flow rate as a 6″ round, the airflow velocity in the oval duct is higher, leading to a greater pressure drop.

What size oval duct do I need?

If you want 6” oval, you really should go with 5” round because that has an equivalent length of only 24′. If you need the 6” round on one end, take the oval up to 8” and your equivalent length is 60′. In short, the oval side needs to be bigger than the round side.

### How do you calculate flat oval duct?

Duct Surface Area Equations

1. Round: Area = Pi * (D / 12) * L.
2. Rectangular: Area = (W * 2 + H * 2) / 12 * L.
3. Flat Oval: Area = (Pi * H + 2 * W) / 12 * L.

Can you convert a round duct to rectangular?

Transition from round to rectangular duct by installing a transition section. The easiest way to transition from round duct to rectangular is to install a transition section.

#### How many CFM is a 6 oval duct?

8-Inch Rectangular Ducts Size Chart (90-1,500 CFM)

6″ Duct 6″ CFM
6×8 160 CFM
8×8 230 CFM
10×8 310 CFM
12×8 400 CFM

How many CFM does a 10 inch round duct have?

325 CFM
CFM Sizing Chart For Metal Round Ducts (50-2,000 CFM)

Duct Size (Inches) Metal Duct Airflow (CFM)
7 inches 125 CFM
8 inches 180 CFM
9 inches 240 CFM
10 inches 325 CFM

## How many CFM does a 6 inch round duct have?

The 0.10 design friction rate is the most commonly passed-down tradition of sizing ducts and the reason many assume a 6-inch duct delivers 100 cfm.

How do you measure a round duct?

For a circular duct, hold the measuring tape vertically at one side, and sight across the top and bottom, then note the measurement as the diameter of a circular duct.

### How do you convert round ducts to square?

How to Calculate Round Duct Area to Square Feet

1. Measure the diameter of the round duct across its widest point.
2. Divide the diameter by 2 to get the radius of the duct.
3. Multiply the radius by itself to get the square of the radius.
4. Multiply the square of the radius by 3.14 to get the area of the duct in square inches.

How much CFM can a duct handle?

A rectangular 6×6-inch duct has an airflow of 110 CFM. Bigger 6×12-inch ducts can handle 270 CFM airflow. The bigger the crosssection of ducts, the bigger CFM; that’s pretty obvious. The smallest 6×4 ducts can handle 60 CFM airflow.

#### How to convert a round duct to rectangular?

a = length of one side of rectangular duct (inch) b = length of adjacent side of rectangular duct (inch) De= circular equivalent of rectangular duct for equal friction and capacity (inch) Source: 2001 ASHRAE Fundamentals, p. 32.10 Example Convert rectangular duct 22″ x 12″ to equivalent round a = 22, b = 12; from above table

How many CFM is a 12 round duct?

How many CFM is a 12 inch round duct? 2000 cfm (0.94 m3/s) of air flows through a 10 x 12 inches rectangular duct. The friction loss according the table above is 0.81 inches water gauge per 100 ft duct (aprox. 6.6 Pa/m). The velocity in the the equivalent 12 inch circular duct according the table above is 2589 ft/min (13.2 m/s).

## How do you calculate CFM of Round duct?

– Find the diameter of the duct you’re using on the outside of the packaging. – Divide the diameter from Step 1 by 2, then multiply it by itself and pi. – Find the length of the duct by finding the duct length per package on the outside of the package, then multiplying by the number of packages you are using.

How to properly size ductwork?

How To Properly Size Duct Work In Residential Homes? In order to calculate CFM, you must know how big your heating or cooling unit is. The average output of an HVAC unit is 400, so multiply this by 400. You can then divide the square footage of your home by the number of rooms. By doing this, you will be able to multiply the CFM of all your rooms.