How do you calculate duct traverse?

The formula is: area x velocity = cfm. Cfm = the calculated airflow moving through the duct, which is also known as cubic feet per minute. Once average velocity readings are gathered and multiplied by the inside area of the duct, airflow is calculated.

Why is duct traverse important?

Why traverse Proper air flow within HVAC ducts is essential to good equipment performance. When air flows are incorrect, the air can’t be conditioned as designed, operating costs are elevated, and equipment life expectancy is shortened.

What is Traverse reading?

The velocity of an air stream in a duct is not uniform over the cross section of the duct. To get an average air velocity, a formal pattern of sensing points is taken over the duct cross section. These are known as traverse readings.

What is duct traverse?

A duct traverse consists of a number of regularly spaced air velocity and pressure measurements throughout a cross sectional area of straight duct (for a diagram, reference this airflow guide).

How do you read a traverse?

When performing a duct traverse, always ensure the nose of the Pitot tube is parallel to the duct wall and facing the airflow. Take readings in long, straight runs of duct, where possible. Avoid taking readings immediately downstream of elbows or other obstructions in the airway.

How many points should be used when taking a Pitot traverse in a square or rectangular duct?

25 points
Traversing a Square Duct A minimum of 25 points must be measured in order to get a good average.

What is a traverse reading?

What do you mean by Traverse?

1a : to go or travel across or over. b : to move or pass along or through light rays traversing a crystal. 2 : to make a study of : examine. 3 : to lie or extend across : cross the bridge traverses a brook. 4a : to move to and fro over or along.

What is Traverse duct?

What is a duct traverse?

A duct traverse consists of a number of regularly spaced air velocity and pressure measurements throughout a cross sectional area of straight duct (for a diagram, reference this airflow guide ). This application note explains how to do that.

How do I perform a traversal with a circular duct?

To perform a traversal with circular duct, essentially follow the same traversal plane placement rules used with rectangular. However, circular ducts require measuring across 3 diameters (see air flow guide ), with a minimum of 6 measurements per diameter.

What is a traverse in air balancing?

Traverses have been used by air balancers for decades. For many, they are the gold standard of airflow measurement in commercial and residential systems. A traverse is a series of measurements used to determine the average velocity of air moving through an opening. Air velocity is measured in a grid pattern through a variety of openings.

What is the best FPM for duct traverses?

Above 1,200 fpm a Pitot tube with an appropriate digital manometer is more accurate, but thermal anemometers have some attractive features and are good to between 4,000 and 6,000 fpm. Here are a few simple rules to follow if you’re thinking about buying your first instrument for duct traverses or adding to your stable: