# How do you calculate friction loss in a duct?

Category:
home and garden
indoor environmental quality

The difference in the character of the flow from the case of water in a pipe stems from the differing Reynolds number Re and the roughness of the

**duct**. The**friction loss**is customarily given as**pressure loss**for a given**duct**length, Δp / L, in units of (US) inches of water for 100 feet or (SI) kg / m^{2}/ s^{2}.

Subsequently, one may also ask, what is friction rate of duct?

**Friction rate** (FR) is the pressure drop between two points in a **duct** system that are separated by a specific distance. **Duct** calculators use 100′ as a reference distance. So, if you were to set the **friction rate** at .

**duct**to arrive at the total system

**duct**length. Multiply the

**static pressure**for 100 feet of

**duct**by the percentage of 100 feet that you have. This will be the

**static pressure**caused by the

**ductwork**.

Similarly, you may ask, how do you calculate the airflow of a duct?

Traverse the **Airflow** in the Exhaust **Duct** An anemometer, a test instrument that measures air velocity is used to **determine** the average air speed in the **duct**. Then the average feet per minute is multiplied by the area of the **duct** in square feet to **determine the airflow** moving through the **duct**.

**How to find force of friction**

- Choose the normal force acting between the object and the ground. Let's assume a normal force of 250 N.
- Determine the friction coefficient.
- Multiply these values by each other: 250 N * 0.13 = 32.5 N .
- You just found the force of friction!