What are the methods that are used for duct design?

- Equal friction method

- Velocity reduction method

- Velocity regain method

Equal Friction Method Velocity Method Pressure method

There are3 methods of duct Designing as under:1.
Equal friction method2.
Velocity reduction method3.
Velocity regain method

Equal Friction method

Equal friction method - Where a constatnt "Head Loss in inches of wg per100 ft" is taken and duct sizes are taken considering this constant loss throughout the ducting. Most commonly used method because of easier calculation.

Velocity Reduction Method : Here duct sizing is done by varying the velocity in the main and bracnch ducts.

Static regain method : Here the total frictional drop and fitting pressure drop is calculated for the ducts, and the line with the biggest pressure drop is taken. This method is the most accurate but take lots of time for calculation.

1-Equal friction method.

2-Velocity Reduction method.

3- Static regain method. Most popular one is the equal friction method normally used in low pressure duct sizing.

THERE IS READY RULER TO DO THAT.

1- equal friction
2- static regain

Equal friction method, Velocity Reduction method and Static regain method.
Most popular one is the equal friction method normally used in low pressure duct sizing.

There are basically three types of duct design, they are1)equal friction method2)velocity reduction method  3)static regain method.
 The first one is the widely used and simplest one.

WE HAVE2 METHODS FOR CALCULATION1) EQUAL FRICTION &2)EQUAL VELOCITY.
IN THIS THE POPULAR METHOD USED IS EQUAL FRICTION FOR LOW PRESSURE DUCTS.

constant velocity or pressure