Nova HVAC Systems Interview Questions, Process, and Tips for Experienced

Formula for calculating duct area in HVAC engineering.

• The formula for calculating duct area is A = (π/4) x D²

• A is the area of the duct in square feet

• D is the diameter of the duct in feet

• π is a mathematical constant approximately equal to 3.14

• The formula assumes the duct is circular in shape

Ducts are used to distribute air in HVAC systems. They come in various types and shapes.

• Types of ducts include rectangular, round, oval, and flexible.

• Rectangular ducts are commonly used in commercial buildings.

• Round ducts are more efficient for air flow and are used in residential buildings.

• Oval ducts are used in tight spaces where round ducts cannot fit.

• Flexible ducts are used for easy installation and can be bent to ...read more

Insulation types include fiberglass, foam, cellulose, and mineral wool.

• Fiberglass insulation is made of tiny glass fibers and is commonly used in residential and commercial buildings.

• Foam insulation can be made of polyurethane, polystyrene, or polyisocyanurate and is often used in walls, roofs, and foundations.

• Cellulose insulation is made of recycled paper and is blown into walls and attics.

• Mineral wool insulation is m...read more

The thickness of GI sheet varies according to its gauge.

• GI sheet thickness is measured in gauge.

• The higher the gauge number, the thinner the sheet.

• For example, a 20-gauge GI sheet has a thickness of 0.0359 inches.

• A 16-gauge GI sheet has a thickness of 0.0598 inches.