HVAC - How to Size and Design Ducts - M06-032

Oct 28, 2026

Course material on HVAC ductwork design focuses on fundamentals of airflow and pressure, explaining key terms such as cfm, fpm, duct cross-sectional area, and the relationships for calculating air volume. It covers gauge versus absolute pressure, definitions of static and velocity pressure, and how duct pressure is used for fan selection. The document further outlines duct principles including components, classifications, shapes, sizing methods, pressure-loss concepts, fan sizing and balancing, and system elements from supply and return ductwork to fittings and terminal units.

LanguageEnglish

CategoryTechnology

FormatPDF

Pages91

Reading Time3 h 49 min

AccessFree to download

1. DUCTWORK DESIGN PRINCIPLES

1.1 Basic Definitions

1.2 Air Flow Principles

1.3 Total Pressure, Velocity Pressure, and Static Pressure

1.4 Air Flow Characteristics in Duct

2. DUCT COMPONENTS & MATERIALS

3. DUCT CLASSIFICATION

4. DUCT SHAPES

5. DUCT SIZING

6. PRESSURE LOSSES IN AIR DISTRIBUTION SYSTEM

7. FAN SIZING

8. THE SUPPLY DUCT SYSTEM

9. RETURN DUCT SYSTEMS

10. DUCT FITTINGS AND TERMINAL UNITS

11. DUCT CONSTRUCTION & REINFORCEMENT

12. GOOD ENGINEERING PRACTICES

13. DUCTWORK INSULATION AND SEALING

14. DUCT ATTENUATION AND NOISE CONSIDERATIONS

15. DUCTWORK TESTING & SYSTEM PERFORMANCE

16. DUCT CLEANING

| | | --- | | HVAC – How to Size and Design Ducts
Course No: M06-032
Credit: 6 PDH | |
A. Bhatia | |

Continuing Education and Development, Inc.
P: (877) 322-5800
[info@cedengineering.ca](info@cedengineering.ca) | HVAC – How to Size and Design Ducts – M06-032 HVAC HOW TO SIZE AND DESIGN DUCTS HVAC – How to Size and Design Ducts – M06-032 | 1.0. | CONTENTS
DUCTWORK DESIGN PRINCIPLES
1.1 Basic Definitions
1.2 Air Flow Principles
1.3 Total Pressure, Velocity Pressure, and Static Pressure
1.4 Air Flow Characteristics in Duct | | --- | --- | | 2.0. | DUCT COMPONENTS & MATERIALS
2.1 Duct Components
2.2 Duct Materials | | 3.0. | DUCT CLASSIFICATION | | 4.0. | 3.1 Velocity Classification
3.2 Pressure classification
3.3 Velocity classification v/s Pressure classification
DUCT SHAPES | | 5.0. | 4.1 Round Ducts
4.2 Rectangular Ducts
4.3 Oval Ducts
4.4 Equivalent Diameter
DUCT SIZING | | 6.0. | 5.1 Equal friction method
5.2 Velocity Reduction Method
5.3 Static Regain Method
PRESSURE LOSSES IN AIR DISTRIBUTION SYSTEM
6.1 Duct Friction Losses
6.2 Duct Fitting Dynamic Losses
6.3 The Concept of Duct Equivalent Length | i HVAC – How to Size and Design Ducts – M06-032 | 7.0. | 6.4 Pressure Loss across Components
FAN SIZING | | --- | --- | | 8.0. | 7.1 Fan Selection Example
7.2 Balancing Air
7.3 Fan System Effect
THE SUPPLY DUCT SYSTEM | | 9.0. | 8.1 Extended Plenum Systems
8.2 Reducing Plenum System
8.3 Reducing Trunk System
8.4 Spider System
8.5 Radial System
8.6 Perimeter Loop System
8.7 Rules of Duct Design (ACCA Manual D – Residential Duct Systems)
RETURN DUCT SYSTEMS | | 10.0. | 9.1 Distributed Return
9.2 Central Return
9.3 Pressure Balancing
DUCT FITTINGS AND TERMINAL UNITS
10.1 Duct Fittings and Transitions
10.2 Volume Control Dampers
10.3 Fire and Smoke Dampers
10.4 Diffusers, Grilles & Registers
10.5 Location of Air Inlets and Outlets | | 11.0. | DUCT CONSTRUCTION & REINFORCEMENT
11.1 Duct Construction
11.2 Duct Sheet Metal Thickness | ii HVAC – How to Size and Design Ducts – M06-032 | 12.0. | 11.3 Aspect Ratio
11.4 Standard Duct Sizes
11.5 Duct Fabrication and Lengths 11.6 Duct Hanger Spacing
GOOD ENGINEERING PRACTICES | | --- | --- | | 13.0. | 12.1 Energy Conservation
12.2 Good Engineering Practices for Designing Ductwork
DUCTWORK INSULATION AND SEALING | | 14.0. | 13.1 Ductwork Insulation
13.2 Ductwork Air Leakage
13.3 Duct Leakage Tests
13.4 Duct Sealing
DUCT ATTENUATION AND NOISE CONSIDERATIONS
14.1 HVAC Noise Points | | 15.0. | 14.2 Acoustical Analysis of a Ductwork System
DUCTWORK TESTING & SYSTEM PERFORMANCE | | 16.0. | 15.1 Balancing the System
15.2 Testing Methods and Equipment
15.3 Air Flow Measurement Instruments
15.4 Determining Air Flow at Grilles
15.5 Determining Air Flow in Ducts
15.6 Provisions during Design for Testing, Adjusting, and Balancing
DUCT CLEANING
16.1 Duct Cleaning Methods
16.2 Coordination between Design Specialties | iii HVAC – How to Size and Design Ducts – M06-032 HVAC – HOW TO SIZE AND DESIGN DUCTS Air flow problems have plagued the HVAC industry for years. No matter how much money you spend on a high-quality HVAC system, the equipment won’t work at its best without properly designed and installed ductwork. Ducts that are not well designed result in discomfort, high energy costs, bad air quality, and increased noise levels. A well-designed ductwork system should deliver maximum interior comfort at the lowest operating cost while also preserving indoor air quality. The chief requirements of an air conditioning duct system are: 1. It should convey specified rates of air flow to prescribed locations. 2. It should be economical in combined initial cost, fan operating cost and cost of building space. 3. It should not transmit or generate objectionable noise. A primary

FAQs

What is the purpose of properly designed HVAC ductwork?

Proper duct design and installation deliver maximum interior comfort at lower operating cost while preserving indoor air quality. It also helps avoid discomfort, high energy costs, poor air quality, and excessive noise.

How are air volume, velocity, and duct area related in the course?

The document states that air volume in cfm can be calculated by multiplying velocity (fpm) by duct cross-sectional area in square feet. It also provides rearranged forms: fpm = cfm/area and Area = cfm/fpm.

What is the difference between gauge pressure and absolute pressure?

Gauge pressure is what the gauge indicates, while absolute pressure equals gauge pressure plus atmospheric pressure. The course gives the general equation: Gauge pressure + atmospheric pressure = absolute pressure and illustrates it with 10 psig to 24.7 psia.

Oct 28, 2026

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