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Variable Air Volume Systems

COURSE NO: M06-007
Variable Air Volume Systems
Course Highlights

This online engineering PDH course discusses the HVAC air distribution system with focus on Variable Air Volume (VAV) systems.


In central air conditioning systems there are two basic methods for delivering air to the conditioned space 1) the constant air volume (CAV) systems and 2) the variable air volume (VAV) systems. As the name implies, constant volume systems deliver a constant air volume to the conditioned space irrespective of the load.


VAV systems, on the other hand, are designed to simultaneously meet a variety of cooling and heating loads in a relatively efficient manner.  The system achieves this by varying the distribution of air depending on the cooling or heating loads of each area.  The air flow variation allows for adjusting the temperature in a single zone without changing the temperature of air in the whole system, minimizing any instances of overcooling or overheating.  This flexibility has made this one of the most popular HVAC systems for large buildings with varying conditioning needs such as office buildings, schools, or apartments.


This 6 PDH online course is applicable to mechanical engineers, design and construction personnel, technical staff and facility personnel who are interested in gaining a better understanding of variable air volume systems.

Learning Objectives

This PE continuing education course is intended to provide you with the following specific knowledge and skills:

  • What is the operational philosophy of variable air volume (VAV) systems
  • What are the differences between pressure dependent, pressure independent and volume limiting VAV boxes
  • What are the various types of fans used in air handling systems including forward curved, backward curved, radial and aerofoil construction
  • What are the different types of cooling coils used in air handling systems and which among face split, vertical split and intertwined coils is appropriate for VAV systems
  • What is duct pressure classification and how it is used in selecting appropriate duct sheet thickness
  • How is duct design using equal friction method different from static regain and T-method
  • What are different types of outlets and which parameters govern their selection
  • What is difference between fan powered, single duct, dual duct and bypass VAV boxes
  • What are different types of VAV controls including direct digital controls
  • What are the common instruments used in acceptance testing and monitoring of VAV systems
Course Document

In this professional engineering CEU course, you need to review Appendix A, "Variable Air Volume Systems" of the US Corps of Engineers Construction Engineering Research Laboratory (USACERL) technical report 99/20, May 1999.

To view, print and study the course document, please click on the following link(s):
Variable Air Volume Systems (6.30 MB)
Course Quiz
Once you complete your course review, you need to take a multiple-choice quiz consisting of thirty (30) questions to earn 6 PDH credits. The quiz will be based on this USACERL technical report.
The minimum passing score is 70%. There is no time limit on the quiz, and you can take it multiple times until you pass at no additional cost.
Certificate of Completion

Upon successful completion of the quiz, print your Certificate of Completion instantly. (Note: if you are paying by check or money order, you may print your Certificate of Completion after we receive your payment.) For your convenience, we will also email you your Certificate of Completion. Also, you can log in to your account at any time to access and print your Certificate of Completion.

To buy the course and take the quiz, please click on: