Air Distribution

I.     Course Prefix/Number: AHR 204

       Course Name: Air Distribution

       Credits: 3 (3 lecture; 0 lab)

II.    Prerequisite

AHR 101

III.   Course (Catalog) Description

Course covers air moving and treating equipment, and distribution of air using appropriate devices. Content includes blower performance; static and dynamic pressures and pressure drop due to friction; sizing and selection of ductwork and blowers, diffusers, registers and grilles; and evaluation of system performance.

IV.   Learning Objectives

Upon completion of this course, students will be able to evaluate a structure -- residential and/or commercial -- and select the proper distribution pattern.  They will also know how to size ductwork, computer blower size, do motor calculations and perform balancing for effective air control.  In addition, they will know how to size a complete air distribution system for a residence and for a small commercial system.

V.    Academic Integrity and Student Conduct

Students and employees at Oakton Community College are required to demonstrate academic integrity and follow Oakton's Code of Academic Conduct. This code prohibits:

• cheating,
• plagiarism (turning in work not written by you, or lacking proper citation),
• falsification and fabrication (lying or distorting the truth),
• helping others to cheat,
• unauthorized changes on official documents,
• pretending to be someone else or having someone else pretend to be you,
• making or accepting bribes, special favors, or threats, and
• any other behavior that violates academic integrity.

There are serious consequences to violations of the academic integrity policy. Oakton's policies and procedures provide students a fair hearing if a complaint is made against you. If you are found to have violated the policy, the minimum penalty is failure on the assignment and, a disciplinary record will be established and kept on file in the office of the Vice President for Student Affairs for a period of 3 years.

Please review the Code of Academic Conduct and the Code of Student Conduct, both located online at

VI.   Sequence of Topics

Class    Topic       

    1    Introduction
          Purpose of Air Distribution Systems
          Basic Components
          Pressure - Atmospheric, Gauge, Absolute

    2    Pressure - Static, Velocity,
          Total Friction Loss in Straight Duct
          Friction Loss in Flexible Duct
          Round and Rectangular Duct

    3    Fan Conversion Pressure Gain/Loss
          Pressure Drop Through Components
          Pressure Drop Through Single Duct

    4    Quiz #1
          Duct Sizings Considerations
          Introduction to Duct Sizing Methods

    5    Velocity Reduction Method

    6    Equal Friction Method

    7    Equal Friction Method (continued)
          Static Regain Method

    8    Static Regain Method (continued)

    9    Diffusers, Registers, Grilles

    10    Fans (continued)

    11    Misc. Duct Accessories
           Quiz #2

    12    Total System - Residential

    13    Total System - Residential (continued)
            Total System - Commercial

    14    Total System - Commercial (continued)

    15    Testing and Balancing

    16    Final Examination

VII.  Methods of Instruction

Reading, Mathematics, Interpretive Skills
Course may be taught as face-to-face, hybrid or online course.

VIII. Course Practices Required

IX.   Instructional Materials

Note: Current textbook information for each course and section is available on Oakton's Schedule of Classes.

Required Books:

Air Conditioning Contactors Association Manual J. Residential Load Calculations.

X.    Methods of Evaluating Student Progress

Average of two quizzes, plus mid-term, plus final.  Three (3) absences lowers one letter grade; six (6) absences results in "F" grade.  Two major exams.

XI.   Other Course Information

If you have a documented learning, psychological, or physical disability you may be entitled to reasonable academic accommodations or services. To request accommodations or services, contact the Access and Disability Resource Center at the Des Plaines or Skokie campus. All students are expected to fulfill essential course requirements. The College will not waive any essential skill or requirement of a course or degree program.

Oakton Community College is committed to maintaining a campus environment emphasizing the dignity and worth of all members of the community, and complies with all federal and state Title IX requirements.

Resources and support for
  • pregnancy-related and parenting accommodations; and
  • victims of sexual misconduct
can be found at

Resources and support for LGBTQ+ students can be found at