The Why, What and How of Air Flow Control, Not Just for Techies

Jim Coogan, Siemens

Air flow control is one of the technical building blocks of a functional laboratory. Ventilation systems support the exposure control devices and pressurization strategies that protect lab workers and their colleagues. These systems are built on individual air flow controllers. The way these subsystems perform enables the larger objectives of the ventilation system. Additionally, air flow control is the primary lever affecting energy use in many laboratories.
Performance is defined with reference to control technology concepts and practical implications. Steps to achieve performance are described: specification, execution, testing and maintenance.
Components, systems and design concepts are developed and explained. Applicability of particular devices to certain performance objectives is made clear. Their physical characteristics are related to the performance of a flow control loop. Different types of flow sensors, controllers and air valves are all discussed from this point of view.
In the end, the talk comes back to the real objectives, as affected by the technical details that were explained.

Learning Objectives

  • Connect flow control performance with operating objectives for the building and the ventilation system.
  • Evaluate and compare statements of flow control accuracy
  • Apply instrument accuracy concepts in evaluation of air flow control systems, recognizing the effects of components on overall accuracy.
  • Recognize various kinds of flow control components, their strengths, weaknesses and applicability.


Jim Coogan, P.E., is a Principal in product development at Siemens Building Technologies. In 35 years designing controls for mechanical systems, he has contributed to products ranging from room controllers to Internet-based interfaces. Jim has chaired several ASHRAE committees. He is member of the committee currently revising the Z9.5 Laboratory Ventilation standard and participates in programs with the International Institute for Sustainable Labs. Jim earned his SB in engineering at MIT.


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