Basic Documentation
Table Of Contents
- About this Application Guide
- Chapter 1–Introduction
- Chapter 2–Goals of the Laboratory Environment
- Chapter 3–Unique Ventilation Needs of a Laboratory Facility
- Chapter 4–Ventilation Systems Classification
- Chapter 5–Laboratory Facility Exhaust Systems
- Chapter 6–Laboratory Containment Units - Ventilation
- Chapter 7–Room Ventilation, Makeup Air, and Pressurization Control Systems
- Chapter 8–Laboratory Temperature and Humidity Control Systems
- Chapter 9–Laboratory Emergencies - Ventilation System Response
- Chapter 10–Laboratory Ventilation System - Validation
- Chapter 11–Laboratory Ventilation System - Commissioning
- Glossary
- Index
Chapter 4–Ventilation Systems Classification
18 Siemens Building Technologies, Inc.
The full benefit of a VAV system is most apt to be realized in larger research facilities where
there is a multitude of fume hoods, laboratories, and perhaps extensive usage periods in
individual laboratory operations. Such situations enable a VAV system to achieve its savings
during the longer occupied periods and the incorporation of a VAV diversity factor in the
overall HVAC system design. In addition, where the chemical hazards may be more serious,
the additional controls that accompany a VAV system may result in a somewhat safer
environment.
5
In smaller facilities where usage patterns are rather constant and the laboratory occupied
time somewhat limited, and the hazard only moderate (that is, colleges and universities), a
two position CAV system may be more practical and yield comparable savings while also
having the lower installed cost.
When CAV is utilized, it is recommended that the planner and designer consider the energy
saving potential of a two position CAV system. Few laboratory facilities operate on a 24-hour,
7-day per week basis, so the energy savings, that can be achieved if the ventilation rate is
reduced during unoccupancy, is substantial.
5
VAV systems have the potential of also providing a safer laboratory room environment since the fume hood makeup air required
is normally less than with CAV systems and fume hoods. Less makeup air required results in lower room air currents and thus
helps maintain a less disruptive room airflow pattern resulting in better fume hood containment performance.