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 5–Laboratory Facility Exhaust Systems
In larger research facilities with many laboratories and considerable numbers of
containment units in close proximity to each other, individual exhaust systems are not
the best solution. The accumulation of individual ductwork, fans, and stacks, along
with the incremental costs, make individual exhaust systems more costly initially.
Further, maintenance may become a significant factor due to the large number of
motors, drive belts and roof penetrations that need continual inspection, servicing
and attention. In multi-story facilities, individual exhaust system arrangements may
not be attainable or practical due to the sheer number of vertical ducts and roof
space required. In general, larger laboratories should only use individual exhaust
systems for specialty containment units such as radioactive fume hoods, perchloric
acid fume hoods and Class III biosafety cabinets that require special exhaust
handling such as filtering, washdown, scrubbing and so forth. (Additional information
on specialty exhaust systems is given under that heading at the end of this section.)
Figure 4. Centralized Exhaust System Arrangement Showing Common Exhaust System
Fans and Single Exhaust Stack.
Centralized Exhaust Systems
Multi-story facilities, or those having large numbers of chemical fume hoods and
biological safety cabinets that are exhausted outdoors, will clearly benefit from the
economy and other advantages offered by centralized exhaust systems. Centralized
exhaust systems can be arranged to serve all or large groups of different types of
containment units utilizing common ductwork and only a few larger fans per exhaust
system. A distinct advantage of such systems is less total internal ductwork space
within the building. Centralized exhaust systems typically provide better overall
exhaust system performance and increased operating economy over individual
exhaust systems. Another important benefit of centralized exhaust systems is the
greater dilution of the exhaust effluent due to the contribution of exhaust air from
containment units that may not have highly toxic or hazardous materials present
much of the time.
22 Siemens Building Technologies, Inc.