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 6–Laboratory Containment Units - Ventilation
Thus, a proper facility ventilation system design is a fundamental requirement for
attaining the protective functionality of a containment unit. This section provides
information on how the various types of containment units must interact with the
facility ventilation system to achieve maximum protection of the laboratory worker.
Biological Safety Cabinets
Although the ventilation system designer does not normally select the type of
biosafety cabinets that may be present in individual laboratory rooms, the designer
must know the operational characteristics of the units in order to ensure that the
ventilation system design will address the exhaust and makeup air requirements of
these cabinets. Biosafety cabinets conform to the standard overall classification as to
Class I, Class II or Class III. Within Class II, these cabinets are sub-classified as
Type A, B1, B2 or B3. Each different classification refers to the suitability of the
cabinet for use where different biological substances and chemicals may be present
and where the biological cabinet may need protection against contamination.
The different laboratory biosafety levels (BSL1 through BSL4) covered previously do
not directly relate to the different types of biosafety cabinets even though the
nomenclature is somewhat similar.
Table 3 provides a concise summary of the different types of biological safety
cabinets and their applicability to different biological laboratory activities for the
benefit of the ventilation system designer. This table is intended as a handy
reference of the requirements that a specific type of biological safety cabinet will
have on the laboratory room’s ventilation. For more detailed information on biological
safety cabinets and their use, see the CDC - NIH Publication, “Primary Containment
for Biohazards: Selection, Installation and use of Biological Safety Cabinets”.
Note that each classification of a biosafety cabinet poses specific requirements as to
how much air must be exhausted from the cabinet and what type of connection (hard
duct or canopy) must be made to the laboratory exhaust system. Therefore, the
ventilation system designer must know the quantity and classification of the biosafety
cabinets that will be in each individual laboratory room in order to provide the
appropriate amount of exhaust and makeup air. In addition, the designer must know
of any special room ambient requirements (that is, temperature and humidity) to
ensure that the makeup air that enters a biosafety cabinet is compatible with the
need.
Table 3. Comparison of Biosafety Cabinet Characteristics.
Class and
Type of
Biosafety
Cabinet:
Class I
Class II
Type A
Class II
Type B3
Class II
Type B1
Class II
Type B2
Class III
Worker
protection
provided by
the cabinet:
Good Good Better Better Better Best
42 Siemens Building Technologies, Inc.