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
Chapter 6 discusses containment units specifically intended to allow laboratory
occupants to work with and manipulate chemicals, biological specimens, and other
potentially hazardous elements.
Containment Units
As used in this guide, the term containment unit refers to those devices that are
specifically intended to allow a laboratory occupant to work with and manipulate
chemicals, biological specimens, and other potentially hazardous elements while
keeping harmful airborne agents away from the worker’s breathing zone, face, and
other exposed bodily areas. Usually, containment units can be classified as a type of
biological safety cabinet or chemical fume hood. These types of containment units
perform their safety function by providing a physical enclosure around much of the
hazard while still providing a means of user access.
Except in the case of a glove box which prevents direct user contact with the inside,
most containment units allow the user appreciable direct contact with and access to
the inside through an opening. In the case of a biological safety cabinet, the access
opening is limited in size and an inward airflow is maintained through the access to
keep harmful airborne aerosols and biological pathogens from harming the worker.
With respect to chemical fume hoods, the need to set up experimental apparatus
often requires a larger access provision so a movable sash arrangement is provided.
Thus, the worker can vary the size of the access opening as needed. Regardless of
the extent of the sash opening, an inward airflow is constantly maintained to prevent
chemical fumes, gasses and other airborne substances from leaving the fume hood
through the sash opening. It should also be noted that when closed, the sash also
acts as a physical barrier to protect laboratory workers from other potential hazards
such as a violent chemical reaction, fire or detonation that may occur in conjunction
with an experiment.
Containment Units and Ventilation
The effectiveness of both biological cabinets and chemical fume hoods are highly
dependent upon proper directional airflow to provide worker protection. Very often,
the proper functioning of the facility ventilation system (laboratory room supply and
exhaust system) provides the required directional airflow for the containment units.
In the case of biological safety cabinets, some types are equipped with internal fans
to provide the required airflow. However, in the case of chemical fume hoods, the
airflow component must always be provided by means of the facility’s ventilation
system, which must be designed to perform this function.
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