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
Room Temperature Control by BTU Compensation
Individual Laboratory Room Humidity Control
Certain laboratories (biology, pathology, animal rooms, etc.), require closer control of
relative humidity. Therefore, the preceding common room control arrangement would
not be applicable whenever any of the following situations exist:
• Each room requires a different relative humidity.
• Equipment in one or more rooms gives off appreciable moisture and can
affect the room humidity.
• The humidity must be maintained within +/- 5% rh.
Figure 18 shows a more elaborate humidifying and control arrangement to meet the
need for tighter room humidity control. The arrangement in Figure 18 consists of
individual humidifiers and individual humidity control loops for each laboratory room.
Since it is unlikely that all laboratories in a facility would need individual humidifiers
and individual controls, it would be more cost effective during the facility planning
stage to group the laboratories requiring such provisions together so that they could
be served by a single primary air handling unit that does not have a humidifier.
Likewise, it would be beneficial for laboratories that can be satisfied with a common
humidifying system (Figure 17) to also be grouped on the same primary air handling
unit.
Humidity Sensor Location
In all humidity control arrangements, the humidity sensors should always be located
where they will provide fast response and also the best representation of the average
relative humidity in the room. Of course, this means that they should not be in
proximity to any laboratory equipment that gives off moisture or heat. The best
general location for the sensor is within the room's general exhaust duct (not in any
fume hood or biological safety cabinet exhaust duct). The rapid air movement over
the sensor will provide the best response time and the room general exhaust will
provide the best sampling of the overall room relative humidity. In animal rooms or
rooms in which particulate may be present in the room atmosphere, filtering must be
provided prior to the humidity sensor to prevent accumulation of animal hair and
other airborne material.
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