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 2–Goals of the Laboratory Environment
8 Siemens Building Technologies, Inc.
Research by ASHRAE has established the range of ambient conditions over which the
largest percentage of persons feel comfortable when involved in the type of activity generally
associated with laboratory work. These conditions range from 71.6°F throughout the winter
months to 72.7°F during the summer months. Relative humidity should be maintained within
the limits of 30% (winter minimum) to 70% (summer maximum). Adequate room air
movement is essential for comfort, but air movement should not exceed 50 feet per minute as
most persons perceive a draft with rates higher than that.
Room Sound Level
Finally, designers must be aware of that the ambient sound level of a laboratory room is a
very important component of overall occupant comfort. Since laboratory rooms must be
ventilated at higher rates than typical office spaces, the potential problem of excessive
ventilation system sound exists. Therefore, HVAC designers must configure the ventilation
system design so as to achieve an acceptable sound level. For most laboratories this means
the ambient sound level is best if it is in the range of 35 to 45 dB based upon standard
acoustical room criteria (RC) curves. Where chemical fume hoods are present, it is generally
acceptable to allow an ambient sound level of 65dB at the fume hood with the fume hood
sash fully open. In particular, it is very important to ensure that low frequency sound does not
exceed the maximums permitted by the RC curves. Research indicates that low frequency
sound has a very adverse affect on one’s ability to maintain concentration. In addition, low
frequency sound has a tendency to induce a feeling of general discomfort and sometimes
even irritability.
Emergency Provisions
Aside from achieving a ventilation system design that provides the required ventilation rate,
occupant comfort and other necessary qualities, a conscientious laboratory planner or HVAC
designer must address laboratory room emergencies. At some time, it is inevitable that
emergency situations will occur in a laboratory. This may consist of a hazardous or toxic
chemical spill, possible release of noxious gasses, escape of harmful airborne biological
pathogens, fire and of course various injuries or medical emergencies. The design of a
laboratory ventilation system must include provisions to enable the ventilation system to
specifically respond to such emergencies. For instance, room ventilation rates may need to
be increased in response to a toxic spill. The room supply and exhaust airflow rates may
need to be changed to create larger static pressure differences to prevent smoke spread
during a fire.
Various standards and practices exist that specifically address the proper use and operation
of ventilation systems in response to emergency situations and these will be discussed in
detail later in this guide.