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
Exhaust System Energy Recovery
Studies and analysis that have been done on adding energy reclaim systems such
as run-around coils or other direct heat transfer methods seldom indicate a payback
period that would make such systems economically viable. In contrast, adding
additional equipment or mechanisms to the exhaust system usually will result in
higher maintenance costs and add additional system reliability concerns.
Any equipment that is added within an exhaust system will lower the exhaust system
operating efficiency since it will create an appreciable pressure drop. This can also
result in added system operating sound. Additionally, such devices pose the potential
risk of clogging and thus causing a serious loss of system capacity. Lastly, since the
exhaust system will likely be conveying corrosive elements, the normal life
expectancy of such equipment may be substantially shortened. Thus, any
consideration or analysis of energy recovery systems should include these additional
considerations in addition to the initial installed cost.
Cleaning Systems for Exhaust Air
In general,
it is not economical to design a system that will filter or clean laboratory exhaust air
adequately enough to allow reusing a portion of the exhaust air in order to achieve
an energy savings. (If such re-utilization is being considered, refer to the local
building code and applicable regulatory requirements to determine if this is
permissible in your locale.)
Certain local regulatory or zoning requirements may mandate the use of a filtration or
air cleaning system before allowing laboratory or fume hood exhaust to be
discharged into the atmosphere, especially if a real or perceived health hazard
exists. Where air cleaning is required prior to atmospheric discharge, high efficiency
air particulate (HEPA) filtering systems are available along with charcoal filters and
air scrubber systems to remove nearly all undesirable components of the exhaust.
These components add complexity to a laboratory exhaust system, substantially
increase the installed cost and add to the ongoing operational cost. The laboratory
ventilation system designer must ensure such ancillary systems and equipment will
be properly installed and must also ensure that the exhaust system fans, motors and
ductwork are designed the handle the increased resistance (pressure drop) that such
equipment will add to the exhaust system.
Those responsible for operating the laboratory facility must also be made aware that
including such additional exhaust system filtering or cleaning equipment requires
adequate budgeting to cover the ongoing operation and maintenance required.
Personnel who will be performing filter replacement and system maintenance must
also be properly trained with regard to the hazards involved, proper handling and
disposal of contaminated waste material and provided with appropriate personal
protective equipment (PPE) to ensure their personal safety. In addition, the
contaminated filters and other agents associated with an exhaust cleaning system
must be treated as hazardous waste and incur extra handling and disposal costs.
24 Siemens Building Technologies, Inc.