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
Glossary
reheat
Applying sensible heat to supply air that has been previously cooled below the desired
temperature. It can be related to the humidity control process or to the introduction of cold
outdoor air for cooling.
reheat coil
Hot water, steam, or electric coil located at a branch of a HVAC system that supplies air to an
individual room or zone. Reheat coils are commonly used to allow each room or zone served
by a primary air handling unit to add just as much heat as necessary to satisfy the individual
zone’s comfort or ambient temperature needs.
return air
Portion of the air that is removed from an internal building space such as an office, and is
circulated back into the primary air handling unit (in place of taking in all outdoor air) as a
means of conserving energy. Building codes require ventilation systems to supply a certain
amount of outdoor air per person depending upon the type of building or occupancy
(commonly 20 cubic feet per minute (cfm) per person and 0.7 cfm per square feet for an
office occupancy). When the total amount of air being supplied by the HVAC system exceeds
these minimum outdoor air requirements, any additional air delivered may be composed of
circulated (return) air. Using return air to make up the difference in the total air supplied
saves energy particularly during the cold winter and hot summer months. Note that the air
exhausted from certain hazardous occupancies such as laboratory rooms, operating rooms,
and isolation rooms cannot be used as return air.
sash
Moveable glass panel used to cover the face area of a chemical fume hood to protect the
user. Fume hoods can have different sash arrangements for vertical (up and down) as well
as horizontal (sideways) movement. Some fume hoods have multiple horizontal sash
components within their vertical sash.
system effect factor
Degradation in fan performance when the fan is applied to a specific HVAC system. Fan
curves and fan performance data are obtained by the fan manufacturer at a specific test
(optimum) configuration and is usually not obtainable in actual practice. Typical reasons for
system effect are inlet and outlet connections with insufficient straight duct and dampers and
other HVAC components located close to a fan’s inlet or outlet. The system effect factor
should be estimated and taken into account when referring to fan performance curves.
stack velocity
Speed at which the air exhausted from a laboratory facility is discharged upward when it
leaves the exhaust stack. Stack velocity should typically be at least 3,000 feet per minute
(fpm) to ensure adequate dispersion into the outdoor air and to prevent re-entrainment into
fresh air intakes.
Siemens Building Technologies, Inc. 101