Basic Documentation

Siemens Industry, Inc. Page 7 of 10
Document No. 149-980
Table 2. Comparison of Ventilation System Characteristics.
Ventilation System Benefits Limitations
CAV - 1-Position
 Lowest first cost
 Easiest to design and implement
 Least impact on facility support
personnel.
 High ventilation related sound
 Highest energy consumption
CAV - 2-Position
 Relatively low first cost
 Good potential for energy reduction
 Not overly difficult to design and
implement
 Modest impact on support personnel
 High ventilation related sound during
occupancy
 Requires fairly rigid occupancy schedule
to achieve energy savings
 Requires somewhat knowledgeable
support personnel
LAF - 1-Position
 Lower ventilation related sound
 Reduced energy consumption at all times
 Not overly difficult to design and
implement
 High fume hood first cost
 May not comply with face velocity
requirements of local (state or provincial)
governing body
 Requires close monitoring to ensure
proper functionality is maintained
 Requires knowledgeable support
personnel
LAF - 2-Position
 Lower ventilation related sound
 Significant reduction in energy
consumption
 Not overly difficult to design and
implement
 High fume hood first cost
 May not comply with face velocity
requirements of local (state or provincial)
governing body
 More involved system design and
implementation
 Requires fairly rigid lab occupancy
schedule to maximize energy savings
 Requires close monitoring to ensure
proper functionality
 Requires competent support personnel
VAV
 Lower ventilation related sound
 Potential for lowest energy consumption
 Greatest usage flexibility
5
 Increased first cost
 Requires sophisticated system design
effort and implementation
 System requires close monitoring to
ensure maximum benefit
 Requires higher level support personnel
5
VAV Allows changing room ventilation and fume hood operational parameters as changes in laboratory usage occur.