Lecture 10: Ventilation

Question 1

Ventilation Types

Answer 1

HVAC, dilution, local exhaust, local supply, natural ventilation, make-up

Question 2

Dilution (also called)

Answer 2

dilution of contaminated air, general exhaust ventilation

used for controlling: airborne health hazards, fire and explosive conditions, odors, nuisances

for health hazard control, local exhaust ventilation is preferred (especially for highly toxic pollutants)

Question 3

HVAC vs Industrial Ventilation

Answer 3

HVAC provide temperature, humidity and odor control (originally for comfort, being adapted to taper airborne contaminants)

Industrial ventilation serves many of the same functions, but its primary goal is control airbone contaminants (levels maintained below TLV or PEL)

Question 4

Local exhaust ventilation

Answer 4

contaminant capture near points of release and removed from work area

prevents migration, lower total volume moved than dilution, systems always mechanical, sometimes you can capitalize on natural movement of particles (receiving hood)

Question 5

Components of LEV systems

Answer 5

hoods, ducting, air cleaning, fan, stack

Question 6

When is LEV needed?

Answer 6

highly toxic contaminants, close proximity to source, variable rates and periods, localized sources, fixed locations,

required by building codes, emphasis on employee, consumer and public relations

Question 7

Capture velocity

Answer 7

velocity of air in the vicinity of the emission source sufficient enough to capture the emission and carry it to the hood and ductwork

Question 8

air cleaners - objectives, types

Answer 8

filter air for release to env / working environment

filters our aerosols / particulates (cyclones, scrubbers, baghouses, electrostatic precipitators)
gases and vapors using scrubbers