Local exhaust ventilation (lev) system PDF

 
LOCAL EXHAUST
VENTILATION (LEV)
SYSTEMS

Outline
Ventilation systems approaches
Main features
Proper design considerations for local
ventilation
Maintenance and inspection

Main types of Ventilation
General/DilutionoControl of heat and/or contaminants removal
oAlso called dilution ventilation
oUsed in controlling contaminants only in cases local
exhaust cant work
oUneconomical and ineffective
Local ventilationoTraps contaminants at source
oIs a preferred control method because:
omore economical
omore effective

Local Exhaust Ventilation (LEV)
Characteristics of contaminants:
oparticle speed
osource directionality
ogas/fume particles
oparticle size
otemperature
oAn ideal solution for one is impractical in another
oThe solution has to be suited to source

Typical sources of contaminants

Typical sources of
contaminants