Local Exhaust Ventilation and Fume Extraction Systems

Description

Local exhaust system is used to control air contaminants by trapping them at or near the source, in contrast to dilution ventilation which lets the contaminant spread throughout the workplace.

Local exhaust is generally a far more effective way of controlling highly toxic contaminants before they reach the workers’ breathing zones.

This type of system is usually the preferred control method if :

  • Air contaminants pose serious health risk.
  • Large amounts of dusts or fumes are generated.
  • Increased heating costs from ventilation in cold weather are a concern.
  • Emission sources are few in number and near the workers’ breathing zones.

 

Salient Features

  • A “hood” that captures the contaminant at the source.
  • Ducts that transport the airborne contaminants through the system.
  • An air-cleaning device that removes the contaminant from the moving air in the system.
  • Fans that move the air through the system and discharge the exhaust air outdoors.
  • An exhaust stack through which the contaminated air is discharged.
  • Make up air that replaces the exhausted air.

 

Advantages

  • Captures contaminant at source and removes it from the workplace
  • Only choice for highly toxic airborne chemicals
  • Can handle many types of contaminants including dusts and metal fumes
  • Requires smaller amount of makeup air since smaller amounts of air are being exhausted
  • Less energy costs

 

Application

  • Stone Crushing
  • Material Handling
  • Chemical Packaging and Storage Facilities
  • Foundries
  • Induction Furnaces
  • Product Recovery