Alert: Due to routine maintenance on the OSHA website, some pages are temporarily unavailable.
To report an emergency, file a complaint with OSHA or ask a safety and health question, call 1-800-321-6742 (OSHA).

<< Return to Previous Page

Secondary Hoods for Fugitive Emission Control

Applications Tips:
  • Thoroughly characterize fugitive emissions prior to design
  • Provide Make-up air
  • Avoid the use of man-cooling fans
Design Characteristics:
  • Q = (Natural rising velocity at hood face at 100 FPM) times surface area of hood in square feet
  • V is greater or equal to 4000 FPM transport (horizontal runs)
  • he = 2.2VP

For problems with accessibility in using figures and illustrations in this document, please contact the Directorate of Technical Support and Emergency Management at (202) 693-2300.