Facilities Operations and Development (FOD) and Environmental Health and Safety (EHS) worked to update the existing chemical fume hood performance testing and certification procedure. This procedure covers hoods with traditional vertical and/or horizontal sashes, walk-in units, and hoods with either low or traditional air flow capabilities. Other engineering controls such as benchtop hoods, wet benches and local exhaust ventilation do not fall within the scope of this procedure and may require the services of a contractor to be certified annually. The testing and certification process will continue to be conducted annually if airflow changes are made or repairs have occurred. Elements of the procedure include:
Visual Inspection:
- Sash operation and condition, i.e. cracks, chips.
- Visual confirmation that all hood components are in place and not damaged, i.e., baffles and air foil.
Average face velocity measurements:
- Measurements using a thermal anemometer will measure the average face velocity between 80-150 fpm at a sash height of 18”.
Containment Verification/Visualization (smoke test):
- A final performance test will provide visual observation of the hoods ability to contain vapors and will be conducted all side of the hoods exterior face using a portable smoke generator.
All conditions outlined above must be met before the hood will be certified for continued use. Hoods that do not meet these conditions will be removed from service until repairs can be made to the hood. “Out of Order” signage will be posted on the hood until the necessary repairs have been made. The hood must meet the required certification conditions before use. All hood performance testing and observations will be documented by FOD technicians using the CMS system used to generate and document work orders.
Because research activities at the university are varied, misusing the hood can easily affect the hood’s performance. In addition, the increased desire to lower energy consumption has influenced fume hood manufacturers to design and develop low flow fume hood systems. In an effort to limit hood failures, EHS is recommends some basic fume hood work practices:
- Limit storing large instrumentation, furnaces, or apparatus inside the hood that would impede airflow. Fans or other air moving devices are prohibited.
- Keep hood slots/baffles unobstructed.
- Utilize jackstands to elevate small equipment such as hotplates, water baths and stirrers.
- Keep work at least 6” back from the face of the hood.
- Keep sash closed as much as possible to protect the user. The sash should be closed when unattended.
- Limit foot traffic in front of the fume hood.
- Visually inspect the hood before each use. If the hoods structural integrity has been compromised, i.e., broken, cracked or fractured sash or missing parts it should be removed from service until repaired.
- Opening and closing or propping open lab doors can affect the room pressure resulting in decreased hood efficiency.
If you have questions concerning the use of your fume hood or the procedure for testing and certification please contact Mitch Baker, baker.779@osu.edu