2.1 Chemical Fume Hoods

Fume hoods and other capture devices are used to contain the release of toxic chemical vapors, fumes, and dusts. Bench top use of chemicals that present an inhalation hazard is strongly discouraged. Fume hoods are to be used when conducting new experiments with unknown consequences from reactions or when the potential for a fire exists.

To achieve optimum performance, the greatest personal protection and reduce energy usage when using a fume hood:

Ensure the fume hood is working by checking the tell-tale (crepe paper hanging from hood sash) and air monitoring device if the hood is equipped with one. DO NOT use an improperly working fume hood.
If the fume hood is not working properly, let other people in the lab know by hanging up a Do Not Use Sign (docx) on the hood.
Work several inches inside the hood. This provides for the greatest amount of capture and removal of airborne contaminants. Also, do not place items on the airfoil or work with chemicals at the face of the hood.
Do not block the baffles at the back of the hood. These allow for proper exhausting of contaminants from the hood.
Keeping the hood sash lowered improves the performance of the fume hood by maintaining the internal vortex and containment. It also helps to conserve energy.
Keep the fume hood sash closed all of the way whenever the fume hood is not being used. Shut the Sash!
Do not use fume hoods to evaporate hazardous waste. Evaporating hazardous waste is illegal.
For work involving particularly hazardous substances or chemicals that can form toxic vapors, fumes, or dusts, the hood or equipment within the hood may need to be fitted with condensers, traps, or scrubbers in order to prevent the vapors, fumes, and dusts from being released into the environment.
Do not exhaust items, such as vacuum pumps, through the face of the fume hood as this will disrupt the airflow into the hood and may cause noncontainment. This will also not allow for the sash to be fully closed.
As with any work involving chemicals, always practice good housekeeping and clean up all chemical spills immediately. Be sure to wash both the working surface and hood sash frequently and always maintain a clean and dry work surface that is free of clutter.
In addition to annual fume hood inspection, face velocity testing, and dry ice capture testing, EHS also offers an online training program on the safe use of fume hoods. Additional information can be found in the Safe Fume Hood Use Guide.

2.1.1 Heating Perchloric Acid

DO NOT use heated Perchloric acid in a regular fume hood. If heated Perchloric acid is used in a regular fume hood (without a wash down function), shock sensitive metallic perchlorate crystals can form inside the duct work, and could result in causing an explosion during maintenance work on the ventilation system. Use of heated Perchloric acid requires a special perchloric acid fume hood with a wash down function. If you suspect your fume hood has perchlorate contamination or would like more information on perchloric acid fume hoods, then contact askEHS.

Laboratory groups who use these hoods shall document standard procedures for the frequency and length of running the washdown system. In some cases, this may be with every use. This procedure shall also include how often a complete cleaning of the hood surfaces is required in order to ensure that dust and splatter on the inside of the hood, that may contain perchlorate salts, do not build up.

2.1.2 Fume Hood Inspection and Testing Program

EHS and Facilities and Campus Services share the responsibility for the annual testing and inspection of fume hoods on campus. After each inspection, an inspection sticker is affixed to the fume hood. If a hood is found to be unacceptable, a warning sign indicating the hood did not pass inspection and should not be used is fixed to the sash. This information will be provided to the building coordinator who will follow through with the repair and arrangements with other laboratories for the use of a different hood.

See the EHS Laboratory Ventilation page for details of this process. For questions or concerns contact askEHS.

If your fume hood does not have an inspection sticker or if the existing inspection sticker on your fume hood indicates a year or more has passed since the hood was last inspected or for other questions please see the EHS page.

Fume hood testing and inspection consists of the following:

The face velocity will be tested for compliance with American National Standards Institute (ANSI) and American Industrial Hygiene Association (AIHA) standard Z9.5;
A visual performance inspection for compliance with the ANSI/American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) standard 110;
Verification of proper room pressurization;
A score will be taken based on the proper use and cleanliness of the hood.
The higher the Hood Housekeeping Score, the more serious the concern.

Hood Housekeeping Score (HHS)	Reason for Concern
1	Hood hibernated
2	Hood on, used for a single chemical process or well organized multiple purposes
3	Hood on, but empty or being used for storage
4	Hood on, crowded or used for competing multiple chemical uses
5	Hood on and contamination evident
6	Hood Decommissioned

2.1.3 Installation of New Fume Hoods

Installation of a new fume hood requires careful planning and knowledge of the existing building ventilation systems and capabilities. Improperly installed fume hoods or other capture devices can seriously disrupt the existing ventilation system and have a negative impact in the immediate room, other fume hoods, and the ventilation system throughout the building.

All fume hoods and other capture devices must be installed in consultation with Facilities and Campus Services and EHS. All new installations of fume hoods must comply with Cornell Design Standards and be commissioned by EHS to be included in the inspection and testing program. To request a new or relocated fume hood be commissioned please submit the following form: Fume Hood Commissioning form.

EHS can provide information regarding the selection, purchase, and inspection requirements for laminar flow clean benches, biosafety cabinets, and ductless fume hoods.

2.1.4 Removal of Existing Fume Hoods

Any removal of fume hoods and capture devices requires prior consultation with your Building Coordinator, Facilities Services, and EHS. This is necessary to ensure building ventilation systems are not affected by removal of fume hoods and capture devices, and so utility services such as electrical lines, plumbing systems, and water and gas supply lines are properly disconnected. For more information about decommissioning of fume hoods, go to the Laboratory Ventilation page.

There is an additional concern for the presence of asbestos within the fume hood itself, and potentially in any pipe insulation associated with the ductwork and/or Mercury in cup sinks. Any asbestos must be properly removed and disposed of by a certified asbestos removal company. EHS can assist laboratories with the cleanup of any Mercury contamination. Contact EHS at 607-255-8200 for more information or questions about potential asbestos or Mercury contamination. See the Lab Move Guide in the appendix for more information.

2.1.5 Maintenance Procedures For Fume Hoods

Please see the Laboratory Ventilation page for reference and training material.

Environment, Health and Safety