(adapted from Manual 230 - updated: 12/5/2005)
ARS Ventilation and Fume Hood Standards are implemented by each location in accordance with P.L. 91-596, Section 19, OSHAct; Executive Order 12196, Occupational Safety and Health Program for Federal Employees; and ARS Manual 242.1, "ARS Facilities Design Standards."
Laboratory buildings must be designed and constructed in order to avoid indoor air quality problems. Fume hoods are often an integral part of the design and are intended to protect occupants from exposure to hazardous chemicals by preventing or minimizing the escape of contaminants into the laboratory. This is accomplished by Drawing air from the laboratory, past the occupants, into the hood.
The ability of a laboratory hood to provide adequate protection for the user depends on many factors. Prime concerns include:
- air movement and flow patterns in the room,
- turbulence within the hood workspace,
- the effect of the operator on the airflow pattern at the hood face, and
- the control velocity at the hood face.
These factors will be considered during design of the fume hood installation. In order to ensure optimal performance standards of each fume hood, the location must perform the following actions:
- Develop an Operating Protocol for Each Fume Hood: The protocol must include, at a minimum, the permitted uses of the hood, operating procedures, and allowable sash height (based on results of performance tests). To ensure that the hood is used as a proper sash height, the fume hood must be marked at the permissible sash heights(s).
- Train Employees: It is the supervisor's responsibility to ensure that employees are trained to properly operate the fume hoods under their control.
- Measure Face Velocities Annually: Fume hood face velocities must be measured annually to ensure that their performance is acceptable. For the Madison location, annual fume hood inspections are handled by the UW Safety Department (608/262-8769). A standard protocol and form are available on the FD/SHEMB Home page. Hoods that fail the performance test will be taken out of service until repaired.
- Prohibit Chemical Storage or Disposal in Fume Hood: Fume hoods are never to be used as a waste disposal mechanism or for storage of waste materials. It is an EPA violation (Clean Air Act) to deliberately evaporate volatile chemicals in a hood unless the vapors are trapped for reuse or for approved disposal elsewhere. The fume hood is not a storage cabinet. Do not store chemicals or apparatus in the hood unless absolutely necessary. These stored materials can obstruct the airflow or exacerbate an incident or emergency in the hood. Store hazardous chemicals in an approved safety cabinet.
For more information about laboratory design including pressurization, as well as exhaust and intake, refer to ARS Manual 242.1, "ARS Facilities Design Standards." Performance standards for fume hoods are also included in the Manual.