Office of Security, Safety and Risk Management
Chemical Hygiene Plan
| C. | Control Measures and Equipment Chemical safety is achieved by continual awareness of chemical hazards and by keeping the chemical under control by using precautions, including engineering safeguards such as hoods. Laboratory personnel should be familiar with the precautions to be taken, including the use of engineering and other safeguards. Laboratory supervisors should be alert to detect the malfunction of engineering and other safeguards. All engineering safeguards and controls must be properly maintained, inspected on a regular basis, and never overloaded beyond their design limits. |
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| C1. | Ventilation The Material Safety Data Sheets (MSDS) for many of the chemicals used in the laboratory will state recommended limits or OSHA-mandated limits, or both, as guidelines for exposure. Typical limits are threshold limit values (TLV), permissible exposure limits (PEL), and action levels. When such limits are stated, they will be used to assist the chemical hygiene officer in determining the safety precautions, control measures, and safety apparel that apply when working with toxic chemicals. |
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| 1. | Laboratory ventilation should be not less than eight air changes per hour (calculated). This flow is not necessarily sufficient to prevent accumulation of chemical vapors. Work with toxic chemicals that have low air concentration limits, or that have high vapor pressures, should always be done in a hood, if available. | |||
| 2. | Fume hoods should provide 70 to 90 linear feet per minute of air flow. | |||
| 3. | Laboratory employees should understand and comply with: | |||
| a. | A fume hood is a safety backup for condensers, traps, or other devices that collect vapors and fumes. It is not used to "dispose" of chemicals by evaporation unless the vapors are trapped and recovered for proper waste disposal. | |||
| b. | The apparatus inside the hood should be placed on the floor of the hood at least six inches away from the front edge. | |||
| c. | Fume hood windows should be lowered at all times except when necessary to raise (open) them to adjust the apparatus that is inside the hood. | |||
| d. | The hood fan should be kept "on" whenever a chemical is inside the hood, whether or not any work is being done in the hood. | |||
| e. | Personnel should be aware of the steps to be taken in the event of power failure or other hood failure and, if necessary, contact maintenance or repair personnel. | |||
| f. | Inspect hood vent ducts and fans at frequent intervals to be sure they are both clean and clear of obstructions. This maintenance is to be performed by maintenance or repair personnel. | |||
| g. | Hoods should never be used as storage areas for chemicals, apparatus or other materials. | |||