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Training Programs & Policies Documents
After hygiene, engineering controls are the next most important means of controlling exposure to hazardous chemicals. Engineering controls are anything that that is built or installed to separate people from chemical, biological or physical hazards, and can include fume hoods, biosafety cabinets, glove boxes, and blast protectors. For help in determining what type of engineering control is appropriate for your process, contact EHS (404-894-4635).
Fume hoods are containment devices used to control exposure of the hood user and lab occupants to hazardous or odorous chemicals by preventing their release into the laboratory. A secondary purpose is to limit the effects of a spill by partially enclosing the work area and drawing air into the enclosure by means of an exhaust fan. This inward flow of air creates a dynamic barrier that minimizes the movement of material out of the hood and into the lab. Fume hoods are safety equipment and should be reserved for handling hazardous or odorous materials. They should not be wasted by using them to store unwanted equipment, chemicals, or garbage.
On hoods where sashes open vertically, work with the hood sash in the lowest possible position; this is generally elbow height. Never work with the sash in the fully open position.
On hoods where sashes open horizontally, position one of the doors to act as a shield in the event on an accident in the hood.
Perchloric acid is a clear liquid that has no odor. Solutions below 73% at room temperature are strong non-oxidizing acids. Perchloric acid becomes a strong oxidizer when heated or at higher concentrations; at or above 73%. Organic, metallic and non-organic salts formed from perchloric acid oxidation are shock sensitive and pose a serious fire and explosion hazard. There are many documented accidents resulting from the formation of perchloric acid salts.
Digestions and other procedures performed with perchloric acid at elevated temperatures must be done in a specially designed perchloric acid (wash down) fume hoods.
Perchloric acid hoods are equipped with water sources that spray the ducts and baffles of the hood to remove any perchlorates that may have formed there. Hoods must be washed down per the manufacturer’s recommendations after each use.
If procedures involving heated perchloric acid are performed only rarely, other accepted methods to capture and contain vapors may be used in place of a perchloric acid hood with EHS approval.
If you have been performing perchloric acid digestions in a fume hood not designed for perchloric acid, contact EHS at (404-894-4635) immediately for an evaluation of perchlorate contamination of the hood.
Perchloric acid hoods may only be used for perchloric acid processes. Other processes/chemicals may not be accomplished in perchloric acid hoods.
Various forms of local exhaust ventilation are seen in GT Labs and may have been designed and installed for specific processes. These include:
Are useful for small sources of emissions
These are useful for hot operations or to exhaust materials that are lighter than air
Are useful for heavy vapors or particulates because they pull the contaminant backwards, away from the user, into the plenum before exhausting it up and out
Persons who have a need for local exhaust ventilation should contact EHS for an evaluation to determine what type of system will work best for your process.
Laminar flow hoods are work benches that continuously bathe the work area with clean, filtered air. Their primary purpose is to protect what ever is being worked on, or "product", not the user. Some laminar flow hoods are also chemical benches which both protect the user and the products. These benches exhaust air via an exhaust ventilation system and do not recirculate it back into the lab.
Biosafety cabinets (BSCs) and laminar flow hoods (LFHs) are serviced and certified by a contracted vendor and documented by sticker affixed to the hood. Problems with BSLs or LFHs should be reported to the GT Biosafety Officer. If your hood does not have a sticker indicating that it has been serviced within the last 12 months, or if it does not have a sticker at all, please contact EHS (404-894-4635).
Ventilating chemical storage cabinets is regulated under National Fire Protection Association Standard 45, Standard on Fire Protection for Laboratories Using Chemicals. Ventilation of chemical storage cabinets may only be accomplished with prior approval by GT EHS and requires that the PI or designee start the installation process by filing a project request form with GT Facilities. Laboratory staff may not ventilate cabinets themselves.
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Georgia Institute of TechnologyNorth Avenue, Atlanta, GA 30332Phone: 404-894-2000