Environmental Health & Safety uid as trap coolant when pump- sible, use molded ing organic compounds (liquid plastic desiccators may condense in the trap, leading to ex- with high tensile plosive oxidation). strength. For glass A disinfectant trap should be used in-line desiccators, use a when a is used with hazardous perforated metal des- biological materials. iccator guard. Laboratory Air admittance should be carried out gradually. When opening, make sure Container Selection atmospheric pressure has been restored. Vacuum Do not apply a vacuum to a flat- Never carry an evacuated desiccator. bottomed flask. Use only containers that can withstand vacuum op- erations – heavy-walled Getting Assistance Pumps round-bottomed glassware If you have questions regarding the or specifically-designed safe use of vacuum pumps, contact your su- glassware (e.g., Erlen- pervisor or EH&S. meyer filtration flasks). Wrap exposed glass with tape to prevent flying glass if an implosion occurs. Carefully inspect vacuum glassware be- fore and after each use. Dispose of any glass that is chipped, scratched, broken, or otherwise stressed.

Desiccators It is important to use properly de- Environmental Health & Safety P.O. Box 641172 signed equipment for experiments carried Pullman, WA 99164-1172 out under reduced or elevated pressure. (509) 335-3041 Vacuum desiccators should be enclosed in approved shielding device or protected Wenatchee....509-663-8181 with a framework of wire, nylon or other TriCities...... 509-372-7163 suitable material. Vancouver.....360-546-9706 Glass desiccators often have a slight vac- Spokane...... 509-358-7993 uum due to contents cooling. When pos- http://www.ehs.wsu.edu Care and Use

World Class. Face to Face. Think Safety. Act Safely! Mechanical vacuum pumps used in condensate. Used pump oil must be dis- quantities of gases over a long period of laboratories pose common hazards. These posed as hazardous waste. time, contact Environmental Health & Safety are the mechanical hazards associated with Conduct all vacuum operations behind a for assistance in identifying appropriate fil- any moving parts and the chemical hazards table shield or in a fume hood and al- ters for minimizing vapor release. of contaminating the pump oil with volatile ways wear safety glasses. If a is required for substances and subsequently releasing them Always use a trap on vacuum lines to lower pressures, the pump must be fitted into the lab. A few guidelines will help in prevent liquids from being drawn into with a cold trap to condense the volatiles. A the safe use of these devices. the pump, house vacuum line, or cold trap is a condensing device to prevent drain. moisture contamination in a vacuum line. When using a cold trap: Vacuum System Locate the cold trap between the system Vacuum systems pose severe implo- Traps and vacuum pump. sion hazards. Follow these guidelines and When using a vacuum source, it is Ensure that the cold trap is of sufficient requirements to ensure system safety: important to place a trap between the experi- size and cold enough to condense vapors Ensure that pumps have belt guards in mental apparatus and the vacuum source. present in the system. place during operation. The vacuum trap: Check frequently for blockages in the Ensure that service cords and switches protects the pump and cold trap. are free from defects. the piping from the po- Use isopropanol/ or ethanol/dry Do not place pumps in an enclosed, un- tentially damaging ef- ice instead of /dry ice to create a ventilated cabinet. fects of the material, cold trap. Isopropanol and ethanol are Do not operate pumps near containers of protects people who less expensive, less toxic, and less prone flammable chemicals. must work on the vac- to foam. Do not use solvents which might damage uum lines or system, Use gloves when handling the dry ice. the pump. and Do not use dry ice or liquefied gas refrig- Always close the valve between the vac- prevents vapors and related odors from erant bath as a closed system. These can uum vessel and the pump before shutting being emitted back into the laboratory or create uncontrolled and dangerously high off the pump to avoid sucking vacuum system exhaust. pressures. oil into the system. When using a vacuum-filtration as- should only be used with Place a pan under sembly, pay strict attention to the liquid lev- sealed or evacuated equipment, and then pumps to catch oil els in the trap bottle. Use a secondary trap only with extreme caution. If the system drips. bottle so that if liquid in the primary trap bot- is opened while the is still Check oil levels and tle reaches the inlet tubes, the liquid will be in contact with the trap, oxygen may change oil when neces- vacuumed into the secondary container in- condense from the atmosphere and react sary. Replace and stead of the pump. This will help reduce va- vigorously with any organic material pre- properly dispose of pors in the atmosphere and expensive vac- sent. vacuum pump oil that uum pump replacement costs. Maintain a cold trap between a vacuum is contaminated with If you are directly vacuuming large pump and the apparatus - do not use liq-

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