Working on Contaminated Laboratory Vacuum Systems
This guideline has been developed to minimize potential chemical exposure to employees while performing installation, repair or maintenance work on laboratory vacuum systems.
Background
Vacuum systems are used frequently in laboratory research. Their use is associated with several types of laboratory equipment and processes including:
- Vacuum ovens
- Gel dryers
- Solvent degassing
- Freeze dryers
- Filtration
- Desiccators
- Vacuum concentrators
- Rotary evaporators.
In some cases these applications may require the venting of small amounts of hazardous laboratory chemicals. Ideally, highly toxic materials are identified and appropriate traps are used to remove the contamination at the point of use. Unfortunately, this is not always the case so hazardous materials are occasionally drawn through the system.
Once in the vacuum system most volatile contaminants pass through and are exhausted. However, in some cases chemical residues may contaminate parts of the vacuum system. Three potential sites of contamination may occur:
- The sealing liquid in liquid sealed pumps (except dry pumps)
- Solid internal surfaces within the pump and/or piping system
- The water in the air-receiving tanks (in larger systems)
Contamination of the sealing liquid can occur because the liquid (often oil) has direct contact with any contaminant passing through the vacuum system. Depending on the chemistry of the sealing liquid and the contaminant, chemical residues or a byproduct of a chemical reaction between the two may be present. Contamination of hard surfaces within the system is less likely, but under some conditions surfaces could become contaminated as a result of the condensation of liquids or gases, adsorption, or the settling of aerosols within the system. Finally, water in the air- receiving tank on larger systems could potentially become contaminated because the vented material passes through the air space above the water.
As a result of this contamination, facilities personnel could potentially be exposed to small amounts of a variety of hazardous materials, during removal, maintenance or reconfiguration of vacuum systems.
The following guidelines have been developed to minimize risk when working on laboratory vacuum systems:
Preparation for Work
1. Hazard Determination
- For small vacuum systems using portable pumps, it may be possible to identify specific hazardous chemicals entering the system as part of a risk assessment. Facilities personnel should always confer with laboratory personnel regarding the uses of vacuum systems and the extent that traps or other control devices have been used. If the history of usage indicates that a dangerous material has been used in the system and may have potentially left residue or hazardous byproducts, contact EH&S (5-2060 Cambridge/Allston; 2-1720 Longwood/Southboro)
- In many cases chemical specific information will not be available, especially for work on larger vacuum systems with many end users (Central Vacuum). In cases where work is conducted on central vacuum systems, or where the use of the vacuum system is unknown, assume that the system components are contaminated with chemical residues.
2. Notifications
- Follow all notification procedures described in the Overview Document - Responsibilities -
- Special notification procedures for central vacuum: Several locations may share the same vacuum system. Post a shutdown notice at all affected locations.
3. Preparation of Work Area
- Ensure that laboratory personnel have followed all safety precautions and preparatory measures described in reference appropriate part of summary document here.
- Clean visibly contaminated surfaces before working on them. Use a vacuum if there is significant particulate contamination is present.
- If any work is to be performed in a confined space refer to Harvard University's Confined Space Program or contact H&S Safety Coordinator.
- Obtain Hot Work Permits if required.
- Control energy sources when required using appropriate lock out or tag out procedures. (Refer to Harvard University's Lock Out Tag Out Program or contact EH&S Safety Coordinator)
- Close appropriate valves to isolate effected parts of the system.
- Where possible, purge the system with clean air before beginning work.
- Ensure there is proper ventilation to the work area, particularly when working in small areas.
4. Personal Protective Equipment
- Latex or nitrile gloves are adequate for most applications. Specialty gloves may be needed if extreme contamination is present. If cut protective gloves are indicated, they should be worn over chemical protective gloves.
- If cutting or other work generates dusts, safety glasses with side shields are indicated. If work generates mists or the possibility of liquid splash, goggles are indicated.
Doing the Work
1. Break existing lines using the least disruptive methods (e.g. avoid sawing lines if tubing cutters can be used.) After removing seal all open ends with caps or plastic film.
2. If applicable, remove sealing liquid carefully. Avoid splashing or excessive pouring. Place in a sealed container. Liquid should be containerized and disposed of as a hazardous waste (see below). Smaller vacuuum pumps or systems can be drained in laboratory hoods to avoid exposure.
3. When soldering existing lines, avoid exposure by connecting fittings and piping before soldering (i.e. avoid working at open ends, if possible).
4. When draining water from air-receiving tanks, use direct hose connections, wherever possible. Run hoses directly to receiving container or drain. Avoid pouring and splashing as much as possible.
5. Handle all materials carefully. Avoid rough handling that may dislodge chemical residues adhered to surfaces.
Completion of activities
1. Clean up work site
- Wash down the area if appropriate. In general, only wet cleaning methods should be used.
- Gather up tarps or drop cloths and clean up area.
2. Dispose of materials
- Sealing liquid that is removed during the course of service must be disposed of as a hazardous waste. If you have any questions regarding hazardous waste contact EH&S Hazardous Waste line at 6-3322.
- Reusable gloves, drop cloths, and/or coveralls may be rinsed or laundered and reused. Disposable or damaged personal protective equipment can be disposed of as regular trash.
3. Hygiene
- Wash hands after service activities.
