University Safety and Assurances

Lab Safety: Vacuum Systems


chemistry vacuum system

Many laboratories at UWM require the use of vacuum systems. Several buildings have centralized vacuum systems for laboratories (e.g., Chemistry, Lapham, Enderis). Laboratories may also use other dedicated vacuum equipment. Vacuum may be used for:

  • evacuating glass vessels, Dewar flasks, desiccators, cold traps and other chambers
  • separation procedures involving distillation and extraction

Your building's central vacuum system is not intended and must not be used to eliminate chemical wastes. Using the system for chemical waste disposal is in violation of good environmental stewardship and applicable regulations. Improper use of the system will result in reduced service life of the system and increased maintenance costs for your department.

Prior to set up and operation, you need to perform a risk assessment regarding potential hazards.

Vacuum work can result in an implosion, creating the hazard of flying glass and spilled chemicals. Systems at reduced pressure, which are subject to rapid pressure changes, may result in the possibility of liquids being pushed into unwanted locations.

Water-sealed or carbon rotary vane pumps can generate significant heat and friction. Therefore, when pulling a vacuum on a system that generates flammable vapors, care must be taken to ensure hazardous concentrations are not generated in the system.

Please consult with your instructor, supervisor or safety committee for additional safe lab practices involving vacuum systems. Please be sure to document these procedures in your chemical hygiene plan. You need to consider:

  • How will you prevent liquids and corrosive gases from being drawn into other laboratory components or the building's central vacuum system? Traps (Kjeldahl) and condensers should be used to insure these chemicals do not enter the vacuum system.
  • Whether relief valves are necesssary for your vacuum work?
  • What methods are necessary to protect vacuum pumps?
  • What maintenance schedules are necessary, including changing the vacuum pump oil? Pump oil needs to be disposed as a chemical waste.
  • How to properly vent the vacuum pump exhaust in a safe and environmentally acceptable way? In most cases, vacuum procedures shall be performed in a fume hood.

Other laboratory safety considerations involving vacuum systems may include:

  • What glassware is suitable for vacuum work, and how do you inspect this glassware?
  • What methods will you use to protect from implosion? Vessels and other glassware shall be wrapped to reduce fragmentation upon implosion.
  • What methods and safe work practices will you use to perform distillations that involve flammable or toxic materials?
  • How will you instruct and monitor your lab personnel on safe and proper procedures for work involving vacuum systems?