Vacuum and High Pressure System Safety

Vacuum systems usually involve mechanical vacuum pumps, water aspirators, or steam aspirators. On the other hand, high pressure systems are systems that operate at pressure above one atmosphere.

The main hazard associated with operating a vacuum or high pressure system is from flying glass shrapnel released during an implosion or explosion, but other hazards include:

  • Toxicity of the chemicals in the system
  • Fire following breakage of a flask containing flammable solvents

As a result, Care should be taken to select glass apparatus that can safely withstand designated pressure extremes. Procedures should also be implemented to protect against explosion or implosion through appropriate equipment selection and the use of safety shields.

Experiment Design and Setup

Although there is not a specialized expertise at the university EHS. Contact Jeffery Zebrowski at to schedule a review before the first run.

Apparatus Under Vacuum

  •  Vessels used in vacuum operations should be protected with suitable relief valves
  • A protective shield should be placed around evacuated systems
  • Net or electrical tape should be wrapped around all glassware under reduced pressure
Rotary-evaporator taped to prevent implosion hazard
Rotary-evaporator taped to prevent implosion hazard
  • The vacuum system shall be been arranged to allow the equipment to be moved without transmitting strain to the neck of the flask; flasks are to be supported from below as well as by their necks
  • The vacuum apparatus must be well out of the way of traffic to avoid being struck accidentally
  • Never use defective glassware that is cracked or chipped for vacuum use

Apparatus Under Pressure

  • Only perform high-pressure operations in pressure vessels appropriately selected for the operation and protected by pressure-relief and necessary control devices
  • Pressure vessels should be labeled to indicate the maximum allowable working pressure and temperature
  • The pressure-relief device shall be installed so that the discharge is directed away from the area where a person could be affected
  • A protective shield should be placed around pressurized systems

Safety Considerations and Best Practices

Vacuum Systems

  • Use cold traps to protect pumps from corrosive and flammable solvents, and vent pump exhaust into an exhaust system
  • Reduced pressure must never be applied to flat-bottomed flasks unless they have been designed for this purpose
  • Connections in the system under vacuum require clamping to ensure system integrity. Make sure all connections are properly greased, lubricated, or sealed.

High Pressure Systems

  • The pressure levels of high-pressure devices shall be monitored periodically as heating proceeds
  • Pressure vessels containing liquids shall not be filled above capacity


  • Always use tubing (e.g., metal, thick walled rubber) that is rated for the conditions you will be using
  • Use personal protective equipment, such as safety glasses or chemical goggles, face shields, and/or an explosion shield to protect against the hazards of vacuum or high pressure procedures


  • Regularly monitor the condition of the pump oil and filters. Maintain a record for pump oil change dates, and keep track of the maintenance schedule
  • Inspect and test all pressure equipment at intervals determined by the severity of the equipment’s usage. Perform a visual inspection before each use


  • Emergency Spill: Notify others around you, call 911 immediately
  • Non Emergency Spill: Contact PI and EHS at 608/265-5000.
  • Always place broken vessel in sharp containers if no chemical procedure was involved
  • Contact EHS disposal service at for chemical disposal


EHS Chemical Safety Officer: Jeffery Zebrowski at

Prudent Practices in the Laboratory-