SESHA 2011 Symposium / SIA IHTESH 2011 --- PDC2

Vacuum and Cryogen Safety Concerns for Laboratory Applications

Roger Shrouf

Vacuum systems can present a variety of hazards to the laboratory worker. This course will provide an in-depth discussion of a wide variety of hazards and mitigation techniques related to vacuum systems in a research laboratory environment. A thorough discussion of the interface between the vacuum system and commonly associated pressure sources (such as backfill or process gases) will be provided. The limitations and safety concerns associated with vacuum purging of associated pressure systems will be included. Potential accidental overpressure of the vacuum system will be emphasized as well as safety concerns for the use of brittle materials in vacuum applications. Course discussions will also include ancillary hazards commonly associated with vacuum applications such as vacuum pump issues, electrical safety hazards, and mechanical concerns. Many vacuum processes involve the use of cryogenic fluids and nearly all cryogenic fluid applications involve the use of vacuum. Therefore, cryogenic fluid properties and hazards as well as mitigation techniques will be discussed. The primary focus of the cryogen safety segment of the course will be on liquid nitrogen and liquid helium applications. A wide variety of hazards will be discussed including the highlighted hazards of pressure build up from the warming of trapped cryogens and asphyxiation concerns. The features and safety concerns of cryogenic liquid Dewars will also be illustrated. Open discussion will be encouraged throughout the course and lessons learned from accident scenarios will be included where applicable.