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ESH Manual Page: 11000: Cryogenic Systems and Radiation Safety

Cryogenic fluids may be used at The Sanford Underground Laboratory at Homestake (hereafter referred to as Sanford Laboratory) in a variety of research applications. It is the policy of Sanford Laboratory to control the use of these fluids so as to avoid burns and/or serious life-threatening injury due to the displacement of oxygen that could occur if spilled, leaked, or otherwise released into poorly ventilated spaces. 


This chapter describes procedures for reviewing the safety aspects of cryogenic systems as well as the required occupational training for cryogenic personnel.  It pertains to all cryogenic systems.  It also includes cryogenic systems supplying purge gas.


3.1. The Science Liaison Department Director (SLDD) is responsible for ensuring that no cryogenic systems are introduced into the facility before the requirements of this chapter are satisfied.  Specifically, the SLDD shall:

  • Implement such administrative controls as are necessary to prevent the introduction of unauthorized cryogens into the facility.
  • Ensure that the EHS Department is advised as early as possible of any proposal to introduce cryogenic systems into facility spaces not previously authorized.
  • Ensure that a cryogenic safety analysis and review is completed and that any requirements stipulated by that review are met prior to the initial operation of the system.
  • Maintaining safety documentation for each cryogenic system authorized for use.

3.2. The EHS Department shall support the Science Liaison Department by:

  • Arranging for each new cryogenic system to be reviewed by a Cryogenic Safety Subcommittee. 
  • Auditing the cryogenic system pre- and post-start-up to ensure that all prescribed safeguards are in place to prevent inadvertent spills or releases.

3.3. The Cryogenic Safety Subcommittee shall serve in a consulting capacity on all cryogenic system matters.  The subcommittee shall:

  • Provide consultative support to the Science Liaison Department Director, when requested.
  • Develop an in-house expertise and capability for evaluating cryogenic systems. Propose appropriate modifications to this chapter as necessary.


Cryogenic – A liquid with a boiling point below -150°C.

 Cryogenic Facility – An area where cryogenic liquids are produced, used, or stored.

Cryogenic Personnel – Those engaged in or responsible for the production, use, transport, or storage of cryogenic fluids and/or materials.


As specified by the scope, cryogenic systems within the scope of this chapter shall be reviewed before initial system operation; after a shutdown and warm-up to room temperature of longer than two months; or anytime a change in system configuration has been made. A change in system configuration is not an engine swap or the pumping of a vacuum jacket. System configuration changes are more substantive such as adding a new (including temporary) line, off normal operations not described in procedures, or unusual maintenance operations not previously documented.

5.2. Safety Review

a) The analysis and review shall be directed to all aspects of the system which could present a hazard to personnel.

b) The analysis shall demonstrate that the system can be brought into operation safely.  It should also demonstrate that safe operation can be maintained.

c) The analysis shall demonstrate that all cryogenic pressure vessels falling under the scope of ASME Boiler and Pressure Vessel Code Section VIII are met. In the case of vacuum insulated vessels, the inner vessel shall be considered a cryogenic pressure vessel and the outer vessel shall be considered a vacuum vessel.

 5.3. Training

Training plays a key role in the safe and efficient operation of cryogenic systems.  Training may take the form of safety orientations, safety qualification courses, or training by supervisors as prescribed by Sanford Laboratory’s safety training requirements.  Both formal and on-the-job training shall be documented.

  • a) Cryogenic personnel shall have sufficient education, training, and supervision to assure that they can safely perform their duties.  Furthermore, personnel shall be instructed in cryogenic hazards peculiar to the facility at which they work.  Assistance from a person knowledgeable of these hazards shall be available to any individual newly assigned to perform cryogenic work at a facility until the supervisor determines that the individual can perform his or her duties unassisted.
  • b) Cryogenic personnel should attend the Sanford Laboratory (or equivalent) safety courses on such topics as: “Oxygen Deficiency Hazards”, “Cryogenic Safety”, and “Pressurized Gas Safety.” Other courses, as defined by the EHS Department, may also be appropriate.  General training in cryogenic principles may also be beneficial, particularly to personnel involved in operations.

5.4. A technical appendix describing procedures which should be followed by those preparing a safety analysis is attached.


6.1. Appendices

  • Technical Appendix to Cryogenic System Review: Cryogenic Safety Analysis Procedure
  • Appendix A:  Failure Mode and Effects Analysis
  • Appendix B:  What-If Analysis 
  • Appendix C:  Job Hazard Analysis