16.10.1 Cryogenic Safety Guidelines
Personnel who are responsible for any cryogenic equipment must conduct a safety review prior to the commencement of operation of the equipment. Supplementary safety reviews must follow any system modification to ensure that no potentially hazardous condition is overlooked or created, and that updated operational and safety procedures remain adequate.
Clothing and Personal Protective Equipment
Wear the appropriate clothing and PPE when working and transferring cryogenic materials.
- Safety glasses are a minimum to be worn during the transfer and normal handling of cryogenic fluids. Face shields must be worn over safety glasses if there is the potential for splashing in the face, such as filling dewars.
- Loose fitting, heavy leather or other insulating protective gloves must be worn when handling cryogenic fluids.
- Shirt sleeves should be rolled down and buttoned over glove cuffs, or equivalent protection, such as a lab coat, should be worn in order to prevent liquid from spraying or spilling inside the gloves. Do not wear short sleeves when working with cryogenic liquids.
- Long pants without cuffs and that don’t expose skin must be worn.
- Shoes that cover the feet are required. These must not allow cryogenic materials to come into contact with skin. Shoes must not allow a cryogenic liquid to become trapped in the material or soak in liquid in the event of a spill. Leather or other non-woven material is recommended.
Cryogenic fluids must be handled and stored only in containers and piping systems specifically designed to withstand the extremely cold temperatures, and in accordance with applicable standards, procedures, and proven safe practices, and be based on the specific cryogen.
Transfer operations involving open cryogenic containers such as dewars must be conducted slowly to minimize boiling and splashing of the cryogenic fluid. Transfer of cryogenic fluids from open containers must occur below chest level of the person pouring the liquid and on a steady surface.
Only conduct such operations in well-ventilated areas to prevent possible gas or vapor accumulation that may produce an oxygen-deficient atmosphere and lead to asphyxiation. If this is not possible, an oxygen monitor must be installed.
Small spaces, environmental chambers, and cold rooms often do not have sufficient exhaust ventilation to support storage and use of cryogenic materials. Contact EHS with any questions and to conduct a risk assessment.
All cryogenic systems, including piping, must be equipped with pressure relief devices to prevent excessive pressure build-up. If a container vents continuously, shows signs of blockage by not venting at all, or there is frost buildup on the outside, which indicates that there is loss of vacuum, do the following:
Do not attempt to remove a blockage;
Move the vessel to a remote location or notify others of the problem;
Contact the supplier for assistance with the vessel.
- The caps of liquid nitrogen dewars are designed to fit snugly to contain the liquid nitrogen, but also allow the periodic venting that will occur to prevent over pressurization of the vessel. Do not ever attempt to seal the caps of liquid nitrogen dewars. Doing so can present a significant hazard of over pressurization that could rupture the container and cause splashes of liquid nitrogen. Depending on the amount of liquid nitrogen that may be spilled, this could cause an oxygen deficient atmosphere within a laboratory due to the sudden release and vaporization of the cryogenic liquid.
- In the event of a spill, oxygen deficiency or a flammable atmosphere will exist beyond any visible fog cloud.
Emergency treatment if skin or eyes come into contact with cryogenic liquid or vapor is as follows:
- If the cryogenic fluid comes in contact with the skin or eyes, flush the affected area with generous quantities of cold water. Never use dry heat. Splashes on bare skin cause a stinging sensation, but in general are not harmful.
- If clothing becomes soaked with liquid, it should be removed as quickly as possible and the affected area should be flooded with water as above.
- Where clothing has frozen to the underlying skin, cold water should be poured on the area, but no attempt should be made to remove the clothing until it is completely free.
- If inhalation of the cold vapors has occurred, move the person to warm, fresh air. The person may be suffering from frostbite tissue in their throat and lungs, and also asphyxia.
- Do NOT rub frostbitten skin as tissue damage may occur. Place in a warm bath that is not above 105°F (40°C).
- For emergencies: Call 607-255-1111 from a cell phone or 911 from a campus phone.
- Complete an Injury/Illness Report