Lab Safety Series: Cryogen Safety | Cambridge Environmental
Things are about to get chilly! Luckily, Ollie the Lab Collie suited up with proper PPE to bring you today's Friday Lab Safety Series: Cryogen Safety.
A cryogen is a liquefied gas stored or used at cryogenic temperatures. As defined by the National Institute of Standards and Technology, these liquefied gases have a temperature of below -150C. Some examples of commonly used cryogens are liquid nitrogen, argon, neon, helium and oxygen. Each has its own unique properties and hazards - so it is essential to ensure you have proper training on the use of the specific cryogen you are handling, and access to the MSDS.
All cryogens will vaporize, and it is important to know how to handle these vapors. Liquid oxygen vapors will create an oxygen-enriched environment - and can make inert objects susceptible to explosion or flammability.
Most cryogens carry the same hazards. Be sure to recognize these hazards and ensure you have a plan to mitigate each hazard. Known hazards include:
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Oxygen Deficiency - heavy gasses can displace oxygen, carrying an asphyxiation risk.
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Tissue (skin/eye) contact with extreme cold - can case skin to rip, will cause frostbite.
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Oxygen-enriched environment - can cause inert objects to explode
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Pressure Buildup - buildup of gasses in container can cause explosion of container.
It is important to use PPE to protect yourself. Use:
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Goggles / eye protection when handling
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Face Shield when pouring or transferring
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Cryogen appropriate gloves that fit loosely to aid removal in case of accidental splash into glove
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Non-porous lab coat and/or apron
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Long pants that cover shoes
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Closed toed shoes
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No jewellery
Because each cryogen is unique it is important to have proper training related to the material you are handling such as:
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Safe handling of both liquid and gas states
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Functioning of any "fail safe" devices
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Materials not compatible with the cryogen
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Emergency response to spills, fire, explosion, etc.
Know your hazards - cryogenic liquids cannot be indefinitely maintained as a liquid, so it is important all vessels for cryogens must have a pressure valve release system to vent gas build up. These gasses should be ventilated directly outdoors.
Precautions:
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Always wear PPE, and be trained in use before beginning.
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Read over MSDS if it's been a while since working with material.
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Avoid eye/skin contact, will cause extensive damage to tissues.
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Never handle with bare hands, use cryogenic gloves designed for working with the temperature you are handling.
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Gloves must be loose fitting so they can be easily removed in case of splash
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Eye protection is essential
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Absorbant materials should not be exposed to cryogens.
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Do not use/store in confined areas with no ventilation.
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Never place on tile or laminated counters - will destroy adhesive
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Will make plastics brittle, use caution
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Frostbite happens instantly in the presence of moisture
A Note on Containers:
Proceed slowly when filling a container or inserting an object into a container to minimize boiling and splashing. Boiling and splashing will always occur when filling a warm container or inserting objects. All vessels must have a pressure release system and be designed for the cryogenic it is to hold. Fill the vessel only to the indicated level, never overfill. Never roll, drag, or drop vessels or allow them to strike each other. Ensure pressure valves work before filling completely, and never tamper with safety devices, valves or equipment. Be mindful to never store in a sealed/air tight container at a temperature above its boiling point.
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