Speak to your supervisor or lab safety manager-they should provide appropriate training, including on PPE, safe handling, and what to do in an emergency. Get Proper Liquid Nitrogen Safety Trainingīefore you start work with liquid nitrogen in the lab, whether it is using a Dewar flask for flash-freezing or placing your cells in for cryo-storage, you need to get proper safety training. Now you know the dangers of liquid nitrogen, let’s look at how you can handle it safely in the lab. Top Tips for Safety Handling Liquid Nitrogen Image of researcher safely using liquid nitrogen with correct safety equipment. Therefore, liquid nitrogen storage equipment should have appropriate pressure-relief devices.įigure 1. The large expansion ratio also means that if liquid nitrogen boils in a confined space with no escape, the pressure buildup can result in an explosion. If you need to transport it between floors, send the Dewar in the lift and take the stairs.Īlso, this is why areas where liquid nitrogen is stored and handled should have appropriate oxygen sensors that alarm when the oxygen concentration falls. Never travel in a lift with liquid nitrogen. So it wouldn’t trip the oxygen depletion alarm, but it’s close. How much oxygen would remain? If 1L of liquid nitrogen produces 694 L of gas, 25 L of liquid produces 17,350 L of gas. Let’s imagine a scenario in which a 25 L Dewar of liquid nitrogen fails in a 300 m 3 lab. %O 2 remaining = 100 x (21 x ) / Īnd since it’s useful to keep all units in meters, m: We can use the expansion ratio of LN 2 and the volume of a lab to calculate how much the atmospheric oxygen percentage would remain after a spillage. Oxygen depletion alarms usually sound at 19.5%, and some two-stage alarms sound again at 18%. Generally speaking, we shouldn’t enter rooms containing less than 20% oxygen. Wondering how much oxygen would get displaced if the liquid nitrogen Dewar in your lab failed while full? Need to know this calculation for your risk assessments? Here’s how to work it out. How to Calculate Percentage Oxygen Depletion Incase of Dewar Failure The reduced oxygen concentration can quickly result in feeling dizzy and render you unconscious with little warning, as nitrogen gas is colorless, odorless, and tasteless. If enough liquid boils in a confined space, the air can be displaced, resulting in an oxygen deficiency. This means 1 L of liquid nitrogen can expand to 694 L of gas. The liquid-to-gas expansion ratio is 1:694 at 20✬/68✯. One of the most dangerous properties of liquid nitrogen is its ability to boil into large volumes of gas. Liquid nitrogen can also cause common materials such as plastic, carbon steel, and rubber to fatigue and eventually fracture. The extreme cold of this liquid means that contact with bare skin can result in cold burns, cell damage, and life-changing injuries such as retinal detachment in a person’s eye. The boiling point of liquid nitrogen is -196✬/-321✯, and it freezes at -210✬/-346✯.īetween these values, liquid nitrogen is in the liquid state. Liquid Nitrogen Dangers It’s Extremely Cold Unfortunately, researchers have had life-changing injuries and even lost their lives because of accidents involving liquid nitrogen, making it critical that only working with this liquid fully appreciates the dangers. This is a critical application in many research settings, which means if you work in a biology lab, you will probably have to handle liquid nitrogen at some point. In biology research settings, its primary use is for preserving biological materials such as tissue samples and cells. Liquid nitrogen (also referred to as LN2) is a cryogenic liquid commonly used in labs. Liquid Nitrogen Safety: Why is it Important in the Lab? In this article, we highlight the dangers of liquid nitrogen, discuss the necessity of appropriate liquid nitrogen safety training, and share our top tips for avoiding liquid nitrogen dangers in the lab. However, whether you are going to use it to make homemade ice cream or to snap-freeze samples in the lab, liquid nitrogen safety is critical, as this reagent is not something to fool around with. The image of liquid nitrogen has been glamorized recently in TV cookery programs by chefs such as Heston Blumenthal.
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