2019

October 1, 2019

Storing Liquid Nitrogen in Laboratories: Which Safety Precautions and Sensors Will Protect Your Employees?

Liquid nitrogen is frequently used in scientific research, chemistry classes, and even culinary arts nowadays. The substance is safe when properly stored, and as long as everyone follows safety protocols while handling the liquid nitrogen. As part of an environmental health and safety review (EHS review), learn safety considerations regarding storing liquid nitrogen in the lab setting.

EHS Review: Understand Liquid Nitrogen Risks

Liquid nitrogen is known for its cryogenic properties. It can freeze things incredibly quickly. This property also applies to people, so staff must take safety precautions when handling liquid nitrogen. Even seconds of exposure can damage skin and eye tissue, and may cause frostbite.

Staff should never transport liquid nitrogen in open containers. They should never reach directly into vats of the substance.

The main health risk with liquid nitrogen occurs when the liquid vaporizes into gas, which happens if it leaks into the atmosphere. Nitrogen expands in volume when it turns into gas, and depletes oxygen from the air. The gas has no odor or color, so there is no way staff can tell a leak has occurred without an alarm system. If a nitrogen leak occurs, oxygen levels will fall below safe thresholds. This causes severe cognitive and respiratory problems, as well as death by asphyxiation.

Liquid nitrogen, like other cryogenic liquids, needs a pressure-relief valve during storage. Without such a valve, internal pressure could cause the storage tank to explode. Liquid nitrogen should be stored in a room that has proper ventilation as a precaution around leaks. If a leak occurs, the ventilation system can help shunt gases outdoors, protecting the health of workers.

How to Protect Your Employees’ Environmental Health and Safety With an Oxygen Monitor

Facilities must install, calibrate, and maintain oxygen sensors to comply with safety policies regarding the storage of liquid nitrogen in the lab setting. These units act as a secondary precaution against the dangers of a nitrogen leak. An oxygen deficiency monitor or O₂ sensor measures the levels of oxygen in the environment at all times. These devices provide labs with a cost-effective and reliable way to make sure there are no leaks in nitrogen storage areas.

For safety precautions, install one oxygen deficiency monitor anywhere liquid nitrogen is stored, handled, or used. These monitors mount to the wall quickly and provide continuous sampling of oxygen levels. As long as there is no leak, and the room contains enough oxygen, the monitors stay silent. If nitrogen leaked it would cause a decline in oxygen levels, eventually triggering an alarm and flashing light. The oxygen monitor would provide enough time for anyone working in the area to vacate the premises and avoid being harmed or killed.

While there are several styles of O₂ sensor on the market, those from PureAire are preferred for their high quality and cost efficiency. PureAire’s O₂ sensors feature zirconium, which lasts for 10+ years on average with no maintenance and no calibration. Once the monitor in installed, there’s nothing more that needs to be done. Since PureAire’s oxygen monitors are reliable once installed, and require less maintenance than the competition, they make it easier and cheaper for labs to protect worker safety. Learn more about PureAire’s products by visiting www.pureairemonitoring.com.

By : PureAire Monitoring Systems – pureairemonitoring.com

Cryo West

October 1, 2019

September 16, 2019

Liquid Nitrogen vs. Carbon Dioxide Food Freezing

Liquid Nitrogen and Carbon Dioxide can be used interchangeably in many food freezing applications. However, Liquid Nitrogen often offers many advantages over Carbon Dioxide.

	Liquid Nitrogen	Carbon Dioxide
Safety and Environmental Considerations	LN2 is chemically inert. An increase in N2 levels of 2% is not dangerous to humans. LN2 is much easier to exhaust than C02.	C02 is faintly reactive and toxic. OSHA’s carbon dioxide exposure limit in the breathing atmosphere is just 0.5 percent. If incorrectly sized or operated, dry ice snow may collect on the process room floor.
Recommended Safety Equipment	Matheson Tri-Gas recommends an oxygen deficiency monitoring system installed in the processing room for both Liquid Nitrogen and Carbon Dioxide freezing equipment.	Matheson Tri-Gas recommends an oxygen deficiency monitoring system installed in the processing room for both Liquid Nitrogen and Carbon Dioxide freezing equipment.
Food Quality	Rapid freezing locks in moisture and preserves texture.	Slower freezing can negatively affect food quality.
Investment Cost	Lower freezing temperatures mean quicker freezing so equipment needed to produce same amount of product is smaller. Smaller size equipment means lower cost.	Higher freezing temperatures mean the equipment has to be proportionally larger to achieve the same throughput.
Operating Cost	LN2 has about an 18% higher refrigeration value (see chart on back) when compared to C02*. Therefore, on a pound per pound basis, the freezing process would use about 18% less LN2 than C02.	Even if LN2 is more expensive than CO2, the price per pound of frozen product can be less using LN2 since the freezing process would use less cryogen.
Maintenance Cost	Simple equipment with low maintenance requirements.	Complicated equipment requires more maintenance.
Production Rate	Lower operating temperatures and shorter dwell time result in almost twice the throughput in the same footprint. For example, a 20 foot LN2 tunnel can deliver the same output as a 30 foot CO2 tunnel	Higher operating temperatures and longer dwell time require 50% larger freezer to produce the same amount of product.
Operational Flexibility	Smaller freezing equipment leaves more room for expansion. Simple to operate and user-friendly. Precise sizing not as critical, can operate efficiently outside of the original design parameters.	Larger freezing equipment takes up more plant space. Less user-friendly, requires more vigilant operator. Freezer must be sized precisely for a specific product and throughput.

*The actual value depends on the pressure of the gas, the type of freezer, the freezer’s operating temperature, and other factors.

Cryo West

September 16, 2019

September 9, 2019

Workforce a security

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