Ban on use of Liquid Nitrogen

•  The Haryana government had recently banned the use of liquid nitrogen.
• The Haryana food and drugs administration department issued an order under section 34 of Food Safety and Standards Act, 2006 (Central Act 34 of 2006).

About Liquid Nitrogen:

• Liquid nitrogen is nitrogen that is cold enough to exist in liquid form. It is used for many cooling and cryogenic applications. Here are some liquid nitrogen facts and information about handling liquid nitrogen safely.
• Liquid nitrogen is the liquefied form of the element nitrogen that is commercially produced by fractional distillation of liquid air. Like nitrogen gas, it consists of two nitrogen atoms sharing covalent bonds (N2).
• At normal pressure, liquid nitrogen boils at 77 K (-195.8°C or -320.4°F).
• Liquid nitrogen is stored in special insulated containers that are vented to prevent pressure build-up.
• Since past few years, liquid nitrogen is being extensively used by restaurants and food industries to prepare frozen desserts like ice creams, which can be created a moment before serving on the table. It cools any substance immediately. The rapidity of cooling is also responsible for smaller ice crystals which give a smooth texture to the ice cream.
• Recently, it is also being popular in preparing cocktails, as it can immediately chills glasses of ingredients. It also adds a smoking effect to the drink.

Hazards Associated with Liquid Nitrogen Handling.

• Extreme Cold: The vapor of liquid nitrogen can rapidly freeze skin tissue and eye fluid, resulting in cold burns, frostbite, and permanent eye damage even by brief exposure.
• Asphyxiation: Liquid nitrogen expands 695 times in volume when it vaporizes and has no warning properties such as odor or color. Hence, if sufficient liquid nitrogen is vaporized so as to reduce the oxygen percentage to below 19.5%, there is a risk of oxygen deficiency which may cause unconsciousness. Death may result if oxygen deficiency is extreme. To prevent asphyxiation hazards, handlers have to make sure that the room is well ventilated when using cryogens indoors.
• Oxygen Enrichment: When transferring liquid nitrogen, oxygen in the air surrounding a cryogen containment system can dissolve and create an oxygen-enriched environment. Since the boiling point of nitrogen is lower than oxygen’s, liquid oxygen evaporates slower than nitrogen and may build up to levels which can increase the flammability of materials such as clothing near the system. Equipment containing cryogenic fluids must be kept clear of combustible materials in order to minimize the fire hazard potential. Condensed oxygen in a cold trap may combine with organic material in the trap to create an explosive mixture.
• Pressure Buildup and Explosions: Without adequate venting or pressure-relief devices on the containers, enormous pressures can build upon cryogen evaporation. Users must make sure that cryogenic liquids are never contained in a closed system. Use a pressure relief vessel or a venting lid to protect against pressure build-up.

By: Vishal