Nitrogen Tank or Cryogenic Dewar? Not Sure Where they are Installed? Here's the List!

Liquid nitrogen is used in a broad range of industries, from steelmaking and pharmaceutical to health care and ceramics. The inert gas is also used in laboratories, breweries, fine cooking, and more. Wherever liquid nitrogen is used, it must be stored securely so as not to mingle with air. Learn why nitrogen must be so carefully contained and where and how N₂ gas is stored. 

Bulk Nitrogen Tank Storage 

Liquid nitrogen is stored in a bulk nitrogen tank, also known as a nitrogen dewar. Nitrogen dewars exist wherever nitrogen is used, including in: 

• Labs
• Research universities 
• Restaurants, bars, and hotels 
• Freezers
• Hospitals 
• Flash freezing facilities
• Food processing facilities
• Cryotherapy facilities 
• Manufacturing plants 

The nitrogen dewar features a vacuum stopper, which protects the substance inside and prevents the nitrogen from boiling off. Dewars must have pressure release valves to prevent a bulk nitrogen tank explosion, which can occur when pressure builds up inside the tank. Since liquid nitrogen vaporizes at room temperature, it's critical that the tank stay sealed at all times.

Nitrogen and other insert gases, including argon, displace air when they are released into the environment. As oxygen is displaced, the air becomes oxygen deficient. Breathing oxygen deficient air causes respiratory distress and death via asphyxiation. Since nitrogen is colorless and odorless, there is no way to tell that a leak occurs unless you use an oxygen monitor, which samples oxygen levels. 

Given the risks posed by the material, bulk nitrogen tanks must be stored and transported safely and securely. Workers must bleed out pressure before transporting the tanks, for example, to reduce the risk of incident during transport. 

A robust ventilation system should be installed where the nitrogen is kept, so escaped nitrogen can be vented away, and fresh air should be circulated into the storage room several times per hour. 

Other safety measures include checking that fittings are appropriate, wearing gloves to prevent the nitrogen from burning the skin, and never filling dewars more than 80 percent full. 

While liquid nitrogen can be transferred from the bulk nitrogen tank into a smaller tank for small scale use, it must only be transferred into approved container. If you use the wrong container, it could shatter, leaking nitrogen into the air and decreasing available oxygen. 

Wherever nitrogen is stored or used, signs warning of the risks associated with the material should be posted as a warning to employees. When working with nitrogen, staff should wear eye protection, cryogenic gloves, and other safety equipment. 

Anyone who handles or works with the gas should be trained in safe use, storage, and handling of bulk nitrogen tanks as well. The valves, gauges, and other components of the nitrogen storage tank should be inspected regularly for safety, and replaced whenever you notice wear and tear. 

Why You Need an Oxygen Monitor Where Nitrogen is Stored

By placing an oxygen monitor wherever nitrogen is used, you can protect worker safety and prevent injury or fatality onsite. Oxygen monitors continually sample oxygen levels in the room, making sure that oxygen falls within acceptable levels. Should nitrogen gas leak from the dewar, ambient oxygen levels will start to tumble as the air is displaced by nitrogen. 

When oxygen levels fall to the threshold set by OSHA, which is 19.5 percent, the oxygen deficiency monitor will sound and flash alarms to notify workers onsite. Staff can exit the room before they begin to experience the adverse effects of being in an oxygen deficient atmosphere, then call 911 so emergency personnel can respond to the threat. 

PureAire offers a robust oxygen deficiency monitor capable of withstanding low temperatures of -40 Celsius. Once installed, the oxygen monitor works as intended for 10+ years with no annual maintenance or calibration. An ultra-loud alarm is audible throughout the premises, while a flashing light provides a secondary alert for employees. The unit easily mounts on the wall with brackets and comes with a 3-year warranty. Learn more about oxygen monitors from PureAire at www.pureairemonitoring.com. 

               

Oxygen Monitors now Required for Nitrogen, Argon, Helium, and CO2 use in Denver

Oxygen Monitors now Required for Nitrogen, Argon, Helium, and CO2 use in Denver

The Colorado city of Denver recently passed a new law that requires facilities that use insert gas to install oxygen deficiency monitors wherever these gases are used in excess of 100 pounds. Learn what the new law requires from businesses and how an oxygen sensor protects your employees, your business, and your peace of mind. 

What Denver's New Law Requires 

The law specifically applies to Colorado commercial, industrial, or manufacturing facilities that use inert gases, including nitrogen, argon, carbon dioxide, and helium. Facilities covered by the new law include water treatment plants, laboratories, and food processing plants. 

Fire suppression systems and medical gas systems are not covered by the Denver law. 

Under the new law: 

• Inert gas storage tanks must be placed in approved locations, whether stored inside or outside of the building 
• Storage containers must be secured to prevent tip-overs
• All valves and tubing used with the gas system must meet applicable standards
• Gases must vent outside the building
• All areas where gas is used must either have an oxygen deficiency monitor or continuous ventilation system, which keeps the oxygen levels in the room steady 
• Oxygen alarms should be visually inspected daily by trained staff members
•  Storage tanks, piping, and other parts of the system must be checked on a monthly basis 
• Tests of the system must be conducted regularly with either air or an inert gas

The Denver law sets out regulations for the type of oxygen deficiency monitor, plus where and how to use them. Acceptable monitors must be installed in any location where an inert gas leak could result in an oxygen deficient environment where public health could be at stake. 

Oxygen detectors must be on an approved device list and directly connected to the electrical supply and fire alarm system for the site. The oxygen detectors must be permanently mounted to the wall at a height which is consistent with the given gas's vapor density, so they can work properly. The devices must be located within their specified ranges of operation, in order to ensure the monitors can work as intended. 

The law prohibits self-zeroing or auto calibrating devices, unless they can be spanned or zeroed to check that the oxygen monitor is working as it should be. All installed oxygen monitors must be calibrated regularly to ensure safe and reliable operation. 

Alongside mounted alarms, companies must place signage that notifies employees of the oxygen monitor and gives instructions for what to do in the event of an alarm. Typical instructions tell staff to leave the building and call 911 if the alarm is going off. 

Signs notifying employees of the risk for oxygen deficiency must be posted anywhere inert gas is stored or used.

To further protect employees, the Denver law mandates that gas be transported, filled, or moved only by qualified individuals who follow protocol. All equipment, including piping systems, must be inspected for competency and the organization must maintain records for a period of three years. 

Why an Oxygen Monitor is a Practical Suggestion 

Oxygen deficient environments occur when an inert gas, such as helium, nitrogen, or argon, escapes into the environment and begins to displace oxygen. Since these gases have no odor or color, there is no way that staff working in the room can tell something is leaking. As the oxygen levels fall, employees can experience confusion and respiratory distress, resulting in death by asphyxiation. 

An oxygen monitor tracks ambient levels of oxygen and sets off an alarm when oxygen levels fall below the safe threshold, thus protecting employee safety. Since employees can both hear and see the alarm, they will know there is a problem even if they are operating loud equipment that overrides the noise of the sensor. 

Oxygen monitors are simple solutions to pressing problems faced by organizations that rely on inert gases and want to mitigate their risk. 

PureAire's oxygen sensors are cost-efficient and high quality. They are designed with a zirconium sensor, which is capable of lasting for as long as 10 years. PureAire's oxygen sensor is accurate in diverse environments, from storage freezers to basements. The sensor functions between -40 and 55 C. While PureAire's oxygen monitors do not need to be calibrated, they are capable of calibration, thus eligible for use in Denver. 

PureAire's monitors need little maintenance to work reliably once they are installed using the included wall-mounting brackets, and they are not affected by changes in the barometric pressure, a known problem with other types of oxygen sensors. PureAire's products can be set to measure oxygen levels of either 18 percent or 19.5 percent (which is the OSHA action level), to comply with standards. 

To learn more about oxygen monitors from PureAire, and view specifications, go to www.pureairemonitoring.com.