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.
