Hanse VTC Series, Installation, Operation And Maintenance Instructions

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Liquid Nitrogen Safety
Properties: Liquid Nitrogen
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Liquid Nitrogen has a boiling point of -195.8°C
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Volume of expansion liquid to gas (at 15°C, 1 atm.) = 682.1
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Sg = 0.808 (at -195.8°C).
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Density of liquid (normal boiling point, 1 atm.) = 0.807 g/cc
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Colorless, Odorless liquid similar in appearance to water.
Known or Expected Hazards
Temperature Related
•
The extremely low temperature of the liquid can cause severe burn-like
damage to the skin either by contact with the fluid, surfaces cooled by the fluid
or evolving gases. The hazard level is comparable to that of handling boiling
water.
•
The low temperature of the vapor can cause damage to softer tissues e.g . eyes
and lungs but may not a ff ect the skin during short exposure.
•
Skin can freeze and adhere to liquid nitrogen cooled surfaces causing tearing on
removal.
•
Soft materials e.g . rubber and plastics become brittle when cooled by liquid
nitrogen and may shatter unexpectedly.
Vapor Related
•
Large volumes of nitrogen gas are evolved from small volumes of liquid nitrogen
(1 liter of liquid giving 0.7 m
3
of vapor) and this can easily replace normal air in
poorly ventilated areas leading to the danger of asphyxiation. It should be noted
that oxygen normally constitutes 21% of air. Atmospheres containing less than
10% oxygen can result in brain damage and death (the gasping reflex is
triggered by excess carbon dioxide and not by shortage of oxygen), levels of
18% or less are dangerous and entry into regions with levels less than 20% is
not recommended.
Risks
For an untrained person, the risk of injury is moderate with cryogenic burns the most
likely injury. However in exceptional circumstances when large amounts of material are
spilled in an enclosed space, asphyxiation may be fatal.
Who is likely to be injured?
The most likely injury is to the person using the material although following major
spillage all inhabitants of a room may be a
ff ected.
Authorization and Copyright of this document is
controlled by Hanse Environmental Inc.
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