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Safety SafetyProduct Manual - Perma-Cyl®1500 ZX VHP MicroBulk Storage System Product Manual - Perma-Cyl®1500 ZX VHP MicroBulk Storage System
Cryogenic containers, stationary or portable, are from time
to time subjected to assorted environmental conditions of
an unforeseen nature. This safety bulletin is intended to call
attention to the fact that whenever a cryogenic container
is involved in any incident whereby the container or its
safety devices are damaged, good safety practices must be
followed. The same holds true whenever the integrity or
function of a container is suspected of abnormal operation.
Incidents which require that such practices be followed
include: highway accidents, immersion of a container in
water, exposure to extreme heat or re, and exposure to most
adverse weather conditions (earthquake, tornadoes, etc.).
Under no circumstances should a damaged container be left
with product in it for an extended period of time.
Prior to reusing a damaged container, the unit must be
tested, evaluated, and repaired as necessary. It is highly
recommended that any damaged container be returned to
Chart for repair and re-certication.
In the event of known or suspected container vacuum
problems (even if extraordinary circumstances such as those
noted above have not occurred), do not continue to use
the unit. Continued use of a cryogenic container that has a
vacuum problem can lead to embrittlement and cracking.
The remainder of this safety bulletin addresses those adverse
environments that may be encountered when a cryogenic
container has been severely damaged. These are oxygen
decient atmospheres, oxygen enriched atmospheres, and
exposure to inert gases.
Caution! Before locating oxygen
equipment, become familiar
with the NFPA standard No.
55 “Compressed Gases and
Cryogenic Fluids Code” (www.
nfpa.org) and with all local safety
codes.
Oxygen Decient Atmospheres
Warning! Nitrogen and argon vapors in air
may dilute the concentration of
oxygen necessary to support or
sustain life. Exposure to such
an oxygen decient atmosphere
can lead to unconsciousness and
serious injury, including death.
Oxygen Cleaning
When replacing components, only use parts which are
considered compatible with liquid oxygen and have been
properly cleaned for oxygen service (Refer to CGA Bulletin
G-4.1 “Equipment Cleaned for Oxygen Service”). Do not
use regulators, ttings, or hoses which were previously
used in a compressed air environment on these tanks. Only
oxygen compatible sealants or Teon tape should be used on
threaded ttings. All new piping joints should be leak tested
with an oxygen compatible leak-test solution.
Oxygen Enriched Atmospheres
An oxygen-enriched atmosphere occurs whenever the normal
oxygen content of air is allowed to rise above 23%. While
oxygen is nonammable, ignition of combustible materials
can occur more readily in an oxygen-rich atmosphere than
in air; and combustion proceeds at a faster rate although no
more heat is released.
It is important to locate an oxygen system in a well
ventilated location since oxygen-rich atmospheres may
collect temporarily in conned areas during the functioning
of a safety relief device or leakage from the system.
Oxygen system components, including but not limited to,
containers, valves, valve seats, lubricants, ttings, gaskets
and interconnecting equipment including hoses, shall have
adequate compatibility with oxygen under the conditions
of temperature and pressure to which the components may
be exposed in the containment and use of oxygen. Easily
ignitable materials shall be avoided unless they are parts of
equipment or systems that are approved, listed, or proven
suitable by tests or by past experience.
Compatibility involves both combustibility and ease of
ignition. Materials that burn in air may burn violently in pure
oxygen at normal pressure, and explosively in pressurized
oxygen. In addition, many materials that do not burn in
air may do so in pure oxygen, particularly when under
pressure. Metals for containers and piping must be carefully
selected, depending on service conditions. The various steels
are acceptable for many applications, but some service
conditions may call for other materials (usually copper or
its alloy) because of their greater resistance to ignition and
lower rate of combustion.
Similarly, materials that can be ignited in air have lower
ignition energies in oxygen. Many such materials may
be ignited by friction at a valve seat or stem packing, or
by adiabatic compression produced when oxygen at high
pressure is rapidly introduced into a system initially at low
pressure.
The normal oxygen content of air is approximately 21%.
Depletion of oxygen content in air, either by combustion
or by displacement with inert gas, is a potential hazard and
users should exercise suitable precautions.
One aspect of this possible hazard is the response of humans
when exposed to an atmosphere containing only 8 to 12%
oxygen. In this environment, unconsciousness can be
immediate with virtually no warning.
When the oxygen content of air is reduced to about 15
to 16%, the ame of ordinary combustible materials,
including those commonly used as fuel for heat or light,
may be extinguished. Somewhat below this concentration,
an individual breathing the air is mentally incapable of
diagnosing the situation because the onset of symptoms
such as sleepiness, fatigue, lassitude, loss of coordination,
errors in judgment and confusion can be masked by a state of
“euphoria,” leaving the victim with a false sense of security
and well being.
Human exposure to atmosphere containing 12% or less
oxygen leads to rapid unconsciousness. Unconsciousness can
occur so rapidly that the user is rendered essentially helpless.
This can occur if the condition is reached by an immediate
change of environment, or through the gradual depletion of
oxygen.
Most individuals working in or around oxygen decient
atmospheres rely on the “buddy system” for protection -
obviously the “buddy” is equally susceptible to asphyxiation
if he or she enters the area to assist the unconscious partner
unless equipped with a portable air supply. Best protection
is obtainable by equipping all individuals with a portable
supply of respirable air. Life lines are acceptable only if the
area is essentially free of obstructions and individuals can
assist one another without constraint.
If an oxygen decient atmosphere is suspected or known to
exist:
1. Use the “buddy system.” Use more than one “buddy” if
necessary to move a fellow worker in an emergency.
2. Both the worker and “buddy” should be equipped with
self-contained or airline breathing equipment.
Warning! If clothing should be splashed
with liquid oxygen it will become
highly ammable and easily
ignited while concentrated
oxygen remains. Such clothing
must be aired out immediately,
removing the clothing if possible,
and should not be considered
safe for at least 30 minutes.
Nitrogen and Argon
Nitrogen and argon (inert gases) are simple asphyxiates.
Neither gas will support or sustain life and can produce
immediate hazardous conditions through the displacement
of oxygen. Under high pressure these gases may produce
narcosis even though an adequate oxygen supply sucient
for life is present.
Nitrogen and argon vapors in air dilute the concentration
of oxygen necessary to support or sustain life. Inhalation
of high concentrations of these gases can cause anoxia,
resulting in dizziness, nausea, vomiting, or unconsciousness
and possibly death. Individuals should be prohibited from
entering areas where the oxygen content is below 19%
unless equipped with a self-contained breathing apparatus.
Unconsciousness and death may occur with virtually no
warning if the oxygen concentration is below approximately
8%. Contact with cold nitrogen or argon gas or liquid can
cause cryogenic (extreme low temperature) burns and freeze
body tissue.
Persons suering from lack of oxygen should be
immediately moved to areas with normal atmospheres.
SELF-CONTAINED BREATHING APPARATUS MAY BE
REQUIRED TO PREVENT ASPHYXIATION OF RESCUE
WORKERS. Assisted respiration and supplemental oxygen
should be given if the victim is not breathing. If cryogenic
liquid or cold boil-o gas contacts worker’s skin or eyes,
the aected tissue should be ooded or soaked with tepid
water (105-115ºF or 41-46ºC). DO NOT USE HOT WATER.
Cryogenic burns that result in blistering or deeper tissue
freezing should be examined promptly by a physician.
