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Liquid Nitrogen Safety Standards
1. Safety
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1.1. Working With Cryogenic Refrigerants
Liquid Nitrogen is a water-looking liquid (referred to
as a "cryogenic refrigerant") that "boils" at a very low
temperature, about 320* F. This "boiling" requires lots of
heat input, just like the boiling of water. That required
heat is drawn from any objects which the liquid
refrigerant touches. In simplified terms, the refrigerant
boils by sucking the heat out of something. That's why it
freezes water at room temperature, and that's why it'll
freeze or frostbite your skin quickly. This must and can
be easily avoided by following Cryostop™
International's safety procedures.
Also, as this material "boils", its "steam" is nitrogen
gas. This gas is a major part of the air we breath.
However, if the nitrogen is allowed to concentrate in a
work area, and displace (push) the available oxygen away
from the work area, asphyxiation (oxygen starvation) of
workers can occur. This must and can be carefully avoided
by following Cryostop International's safety procedures.
LIQUID NITROGEN IS HANDLED SAFELY AT ALL TIMES |
1.1.1. Personal Protection
During the Cryostop™ Freeze Seal Plug Operation and
while on any job site location, Cryostop™ International
employees are required to wear all conventional PPE
equipment as dictated by our normal safety standards.
In addition, during all phases of the Cryostop™ Freeze
Seal Plug operations when refrigerant or its vapors are in
use the following additional specific Cryostop™ safety
equipment must be worn/used:
| Safety
glasses |
all personnel inside safety perimeter and
operating Liquid Nitrogen Source. |
| Face shield |
all personnel inside safety perimeter and
operating Liquid Nitrogen Source. |
| Low temp.
gloves |
all personnel having direct contact with chilled equipment. |
| Oxygen
monitor |
per training standards (minimum one per
crew inside the safety perimeter or inside the work site
if it is a Confined Space).
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1.1.2.
Non-Cryostop International Personnel
Frequently, non-Cryostop™ International
personnel will need to enter the safety perimeter (defined
below) to perform work, etc. The senior Cryostop™
International employee on site shall inform these non-Cryostop™
International personnel of the hazards associated with
working around Cryostop ™ and firmly insist that safety
protection and precautions as outlined herein be observed
by these non-Cryostop™ International personnel. Very
importantly, this includes insisting that they are
protected with their own oxygen monitors.
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1.1.3. Area & Equipment
Protection
A Safety Perimeter around all of Cryostop™ International's
in-use tanks, dewars and equipment shall be set up and "roped
off" with yellow and black safety tape whenever liquid
nitrogen is present on the work site outside of its tanks or
dewars, ie., during the Cryostop™ freeze plug operation and
until all chambers, hoses and piping are boiled free of liquid
nitrogen.
This Safety Perimeter shall be set up on a radius of at least
2 times the elevation of the Cryostop™ chambers above the
lowest unprotected floor/deck level beneath them, or 20 feet,
whichever is greater, and an equal Perimeter around all
operating dewars, tanks, hoses and piping.
While the Cryostop™ frreze plug operation is under way, no
persons shall be allowed inside this Safety Perimeter without
the proper protective clothing, equipment, & monitors, as
outlined herein; nor, shall any person be allowed inside this
Safety Perimeter that has not been instructed of the hazards
inside the Perimeter as outlined in "Working With Cryogenic
Refrigerants" under the "Safety" section herein.
Electrical and rotating equipment within this safety perimeter
shall be disconnected or stopped or protected by the customer
in such a way that an accidental direct hit by a liquid
nitrogen stream will not damage the equipment, cause an
electrical short incident, or be splashed outside the safety
perimeter. The minimum protection acceptable to Cryostop™
International is draped and taped 6-mil polyethylene sheeting.
Any finished (ie., painted or coated) or plastic surfaces
inside the safety perimeter, which the customer does not want
destroyed in the event of an accidental direct hit by a liquid
nitrogen stream, shall be suitably protected by the customer.
1.1.4. Ventilation
Excellent ventilation is critical to safe work around liquid
nitrogen and its vapor.
Specific Cryostop™ International rules about ventilation are
detailed below.
Control Measures
Respiratory Protection: SCBA for confined space or where
ventilation cannot maintain greater than 19.5% oxygen level.
Ventilation: excellent natural or forced air mandatory. It may
be necessary to both exhaust nitrogen gas away from work area
and move fresh (fully oxygenated) air into work area.
Gloves: liquid-proof/insulated Eye Protection: splash goggles
and face shied
Other Protection: full body cover as specified in Cryostop™
International procedures
Work/Hygienic Practices: N/A
1.2. About Liquid Nitrogen
Cryostop™ freeze plugging is normally done using liquefied
nitrogen as the cooling material to form the plug. The
following information is important for Cryostop™ International
personnel to have an adequate understanding of this special
material.
Below is a typical MSDS sheet on liquid nitrogen.
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MATERIAL SAFETY DATA SHEET
SECTION 1. PRODUCT IDENTIFICATION
PRODUCT NAME:
CHEMICAL NAME:
SYNONYMS:
MANUFACTURER:
PRODUCT INFORMATION:
MSDS NUMBER:
REVISION DATE: |
Nitrogen,
refrigerated liquid
Nitrogen FORMULA: N2
Liquid Nitrogen, LIN, Cryogenic Liquid Nitrogen, Nitrogen
Air Products and Chemicals, Inc.
7201 Hamilton Boulevard
Allentown, PA 18195-1501
1-800-752-1597
1041 REVISION: 5
July 1995** |
SECTION 2. COMPOSITION/INFORMATION ON INGREDIENTS
Nitrogen is sold as pure product > 99%.
CAS NUMBER: 7727-37-9
EXPOSURE LIMITS:
OSHA: Not established ACGIH: Simple asphyxiant
SECTION 3. HAZARD IDENTIFICATION
EMERGENCY OVERVIEW
Liquid nitrogen is a colorless, odorless, extremely cold
liquid and gas under pressure. It can cause rapid suffocation
when concentrations are sufficient to reduce oxygen levels
below 19.5%. Self Contained Breathing Apparatus (SCBA) may be
required. Contact with liquid or cold vapors can cause severe
frostbite. Cold vapors in the air will appear as a white fog
due to condensation of moisture. While this may indicate the
presence of the gas it should not be used to determine its
concentration in the atmosphere. Oxygen concentrations must be
monitored in the release area. All cryogenic liquids produce
large volumes of gas when they vaporize. One volume of liquid
nitrogen will expand to produce 696.5 equivalent volumes of
gas.
EMERGENCY TELEPHONE NUMBERS:
800-523-9374 Continental U.S., Canada and Puerto Rico
610-481-7711 other locations
POTENTIAL HEALTH EFFECTS INFORMATION:
INHALATION: Simple asphyxiant.
EYE CONTACT: Tissue freezing and severe cryogenic burns if
contacted into eyes.
SKIN CONTACT: Tissue freezing and severe cryogenic burn of
skin.
CHRONIC EFFECTS: None established.
EXPOSURE INFORMATION:
ROUTE OF ENTRY: Inhalation
TARGET ORGANS: None
EFFECT: Asphyxiation (suffocation)
SYMPTOMS:
Exposure to an oxygen deficient atmosphere (<19.5%) may cause
dizziness, drowsiness, nausea, vomiting, excess salivation,
diminished mental alertness, loss of consciousness and death.
Exposure to atmospheres containing 8-10% or less oxygen will
quickly bring about unconsciousness without warning, leaving
individuals unable to help or protect themselves. Lack of
sufficient oxygen can cause serious injury or death.
Skin contact with liquid nitrogen can cause tissue freezing,
resulting in severe burns. The burns are caused by the
extremely low temperature of the cryogenic liquid and not the
result of chemical action. Skin may appear red with the
formation of blisters. In cases that involve prolonged or
severe exposure, tissue may freeze and have a waxy or yellow
appearance.
MEDICAL CONDITIONS AGGRAVATED BY OVEREXPOSURE: None
CARCINOGENIC POTENTIAL: Nitrogen is not listed by NTP, OSHA or
IARC as a carcinogen or suspected carcinogen.
SECTION 4. FIRST AID
INHALATION: Persons suffering from lack of oxygen should be
moved to fresh air. If victim is not breathing, administer
artificial respiration. If breathing is difficult, administer
oxygen. Obtain prompt medical attention.
SKIN CONTACT: Remove any clothing that may restrict
circulation to frozen area. Do not rub frozen parts as tissue
damage may result. As soon as practical place the affected
area in a warm water bath which has a temperature not to
exceed 105°F (40°C). Never use dry heat. Call a physician as
soon as possible.
Frozen tissue is painless and appears waxy with a possible
yellow color. It will become swollen, painful, and prone to
infection when thawed. If the frozen part of the body has been
thawed, cover the area with dry sterile dressing with a large
bulky protective covering, pending medical care. In case of
massive exposure, remove clothing while showering with warm
water. Call a physician.
EYE CONTACT: For exposure to liquid, immediately warm
frostbite area with warm water (not to exceed 105°F).
SECTION 5. FIRE AND EXPLOSION
FLASH POINT: AUTO IGNITION: FLAMMABLE LIMIT:
Not Applicable Nonflammable Nonflammable
EXTINGUISHING MEDIA: Nitrogen is nonflammable and does not
support combustion. Use extinguishing media appropriate for
the surrounding fire.
HAZARDOUS COMBUSTION PRODUCTS: None
SPECIAL FIRE FIGHTING INSTRUCTIONS: Nitrogen is a simple
asphyxiant. If possible, remove nitrogen containers from fire
area or cool with water. Do not direct water spray at the
container vent. Self contained breathing apparatus may be
required for rescue workers. Evacuate the area.
UNUSUAL FIRE AND EXPLOSION HAZARDS: Liquid nitrogen when
spilled will vaporize rapidly forming an oxygen deficient
vapor cloud. Evacuate this area. Pressure in a container can
build up due to heat and it may rupture if pressure relief
devices should fail to function. Contact with cold liquid or
gaseous oxygen may cause frostbite. Visibility may be obscured
in its vapor cloud.
SECTION 6. ACCIDENTAL RELEASE MEASURES
Evacuate all personnel from affected area. Increase
ventilation to release area and monitor oxygen level. Use
appropriate protective equipment (SCBA). To increase rate of
vaporization spray large amounts of water on to the spill from
an upwind position. If leak is from container or it's valve,
call the Air Products emergency telephone number. Do NOT spray
water directly at leak. If leak is in user’s system close
cylinder valve and vent pressure before attempting repairs.
SECTION 7. HANDLING AND STORAGE
STORAGE:
Store and use with adequate ventilation. Do not store in a
confined space. Cryogenic containers are equipped with
pressure relief devices to control internal pressure. Under
normal conditions these containers will periodically vent
product. Do not plug, remove, or tamper with pressure relief
device.
HANDLING:
Never allow any unprotected part of the body to touch
uninsulated pipes or vessels which contain cryogenic fluids.
The extremely cold metal will cause the flesh to stick fast
and tear when one attempts to withdraw from it.
Use a suitable hand truck for container movement. Containers
shall be handled and stored in an upright position. Do not
drop, tip, or roll containers on their sides. Do not remove or
interchange connections. If user experiences any difficulty
operating container valve or with container connections
discontinue use and contact supplier. Use the proper
connection.
DO NOT USE ADAPTERS.
Use piping and equipment adequately designed to withstand
pressures to be encountered. Use a check valve or other
protective apparatus in any line or piping from the cylinder
to prevent reverse flow. To prevent cryogenic liquids or cold
gas from being trapped in piping between valves the piping
shall be equipped with pressure relief devices. Only transfer
lines designed for cryogenic liquids shall be used. Some
metals such as carbon steel may become brittle at low
temperatures, will easily fracture and should not be used with
cryogenic liquids. It is recommended that all vents be piped
to the exterior of the building.
SPECIAL PRECAUTIONS:
Some metals, such as carbon steel, may become brittle and
fracture at low temperatures.
For additional information concerning storage and handling
refer to Compressed Gas Association pamphlet P-12 Safe
Handling of Cryogenic Liquids available from the Compressed
Gas Association, Inc., 1725 Jefferson Davis Highway,
Arlington, VA 22202-4102 Telephone (703) 412-0900.
SECTION 8. PERSONAL PROTECTION / EXPOSURE CONTROL
ENGINEERING CONTROLS: Natural or mechanical ventilation to
prevent oxygen deficient atmospheres under 19.5% oxygen.
RESPIRATORY PROTECTION:
General Use: None required.
Emergency Use: Self contained breathing apparatus (SCBA) or
positive pressure airline with mask and escape pack are to be
used in oxygen deficient atmosphere. Respirators will not
function.
PROTECTIVE GLOVES: Loose fitting thermal insulated or leather
gloves.
EYE PROTECTION: Full face shield and safety glasses are
recommended.
OTHER PROTECTIVE EQUIPMENT: Safety shoes when handling
containers. Long sleeve shirts and trousers without cuffs.
SECTION 9. PHYSICAL AND CHEMICAL PROPERTIES
APPEARANCE: Colorless, cryogenic liquid
ODOR: Odorless
MOLECULAR WEIGHT: 28.01
BOILING POINT (1 atm): -320.4 ° F (-195.8 ° C)
SPECIFIC GRAVITY (Air = 1): 0.967
FREEZING POINT/MELTING POINT: -345.8 ° F (-209.9 ° C)
VAPOR PRESSURE (AT 20 ° C): Not applicable
GAS DENSITY (At 70 ° F (21.1 ° C) and 1 Atm): 0.072 lb/ft3
(1.153 kg/m3)
SOLUBILITY IN WATER (Vol/Vol at 32 ° F (0 ° C)): 0.023
EXPANSION RATIO: (For liquid to gas) at 70 ° F (21.1 ° C): 1
to 696.5
SECTION 10. REACTIVITY / STABILITY
CHEMICAL STABILITY: Stable
CONDITIONS TO AVOID: None
INCOMPATIBILITY: None
HAZARDOUS DECOMPOSITION PRODUCTS: None
HAZARDOUS POLYMERIZATION: Will not occur.
SECTION 11. TOXICOLOGICAL INFORMATION
Nitrogen is a simple asphyxiant.
SECTION 12. ECOLOGICAL INFORMATION
The atmosphere contains approximately 78% nitrogen. No adverse
ecological effects are expected. Nitrogen does not contain any
Class I or Class II ozone depleting chemicals. Nitrogen is not
listed as a marine pollutant by DOT 49 CFR.
SECTION 13. DISPOSAL
UNUSED PRODUCT/EMPTY CONTAINER: Return container and unused
product to supplier. Do not attempt to dispose of unused
product.
DISPOSAL: For emergency disposal, discharge slowly to the
atmosphere in a well ventilated area or outdoors.
SECTION 14. TRANSPORTATION
DOT HAZARD CLASS: 2.2
DOT SHIPPING LABEL: Nonflammable Gas
DOT SHIPPING NAME: Nitrogen, Refrigerated Liquid
IDENTIFICATION NUMBER: UN1977
REPORTABLE QUANTITY (RQ): None
SPECIAL SHIPPING INFORMATION: Containers should be transported
in a secure upright position in a well ventilated truck. Never
transport in passenger compartment of a vehicle.
SECTION 15. REGULATORY INFORMATION
U.S. FEDERAL REGULATIONS:
CERCLA: Comprehensive Environmental Response, Compensation,
and Liability Act of 1980 requires notification to the
National Response Center of a release of quantities of
hazardous substances equal to or greater than the reportable
quantities (RQ) in 40 CFR 302.4.
CERCLA REPORTABLE QUANTITY: None
SARA TITLE III: SUPERFUND AMENDMENT AND REAUTHORIZATION ACT OF
1986
SECTION 302: Requires emergency planning based on threshold
planning quantities (TPQ) and release reporting based on
reportable quantities (RQ) of EPA’s extremely hazardous
substances (40 CFR 355).
Nitrogen is not listed as an Extremely Hazardous Substance.
SECTIONS 311/312: Require submission of material safety data
sheets (MSDSs) and chemical inventory reporting with
identification of EPA defined hazard classes. The hazard
classes for this product are:
IMMEDIATE HEALTH: Yes PRESSURE: Yes
DELAYED HEALTH: No REACTIVITY: No
FIRE: No
SECTION 313: Requires submission of annual reports of release
of toxic chemicals that appear in 40 CFR 372. This information
should be included in all MSDSs that are copied and
distributed for this material.
Nitrogen is not listed as a toxic chemical.
TOXIC SUBSTANCE CONTROL ACT (TSCA): Nitrogen is listed on the
TSCA inventory.
Environmental Protection Agency (EPA)
40 CFR Part 68: Risk Management for Chemical Accident Release
Prevention.
Nitrogen is not listed as a regulated substance.
OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION (OSHA)
29 CFR 1910.119: Process Safety Management of Highly Hazardous
Chemicals. Requires facilities to develop a process safety
management program based on Threshold Quantities (TQ) of
highly hazardous chemicals.
Nitrogen is not listed as a Highly Hazardous Chemical.
SECTION 16. SUPPLEMENTAL INFORMATION
NFPA RATINGS: HMIS RATINGS:
HEALTH: 3 HEALTH: 3
FLAMMABILITY: 0 FLAMMABILITY: 0
REACTIVITY: 0 REACTIVITY: 0
SPECIAL: SA*
*Compressed Gas Association recommendation to designate simple
asphyxiant.
** Documents with effective dates of July 1995 and July 1998
are identical in content and either may be used.
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