Cryogenic Liquids: Gases that have been transformed into extremely cold liquids and stored at temperatures below -130 F. Cryogenic liquid spills will vaporize rapidly when exposed to the higher ambient temperatures outside the container. Because of this rapid vaporization a small spill can turn into a large incident very fast. Some of the common expansion ratios are 694 to 1 for nitrogen all the way up to 1445 to 1 for neon.
Use Extreme Caution when dealing with high expansion ratio materials in a building, because these materials can expand and displacing all available oxygen causing asphyxiation.
Cryogenic or Refrigerated Liquids are unique hazardous materials in that they do not have a Department of Transportation (DOT) hazard classification. Cryogenics are not placarded or labeled unless they have another hazard such as pressure, flammability, or Oxidizer. The fact that DOT does not consider them hazardous does not mean they do not have hazards. Cryogenics are very cold and can cause frost bite, asphyxiation (displace oxygen in the air), and solidification of body parts, equipment, and personnel protective equipment. Response personnel need to take special precautions when responding to incidents involving cryogenic liquids. Little personnel protective equipment is available for protection against cryogenic liquids and vapors close to the liquids.
Cryogenic Tanks
Liquid oxygen, liquid nitrogen and liquid argon are cryogenic liquids. Their boiling temperatures are:
Cryogenic liquids storage vessels have three basic components:
1. Inner Pressure Vessel –
A vessel usually made of stainless steel or other materials that have favorable strength characteristics when exposed to cryogenic temperatures.2. Outer Vessel –
A vessel made of carbon steel or stainless steel. Under normal operating conditions, this vessel retains the insulation around the inner pressure vessel, and can also maintain a vacuum around the inner vessel. Typically, the outer vessel is not exposed to cryogenic temperatures.3. Insulation –
The space between the inner and outer vessel, containing several inches of insulating material maintained in a vacuum. The vacuum and insulating material help to reduce heat transfer and thereby reduce the boil-off of the liquid oxygen, liquid nitrogen or liquid argon stored within the vessel.The inner vessel of the storage tank is typically designed to sustain a maximum allowable working pressure of 250 psig (1724 kPa). Vessels may be fabricated for higher or lower working pressures and special applications. The service pressure of the vessel is adjustable.
Dewar:
A typical, vacuum- jacketed dewar is shown here. This type of container is non-pressurized. the most common unit of measure for the capacity of a dewar are liters, which range from 5 - to 200 - liters.
All shipments of refrigerated liquid (cryogenic), must
comply with DOT regulations. This applies to motor freight, rail, air, and
water shipments. Water vessel shipments
must also be prepared in accordance with the International Maritime
Organization (IMO) regulations.
Intermodal (Marine, Rail and Highway)
- Pressurized containers within a box or beam supporting frame.
- normal capacities range from 4,500 to 5,00 gallons. Capacity can be determined from tank dataplate.
Highway MC-338
Design & Construction
- Large, well insulated "Thermos bottle" design. Inner container holds the product, and the vacuum-sealed outer shell is filled with insulation.
- Many versions include a work box "dog house" at the rear of the unit and evaporator coils underneath the belly of the tank. Work box includes discharge & fill piping, valves and pump.
- Single compartment unit with working pressures ranging from 25 psi to 500 psi. Capacity of 8,000 to 10,000 gallons.
- Safety features include pressure relief devices on both inner & outer tanks, excess flow valves, fusible links and emergency remote shutoff.
Cryogenic Liquid Tank Rail Car
Fixed Facility Cryogenic Tanks
Vertical cryogenic storage tanks are often found next to manufacturing buildings, hospitals, bottled-gas companies and welding-supply houses. A heat exchanger next to the tanks is confirmation that these are indeed cryogenic tanks. Heat exchangers are a series of silver-colored tubes with fins next to the tanks. The heat exchanger allows for the cold liquids to be turned back into gases for use. Ambient air around the tubes and fins of the heat exchanger warms the cold cryogenic liquids into their gas state.
Cryogenic tanks have narrow circumferences and are very tall. These are high-pressure tanks used to store cryogenic liquids, which are very cold. Cryogenics have boiling points of -130 to -452 degrees. Some tanks, particularly those found at cryogenic-production facilities, may each hold as much as 400,000 gallons. Types of materials found in cryogenic containers include natural gas, argon, nitrogen, chlorine and oxygen. They can be flammable, oxidizers or poisons.
Design and
Construction:
- · Large, well insulated “thermos bottle” design. Inner container constructed of stainless steel or metal suitable for low temperature service, while the outer shell is typically a gastight carbon steel jacket, with the space filled with insulation and under vacuum. Constructed to ASME standards.
- Normally have vaporizing unit and pumps to warm the product and convert it to a gas, as well as pressurize the container and “move” the gas.
- Liquid oxygen tanks will always be over a concrete pad; never over asphalt or grass.
- Capacities range from 500 to 20,000 gallons (most are in the range of 1,500 to 11,000 gallons), with design working pressures up to 250 psi.
- Capacity can be determined from tank spec plate or pre-incident planning (if not marked).
- Safety features include pressure relief devices on both the inner tank and the outer tank, excess flow valves, fusible links and nuts, and emergency remote shutoff.
-
· Insulated and refrigerated cylindrical bulk storage tank. Depending upon product and service, may be a combination of single steel wall, double steel wall, or a concrete exterior and double steel interior wall combined with insulation.
-
· Products are stored at temperatures near their boiling point.
-
· Typically 50 to 150 ft. diameter, but can be as large as 200+ ft. Depending upon tank diameter and height, capacities can range from 20,000 to 2000,000+ barrels (NOTE: 1 barrel = 42 gallons).
-
· Design working pressures <15 psi.
-
Cryogenic SpillsLarge leaks from containment systems can create pooled LNG cryogenic liquid on the ground or inside diked areas. Contact with cryogenic LNG (-250°F) can cause severe damage to the skin and eyes. Never walk into an LNG spill. Avoid contacting the liquid or any refrigerated pipe, appliance, or tank. Coming into contact with liquid LNG can result in a life-threatening injury.Cryogenic LNG can make ordinary metals subject to embrittlement and fracture; therefore, cryogenic operations require specialized containers and piping. LNG is stored in containers made of metals such as 9% nickel, steel, or aluminum, and moved through stainless steel pipes capable of handling these temperatures. Insulation on cryogenic transfer lines protects workers from the potential for contact freeze burns.Hazard & Risk Evaluation:The Hazard And Risk Evaluation Process For Cryogenic Chemicals Should Focus On The Following Factors:• Hazardous Nature of The Material Involved.• Quantity of The Material Involved.• Design and Construction of The Container.• Fixed or Engineered Safety Systems.• Type of Stress Applied To The Hazmat And/or Its Container.• Size and Type of Area Being Affected.• Identifying and Prioritizing Exposures.• Level of Available Resources.
Hazmat responders must carefully weigh the hazards and risks of intervention, when selecting the strategic goals and tactical objectives.
Tactical options include the following:
Nonintervention— this is A “No Win” Situation in which
influence the sequence of events.
Defensive Tactics— these tactics involve protecting
exposures and allowing the fire to burn or the chemical reaction to run its course.
Offensive Tactics— these tactics are implemented when
sufficient resources are available to control and extinguish the fire or leak.
Recent Event:
Article Link: One officer dead! Liquid Nitrogen Incident 2-6-2017
NOTE:
Once you have completed the Hands-On Drill and reviewed the material above. Your instructor can sign off on the following NFPA JPR in you hazmat task book.
7.2.1.1.1 and 7.2.1.1.2
Given examples of the following railroad cars and
intermodal tanks, identify the containers by name and specification and
identify the typical contents by name and hazard class:
Type
|
Grading Criteria
|
||
Cryogenic Liquid tank
Car
|
Passed
|
Remediated Required
|
Instructor Signature
& Date
|
Specification,
Contents, and Hazard Class
|
|||
Specialized
Cryogenic Intermodal Tank
|
|||
Specification,
Contents, and Hazard Class
|
7.2.1.1.3
Given
examples of the following Cargo
Tanks, identify the containers by name and specification and identify the typical contents by name
and hazard class:
Cryogenic Liquid
Tanks
|
|||
Specification,
Contents, and Hazard Class
|
7.2.1.1.3
Given
examples of the following Facility Storage Tanks, identify
the containers by name and specification
and identify the typical contents by name and hazard class:
Type
|
Grading
Criteria
|
||
Cryogenic Liquid Tank
|
Passed
|
Remediated Required
|
Instructor Signature
& Date
|
Contents
|
|||
Hazard Class
|
|||
7.2.1.1.3
Given examples of the following Hazardous
Materials Packages, identify the containers by name and specification and identify the typical contents
by name and hazard class:
Type
|
Grading
Criteria
|
||
Cryogenic Liquid Tank
|
Passed
|
Remediated Required
|
Instructor Signature
& Date
|
Contents and Hazard
Class
|
|||
7.2.1.2.2
Type
|
Grading
Criteria
|
||
Using
the markings on the container and other available resources, identify the
capacity (by weight or volume) of the following examples of transportation
vehicles:
|
Passed
|
Remediated Required
|
Instructor Signature & Date
|
Cryogenic Liquid Tank
|
|||
7.2.2.3
Criteria
|
Grading Criteria
|
||
Describe
the heat transfer process that occur as a result of a cryogenic liquid spill
|
Passed
|
Remediated Required
|
Instructor Signature
& Date
|
Criteria
|
Grading Criteria
|
||
Identify
the basic design and construction features, including closures for the
following Fixed Facility Tanks:
|
Passed
|
Remediated Required
|
Instructor
Signature & Date
|
Cryogenic Liquid
Tanks
|
|||
Criteria
|
Grading
Criteria
|
||
Identify
the basic design and construction features, including closures for the
following Intermodal Tanks:
|
Passed
|
Remediated Required
|
Instructor Signature & Date
|
Specialized
Intermodal Tanks including Cryogenic Intermodal and Tube Modules
|
Criteria
|
Grading
Criteria
|
||
Identify
the basic design and construction features, including closures for Railroad Cars including:
|
Passed
|
Remediated Required
|
Instructor Signature
& Date
|
Cryogenic Liquid Tank
Cars
|
|||
If you have any questions feel free to contact me.
John Shafer
Sources:
Hazardous Materials "Managing the Incident" 4th edition
https://www.praxairdirect.com/Resource-Center/Cylinders-Tanks-and-Gas-Systems/Cryogenic-Tanks.html
http://www.fireengineering.com/articles/print/volume-160/issue-11/features/chemical-profiling-ii-what-you-see-does-make-a-difference.html
http://www.hazmatnation.com/one-deputy-dead-several-injured-liquid-nitrogen-exposure/#sthash.pJiGMn2b.dpbs
http://www.praxair.com/-/media/documents/sds/oxygen/liquid-oxygen-medipure-gas-o2-safety-data-sheet-sds-p4637.pdf?la=en
http://www.lindepremiumproducts.com/internet.lg.lsg.usa/en/images/psa_liquid_oxygen892_21860.pdf?v=.
http://www.firehouse.com/article/10544102/hazardous-materials-containers-part-3-fixed-facilities
