Container Assessment from the fist manual

Chapter 7
Container Assessment
Courtesy of Tyler Bones.

Learning Objectives 1 through 6
1. Describe the process of assessing container damage at a
hazmat/WMD incident.
2. Detail factors to consider when assessing non-bulk containers.
3. Detail factors to consider when assessing intermediate bulk
containers (IBCs).
4. Detail factors to consider when assessing ton containers.
5. Detail factors to consider when assessing railway tank cars.
6. Detail factors to consider when assessing highway cargo
containers.
7–2

Learning Objectives 7 through 12
7. Detail factors to consider when assessing intermodal
containers.
8. Detail factors to consider when assessing air freight
cargo.
9. Detail factors to consider when assessing pipelines.
10. Detail factors to consider when assessing fixed facility
containers.
11. Discuss other storage facility considerations.
12. Detail factors to consider when assessing radioactive
materials packaging.
7–3

Section I: Damage Assessment
Learning Objective 1 — Describe the process of
assessing container damage at a hazmat/WMD incident.
7–4

Damage Assessment (1 of 3)
 Determine container’s
construction materials
 Determine type of stresses to
which the container has been
or is being subjected
 May also check internal
pressure and temperature
while evaluating a container
7–5

 Binoculars, robots, and/or drones may be essential tools to
safely perform an initial assessment, plan a safe approach
 Elevation provided by ladder trucks may also be useful
 Cautiously approach containers with special concerns
 Avoid positioning personnel in line with the ends of pressurized
containers in case of catastrophic failure
 Remote product control operations may take precedence over
on-scene control operations
7–6

 Inner tank and container damage is often difficult to evaluate
due to tank outer jackets or insulation
 Besides container damage, physical and chemical properties of
material being transported must be researched
 “Empty” tanks
 Tanks designated as “empty” may still contain product
 “Empty” simply means that the product level is below that
required for discharge or removal and dispensing operations
are no longer possible
7–7

Types of Container Damage (1 of 2)
 Always inspect containers for signs of damage
 Container storage conditions and weather conditions play an
important part of how the containers will hold up to stresses
 What seems to be an insignificant blemish can be critical
based on the container’s construction material and
manufacture date
 Also important to try to identify the mechanism of damage,
and understand precisely how the container received the
damage
7–8

Types of Container Damage (2 of 2)
7–9

Cracks
 Some container materials are
more brittle and prone to
cracking than others
 A crack in the exterior of any
container must be evaluated
carefully
 Always assume that cracked
containers may fail
catastrophically
7–10

Dents (1 of 2)
 May vary in size
 Should be evaluated in the context of the container
material, pressure, contents and the amount of force
required to produce the dent
 May not be significant in some materials if the
material has natural flexibility and is not otherwise
damaged
 May affect the internal pressure of the container
7–11

WARNING 1
Dents that affect the vapor space of liquid-filled
containers can dramatically change the internal pressure
of the container.
7–12

Dents (2 of 2)
 Dents associated with gouges and
cracks may indicate or cause
container failure
 Other dents may be critical
depending on depth, location on
the container, and their orientation
on the container
7–13

Scores and Gouges
 May not be as critical as a container crack
 Consider longitudinal score that runs a
significant length of the container to be
most dangerous
 Circumferential scores and gouges
constitute a longitudinal notch at any
given section and may pose an elevated
hazard
 Unload tanks having scores or gouges in
place when internal pressure exceeds half
of allowable internal pressure allowed for
the tank
Courtesy of Barry Lindley
7–14

WARNING 2
A long score or gouge adjacent to or crossing a weld is
likely to lead to container failure.
7–15

Heat-Affected Zones: Welds, Flames, and
Friction (1 of 2)
 Heat-affected zone of any metal
container — Area of the tank wall or
shell of the container which has had
its microstructure altered by welding
or other heat-intensive operations
 Heat-affected zones will typically be
less ductile and more prone to failure
than the original
 Mechanical stresses such as friction
or road burn can lead to heat-
affected zones
Courtesy of Richard Moseley
7–16

Heat-Affected Zones: Welds, Flames, and
Friction (2 of 2)
 In reference to rail cars, these are
called rail burn or wheel burn
 If a heat-affected area is severe,
consider off-loading the container
 If damages cross the weld bead of
a pressurized container and come
in contact with the metal wall or
shell, consider the container to be
in danger of imminent failure
7–17

Punctures (1 of 2)
 Occurs when an exterior object is forced through the walls of a
container and/or its insulation, resulting in a hole or
perforation
 Many are caused by sharp, narrow, or pointed objects such as
 Forklift tine
 Spikes
 Unprotected barrier steel
7–18

Punctures (2 of 2)
 May result in a release of product if
the container’s walls or attachments
have been breached
 In insulated and double-walled
containers, exterior wall and/or
insulation can be punctured while the
inner wall remains undamaged
 Important to evaluate how deep a
puncture has penetrated
 Though rare, punctures in
pressurized containers are especially
dangerous
7–19

Cuts and Tears
 Indicates a part or parts of a
container have been
forcefully cut or ripped apart
 Can affect outer layers such
as insulation
 As with punctures, it is
necessary to determine if the
primary container has been
breached by the cut or tear,
or if only exterior features
such as insulation have been
damaged
7–20

Corrosion
 Degradation and destruction of a
material
 Caused by chemical and/or
electrochemical interactions, such as
 Oxidation of metal
 Exposure to incompatible materials
 One of the most common causes of
storage tank and metal drum failure
 Can be internal or external,
weakening tank walls
7–21

Deterioration
 May be caused by wear, corrosion, incompatibilities,
and even sunlight
 Exposure to sunlight (UV radiation) and weather can
also cause deterioration of exposed containers, their
coatings and liners
 For example, many plastics will degrade when
exposed to UV radiation
7–22

Distortion (Bulging or Swelling)
 Typically caused by vapor pressure
building above a liquid product
 An indicator the container has been
subjected to stress
 Bulging containers should be
 Treated as a pressurized container
which could rupture violently
 Considered extremely hazardous
with an increased probability of
failure
7–23

Damaged Fittings and Attachments (1 of 2)
Common cause of releases include
• Valves
• Sample lines
• Gauges
• Access points
• Pressure relief devices
• Closures
• Thermometer wells
7–24

Damaged Fittings and Attachments (2 of 2)
 During accidents, fittings and
attachments can be damaged by
external stresses
 Seals, washers, threads, and other
parts can fail because of wear,
misuse, incompatibilities, or
accidental damage
 After an accident, all container fittings
and attachments must be evaluated
for damage
7–25

Temperature and Pressure
 Measuring temperature and pressure is a critical aspect of
damage assessment and behavior prediction
 Even if a tank is undamaged and not releasing product, a
catastrophic release may occur due to abnormal internal
temperature and pressure
 Always evaluate the incident scene for potential thermal,
pressure, and energy sources that could affect any containers
 Because of the international nature of shipments, verify which
temperature scale (Celsius or Fahrenheit) is being used on
shipping papers and safety information
7–26

Review Question 1
What types of container damage should you scan for?
7–27

Container Materials
 Understanding a container’s
components and materials is critical
for a proper damage assessment
 While container materials are
designed to withstand daily
stresses, they may fail when
subjected to extreme stresses
during a critical event
 Some old containers that are still in
use may withstand far less stress
Courtesy of Tyler Bones
7–28

CAUTION 1
When transferring products or evaluating leaks affecting
surrounding containers, always check compatibility
between the containers and the product.
7–29

Aluminum
 Containers tend to be relatively light and can
withstand impact stress well
 Generally designed to contain atmospheric pressure
(low to nonpressure tanks)
 Does not react with hydrocarbons
 A relatively “soft” metal — Plugging materials and
methods may have variable success
 Before use, check compatibility between products and
materials used for product control
7–30

Steel (1 of 2)
 A ferrous metal
 May be difficult to examine for metal elongation, heat stress,
and fractures
 Easiest of all metals to plug
 Mild steel can often withstand dents but does bend and distort
easily
 May chemically react with many materials, such as acid
 Weakest point will be at either side of the welded seam
 Heat incurred in welding can disrupt original annealing process
and affect steel at alloy level
7–31

Steel (2 of 2)
 When inspecting a steel
container for damage, bends will
reduce the overall thickness of
the metal and increase the
likelihood of failure
 When bends or dents happen,
fractures often occur on the
inside of the container opposite
the damaged portion, which will
not be visible on inspection
7–32

High Strength Low Alloy Steel (Carbon
Steel)
 High strength low alloy steel
has high carbon content
 Extremely strong and
abrasion resistive
 Used in construction of many
pressure vessels
 Reacts with corrosives
 Fractures easily
 Is difficult to plug
7–33

Stainless Steel Containers
 This alloy is iron-based with
a content of either
chromium or nickel
 Material is corrosion and
abrasion resistive
 Does not fracture easily
 Typically used for materials
that are not compatible with
any other type of container
7–34

CAUTION 2
Stainless steel or exotic containers may indicate that the
product inside has unique properties and/or special
hazards.
7–35

Other Materials (1 of 5)
 Fiberboard
 Slightly sturdier than textile
and paper, easily damaged by
exposure to moisture and
many solvents
 Will tear, dent, crush, and
puncture
 Will burn if subjected to
extreme heat, and, if not
treated, may absorb some
contents
Courtesy of Rich Mahaney
7–36

 Fiberglass
 Containers are rigid and
corrosion resistant
 Fiberglass resin is
susceptible to heat and UV
radiation damage
 Solvents will attack fiberglass,
so most containers come with
a lining to protect from solvent
damage
Courtesy of Bill Hand, Houston Fire Department (ret)
7–37

 Glass, porcelain, or stoneware — Containers are brittle, prone
to crack and fracture if subjected to any source of stress
 Metal (other than steel or aluminum)
 Containers can hold a variety of products, both liquids and
solids
 Rigid, subject to dents, cracks, corrosion, and punctures
 Exposure to extreme heat can damage metal
 Paper — Containers are easily damaged by a variety of
stresses, despite being flexible will typically tear and burn
7–38

 Plastic
 Varies in strength and rigidity
 Rigid plastic may be dented,
punctured, torn, and/or cracked
 Flexible plastic may be cut, torn,
and/or punctured
 Both are subject to degradation
from UV radiation
 Containers may melt and/or
burn if subjected to extreme
heat
7–39

 Textile — Cloth or other woven materials that are flexible
 Containers may be cut, torn, worn, and/or punctured; may
burn
 Typically used to contain solids
 Wood (natural, plywood, and reconstituted)
 Naturally subject to cracking and fracturing under stress
 Easily punctured and torn
 Will burn if subjected to extreme heat, and, if not treated,
may absorb some contents
 Plywood and reconstituted wood may be damaged by
exposure to moisture, corrosives, and many solvents
7–40

Discussion Question 1
What materials are most commonly used to construct
the hazmat containers in your jurisdiction?
7–41

Section II: Assessing Non-Bulk Containers
Learning Objective 2 — Detail factors to consider when
assessing non-bulk containers.
7–42

CAUTION 3
Monitor the atmosphere before and while opening any
container.
7–43

Bags (1 of 2)
 Come in a variety of materials
 May hold a wide array of contents, but are mainly used for
solid materials
 Flexible packaging constructed of
 Paper
 Plastic
 Textiles
 Woven material
 Other similar materials
7–44

NOTE1
49 CFR defines bags but does not specify a weight
limitation.
7–45

Bags (2 of 2)
 Typical contents
 Dry corrosives
 Explosives/blasting agents
 Fertilizers
 Flammable solids
 Oxidizers or organic peroxides
 Poisons
 Pesticides
 Other regulated materials (ORM)
 Non-bulk bags can be stacked and
transported on pallets
Courtesy of the U.S. Bureau of Alcohol,
Tobacco, Firearms, and Explosives and the
Oklahoma Highway Patrol
7–46

Bags — Hazards
 Type of materials used in bag construction causes them to be
fragile and prone to damage and the release of contents
 Structure of bags makes them susceptible to environmental
conditions
 Contamination and spread of material may occur easily
 Containment and confinement techniques may require atypical
combinations of response techniques
 Flammable dust may complicate the incident based on the
material, location, and quantity
7–47

Review Question 2
Which types of hazmat are most likely to be transported
in bags?
7–48

Bottles and Carboys (1 of 2)
 Bottles — Sometimes called jugs or jars
 Hold liquids and solids
 Can be glass, plastic, metal, or ceramic
 Range in size from a few ounces (milliliters) to
multiple gallons (liters)
 Usually packed in some type of outside packing for
transit, such as a wood or fiberboard box
7–49

Bottles and Carboys (2 of 2)
 Carboys — Large rigid or semi-rigid containers meant for
pouring liquids
 In common use, may be typified as used for water cooler
jugs, gas cans, custodial products, food service containers
 In hazmat they may be glass or plastic bottles protected by
an outer cushion container
 Typical sizes range between 5 gallons (20 L) and 16 gallons
(60 L)
 Limited-use, non-bulk container
 Both types of containers have a narrow neck and a larger
internal capacity
7–50

Typical Contents of Bottles and Carboys
Corrosives Flammables
Non-
hazardous
materials
Oxidizers
Reactive solids
dissolved or
suspended in
solvents
Toxic products
7–51

NOTE2
When not in transit, bottles and carboys are often
reused and may contain mixtures.
7–52

Bottles and Carboys Characteristics
 Due to their construction, bottles and carboys are
 Relatively safe mode of transportation for hazardous
materials
 Typically are not prone to the same type of damage and
corrosion that may be found on other types of containment
devices
 Glass bottles and carboys may be shipped with an outer
packaging
 If the outer packaging is damaged or not sized correctly, the
internal vessel may be damaged
7–53

Bottles and Carboys Considerations
 Colored glass often indicates
that the material is
photosensitive
 Outer packaging may react with
contents if a breach occurs
 Crystals on the rim of a bottle or
carboy indicates spillage or
leakage from inside the
container
7–54

WARNING 3
Some solutions may form crystals which are extremely
sensitive to many forms of energy. When crystals are
present on the rim of a container, the integrity of the
container and stability of the product may be in doubt.
7–55

Review Question 3
What is the difference between a bottle and a carboy?
7–56

Boxes and Multicell Packaging (1 of 2)
 Wood and fiberboard boxes may be used as primary packaging
devices or as cases for smaller inner containers such as
carboys
 Boxes may carry an array of hazardous materials, and proper
labeling must be used for identification purposes
 Wooden boxes may be used to carry every classification of
hazardous material including compressed gas cylinders
 Fiberboard boxes may be used to carry every classification of
hazardous material except compressed gases and poisons
7–57

Boxes and Multicell Packaging (2 of 2)
 While boxes cannot carry compressed
gases themselves, they can carry
products such as aerosol cans which
pose a pressurized hazard
 Multicell packaging
 Packaging device that is form-fitted to
other containers
 Can serve as a protective device for
the container
 DOT limits their capacity
7–58

Drums
 Typically used for liquids and solids
and may contain a variety of
materials
 Not designed for compressed
gases or etiological (infectious)
agents
 May be configured with either an
open head or closed head
 Can hold up to 119 gallons (450 L)
liquid capacity (49 CFR 173.3)
 Most common capacity is 55 gallons
(220 L)
7–59

Drum Construction Materials
Metal
Fiberboard
Plastic
Plywood and other suitable materials
7–60

NOTE3
Some drums and pails may incorporate an inner liner.
7–61

Drums Construction Considerations
 Drums may leak from the seams or bung openings
 Metal drums frequently corrode if improperly stored
 Wood and fiberboard based drums may disintegrate
or rot, depending on the environment and material
contained
 Mechanical damage is a concern for all types of drum
material
 Punctures, tears, and overpressure are also causes of
drum damage
7–62

Pails
 May be considered a type of drum, but
with a lower content capacity
 Wide variety of uses and are found in
all types of locations
 May be constructed of metal,
fiberboard, or plastic
 May hold from 1 to 13 gallons (3 L to
50 L) or more of material
 Prone to the same types of leakage
and damage as drums because of
similar construction materials
7–63

Drums and Pails Common Materials
 Corrosives
 Flammable or combustible liquids
 Hazardous wastes and regulated materials
 Oxidizers or organic peroxide
 Poisons
 Radiological materials
7–64

NOTE4
Drums and pails may contain a variety of products,
including most DOT hazard classes. “If it fits, it ships.”
7–65

Drums and Pails — Considerations
 Consider the integrity of the container
 Look for indicators of potential hazards
 Assume that empty drums have residual product or vapor until
proven otherwise
 Drums with multiple rolling rings may be carrying a denser than
normal material
 Look for bulges that indicate that there is a pressure buildup
inside the container
 Vacuums and signs of collapse are also possible
 Drums are used for salvage and cleanup and may inadvertently
contain materials not appropriate for the container
7–66

Review Question 4
What is the difference between open- and closed-head
drums?
7–67

Cylinders
 A pressurized vessel engineered to contain
 Compressed or liquefied gases
 Flammable or combustible liquids
 Poisons
 Corrosives
 Radioactive materials
 Designed for pressures higher than 40 psia (276 kPa)
 Has a circular cross section
 Can be found in a wide variety of locations including
7–68

Cylinders — Basic Identification (1 of 4)
 Although cylinder characteristics are
not standardized, their shape and size
often give clues to their contents
 A cylinder that is short and broad
will typically have a lower pressure
than cylinders that are long and thin
 Cylinders with a weld seam on the
long axis are not designed for high-
pressure containment
7–69

 DOT establishes
regulations for the care,
maintenance, and
manufacture of
cylinders designed to be
transported in the U.S.
7–70

 Per 49 CFR 178 the general requirements for marking
cylinders includes
 DOT specification marking starts with “DOT” followed by the
specification number, followed immediately by the service
pressure
 Serial number and manufacture identifying symbol (letters)
 Inspector’s official mark is placed near the serial number
with the date of the hydrostatic test so that subsequent
tests can be added
7–71

 The Compressed Gas Association
has recommended a color-coding
system for cylinders, which many
medical gas manufacturers follow
 Color-coding system is not
required by law; therefore, cannot
rely on color as a means of
identifying contents of a
compressed gas cylinder
 Use labels to properly identify the
contents of all cylinders
7–72

WARNING 4
Marking and color-coding of cylinders is not an industry
standard and cannot be relied on for identification
purposes. Use labels to identify cylinder contents.
7–73

Cylinders — Construction Features (1 of 3)
 Uses materials with a high tensile strength — Steel is the most
common
 Will include valve devices that are specific to the product
intended to be contained in the cylinder
 Stop angle valves are a common feature of most cylinders
 Pressure relief devices are safety devices that work in
tandem with the valve
 If the pressure of the cylinder exceeds the rated pressure of
the relief device, pressure relief device will activate and
relieve the excess pressure
 In most cases, once a cylinder pressure relief device
activates, it cannot be reset and must be replaced
7–74

 Pressure relief devices may include a simple rupture
(also known as a burst disc)
 Installed in the back of the valve and is nothing
more than a small metal gasket that will rupture at
a predetermined pressure
 A low melting point metal may comprise the
pressure relief device
 In case of fire impingement or temperature increase
the relief device will activate and prevent
catastrophic failure of the cylinder
7–75

NOTE5
Not all cylinders incorporate safety devices.
7–76

 Cylinders are an inherently strong type of containment vessel
 Although leaks are uncommon in a well-maintained cylinder,
mechanical damage may reduce the overall strength of the
cylinder or shear off the valve
 Leaks may occur at the threaded connections for the valve
assembly or within the valve assembly itself
 Based on the orientation of the cylinder and position of the
leak, the leak may either be a
 Gaseous leak
 Liquid leak
7–77

Cryogenic Cylinders
 Designed and manufactured to store
super-cooled materials
 Must be able to accommodate the
material at both its gaseous state and its
liquid state
 Vary in capacity
 Pressure includes low and high ranges
 Valve assemblies on a cryogenic cylinder
will be constructed to dispense both a
gas and a liquid
7–78

Dewar Flask
 Non-pressurized, insulated container that has a vacuum space
between the outer shell and the inner vessel
 Designed for the storage and dispensing of cryogenic materials
such as liquid nitrogen, liquid oxygen, and helium
 Have a bulky appearance due to the insulation that is used to
keep the cryogenic material at the desired temperature
7–79

Y Cylinders (1 of 2)
 Type of compressed gas cylinder
that can be bulk or non-bulk
 Typically will have a specification
such as DOT 3AA-2400 or
DOT3AA-480
 Pressure is dependent on product
 Typically 7 ft (2115 mm) long, 2
ft (600 mm) in diameter, have a
wall thickness of about 0.6 inches
(15 mm), and, when empty,
weigh about 1,200 lbs (600 kg)
7–80

Y Cylinders (2 of 2)
 Water capacity of approximately 120
gallons (480 L)
 Often used for refrigerants,
ammonia, and anhydrous hydrogen
chloride
 Typically operate in a cascade system
 Two specifications of Y cylinders are
defined based on size (49 CFR 178)
 DOT–3AA cylinder
 DOT–3AAX cylinder
7–81

Can you identify a cylinder and its contents by sight
alone?
7–82

Section III: Assessing Intermediate Bulk
Containers (IBCs)
assessing intermediate bulk containers (IBCs).
7–83

Assessing Intermediate Bulk Containers
(IBCs) (Totes)
 Designated by the DOT as either rigid or flexible portable
packaging designed for mechanical handling
 Design standards for IBCs are based on United Nations
Recommendations on the Transportation of Dangerous Goods
 Transport a wide variety of materials
 Alcohols
 Aviation fuel (turbine engine)
 Corrosive liquids
 Gasoline
 Solid materials in powder, flake, and/or granular forms
 Toluene
7–84

Flexible Intermediate Bulk Containers
(FIBCs)
 Flexible, collapsible bags or sacks
that are used to carry solid material
 Designs vary greatly
 Common-sized supersack FIBC can
carry 2,204 pounds (1 000 kg)
 Can be stacked one on top of
another depending on design
 Sometimes transported inside a rigid
exterior container made of
corrugated board or wood
Courtesy of Leslie Miller
7–85

Rigid Intermediate Bulk Containers (RIBCs)
 Typically made of steel, aluminum, wood,
fiberboard, or plastic; often designed to
be stacked
 Can contain both solid materials and
liquids
 Other RIBCs may be large, square or
rectangular boxes or bins
 Rigid portable tanks may be used to carry
various liquids, fertilizers, solvents, and
other chemicals
7–86

Intermediate Bulk Containers (IBCs)
Considerations
 Share many of the same issues as barrels and drums
 Some have valves that have the potential to leak and
sometimes are difficult to access
 Some have containment vessels incorporated into the
container but may not be able to contain the entire volume of
the container
 Specific products have specifically designed containers
 Depending on the protective housing, patching and plugging
operations can be difficult
 Supersacks can be extremely difficult to handle, have some of
the same vulnerabilities as bags
7–87

Review Question 5
Explain the difference between FIBCs and RIBCs.
7–88

Section IV: Assessing Ton Containers
assessing ton containers.
7–89

Assessing Ton Containers (1 of 4)
 DOT refers to ton containers as
multi-unit tank car tanks (DOT
110 and DOT 106)
 Typically stored on their sides
 Ends (heads) are convex or
concave
 Usually rest on a scale to
determine the weight,
indicating how much product is
in the container Courtesy of Rich Mahaney
7–90

 Have two valves in the center of one end, one above the other
 One valve connects to a tube going into the liquid space
 Other valve connects to a tube going into the vapor space
above
7–91

 Some of these containers
 Have a pressure-relief device in case of fire or exposure to
elevated temperatures
 May also have fusible plugs that can melt and relieve
pressure in the container
 Commonly contain chlorine, often found at locations such as
water treatment plants and commercial swimming pools
 May also contain materials such as sulfur dioxide, anhydrous
ammonia, refrigerants
 Are an extremely rigid type of containment device
7–92

 Leaks in this type of container
typically occur at the valves
 Based on the orientation of the
container, the leak may either
be a gaseous leak or a liquid
leak
 Specialized repair kits for
chlorine and sulfur dioxide are
available should a leak occur
in either the valves or fusible
links
7–93

Review Question 6
Where are you most likely to find a ton container in the
community?
7–94

Section V: Assessing Railway Tank Cars
assessing railway tank cars.
7–95

Assessing Railroad Tank Cars (1 of 2)
 Tank cars are classified according to their
 Construction features
 Fittings
 Function
 Responders should evaluate the types of railway tank
cars in their jurisdiction
 ERG provides basic information about rail cars
7–96

Assessing Railroad Tank Cars (2 of 2)
 During a derailment great
potential for extreme mechanical
damage due to the size, weight,
and momentum of the cars
 Cars are not physically
connected to the truck assembly
(body) of the car
 Can be thrown around
 Shipments of hazardous materials
may also be transported in
specialty railcars
7–97

Tank Car Markings, Stencils, and Plates
Reporting
marks (initials
and numbers)
Specification
markings
Capacity
stencils
Identification
plates
Product name
stencils
7–98

Reporting Marks (Initials and Numbers)
 Identify the tank car and its owner
 Stenciled on the left side of the tank
car and on each end
 Some shippers also stencil these
numbers on the top of the tank car
 Reporting marks include
 Up to four letters indicating the
tank car’s owner
 Up to six digits
7–99

NOTE6
The app, AskRail, can provide detailed information on
tank car contents, owners, and other information.
7–100

Specification Markings (1 of 2)
 Stenciled on the right side
of the tank car on the
longitudinal side
 Represent the DOT, TC, or
American Association of
Railroads (AAR) standards
to which the tank car was
constructed
 Do not identify the tank
car’s cargo
7–101

Specification Markings (2 of 2)
7–102

Capacity Stencils
 Shows maximum water volume
 Volume in gallons (and sometimes liters)
is stenciled on both ends of the car under
the car’s reporting marks
 Volume in pounds (and sometimes
kilograms) is stenciled on the sides of the
cars under the reporting marks
 For certain tank cars the water capacity
of the tank in pounds (and typically
kilograms) is stenciled on the sides of the
tank near the center of the car
7–103

Identification Plates
 Tank cars built after June 25, 2012 are equipped with two
identical identification plates on the bolster
 Must be permanently mounted on the inboard surface of the
tank car’s structure
 Information includes
 Material from which the tank is constructed
 Specified equipment such as bottom and top shelf
couplers, head shields
 Any thermal protection
 All other cars have this identification stamped into the heads
of the cars
7–104

Product Name Stencils
 Some materials shipped by rail must feature the
name of that product stenciled on the side of the tank
 Tank cars with stenciled markings are known as
dedicated tank cars
 These cars are allowed to carry only the product
which is stenciled on the tank
 If another product is to be shipped in this container,
the car must qualify for the new product and have
new stenciling applied
7–105

Review Question 7
Describe the types of markings that may be found on
tank cars.
7–106

Tank Car Structure
 Tank
 Truck assembly
 Similar to a chassis
 Includes
 Wheels
 Axles
 Truck bolster
 Bowl
 Pin
 It is possible to construct the car in several different ways
7–107

Stub Sill
 The bottom of the tank may be frameless
 Known as a frameless tank car, or stub sill
 This is where all of the stresses of the railcar will be
borne by the tank itself
 The stub sill
 Short structural member welded to the end of the
tank
 Attaches the tank to the truck assembly and
absorbs the forces of train movement
7–108

Full Sill
 A one-piece assembly runs the length
of the railcar
 Continuous underframe absorbs forces
created by the train’s movement
 Topside of underframe holds tank in
place
 Bottom of underframe rests on truck
assembly
 Body bolster — Structural cross
member mounted at a right angle to
the underframe
7–109

Review Question 8
What is the difference between stub sill and full sill tank
cars?
7–110

Safety Features of Railway Tank Cars
Head shields Insulation
Thermal
protection
Lining and
cladding
Heating
lines and
coils
Top and
bottom shelf
couplers
Skid
protection
7–111

NOTE7
Technicians will find some of these safety features on
other transportation containers, as well.
7–112

Head Shield (1 of 2)
 Help protect the heads of a tank car when transporting
hazardous materials
 All pressure cars must have head shields
 May or may not be visible
 Offer an extra layer of puncture protection on the ends of the
tank
 If required, newly constructed tanks will have full head shields
 Older tanks may have a “half head” or a trapezoidal plate of
steel welded to the lower half of the tank ends
 Jacketed tank cars may incorporate a full plate that protects
the entire head of the tank
7–113

Head Shield (2 of 2)
Full Head Shields
Courtesy of Steve George
Half Head Shields
7–114

Insulation
 Helps protect a tank’s cargo from
outside temperatures
 May be found on both pressure and
nonpressure tank cars
 Cryogenic tank cars always have
insulation
 Fiberglass and polyurethane foams are
common types of insulating materials
 Perlite is typically used to insulate
cryogenic products
 Tank’s outer jacket conceals insulation
7–115

NOTE8
Highway cargo tanks, intermodal containers, and fixed
facility tanks may have thermal insulation, also.
7–116

Thermal Protection
 Designed to protect a tank car from
 Direct flame impingement
 A pool of fire
 Primarily for tank cars shipping either a liquefied flammable
gas or flammable liquids; also required for tank cars
transporting poisonous gases
 Some cars incorporate both thermal protection and insulation
to protect cargo such as ammonia
 Two types: Jacketed thermal protection and spray-on thermal
protection
7–117

CAUTION 4
Older thermal protection materials may contain
asbestos.
7–118

Lining and Cladding
 Some tanks may be equipped with a lining which is applied
after the tank is constructed
 Linings can be applied in sections, sprayed or painted
 Rubber is a common lining for tank cars transporting
hazardous materials
 Cladding is a covering applied to the metal container wall or
shell before the plate is formed — Typical cladding materials
include nickel and stainless steel
 Designed to prevent hazardous materials from reacting with
the tank material — Used to both protect the tank and
maintain purity of the product
7–119

Heating Lines and Coils
 Some tanks may be equipped with
heating lines or coils located either inside
or outside the tank — May be concealed
by insulation and/or an outer shell
 Steam, hot water, or heated oil can be
used to heat thick or solidified materials
such as asphalts or waxes
 Outlets and inlets for interior lines or coils
must have caps in place during transport
 Caps are not required for exterior coils
7–120

Top and Bottom Shelf Couplers
 Also known as double shelf
couplers
 Train car couplers with vertical
restraint mechanisms that
reduce the potential for
coupler disengagement, and
possible head puncture
 Tank cars transporting
hazardous materials must
have this safety equipment in
place
7–121

Skid Protection
 Safety feature that prevents loss of a tank car’s
contents in the event of a derailment
 Skid plate attaches to the tank in the area of the
bottom fittings
 There is also top skid protection, which will help
reduce the amount of mechanical stress on the tank
and any fitting located on the bottom of the car
7–122

Review Question 9
What are shelf couplers?
7–123

Tank Car Fittings
 Tank car fittings — Allow for loading and
unloading of products; gauges to
determine product levels, temperatures
 Safety features such as pressure relief
devices
 Include
 Ladders and platforms
 Access points
 Valves and venting devices
 Safety relief devices
 Other fittings
7–124

NOTE9
Highway cargo tanks, intermodal containers, fixed
facility tanks, and other containers may have similar
fittings.
7–125

Ladders and Platforms
 Ladders on rail cars are for access to the top of the railcar and
its fittings
 Located on the sides and ends
 Since some of these ladders may follow the contour of tanks
 Initial step may be difficult
 Initial climb may be partially inverted
 Platforms
 May or may not have handrails or fall protection
 Do not meet OSHA fall protection standards
 Situational awareness is critical when working on a rail car
platform
7–126

Access Points
 Most obvious fittings found on most tank
cars
 Large openings located at the top of the
cars
 Allow access into the interior of the tank
 Play an integral part in identification
 Often located within a protective housing
 Access point gaskets are a very common
source of leaks
7–127

Valves and Venting Devices
 Valves — Fittings that allow product to
flow in one direction or another
 Primary means of loading/unloading
 Tank cars often include safety features
to protect valves and piping on top or
bottom of the car, including
 Sheer valves
 Skid protection
 Valve protection and housings
7–128

Safety Relief Devices (1 of 3)
 Allow tank’s internal pressure to be
relieved
 Most are spring-operated to allow
device to close when tank’s internal
pressure is reduced to normal limits
 Pressure relief devices (PRDs),
including pressure relief valves, are
typically set to activate at 75 percent of
the tank’s test pressure
 Pressures can be identified by the
stencil on the car
7–129

 Safety vents, also known as rupture discs
 A frangible disk will rupture at a
predetermined temperature or pressure
 Predetermined pressure is typically 33
1
/3 percent of burst pressure of tank
 Unlike relief devices, once a safety vent
opens it cannot be closed
 Once this device has been activated,
someone who has been properly
trained must replace it
7–130

 Some pressure relief devices are combination safety relief
valves that have a rupture disk with or without a breaking pin
plus a spring-loaded relief valve; use of this indicator valve
tells whether the rupture disk has activated
 Vacuum relief valves prevent internal vacuums from occurring
in nonpressure tanks during normal temperature changes;
accidental activation may cause debris to become lodged and
render the car out of service when the valve cannot reseat
7–131

Other Fittings
• Fittings located at the bottom of
the tank, used for off-loading or
cleaning
Bottom outlet
valves
• Tools used to measure the
amount of product or vapor space
in a tank
Gauging devices
• Allow a sample of the tank’s
product to be taken without
unloading the car
Sample lines
• Closed tubes allow a
thermometer to sample
temperature of product
Thermometer wells
7–132

Review Question 10
Explain the purpose of safety release devices.
7–133

General Service (Non-pressure/Low
Pressure) Railway Tank Cars (1 of 6)
 The most common type of tank car in North America
 Commonly categorized as DOT 111
 Some variation in the allowed parameters
 DOT mandated that industry phase out the DOT 111
tank cars that are transporting flammable liquids by
May 2025 and instead transport them in DOT 117
tank cars
7–134

NOTE10
CPC-1232 cars are DOT 111 cars voluntarily built to an
upgraded industry standard specifically for use in
transporting flammable liquids such as crude oil and
ethanol.
7–135

 Carry both hazardous and non-hazardous liquids
 Except for cars carrying flammable liquids, DOT 111 cars are
not required to have head shields to protect the tank car from
an adjacent car in an incident
 Fittings and valves are not protected and are vulnerable to
being sheared off in an incident leading to a release of
contents
 Do not have a pressure relief device sized to protect against
rupture in the event of a large fire
7–136

 DOT 117
 Non-pressurized tank car with a thicker shell and insulating
material providing thermal protection
 Have protected top fittings, a fully protected head shield,
and a bottom outlet valve with an enhanced handle designed
to prevent the tank car from emptying its contents in an
incident
 All the enhancements are designed to protect the tank from
being punctured and to prevent the valves from being
disrupted
7–137

Crude oil Ethanol
Molten
sulfur
Solvents
Sulfuric
acid
Wastes
Consumab
le
products
7–138

CAUTION 5
The appearance of general service/non-pressure/low
pressure tank cars may be changed with the addition of
protective housings intended to protect valves in the
instance of a rollover.
7–139

 Because general service (non-pressure/low pressure) tank cars
are so widely used by the railway industry, only way to
determine tank’s contents is by shipping papers, placards, or
tank markings
 Common hazardous materials transported
 Corrosives
 Flammable and combustible liquids
 Liquid poisons
 Oxidizers and organic peroxides
7–140

WARNING 5
General service/non-pressure/low pressure tank cars
may have pressures up to 100 psi (690 kPa).
7–141

 DOT 120 tank cars
 Built to pressure car standards, but are used to
transport flammable liquids
 Look identical to DOT 117 tank cars
 Specification plate must be referenced to determine
the identity
7–142

General Service (Non-pressure/Low Pressure)
Railway Tank Cars — Basic Identification
(1 of 2)
 Cylindrical in shape with rounded heads;
at least one access point to access interior
of the tank
 Fittings for loading and unloading, other
hardware will sometimes be visible
 DOT 117 tank cars — Have protected top
fittings and a fully protected head shield
 If a single protective housing is present on
a tank car, check the specification marks
to confirm if it is a pressure or general
service (non-pressure/low pressure) car
7–143

NOTE11
DOT 117R tank cars are a DOT 111 or DOT 111 - CPC
1232 tank car that has been upgraded to meet the DOT
117 specifications. The “R” stands for retrofit in the DOT
117R.
7–144

Railway Tank Cars — Basic Identification
(2 of 2)
 Can have pressures up to 100 psig
 Designed for materials with vapor pressures of 25 psig (274
kPa) or less at 70° Fahrenheit (21° Celsius)
 Responders should refer to waybill to determine total contents
of all compartments in the tank
 Sometimes called a consist
 Located in the engine or caboose
 Train conductor is responsible for this paperwork
 New apps can also assist responders by providing access to
waybill
7–145

Railway Tank Cars — Construction Features
(1 of 2)
 Most general service tank cars are constructed from carbon
steel and may be manufactured with a full or stub sill
 May be compartmentalized
 Must be built to mechanical standards designed for rail freight
cars; meet 49 CFR Part 179 and the AAR Specifications for
Tank Cars
 Human error can contribute to leaks from valves and fittings
even when not involved in accidents (nonaccidental related)
 Mechanical damage may occur in the event of a railway
accident and may compromise the tank’s integrity
 Carefully evaluate tank and contents if involved in an accident
7–146

Railway Tank Cars — Construction Features
(2 of 2)
 Damaged tank may fail via a heat-
induced tear when temperatures are
high enough
 When exposed to fire, common for low
pressure tank cars transporting
flammable/combustible liquids
 Fire causes tank shell to tear and fail
 Heat-induced tears primarily occur in
low-pressure containers in contrast
to boiling liquid expanding vapor
explosions (BLEVEs) which primarily
occur in pressure containers
7–147

Pressure Railway Tank Cars (1 of 2)
 Similar in design to general service (non-pressure/low
pressure) tank cars
 Able to carry highly hazardous materials or liquids of a high
vapor pressure
 Pressure tank car specifications include
 DOT 105, a common car for chlorine
 DOT 112, a common tank car for liquefied petroleum gas
(LPG) and ammonia
 DOT 114, a common tank for refrigerants
 Human error can contribute to leaks from valves and fittings,
even when not involved in accidents
7–148

Pressure Railway Tank Cars (2 of 2)
 Common types of
products transported in
pressure tank cars
include
 Corrosives
 Flammables
 Liquefied gases
 Toxics
 Water reactives
7–149

Pressure Railway Tank Cars — Basic
Identification
 Cylindrical in cross-section
 Has an enclosed protective housing mounted on the
pressure plate located around the center tank
 May be insulated
 Refer to the waybill of the relevant tank because they
may vary by
 Manufacture date
 Type of contents
 Capacity
7–150

Pressure Railway Tank Cars — Construction
Features
 Pressure tank cars are constructed of steel, stainless steel, or
aluminum
 Have rounded heads
 Load in a standard way
 Typically have fittings inside a protective housing
 Must be built to meet mechanical standards designed for rail
freight cars
 Carefully evaluate the tank and contents if involved in an
accident
7–151

Review Question 11
How can you visually distinguish between general
service and pressure railway tank cars?
7–152

Cryogenic Railway Tank Cars
 Carry low-pressure refrigerated liquids
 Specifications include
 DOT 113 (three main types: A-423, C-260, and D-155)
 Association of American Railroads (AAR) 204W
 Bulk transportation of LNG is now allowed in DOT-113C120W9
specification tank cars with enhanced outer tank requirements
and additional operational controls
 Refrigerated liquids are transported at temperatures between
-155°F (-104°C) and -423°F (-217°C)
 These products are gases in their natural state but have been
cooled through refrigeration to become a liquid
7–153

Cryogenic Railway Tank Cars — Products
Carried
 Argon
 Ethylene
 Hydrogen
 Liquefied natural gas
(LNG)
 Nitrogen
 Oxygen
7–154

Cryogenic Railway Tank Cars — Basic
Identification
 Have a cylindrical cross-section with round heads
 Size of the tank may not be representative of the amount of
product carried
 Traditionally manufactured as a tank within a tank to allow for
the insulation needed to keep the product cold
 Products shipped
 Are normally gases in their natural state but have been
supercooled to become a liquid
 Have a high expansion ratio if released into the atmosphere
 Refer to the waybill to determine actual amount of product
carried in the tank car
7–155

Cryogenic Railway Tank Cars —
Construction Features (1 of 2)
 High alloy steel inner tank
supported by a strong carbon
steel outer tank
 Fittings for this type of
railway cargo tank, including
loading and unloading valves,
will be kept in ground-level
cabinets on both sides of the
tank or in the center of one
end of the car Courtesy of Rich Mahaney
7–156

Cryogenic Railway Tank Cars —
Construction Features (2 of 2)
 Cryogenic products may also be shipped in a tank located in a
standard boxcar, referred to as an XT boxcar
 When involved in an accident, may leak from valves and
fittings
 While most railway tank cars go through rigorous inspection,
insulated tanks can be difficult to inspect due to the double
tanks and insulation
 Carefully evaluate the tank and its contents if involved in an
accident
7–157

Review Question 12
How does construction of cryogenic railway tank cars
differ from regular pressure tank cars?
7–158

Specialized Cars
 Do not usually possess any specific identifying features
 A bulk hazmat shipment should have placarding/markings,
including a UN number
 Boxcars may carry hazardous materials in
 Drums
 Crates
 Bags
 Boxes
 Liquid bladders
7–159

Agricultural Cars
Although not placarded, cars and intermodal containers
containing agricultural products, such as fruit or other
foodstuffs, may have been treated with fumigants.
Fumigants, such as phosphine, are extremely
hazardous. These cars/containers should be marked, but
these signs may not be conspicuous.
7–160

Pneumatically Unloaded Hopper Cars
 Force their product out of the
hopper using air pressure
 May be designed to withstand up
to 80 psig (650 kPa)
 Some materials transported in
this type of car include
 Caustic soda
 Calcium carbide
 Other dry bulk products Courtesy of Rich Mahaney
7–161

CAUTION 6
Pneumatically unloaded hopper cars present a high risk
for static shock. This can be an ignition source.
7–162

Refrigerated Cars
 Have some integrated hazards aside from the contents
 Insulated, bunkerless cars may have heaters located at the top
of the doorways
 Mechanical refrigerated cars may have an electrical generator
 Generator may carry between 500 and 550 gallons (2 000 L
and 2 200 L) of fuel
 Mechanical refrigerated cars may contain refrigerant gases
 Atmosphere inside refrigerator cars may not contain oxygen
 May also be fumigated and have toxic contents like phosphine
7–163

Are hazmat incidents involving railway cars a concern in
your jurisdiction?
7–164

Section VI: Assessing Highway Cargo
Containers
assessing highway cargo containers.
7–165

Assessing Highway Cargo Containers
(1 of 2)
 ERG provides basic information about cargo tanks
 Have construction features, fittings, attachments, or shapes
that are characteristic of their uses
 Should typically use placards, shipping papers, or other formal
sources of information to identify contents
 Commonly used to transport bulk amounts of hazardous
materials by road
 In the U.S., designed to meet tank-safety specifications
 Minimum tank construction material thicknesses
 Required safety features
 Maximum allowable working pressure (MAWP)
7–166

Assessing Highway Cargo Containers
(2 of 2)
 Two specifications currently in use
 Motor carrier (MC) standards
 DOT/TC standards
 Trucks built to a given specification are designated using
 MC or DOT/TC initials followed by a three-digit number
identifying the specification
 Some cargo tanks have multiple compartments — Each
compartment is considered a separate tank and may contain
different products
7–167

Non-Spec Tanks
 Not constructed to meet one of the
common MC or DOT/ TC specs
 If the tank was designed for a
specific purpose and exempted from
the MC or DOT/TC requirements,
may haul hazardous materials
 Nonhazardous materials may be
hauled in either non-spec cargo
tank trucks or cargo tank trucks
that meet a designated specification
7–168

Review Question 13
What do motor carrier (MC) standards and DOT/TC
numbers and letters indicate?
7–169

Tank Markings
 Many highway cargo vehicle tanks will display a number of
markings
 Some markings may directly correlate to the contents
 Others will not help identify the product
 By DOT regulations
 All compressed gases and cryogenic liquids must have the
product shipping name displayed on the tank’s exterior
 Must be located on both sides of the tank and at both ends
 Highway cargo tanks are frequently marked with product’s
brand name — Cannot interfere with required markings,
labels, or placards
7–170

Specification Plates (1 of 4)
 DOT requires construction of highway specification tanks to be
in accordance with 49 CFR 178
 Included on the cargo tank truck specification plate
 Refer to the specification plate to determine cargo tank truck
specifications
 Pressure — While various transport tanks may generally fall
within an expected range, the actual pressure may be certified
to a higher or lower level
 Both positive and negative pressures pose hazards, typically in
relation to ambient atmospheric pressure
7–171

 Each cargo tank must carry two types of plates
 Nameplate
 Specification plate
 Specification plates must be
 Corrosion-resistant
 Permanently attached to the cargo tank truck or its integral
supporting structure
 Permanently and plainly marked in English
 Affixed to the left side of the vehicle near the front of the
cargo tank truck in a place that is readily accessible for
inspection
7–172

WARNING 6
Always refer to the specification plate for information
about the container you’re dealing with.
7–173

Manufacture
r
Tank type
Original
manufacture
date
Test
pressures
Capacity
Construction
material
Maximum
payload
7–174

 Insulated tank trucks that are certified tanks may have
multiple specification plates
 In addition to the DOT specification plates, some tanks that
are certified to the American Society of Mechanical Engineers
(ASME) code for pressure carriers must also carry a separate
certification plate
 While the Emergency Response Guidebook (ERG) may give a
range for specific tank truck type, individual specification
plates are the definitive source for determining the legal tank
capacity for pressure, volume, and weight
7–175

NOTE12
For many years, gasoline tankers known as a
MC306/DOT406 and TC306/TC406 have been listed in
literature as 3, 3.5 or 4 psi (20, 24, 27 kPa) tankers. In
the 2020 ERG, the DOT widened the range to 3-15 psi
(20-100) on type MC306 and DOT 406 type tankers.
7–176

Review Question 14
What is the definitive source for determining the legal
tank capacity for pressure, volume, and weight?
7–177

Non-pressure Cargo Tanks
 May carry any product from food-grade liquids to petroleum
products such as gasoline and fuel oil
 Carry the MC 306 designation or the DOT/TC 406 designation
 Designed to accommodate pressures not exceeding 3 psig
(122 kPa)
 Often comprise more than one compartment
 Common products shipped in these tanks may include
alcohols, flammable and combustible liquids, food-grade
liquids, fuel oil, gasoline
7–178

Non-pressure Cargo Tanks — Basic
Identification (1 of 2)
 The nonpressure cargo tank can be identified by elliptical or
oval cross-section and nearly flat heads
 Owner’s name is usually permanently marked on oval tanks
 Commonly top loaded and unloaded through discharge valves
located at the bottom of the tank
 Typically have
 Rollover protection running the length of the tank
 Multiple compartments
 A separate access point for each compartment
 An emergency shutoff on driver’s side front
7–179

Non-pressure Cargo Tanks — Basic
 MC 306 and DOT/TC 406 tankers
 May carry a wide variety of product quantities
 Typically carries 9,000 gallons (36 000 L), but may also carry
significantly more
 Each compartment may have a different volume of product
 Refer to the bill of lading for exact quantity of product being
hauled
 Bill of lading is found in the vehicle cab — Driver is
responsible for this paperwork
7–180

Non-pressure Liquid Tank (1 of 2)
Non-pressure Liquid Tank DOT406,
TC406, SCT-306(MC306, TC306)
 Pressure less than 4 psi (28 kPa)
 Typical maximum capacity: 9,000
gallons (34 069 L)
 New tanks made of aluminum
 Old tanks made of steel
 Oval shape
 Multiple compartments
 Recessed access points
7–181

Non-pressure Liquid Tank (2 of 2)
 Rollover protection
 Bottom valves
 Longitudinal rollover protection
 Valve assembly and unloading control box under tank
 Vapor-recovery system on curb side and rear, if present
 Access point assemblies, and vapor-recovery valves on top for
each compartment
 Possible permanent markings for ownership that are locally
identifiable
 Carries: Gasoline, fuel oil, alcohol, other flammable/
combustible liquids, other liquids, and liquid fuel products
7–182

Non-pressure Cargo Tanks — Construction
Features (1 of 4)
 MC 306 and DOT/TC 406 cargo tanks are usually constructed
of aluminum
 Tanks constructed prior to August 31, 1995, may be
constructed of carbon steel
 May be insulated
 Often compartmentalized
 Each compartment has its own access point assembly
located at the top of the tank
 Large compartments may have more than one access point
assembly
7–183

Features (2 of 4)
 Most tanks will have baffles to help
control liquid movement
 Marking indicating that the tank
has baffle holes may be visible on
the front and rear of the tank
 Vapor recovery lines are an integral
part of this type of tank but are not
an indicator of how many
compartments the tank contains Courtesy of Barry Lindley
7–184

Features (3 of 4)
 MC 306 and DOT/TC 406 tanks are equipped with rollover
protection that may run the entire length of the tank
 Emergency shutoffs are usually manual and may be located
on the driver’s side front of the tank
 If hauling flammable materials, this tank may also include a
fusible link
 DOT/TC 406
 Will have a thicker shell than MC 306 tanks
 Allows for a maximum pressure of 3-15 psig (21-103 kPa)
 Access points must be able to withstand higher pressures
and are rated to be leak free at 36 psig (350 kPa)
7–185

Features (4 of 4)
 When involved in an accident, the most common leak point of
MC 306 and DOT/TC 406 cargo tanks is through the access
points and dome covers
 Discharge valves are another common source of leaks
 Additional points may appear if the cargo tank has been
subjected to mechanical damage
 Lower discharge valves are traditionally equipped with
“shear” type leak protection if tank is subject to a motor
vehicle accident
 Even though shear protection is in place and has activated,
discharge piping may still contain a significant volume of
product
7–186

Review Question 15
How much pressure can non-pressure cargo tanks
accommodate?
7–187

Low-Pressure Cargo Tanks
 Also known as low-pressure chemical tanks
 Carry the MC 307 or DOT/TC 407 designation
 Transport liquids that may have a higher vapor pressure than
those products carried in their nonpressure counterparts
 Typical contents carried in the low-pressure tanker
 Flammable and combustible liquids
 Flammable liquids
 Mild corrosives
 Poisons
7–188

Low-Pressure Cargo Tanks — Basic
 Low-pressure liquid chemical cargo tanks will have a circular
cross-section with flat heads
 Shape may vary depending on whether they are insulated
 Viewed from behind, insulated tanks may have a horseshoe
shape
 Will have an access point at the top
 Usually have a single compartment
 Off-loading valve is typically located in the rear of the tank
 Access point rollover protection and ladder are typically in the
center of the tank when viewed from the side
7–189

Low-Pressure Cargo Tanks — Basic
 MC 307 tankers
 Usually have a pressure of 25 to 35 psi (172 to 241 kPa)
 Typical capacities of 5,500 to 7,000 gallons (20 820 L to 26
500 L)
 In some locations, the DOT/TC 407 may be rated with a higher
capacity due to its thicker design
 MAWP can be found on the specification plate
 Refer to the bill of lading for the exact quantity of product
being shipped
7–190

Low-Pressure Cargo Tank (1 of 2)
Low-Pressure Chemical Tank
DOT407, TC407, SCT-307(MC307,
TC307)
 Pressure under 40 psi (172 kPa to
276 kPa)
gallons (26 498 L)
 Rubber lined or steel
 Typically double shell
 Stiffening rings may be visible or
covered
7–191

Low-Pressure Cargo Tank (2 of 2)
 Circumferential rollover protection
 Single or multiple compartments
 Single- or double-top access point assembly protected by a
flash box that also provides rollover protection
 Single-outlet discharge piping at midship or rear
 Fusible plugs, frangible disks, or vents outside the flash box on
top of the tank
 Drain hose from the flash box down the side of the tank
 Rounded or horse shoe-shaped ends
 Carries: Flammable liquids, combustible liquids, acids,
caustics, and poisons
7–192

Low-Pressure Cargo Tanks — Construction
Features (1 of 2)
 May be constructed of aluminum, mild steel, stainless steel
 Will have rollover protection around the access point area
 General use of stiffening rings to increase the tank’s structural
integrity
 May have an incorporated heating system
 DOT/TC 407 cargo tank — Will have a thicker shell and
material
 A small percentage of low-pressure cargo tanks have multiple
compartments
7–193

Low-Pressure Cargo Tanks — Construction
Features (2 of 2)
 Safety features of low-pressure
cargo tanks include a fusible cap if
carrying flammable materials
 As with most cargo tanks, the
access points and valves are a
common point for leakage
 Leaks may be difficult to locate due
to the presence of insulation
 Inspection is paramount for this
type of tank
7–194

Review Question 16
What do low-pressure cargo tanks usually carry?
7–195

Corrosive Liquid Tanks
 Also called a corrosive cargo tank
 Transports heavy, high density liquids and toxic inhalation
hazards
 Either a MC 312 or DOT/TC 412 designation
 Typically carry materials that are corrosive in nature like
sodium hydroxide, hydrochloric acid, and sulfuric acid
 Also used as vacuum trucks
 May carry products besides corrosives
 Traditionally single tanks with no compartmentalization
 For the exact quantity being transported, refer to the bill of
lading
7–196

Corrosive Liquid Tanks — Basic
 Typically features access point and valves located in the rear
and discharge lines located in the top rear of the tank
 Because corrosives are usually heavy, overall volume carried
is typically lower than that of other types
 Because of its relatively small capacity, the tank will appear
to be small in diameter
 Have convex heads
 External stiffening rings are a common trademark of corrosive
tanks
 Can also be insulated and/or heated
7–197

Corrosive Liquid Tank — Basic
Corrosive Liquid Tank DOT412,
TC412, SCT-412(MC312, TC312)
 Pressure less than 75 psi (517 kPa)
gallons (26 498 L) [per NFPA]
 Rubber lined or steel
 Typically single compartment
 Small-diameter round shape
 Exterior stiffening rings may be visible
on uninsulated tanks
7–198

Corrosive Liquid Tank — Basic
 Typical rear top-loading/unloading station with exterior piping
extending to the bottom of the tank
 Splashguard serving as rollover protection around valve
assembly
 Flange-type rupture disk vent either inside or outside the
splashguard
 May have discoloration around loading/unloading area or area
painted or coated with corrosive-resistant material
 Permanent ownership markings that are locally identifiable
 Carries: Corrosive liquids (usually acids)
7–199

Corrosive Liquid Tank — Construction
Features (1 of 2)
 Typically made of stainless steel or carbon steel
 May be lined with several different materials
 Can also be made of aluminum or fiberglass reinforced plastic
 Typical pressure range of 35 to 55 psi (241 kPa to 379 kPa)
and may have a much higher MAWP
 Typical tank capacities are from 3,300 to 6,300 gallons (12
492 L to 23 848 L)
 Can be insulated or noninsulated — Insulation may hide the
tank’s true shape
 Typically contain stiffening rings — If noninsulated, these rings
are visible
7–200

Corrosive Liquid Tank — Construction
Features (2 of 2)
 Rollover and splash protection around access point and fittings
 Typically top unloading
 Typically fittings for the piping and valves are flanged
 Most do not have emergency shutoffs, valves must be manually
opened and closed
 Are often discolored around the loading and unloading areas
 Many carry noncorrosive toxic inhalation hazard materials
 Access points and valves are common leakage points; may be
prone to leakage and failure if product leaks through its liner
 Inspection is paramount for this type of tank
7–201

Review Question 17
How can you visually identify a corrosive liquid tank?
7–202

High-Pressure Cargo Tanks
 Transport liquefied gases and high vapor pressure materials;
contents must remain under pressure in order to maintain a
liquid state
 MC 331 designation
 Common products shipped in high-pressure cargo tanks may
include anhydrous ammonia, chlorine, propane, other gases
that have been liquefied under pressure
 Pressure gauges located on the side or end of the tank
 Capacity gauges that indicate amount of product in the tank
7–203

High-Pressure Cargo Tanks Basic
 Round with protruding, rounded heads
 MC 331 is considered a highway bulk tank; propane “bobtail”
truck is its intercity counterpart
 DOT requires upper two-thirds of noninsulated tanks be
painted white or another highly reflective color
 Chlorine trucks are MC 331 tanks
 Look different from other high-pressure cargo tanks
 Have a domed protective housing on the rear
 Refer to the bill of lading for exact quantity of product
 Liquid gauge can also indicate the amount of liquid in the tank
7–204

High-Pressure Cargo Tanks — Basic
High-Pressure Tank MC 331, TC 331,
SCT 331
 Pressure above 100 psi (689 kPa)
gallons (43 532 L)
 Single steel compartment
 Non-insulated
 Bolted access point at front or rear
 Internal and rear outlet valves
 Typically painted white or other
reflective color
7–205

High-Pressure Cargo Tanks — Basic
 Large hemispherical heads on both ends
 Guard cage around the bottom loading/unloading piping
 Uninsulated tanks, single-shell vessels
 Permanent markings such as the product name
 Carries: Pressurized gases and liquids, anhydrous ammonia,
propane, butane, and other gases that have been liquefied
under pressure
 High-Pressure Bobtail Tank: Used for local delivery of liquefied
petroleum gas and anhydrous ammonia
7–206

High-Pressure Cargo Tanks — Construction
Features (1 of 2)
 High-pressure cargo tanks are
constructed of steel or insulated
aluminum
 Not compartmentalized
 Pressures typically between 100 to
500 psi (690 to 3 448 kPa)
 Typical capacities between 3,000 to
11,000 gallons (11 356 to 41 640 L)
 All valves on the MC 331 tank must
be labeled to indicate whether it will
control liquid or vapor
7–207

High-Pressure Cargo Tanks — Construction
Features (2 of 2)
 If the cargo tank has a water capacity below 3,500 gallons
(14 000 L) it must have at least one emergency shutoff valve
 Any MC 331 tank with a water capacity greater than 3,500
gallons (14 000 L) must have both mechanical and thermal
discharge control valves
 Safety valve thresholds must be set at 110 percent of the
tank’s overall design pressure
 Tanks must include temperature and pressure gauges
 May have liquid gauging devices
 MC 331 is a very rugged tank designed to protect its contents
7–208

Review Question 18
What do MC 331 tank trucks usually carry?
7–209

Cryogenic Tanks (1 of 2)
 Designed to carry gases that have been liquefied by reducing
their overall temperature; contents will be extremely cold
 -130° F (-90° C) or colder
 May pose more of a hazard than those associated with the
product itself
 Due to typically high expansion ratios, a release may displace
normal atmosphere over a wide area
 Classified as MC 338/CGA 341
 Cryogenic materials offer a unique safety hazard, tanks used
to contain them have features intended to safely control the
product, but those features are limited
7–210

Cryogenic Tanks (2 of 2)
 Common products
carried in cryogenic
tanks include
 Liquefied natural gas
(LNG)
 Liquefied oxygen
 Liquid carbon dioxide
 Liquid hydrogen
 Liquid nitrogen
Courtesy of Brent Cowx
7–211

WARNING 7 and 8
The rapid expansion of vapors from cryogens can
quickly displace oxygen.
Liquid hydrogen burns clear due to the lack of carbon
produced, so flames may not be visible.
7–212

Cryogenic Tanks — Basic Identification
(1 of 3)
 Because cryogenic liquids are transported at extremely cold
temperatures, must be adequately insulated to protect their
contents — Will give tank a bulky appearance
 Tank is round with flat ends
 A loading/unloading station will be located either in the rear
of the tank or just forward of the rear wheels
 To determine the actual quantity of product being
transported, refer to the bill of lading
7–213

(2 of 3)
Cryogenic Liquid Tank MC 338, TC
338, SCT 338(TC 341, CGA 341)
 Well-insulated steel or aluminum
tank
 Possibly discharging vapor from
relief valves
 Round tank with flat ends
 Large and bulky double shelling and
heavy insulation
7–214

(3 of 3)
 Loading/unloading station attached either at the rear
or in front of the rear dual wheels, typically called the
doghouse in the field
 Permanent markings such as REFRIGERATED LIQUID
or an identifiable manufacturer name
 Carries: Liquid oxygen, liquid nitrogen, liquid carbon
dioxide, liquid hydrogen, and other gases that have
been liquefied by lowering their temperatures
7–215

Cryogenic Tanks — Construction Features
(1 of 3)
 Constructed of aluminum or stainless steel
 Flat heads
 Comprised of welded inner tank that holds the product
surrounded by a vacuum space that contains insulating
material, final outer shell made of steel
 Pressures can be less than 25 and up to 500 psi (172 to 3 447
kPa)
 Capacities of 8,000 to 10,000 gallons (30 283 to 37 854 L)
 Pressure gauge must be located so that the driver may view it
from the cab
7–216

(2 of 3)
 MC 338/CGA 341 tanks that carry products such as oxygen
 Must have discharge precautions set at 110 percent of the
design pressure of the tank
 A thermal closure must activate at a preset temperature
 Is an extremely rugged tank designed and built as a tank
within a tank
 Valves are the most vulnerable to leakage, due to gasket
material being compromised
 Mechanical damage and stress can compromise the integrity
of the tank
7–217

(3 of 3)
 A unique feature of the CGA
341 is its ability to vent
based on temperature and
pressure — What may
appear as a leak or the
activation of a pressure
relief device may actually be
the result of properly
working safety equipment
7–218

NOTE13
Most cryogenic cargo tanks in service today are
designated CGA 341, and they vent to keep the liquid
cryogenic material cold.
7–219

Review Question 19
What are the three layers that comprise a cryogenic
tank?
7–220

Tube Trailers (1 of 4)
 DOT does not classify tube trailers as cargo tanks; modified
semi-trailer comprised of individual steel tubes that may be
stacked and banded together
 Tubes
 May carry individual quantities of product, or may be linked
together in a cascade-style system
 High internal working pressure
 Typical pressures in the tubes range from 2,400 to 5,000
psi (16 547 kPa to 34 474 kPa)
 Each cylinder typically has an overpressure device
7–221

 Only one product can be carried in each tube at a time, but a
trailer may be carrying more than one product
 When the individual cylinder is opened the gauge in the
loading/unloading compartment will indicate the remaining
pressure in the cylinder
 Carry gas under pressure and occasionally liquefied gases such
as anhydrous hydrochloric acid
7–222

 Argon
 Carbon dioxide
 Helium
 Hydrogen
 Methane
 Nitrogen
 Oxygen
 Refrigerant gases
 Silicon tetrafluoride
 Carbon monoxide
 Other gases
7–223

 Compressed-gas/tube trailers may
 Experience disintegration; runaway cracking; damage to
attachments; punctures, splits or tears
 Release product via violent rupture, rapid relief, or leaks
 Catastrophically fail when exposed to heat or flames
 Flammable gases may explode/ignite when they come into
contact with an ignition source
 Accidental releases from these trailers
 Can be violent
 Liquefied compressed gas will expand rapidly upon release
7–224

Compressed-Gas/Tube Trailer (1 of 2)
 Pressure at 3,000 to
5,000 psi (20 684 kPa to
34 474 kPa) (gas only)
 Individual steel cylinders
stacked and banded
together
 Typically has over-
pressure device for each
cylinder; valves at rear
(protected)
7–225

Compressed-Gas/Tube Trailer (2 of 2)
 Manifold enclosed at the rear
 Permanent markings for the material or ownership
that is locally identifiable
 Carries: Helium, hydrogen, methane, oxygen, and
other gases
7–226

Review Question 20
Explain what is unique about tube trailers.
7–227

Dry Bulk Carriers (1 of 3)
 Not regulated; do not
conform to DOT specifications
 Off-loaded through bottom
ports
 Distinguished by their large
sloping W- or V-shaped
compartments, known as
hoppers
 Common products
transported may include
 Cement
 Coal
 Corrosive solids
 Fertilizers
 Feed products
 Oxidizers
 Plastic pellets
7–228

 While contents are not usually under pressure, low
pressures between 15 to 20 psi (103 to 138 kPa) may
be used to discharge or transfer the product from the
container
 These cargo trailers are constructed to transport
heavy loads, but damage to attachments, punctures,
splits, or tears may occur if they are involved in an
accident
7–229

Dry Bulk Cargo Trailer
 Pressure usually between 15 psi (100 kPa)
to 25 psi (170 kPa); typically not under
pressure
 Bottom valves
 Shapes vary, but has V-shaped bottom-
unloading compartments
 Top access point assemblies
 Carries: Oxidizers, corrosive solids,
cement, plastic pellets, and fertilizers
7–230

CAUTION 7
When product is being moved through dry bulk
containers there is an extreme risk of static shock.
7–231

Review Question 21
How can you visually distinguish dry bulk trailers?
7–232

Section VII: Assessing Intermodal
Containers
assessing intermodal containers.
7–233

Assessing Intermodal Containers (1 of 3)
 Can be both pressurized and non-pressurized
 Materials transported include
 Liquid and solid hazardous materials
 Non-refrigerated liquefied compressed
gases
 Refrigerated liquefied gases
 Appeal to shipping companies, can be
transferred between modes of transportation
without being off-loaded
7–234

 Box containers may transport a variety of hazardous materials
 Intermodal tank containers
 Also called portable tanks
 Are a tank or cylinder within a frame-like structure
 Because handled more frequently than bulk cargo tanks,
there may be a greater risk of damage or leakage
 May be manufactured in and shipped from virtually
anywhere in the world
7–235

 Two major types of frame construction used for intermodal
tank containers
 Box type — Encase the tank within the framework of a box
 Beam type — Only have framework at the ends of the tank
 Intermodal containers may be refrigerated, heated, or lined
7–236

Review Question 22
Why do intermodal containers appeal to shipping
companies?
7–237

Intermodal Tank Markings
Reporting
marks and
numbers
Specification
markings
Kemler Code
hazard
marking
AAR-600
marking
Country, size,
and type
markings
7–238

Reporting Marks and Numbers
 Generally found on the
right-hand side of the tank
or container as you face it
from either the sides or the
ends
 Use this information in
conjunction with shipping
papers to identify and verify
the contents of the tank or
container
7–239

Intermodal Specification Markings
 Indicate tank’s design and construction standard (also called T-
codes); detailed in 49 CFR regulations as tank instruction
codes
 Included in each tank’s identification records
 Correspond to certain design specifications and instructions
 Not required to appear on tank specification plates, but they
are often included on the tank somewhere
 Legacy containers must meet current construction standards
 Also include inspection and testing requirements
 Containers carrying hazardous materials must have proper
shipping names stenciled on two sides along with the owner of
the tank
7–240

Kemler Code Hazard Marking (1 of 2)
 Intermodal containers are more likely to be marked with
Kemler Code markings than regular DOT placards and
markings
 Kemler Code markings will include two orange panels, one on
top of the other
 Top orange panel includes up to four characters, potentially
three numbers and a letter
 Bottom panel is the UN number
 ERG includes a key to the Kemler Code in the front pages
7–241

Kemler Code Hazard Marking (2 of 2)
7–242

AAR-600 Marking
 Tanks with an AAR-600 marking are designed to meet
the requirements of the Association of American
Railroads (AAR)
 Marking will appear in two-inch letters somewhere on
each side of the tank
 These tanks are often used to ship regulated
hazardous materials
7–243

Country, Size, and Type Markings
 The bottom line of tank
markings include
information about the
tank’s country of origin,
size, and type
 Country code is
indicated by two or
three letters
7–244

Review Question 23
Where can you find a key to Kemler Codes?
7–245

Intermodal Tanks for Liquids and Solid
Hazardous Materials
 Most common intermodal tanks used in transportation
 May also carry nonhazardous liquids or solids
 T1-T5 (IM 102) and T6-T14 (IM 101) containers fall into this
category
 T6 to T14 tanks — Formerly known as IM 101 or IMO Type 1
tank container, built to withstand higher MAWP of 25.4 to
100 psi (175 kPa to 689 kPa)
 T1 to T5 tanks — Formerly known as the IM 102 portable
tank or IMO Type 2 tank container, designed to handle MAWP
of 14.5 to 25.4 psi (100 kPa to 175 kPa); gradually being
removed from service
7–246

Intermodal Tanks for Non-Refrigerated
Liquefied Compressed Gases (1 of 2)
 Designated T-50, formerly known as
Spec 51 or IMO Type 5
 Typically designed for working
pressures of 100 to 500 psi (700 kPa to
3 500 kPa) with a total capacity up to
5,500 gallons (21 000 L)
 Pressure-type intermodal containers
usually transport liquefied gases under
pressure such as LPG, chlorine,
anhydrous ammonia
7–247

NOTE14
Chlorine tank inlets and discharge outlets must meet
standards established by the Chlorine Institute.
7–248

Intermodal Tanks for Non-Refrigerated
Liquefied Compressed Gases (2 of 2)
 When equipped with thermal insulation, a device must be
provided to prevent any dangerous pressure from developing
in the insulating shell in the event of a leak
 Data plates must be attached to the frame rail
 May have fittings located on the top and bottom ends
 Safety equipment includes
 Safety relief devices
 Excess flow valves
 Fusible links and nuts
 Emergency remote shutoffs
7–249

Intermodal Tanks for Refrigerated
Liquefied Gases (1 of 2)
 Used to transport cryogenic
liquids
 Designated T-75, formerly
known as IMO Type 7 containers
 Must be of seamless or welded
steel construction and usually
are manufactured in 10 ft to 40
ft (3 m to 12 m) configurations
 Capacities will typically range
around 4,400 gallons (16 600
liters)
7–250

Intermodal Tanks for Refrigerated
Liquefied Gases (2 of 2)
 Will accommodate pressure around 250 psig (1 700 kPa)
 Carry liquefied gases such as
 Nitrogen
 Oxygen
 Hydrogen
 Argon
 Have a thermal insulation system that must include a
complete covering of the shell with effective insulating
materials
 Each filling and discharge opening in intermodal containers
must be fitted with at least three mutually independent shutoff
devices in series
7–251

Multiple Element Gas Containers (MEGCs)
(1 of 3)
 Formerly known as tube modules
 Transport gases in high-pressure
cylinders with MAWPs of 2400 to
5,000 psi (16 547 kPa to 34 474 kPa)
 Defined as assemblies of UN
cylinders, tubes, or bundles of
cylinders interconnected by a
manifold and assembled within a
framework Courtesy of Barry Lindley
7–252

(2 of 3)
 Built in two standard lengths of 20 ft (6 m) and 40 ft (12 m)
 Number of individual tubes typically ranges from five to twelve
and are designed to carry a single product
 Designed to carry both nonrefrigerated liquefied and non-
liquefied compressed gases
 MEGC loading valves are on one end and unloading valves are
on the opposite end
 Each cylinder must have its own pressure relief, and valve
systems can be manifolded together
7–253

(3 of 3)
 Must be equipped with a
corrosion resistant metal
plate permanently attached
 Typically designed to carry
one product
 Valves may be CGA
specification valves for the
particular gas service
 Leaks occur around the
valves such as packing
glands or thread leaks
7–254

Review Question 24
What do MEGCs carry?
7–255

Section VIII: Assessing Air Freight Cargo
assessing air freight cargo.
7–256

Assessing Air Freight Cargo (1 of 2)
 DOT restricts the shipment of
many hazardous materials aboard
aircraft
 If a hazardous material is allowed
to be shipped in the air, the hazard
may be limited by the nature of
the chemical and/or limited
quantity allowed on board
 Aircraft will not display outer
markings or placards indicating the
type of cargo that may be carried
Courtesy of John Demyan
7–257

Assessing Air Freight Cargo (2 of 2)
 There will be little opportunity to evaluate any hazards from a
safe distance
 DOT requires shipping papers be carried within the aircraft to
identify any hazardous materials on board — Shipping papers,
known as an air bill, should be located in the cockpit
 DOT labeling requirements that apply to products shipped by
other modes of transportation are also required for air freight
7–258

Review Question 25
How can you tell what hazardous cargo is carried on an
aircraft?
7–259

Section IX: Assessing Pipelines
assessing pipelines.
7–260

Assessing Pipelines
 Pipelines primarily carry
 Liquid petroleum products
 Natural and manufactured gases
 DOT requires that most pipelines be buried 30 to 36 inches
(750 mm to 900 mm) below ground level
 While requirement is helpful in protecting the pipeline, can
be counterproductive when identifying the location of the
pipeline
7–261

Principles of Pipeline Operation
 Allow shipping of a product under
pressure from one point to another
without the need for off-loading
 Product is introduced into the
pipeline at an injection station
located at the beginning of the
pipeline system
 Storage facilities equipped with
pumps and compressors to aid in
product movement can also be
located at the injection station
7–262

Basic Pipeline Identification (1 of 3)
 Many types of materials, particularly petroleum products, are
transported across both the U.S. and Canada in an extensive
network of pipelines
 Most are buried in the ground
 U.S. DOT Pipeline and Hazardous Materials Safety
Administration (PHMSA) regulates pipelines that carry
hazardous materials across state borders, navigable
waterways, and federal lands in the U.S.
 In Canada, the Canadian National Energy Board regulates oil
and natural gas pipelines
7–263

 Where pipelines cross under (or over) other pipelines, roads,
railroads, and waterways, pipeline companies must provide
markers
 From the marker closest to the crossing point, the next
marker, in both directions, should be visible, so that the
approximate location of the pipeline should be discernible
 Must also provide markers at sufficient intervals along the
rest of the pipeline to identify the pipe’s location
 Markers do not always mark the exact location of the
pipeline
 Do not assume that the pipeline runs in a straight line
between markers
7–264

 Pipeline markers in the U.S. and
Canada include the signal words
 Caution
 Warning, or
 Danger (representing an
increasing level of hazard)
 Contain information describing the
transported commodity and the
name and emergency telephone
number of the carrier
7–265

Pipeline Construction Features (1 of 4)
 Can vary based on what products are intended to be
transported within the pipeline
 Have a large range in sizes depending on their function
 Transmission lines range from 6 to 48 inches (150 mm to 1
200 mm) in diameter
 Distribution lines may be as small as a half-inch (13 mm)
 Odorant is typically added at a city gate
 Marks the end of transmission lines and the beginning of the
distribution lines
 May be the source of odor calls if any error occurs while
odorant is being added
7–266

7–267

 Pipeline construction is a multistep process that may include
preconstruction surveys to clearing and grading of the pipeline
right-of-way
 Valves are placed at regular intervals along the pipeline and
act as a gateway
 Compressor stations — Used to aid the movement of product
 Metering stations and valves can also be found along the
pipeline’s right-of-way
 Control station will monitor and manage all products within its
pipeline
7–268

 Using a sophisticated system like SCADA, control station
operators can view the entire pipeline and act quickly should a
leak or pressure loss occur
 Remote closing of valves along the right-of-way can greatly
reduce the impact of environmental damage
 Most common damages to pipelines occur from careless
digging during third-party construction activities
 Pipelines are well monitored
 Valves may leak
 National Pipeline Mapping System is a useful resource for
locating pipelines
7–269

Review Question 26
What is the most common cause of damage to
pipelines?
7–270

Section X: Assessing Fixed Facility
Containers
assessing fixed facility containers.
7–271

Assessing Fixed Facility Containers (1 of 2)
 Bulk storage containers at
fixed facilities can include
 Aboveground storage tanks
 Buildings
 Open piles or bins
 Pipelines
 Reactors
 Underground storage tanks
 Vats
 Other fixed, on-site
containers
7–272

Assessing Fixed Facility Containers (2 of 2)
 Identifying the type of hazardous material present at a fixed
facility can be much more difficult than simply recognizing the
presence of a hazardous material
 Most storage tanks are designed to meet the specific needs of
both the facility and the commodity
 Fixed facility tanks with rounded ends and pressure relief
valves are designed to withstand higher pressures
 Tanks with flatter ends may store liquids with low vapor
pressures
 Fixed facilities with bulk liquids or gases may have features
that will assist in product and fire control if there is an incident
7–273

Review Question 27
How can you distinguish between low-pressure and
high-pressure fixed facility tanks?
7–274

Atmospheric/Non-pressure Tanks
 Designed to hold contents that are not pressurized
 Despite their name, these tanks may have pressures up to 0.5
psi (3.5 kPa)
 Common types of atmospheric/non-pressure pressure tanks
include
 Horizontal tanks
 Floating roof tanks
 Lifter roof tanks
 Ordinary cone roof tanks
 Vapordome roof tanks
 Underground atmospheric storage tanks
7–275

Atmospheric/Non-pressure Tanks —
Horizontal Tank
 Cylindrical tanks sitting on legs, blocks,
cement pads, or something similar; typically
constructed of steel with flat ends
 Commonly used for bulk storage in
conjunction with fuel-dispensing operations
 Old tanks (pre-1950s) have bolted seams,
whereas new tanks are generally welded
 Tank supported by unprotected steel supports
or stilts may fail quickly during fire conditions
 Contents: Flammable and combustible liquids,
corrosives, poisons, etc.
7–276

Cone Roof Tanks
 Have cone-shaped, pointed roofs
with weak roof-to-shell seams
that break when or if the
container becomes over-
pressurized
 When it is partially full, the
remaining portion of the tank
contains a potentially dangerous
vapor space
 Contents: Flammable,
combustible, and corrosive liquids
7–277

Open Top Floating Roof Tank
 Large-capacity, aboveground holding
tanks; usually much wider than tall
 Roof floats on the surface of the liquid
and moves up and down depending on
the liquid’s level; eliminates the
potentially dangerous vapor space found
in cone roof tanks
 Fabric or rubber seal around the
circumference of the roof provides a
weather-tight seal
 Contents: Flammable and combustible
liquids
7–278

Covered Top Floating Roof Tank
 Have fixed cone roofs with either a
pan or deck-type float inside that
rides directly on the product
surface
 This tank is a combination of the
open top floating roof tank and the
ordinary cone roof tank
 Contents: Flammable and
combustible liquids
7–279

Covered Top Floating Roof Tank with
Geodesic Dome
 Floating roof tanks
covered by geodesic
domes are used to store
flammable liquids
7–280

Lifter Roof Tank
 Have roofs that float within
a series of vertical guides
that allow only a few feet
(meters) of travel
 The roof is designed so that
when the vapor pressure
exceeds a designated limit,
the roof lifts slightly and
relieves the excess pressure
 Contents: Flammable and
combustible liquids
7–281

Vapordome Roof Tank
 Vertical storage tanks that have
lightweight aluminum geodesic
domes on their tops
 Attached to the underside of the
dome is a flexible diaphragm
that moves in conjunction with
changes in vapor pressure
 Contents: Combustible liquids of
medium volatility and other
nonhazardous materials
7–282

Atmospheric Underground Storage Tank
(1 of 2)
 Constructed of steel, fiberglass, or steel with a fiberglass
coating
 Underground tanks will have more than 10 percent of their
surface areas underground
 Can be buried under a building or driveway or adjacent to the
occupancy
 Has fill and vent connections located near the tank
 Vents, fill points, and occupancy type provide visual clues
7–283

Atmospheric Underground Storage Tank
(2 of 2)
 Many commercial and private tanks have been abandoned,
some with product still in them
 Are presenting major problems to many communities
 Contents: Petroleum products
 NOTE: First responders should be aware that some natural
and manmade caverns are used to store natural gas. The
locations of such caverns should be noted in local emergency
response plans.
7–284

CAUTION 8
Atmospheric/non-pressure tanks will often have
pressures up to 0.5 psi (3.5 kPa). When released, this
pressure can cause contents to spray or splatter.
7–285

What types of atmospheric/non-pressure storage tanks
do you have in your jurisdiction?
7–286

Pressure Tanks
 Designed to hold contents under pressure
 Low-pressure storage tanks
 Have operating pressures from 0.5 to 15 psi (3.45 kPa to
103 kPa)
 Pressure vessels
 Have pressures of 15 psi (103 kPa) or greater
 May be found in different configurations
 Horizontal pressure tanks will be easy to distinguish because
of the rounded ends
 Other pressure tanks may be spherical
 May also be stored below ground
7–287

Dome Roof Tank
 Generally classified as low-
pressure tanks with
operating pressures as high
as 15 psi (103 kPa)
 They have domes on their
tops
 Contents: Flammable
liquids, combustible liquids,
fertilizers, solvents, etc.
7–288

Spheroid Tank
 They can store 3,000,000
gallons (11 356 200 L) or
more of liquid
 Contents: Liquefied
petroleum gas (LPG),
methane, and some
flammable liquids such as
gasoline and crude oil
7–289

Noded Spheroid Tank
 They are similar in use to spheroid
tanks, but they can be substantially
larger and flatter in shape
 These tanks are held together by a
series of internal ties and supports
that reduce stresses on the
external shells
 Contents: LPG, methane, and some
flammable liquids such as gasoline
and crude oil
7–290

Horizontal Pressure Vessel
 Have high pressures and capacities
from 500 to over 40,000 gallons (1
893 L to over 151 416 L)
 They have rounded ends and are
not usually insulated
 They usually are painted white or
some other highly reflective color
 Contents: LPG, anhydrous
ammonia, vinyl chloride, butane,
ethane, compressed natural gas
(CNG), chlorine, hydrogen chloride,
and other similar products
7–291

Spherical Pressure Vessel
 Have high pressures and
capacities up to 600,000 gallons
(2 271 240 L)
 They are often supported off the
ground by a series of concrete or
steel legs
 They usually are painted white or
some other highly reflective color
 Contents: Liquefied petroleum
gases and vinyl chloride
7–292

Review Question 28
How can you identify the contents of a below ground
tank?
7–293

Characteristics of Cryogenic Tanks
 May come in many different shapes
 Will have round roofs
 Heavily insulated
 Rest on legs instead of being placed directly on the
ground
 Some have features such as an expansion section
with a radiator-like fin adjacent to the tank
7–294

Cryogenic Liquid Storage Tank
 Insulated, vacuum-jacketed tanks
with safety-relief valves and rupture
disks
 Capacities can range from 300 to
400,000 gallons (1 136 L to 1 514
160 L)
 Pressures vary according to the
materials stored and their uses
 Contents: Cryogenic carbon dioxide,
liquid oxygen, liquid nitrogen, etc.
7–295

Review Question 29
What is a visual clue that a fixed facility storage tank
holds cryogenic material?
7–296

Section XI: Other Storage Facility
Considerations
Learning Objective 11 — Discuss other storage facility
considerations.
7–297

Other Storage Facility Considerations
 Technicians should work diligently to preplan incidents
at facilities that may store large and/or varied
quantities of hazardous materials within their
jurisdiction
 In some cases, facilities may employ staff members
who are well-trained in the use of the materials within
the facility
 In other cases, materials and their containers may
not be handled correctly
7–298

Laboratories
 While the hazardous chemicals may be numerous and varied,
they will likely be stored in non-bulk quantities
 Can be found in just about any community
 Each lab will hold different products based on its primary
objective
 A chemical inventory list, if readily available, may assist the
responding agencies should an incident occur
7–299

Batch Plants
 Manufacturing and distribution facility that can produce
materials such as concrete or asphalt
 Can have a variety of tanks and storage bins based on the
material being produced
 It is not uncommon to find silos and non-pressure storage
tanks where different materials and aggregates are stored
 Be familiar with these types of facilities in your area and
understand the hazards of each facility
 Facility personnel can help identify dangers in the facility
7–300

Non-Regulated and Illicit Container Use
 Manufactured to hold specific products and
predetermined measurements including volumes,
weights, and pressures
 Not used correctly, may be dangerous
 In a situation involving non-regulated and/or illicit use
of containers, technicians should attempt to mitigate
the incident by preserving as much of the container’s
structural integrity as possible
7–301

Review Question 30
What is a batch plant?
7–302

Have you encountered improper usage of containers
that led to a hazmat incident?
7–303

Section XII: Assessing Radioactive
Materials Packaging
assessing radioactive materials containers.
7–304

Assessing Radioactive Materials Packaging
 All shipments of radioactive materials
must be packaged and transported
according to strict regulations
 Regulations protect the public,
transportation workers, and the
environment
 Type of packaging depends primarily on
the level of radioactivity in the materials
 As the level of radioactivity increases,
level of risk increases, so the package
must be stronger
7–305

Excepted Packaging
 Used to transport materials that have limited radioactivity
 Authorized for limited quantities of radioactive material that
would pose a very low hazard if released in an accident
 Empty packaging is excepted
 Not marked or labeled as such
 Because of its low risk, excluded from specific packaging,
labeling, and shipping paper requirements
 Required to have the letters “UN” and the appropriate four-
digit UN identification number marked on the outside of the
package
7–306

Industrial Packaging
 Used in certain shipments of low activity material and
contaminated objects, which are usually categorized as
radioactive waste
 Most low-level radioactive waste is shipped in these packages
 DOT regulations require that these packages allow no
identifiable release of the material to the environment during
normal transportation and handling
 Three categories of industrial packages: IP-1, IP-2, and IP-3
 Category of package will be marked on the exterior of the
package
7–307

Type A Packaging
 Used to transport small quantities of radioactive material with
higher concentrations of radioactivity than those shipped in
industrial packages
 Must meet standard testing requirements designed to ensure
that the package retains its containment integrity and
shielding under normal transport conditions
 Package and shipping papers will have the words “Type A” on
them
 Examples of materials shipped in Type A packaging
 Radiopharmaceuticals
 Industrial products
7–308

Type B Packaging
 Must withstand severe accident
conditions without releasing contents
 Identified on the package itself
 Size of these packages range from
small hand-held containers to large
shipping casks; large, heavy
packages provide shielding against
radiation
 Radioactive materials that exceed
limits of Type A packages must be
shipped in Type B packages
Courtesy of the National Nuclear
Security Administration, Nevada Site
Office
7–309

Type C Packaging
 Rare packages used for high-
activity materials transported by
aircraft
 Designed to withstand severe
accident conditions associated with
air transport without loss of
containment or significant increase
in external radiation levels
 Performance requirements are
significantly more stringent than
those for Type B packages
Courtesy of the National Nuclear
Security Administration
7–310

Descriptions and Types of Radioactive
Labels (1 of 2)
 Packages of radioactive materials must be labeled on opposite
sides with the distinctive warning label
 Each of the three label categories — RADIOACTIVE WHITE-I,
RADIOACTIVE YELLOW-II, or RADIOACTIVE YELLOW-III —
bear the unique trefoil symbol for radiation
 Class 7 Radioactive I, II, and III must contain the isotope
name and radioactive activity
7–311

Descriptions and Types of Radioactive
Labels (2 of 2)
 Radioactive II and III labels also
provide the Transport Index (TI)
which can be used to determine
package integrity
 When a package containing
radioactive materials has been
involved in an accident, detection
results can be compared to the
Transport Index to determine if
the readings differ
7–312

Review Question 31
List the five basic types of container for radioactive
materials in order of increasing level of radioactivity
hazard.
7–313

Takeaway Points
What are your takeaway points from this chapter?
7–314

Container Assessment from the fist manual

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