2. HazMat/WMD
Introduction
This module provides information about the types of highway cargo tanks and tube trailers along with their configurations and safety features.

3. Enabling Learning Objectives
HazMat/WMD
Enabling Learning Objectives
18-1 Identify and describe the hazards
associated with:
MC 306/DOT 406 cargo tanks
MC 307/DOT 407 cargo tanks
MC 312/DOT 412 cargo tanks
MC 331 cargo tanks
MC 338 cargo tanks
Non Specification
Cryogenic
Dry bulk cargo tanks
Tube trailers

4. Enabling Learning Objectives
HazMat/WMD
Enabling Learning Objectives
18-2 Identify the capacity (by weight and
volume) of each of the above tanks/trailers,
using the DOT specification plate.
18-3 Identify the basic design and construction
features of each, and what each carries
18-4 Identify the closures found on each,
including their names and functions.

5. Enabling Learning Objectives
HazMat/WMD
Enabling Learning Objectives
18-5 Identify the required tank identification and
other markings.
18-6 Identify the location and use of the mechanical,
hydraulic, and air emergency remote shut-off
devices found on MC 306/D0T 406, MC 307/DOT
407, MC 312/D0T 412, MC 331, and MC 338
cargo tanks.
18-7 Given a HazMat/WMD highway incident,
demonstrate the methods for controlling releases
from cargo tanks.

6. Definition of a Cargo Tank
HazMat/WMD
Definition of a Cargo Tank
Tank intended to carry liquids or gases
Fittings, closures, reinforcement
Part of motor vehicle during
transportation, loading and unloading
Not a cylinder or
portable tank

7. Spec / Non-Spec Code of Federal Regulations Title 49
HazMat/WMD
Spec / Non-Spec
Code of Federal Regulations Title 49
Bureau of Explosives 6000
Non-specs may resemble spec tanks
Almost all HazMat must be carried in
specification containers

8. Post August 31, 1995, DOT Specifications
HazMat/WMD
Cargo Tank
MC vs. DOT
MC DOT 406
MC DOT 407
MC DOT 412
MC 331
MC 338
Post August 31, 1995, DOT Specifications

9. DOT 400 vs. MC 300 Thicker shells Reinforced rollover protection
HazMat/WMD
DOT 400 vs. MC 300
Thicker shells
Reinforced rollover protection
Manhole pressure capacity
Self-reclosing fittings

10. HazMat/WMD
DOT Specs MC300/DOT400
Construction Material-A bulk liquid cargo tank may be:
Aluminum alloy
Mild steel
Stainless steel
Carbon steel
Carbon steel with a liner
Container must meet CFR 49 standards

11. Structural Components
HazMat/WMD
Structural Components
Circumferential reinforcement-
A cargo tank may or may not have a frame.
Normally shells serve as trailer frame
Less than 3/8” require reinforcement
Bulk head - single and double
Baffle - side drains
Ring stiffeners
Maximum unreinforced span ”
Incompatible may not be hauled in same tank

12. Double Bulkhead

13. Weep Hole

14. Baffle

15. Ring Stiffeners

16. Protection Against Damage
HazMat/WMD
Protection Against Damage
Cargo tanks hauling HazMat also must provide protection against accidental damage:
Mounting pads
Rollover protection
Pressure venting features
Protection of bottom outlets
Bumper protects rear mountings

17. Mounting Pads

18. Rollover Protection

19. Pressure Venting

20. Outlet Protection

21. Bumper

22. Emergency Devices 70% strength of piping
HazMat/WMD
Emergency Devices
 Sheer protection
70% strength of piping
Fusible / frangible devices oF MAX
Rollover protection
Internal valves
Remote Emergency Closing Actuator

23. Emergency Discharge Control
HazMat/WMD
Emergency Discharge Control
 Remote Closing Activator- The location of the Emergency Remote Shut off will vary from one DOT spec cargo tank to another, if required.
Under normal conditions, the valves operate either:
Mechanically
Hydraulically
Pneumatically

24. Mechanical Emergency Shut-off
HazMat/WMD
Mechanical Emergency Shut-off
A clamping nut
and fusible
bushing (<
250oF), attach
each cable to its
handle
Two Trip lever –
One on left side
One at control

25. Hydraulic Emergency Shut-off
HazMat/WMD
Hydraulic Emergency Shut-off
Manual pump opens
and hydraulic
emergency valve
Releasing closes the
valve
The frangible part must
be broken manually
The fusible part
operates (< 250oF)

26. Pneumatic Emergency Shut-off
HazMat/WMD
Pneumatic Emergency Shut-off
Emergency valves
operate essentially
like hydraulic valves
only with air
A remotely located
fusible and frangible
plug
The fusible part of
the operates (<
250oF)

27. Tank Pressure Requirements
HazMat/WMD
Tank Pressure Requirements
MAWP - Maximum Allowable Working Pressure
Service or design pressure
External design pressure
Test pressure to 2 times service
Valves and vents

28. Specification Plate Vehicle manufacturer Vehicle Serial Number
HazMat/WMD
Specification Plate
Vehicle manufacturer
Vehicle Serial Number
Lining material (if any)
Date of manufacture
Certification date
Design service temp.
Test pressure
Maximum weight of lading
Design weight of lading

29. MC 306 Transports petroleum Capacities up to 10,000 gallons.
HazMat/WMD
MC 306
Transports petroleum
Capacities up to
10,000 gallons.
Oval Cross-section
Full-length rollover
protection
Man ways and dome
lids - most common
leak is in the dome lid.

30. MC 306 Some made of carbon steel Most made of .25- inch thick
HazMat/WMD
MC 306
Some made of
carbon steel
Most made of .25-
inch thick
aluminum alloy.
One to eight
compartments
Most common four
to five

31. MC 306 Low pressure vessel MAWP is 3 psig. Internal emergency
HazMat/WMD
MC 306
Low pressure vessel
MAWP is 3 psig.
Internal emergency
shut-off valves
usually mechanical/
pneumatic
Driver's side at the
front of the tank
Control handle at
valve

32. MC 306 Vents Pressure-activated vent vacuum to 1 psig
HazMat/WMD
MC 306 Vents
Pressure-activated
vent vacuum to 1 psig
and pressure to 3 psig
Fusible element
<250°F or less
installed insufficient to
vent 6,000 cubic feet
of vapor at 5 psig.
"Scully" or overfill
protection fails
Push vent

33. DOT 406 Oval in cross-section. Thicker shell and head add from 300 to
HazMat/WMD
DOT 406
Oval in cross-section.
Thicker shell and
head add from 300 to
400 pounds
Tank pressure MAWP
min psig and
max. 4 psig
Relief valve pressure
settings- 125%
MAWP or 3.3 psig

34. DOT 406 Vacuum relief device opens at no more than 6 ounces vacuum
HazMat/WMD
DOT 406
Vacuum relief device
opens at no more
than 6 ounces vacuum
and limit vacuum to 1
psig.
Manhole-assembly
affects integrity, a
static internal fluid
pressure greater than
the tank's test
pressure or 36 psig.
May not have a fusible
vent.

35. MC306/DOT 406-Never Try To Lift
HazMat/WMD
MC306/DOT 406-Never Try To Lift
Ground and bond, drill ,Stinger, off load
Control leaks from dome lids
Vapor suppression

36. HazMat/WMD
MC306/DOT 406

37. HazMat/WMD
MC306/DOT 406

38. MC307 Workhorse of chemical industry Usually stainless steel
HazMat/WMD
MC307
Workhorse of chemical
industry
Usually stainless steel
Cap. 5,000 to 7,000 gal.
Round cross-section
Insulated or non-
insulated
1 to 4 compartments
1 to 2 common
Leaks commonly occur
-manway and safety
relief device.

39. MC307 Structural Features
HazMat/WMD
MC307 Structural Features
External ring stiffeners and in multi-compartment
tanks, bulkheads provide reinforcement  
Internal baffles rarely are used
Rollover protection twice the weight of the loaded
tank and a horizontal load of half the weight of the
loaded tank. 
An insulated will have 5" of fiber glass held with
stainless steel panels. 
Coils are connected to the tractor's cooling system

40. MC307 Tank pressure MAWP a min. 25 psig. Working pressure over 50 psig
HazMat/WMD
MC307
Tank pressure
MAWP a min. 25
psig.
Working pressure
over 50 psig
Tank must meet requirements of the American Society of Mechanical Engineers .

41. MC307-Loading and Un-loading
HazMat/WMD
MC307-Loading and Un-loading
Loaded through the
manway or bottom
internal valves
Load or unload from rear
of the tank
Center un-loaders (belly
unloading, tanks with
multiple compartments)
Single shot MC 307 tanks

42. MC307-Valves and Vents Internal emergency shut-off valves - self-
HazMat/WMD
MC307-Valves and Vents
Internal emergency
shut-off valves - self-
closing internal
emergency shut-off
valve.
Safety relief valves
Spring-loaded,
pressure-activated
vents

43. DOT407 Thicker shell and head Adds approx. 800 lbs. to an
HazMat/WMD
DOT407
Thicker shell and head
Adds approx. 800 lbs. to an
average 5,000-7,000 gallon,
aluminum alloy tank.  
Requires increased overturn
protection 
May be designed for vacuum
service (vacuum loading). 
Vacuum service must meet
minimum external design
pressure standards.

44. DOT407-Tank Pressure Minimum MAWP (25 psig) ASME apply to any
HazMat/WMD
DOT407-Tank Pressure
Minimum MAWP (25
psig)
ASME apply to any
with a minimum
internal MAWP over
35 psig (15 psig lower
than for the MC 307)
Loaded by vacuum
minimum external
design pressure must
be 15 psig.

45. DOT407- Safety Relief Devices
HazMat/WMD
DOT407- Safety Relief Devices
Primary pressure relief one or more reclosing pressure-
relief valves.
Can use a non-reclosing pressure relief device ONLY as
part of a series which includes a reclosing pressure relief
device
A frangible disc only between product and telltale indicator
Primary relief valve must be at least 120% of the MAWP
and not over 132% of the MAWP.
Secondary relief valve must be at least 120% of the MAWP.
Manholes- must withstand the greater of 40 psig or the
tank's test pressure

46. MC312 Primarily transport corrosive products acids
HazMat/WMD
MC312
Primarily transport
corrosive products acids
and bases (caustics).
Made of:
Mild steel
High strength low alloy
steel
Stainless steel
Steel with a lining
  Average capacity of
3,000 to 5,000 gallons.

47. MC312 Structural Features
HazMat/WMD
Round cross-section
Commonly single-
compartment
One to four compartments
Each have own manway.
Use external ring
stiffeners as
reinforcement
Insulated or non-insulated
May be lined or unlined
Usually are clean bore,
for easier cleaning
MC312 Structural Features

48. MC312 Structural Features
HazMat/WMD
Smaller diameter, (greater
specific gravity of
products)
Usually top service.
Bottom outlets are not
common.
Protective coating on
manway, valve
assemblies and tank
Leaks common around
the manway and bottom
sump.
MC312 Structural Features

49. MC312 Structural Features
HazMat/WMD
MC312 Structural Features
Linings
Leaks migrate
Bonded linings
10 years service
Pressure ratings
determined by product
unloading, over 15 psi
ASME must certify

50. MC312 Unloading either top or bottom
HazMat/WMD
MC312
Unloading either top or bottom
Each outlet at or near the top of the tank
must have an external shut-off valve as
close to the tank as possible.
Top of the tank, an eduction line extends
(sump) shut-off valve is at the top of the
tank.
For pressure unloading from the bottom, an
internal emergency shut-off valve must be
installed in the bottom outlet.

51. MC312 Remote closures must be 10 feet away
HazMat/WMD
MC312
Remote closures must be 10 feet away
Blind flange, sealing cap, or shut-off valve at
end of the outlet.
Safety venting devices must activate at a
pressures not over 150% of design pressure
Pressure unloading, the relief valve limit the
tank pressure to 130% of valve's design
pressure for maximum air flow [Sec.
(a)].

52. DOT412 The minimum internal MAWP not designed
HazMat/WMD
DOT412
The minimum internal MAWP not designed
to be loaded by vacuum pressure is 5 psig.
Loaded by vacuum press. min. of 25 psig
internal and external press. min. of 15 psig.
External design pressure of 15 psig or more
must be circular in cross-section
Some may be oval.
Pressure reliefs on DOT 412s are like those
on the DOT 407 [Sec (1)].

53. Multi-purpose Cargo Tanks
HazMat/WMD
Multi-purpose Cargo Tanks
The vents and reliefs that require changing
must be stamped with the appropriate MC
specification number and color-coded:
MC 306 red
MC 307 green
MC 312 yellow
Non-specification-blue
Multipurpose cargo tanks are not common
and the 400 series prohibits them.

54. MC331 Rounded ends 8,000 - 11,500 gallons Normally one compartment
HazMat/WMD
MC331
Rounded ends
8, ,500 gallons
Normally one compartment
Liquefied compressed gas
Steel or aluminum may be
insulated
ASME-MAWP psig
Upper two-thirds of tank
painted white or of a
reflective material

55. MC331 Valves protected Openings must be plugged, capped, or bolted
HazMat/WMD
MC331
Valves protected
Openings must be plugged, capped, or bolted
flange
Protected with an excess flow valve on
product discharge openings or backflow check
valve on product inlet openings
Fitted with an internal self-closing stop valve
Each Cargo Tank inlet and outlet must be
marked liquid or vapor when the tank is
filled

56. MC 331 Safety Devices <3,500 gallons, at least one emergency
HazMat/WMD
MC 331 Safety Devices
<3,500 gallons, at least one emergency
discharge control (remote closing activator)
> 3,500 gallons two emergency discharge
controls (remote closing activators)
Excess flow valves must close
automatically backflow check permit flow
only in one direction.
Safety relief pressure discharge 110%
not to exceed 120%

57. MC331-Markings Stenciled with the proper shipping name must
HazMat/WMD
MC331-Markings
Stenciled with the proper shipping name must
appear on the sides and ends of the tank.
QT (Quenched & Tempered) or NQT (Not Quenched
and Tempered)
QT or NQT appears above or next to the
specification plate.
"NQT" are authorized for all grades of anhydrous ammonia.
"QT" are authorized for anhydrous ammonia having a minimum water
content of 0.2% by weight.
NQT steel are authorized to carry all grades of LPG
QT steel can carry only grades of LPG that are determined
"noncorrosive"

58. MC338 8,000 - 10,000 Gallons Pressures 25.3 psi - 500 psi
HazMat/WMD
MC338
8, ,000 Gallons
Pressures 25.3 psi psi
Design Service Temperature
Left front pressure gauge,
rear view
Cryogenics under -130oF
Boiling Temp
Vacuum and Insulated
Emergency controls same
as MC331
Thermal closure at a temp.
not over 250oF

59. HazMat/WMD
Non-spec Cryogenic
Carry atmospheric gases (oxygen, nitrogen, and helium)
Don't have all the safety features of an MC 338.
Bleed off excess pressure during transport
Special regulation for carrying a cryogenic flammable liquid-No carrier may operate and no driver may drive a motor vehicle transporting a flammable cryogenic liquid in a package exceeding 125 gallons unless written instructions accompany the package.
The instructions must contain with required shipping papers:
General precautions
Manual venting instructions
Emergency procedures
The names and telephone numbers of contact in an emergency.

60. Specification Plate MC338
HazMat/WMD
Specification Plate MC338
Vehicle manufacturer
Vehicle Serial Number
Lining material (if any)
Date of manufacture
Certification date
Design service temperature
Insulation for Oxygen Service or Not Authorized for Oxygen
Service
Maximum weight of lading
Marked holding time
Design weight of lading
MC 338s carrying flammable cryogenic liquids must be marked on the right side, in letters at least two inches high, as follows:
ONE-WAY TRAVEL TIME­­­­­­:_________HRS with the blank filled in with the number of hours.

61. Non-specification Cargo Tanks
Asphalt trailers
Pneumatic Dry Bulk
Tube trailers
Vacuum Trucks

62. Asphalt Trailers

63. Dry Bulk Materials Transport dry bulk materials Manufactured Valves
Aluminum and mild steel
Operates on pressure up
to 15 psi
Blower may be located on
trailer
May be gravity unloaded
Valves
Back flow valves
Blow down valve

64. Tube Trailer – Non Spec Trailer
Each cylinder is a separate DOT spec. cylinder
Manifolded together
Compressed gases only
2500 psi and higher
Venting must be unobstructed and not impinge on other containers

65. Vacuum Trucks

66. Conclusion Participants were given information to provide the
HazMat/WMD
Conclusion
Participants were given information to provide the
ability to:
Identify and describe the hazards associated with:
MC 306/DOT 406 and MC 307/DOT 407 cargo tanks
MC 312/DOT 412 cargo tanks
MC 331 cargo tanks and MC 338 cargo tanks
Non-specification
Asphalt
Dry bulk cargo tanks
Tube trailers
Demonstrate how each of the above differs and how to respond using control measures, valve operation and safety systems.