1. Identifying Equipment & Procedures Used on Propane Transports
2.3.1
Most of the propane used by residential, commercial and industrial customers is transported to bulk plants or directly to large customer accounts by tractor-trailer transports.
In this module, you will learn to:
Identify applications and features of propane transports
Maintain and operate pumps and associated circuits on transports
Identify functions of emergency discharge control systems and safety features of transports
Identify U.S. DOT cargo tank labeling and markings
Student Book  © 2004 Propane Education & Research Council
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2. Features of Propane Transports
In U.S. Department of Transportation regulations in some cases use the term “transport” to refer to any bulk cargo tank motor vehicle, regardless of its size or configuration. DOT regulations also call bulk delivery vehicles cargo tank motor vehicles (CTMVs). In the propane industry, transports are understood to mean tractor/trailer combination vehicles that have semi-trailers that are cargo tanks.
“Metered delivery service” means an unloading operation conducted at a metered flow rate of 100 gallons per minute or less through an attached delivery hose with a nominal inside diameter of 1.25 inches or less. The majority of propane transports are not equipped with liquid meters and small diameter delivery hoses, and are not used in metered delivery service.
2.3.1 Student Book  © 2004 Propane Education & Research Council
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3. Features of Propane Transports
Regardless of their size, application, or devices used to control their operation, all transports have basic features and equipment in common.
Figure 1. Cargo Tank Motor Vehicle
2.3.1 Student Book  © 2004 Propane Education & Research Council
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4. Features of Propane Transports
Cargo Tank
Figure 2. Typical Features of Transport Cargo Tanks
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5. Features of Propane Transports
Data Plate
Name Plate
May be combined in a single data plate.
Specification Plate
Figure 3. Cargo Tank Data Plates
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6. Features of Propane Transports
Data Plate
Figure 4. MC 331 Cargo Tank Data Plate
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7. Features of Propane Transports
Cargo tanks have the following openings for connections:
Liquid level gauges
Temperature well
Pressure gauge
Cargo tank fill and equalizing connections
Cargo tank withdrawal connection
Pressure relief valve(s)
2.3.1 Student Book  © 2004 Propane Education & Research Council
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8. Features of Propane Transports
Rotary Gauge
Figure 5a. Rotary Gauge
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9. Features of Propane Transports
Rotary Gauge
Figure 5b. Cross Sectional View of Rotary Gauge
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10. Features of Propane Transports
Rotary Gauge
Figure 6. Rotary Gauge Face
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11. Features of Propane Transports
Float Gauge
Figure 7a. Float Gauge
Figure 7b. Cargo Tank 50% Liquid Filled
2.3.1 Student Book  © 2004 Propane Education & Research Council
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12. Figure 8b. Cross Sectional View in Cargo Tank
Features of Propane Transports
Fixed Liquid Level Gauges
Figure 8a. Fixed Liquid
Level Gauge Outage
Figure 8b. Cross Sectional View in Cargo Tank
2.3.1 Student Book  © 2004 Propane Education & Research Council
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13. Features of Propane Transports
Thermometer & Pressure Gauge
Fixed maximum liquid level gauges installed in pressure cargo tanks are used each time the tank is filled. The pressure gauge and thermometer are used to check the load of gas in the cargo tank, while the thermometer and scales on the liquid level gauge are used to determine the maximum permitted filling level.
One method of checking the accuracy of rotary and float gauges is to fill the cargo tank with propane until a white mist vents out of the fixed maximum liquid level gauge. The rotary and float gauges should indicate the same percentage of tank volume as indicated by the fixed maximum liquid level gauge if you have a liquid temperature near 40° F.
2.3.1 Student Book  © 2004 Propane Education & Research Council
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14. Figure 9. Fixed Maximum Liquid Level Gauge
Features of Propane Transports
Fixed Liquid Level Gauges
Figure 9. Fixed Maximum Liquid Level Gauge
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15. Figure 10. Temperature Well
Features of Propane Transports
Temperature Well & Thermometer
Figure 10. Temperature Well
Figure 11. Dial Indicating Temperature Gauge
2.3.1 Student Book  © 2004 Propane Education & Research Council
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16. Figure 12. Thermometer, Pressure Gauge And Fixed Liquid Level Gauges
Features of Propane Transports
Temperature Well & Thermometer
Figure 12. Thermometer, Pressure Gauge
And Fixed Liquid Level Gauges
2.3.1 Student Book  © 2004 Propane Education & Research Council
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17. Features of Propane Transports
Loading, Unloading and Vapor Equalizing Connections
The fill and equalizing connections in propane cargo tanks vary according to their applications for metered or un-metered delivery service. The vapor equalizing connections always contain a riser inside the tank that extends to the vapor space in the cargo tank. The fill connection in most cargo tanks connects to a riser used to "spray fill" the tank.
When piping is installed, even though the fill connection and the connected bypass piping will contain liquid propane, the opening at the outside of the cargo tank must be permanently labeled either “VAPOR” or “Spray-Fill” because the piping ultimately communicates with the vapor space of the cargo tank due to the spray fill feature.
2.3.1 Student Book  © 2004 Propane Education & Research Council
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18. Features of Propane Transports
Loading, Unloading and Vapor Equalizing Connections
Figure 13. Schematic Drawing of Transport Cargo Tank
Loading, Unloading and Vapor Equalizing Connections
2.3.1 Student Book  © 2004 Propane Education & Research Council
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19. Figure 14a. Bottom-Center Loading & Unloading Valve Connections
Features of Propane Transports
Loading, Unloading and Vapor Equalizing Connections
Figure 14b. Rear Loading &
Unloading Valve Connections
Figure 14a. Bottom-Center Loading &
Unloading Valve Connections
2.3.1 Student Book  © 2004 Propane Education & Research Council
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20. Figure 15. Internal Valves
Withdrawal Connection
Figure 15. Internal Valves
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21. Withdrawal Connection
Figure 15a. Valve Closed
(Position A)
Position A: When the operating lever is in the closed position, tank pressure (liquid or vapor) holds the main and pilot valves in the closed position.
2.3.1 Student Book  © 2004 Propane Education & Research Council
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22. Figure 15b. Bleed Open, Excess Flow Valve Closed
Withdrawal Connection
Figure 15b. Bleed Open, Excess Flow Valve Closed
(Position B)
Position B: When the operating lever is moved to the open position, the cam moves the valve stem upward, opening the pilot valve orifice. Tank pressure bleeds through the pilot orifice and begins to build up downstream pressure.
2.3.1 Student Book  © 2004 Propane Education & Research Council
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23. Withdrawal Connection
Figure 15c. Valve Open
(Position C)
Position C: As downstream pressure equalizes with tank pressure, the excess flow spring opens the main valve. The system is ready for transfer operations with the main valve acting as an excess flow valve. Releasing the operating lever to the closed position instantly closes both the main valve and the pilot valve (Position A).
2.3.1 Student Book  © 2004 Propane Education & Research Council
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24. Figure 16. Cable Installation
Withdrawal Connection
Figure 16. Cable Installation
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25. Figure 17. Pump Pressure Operated Internal Valve (Flanged)
Withdrawal Connection
Figure 17. Pump Pressure Operated Internal Valve (Flanged)
2.3.1 Student Book  © 2004 Propane Education & Research Council
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26. Figure 18. Three-Way Valve
Withdrawal Connection
Figure 18. Three-Way Valve
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27. Relief Valves Figure 19c. Open Figure 19b. Closed Figure 19a. Internal
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28. Figure 20. Relief Valve Caps and Covers
Relief Valves
Figure 20. Relief Valve Caps and Covers
Relief valves are removed and independently tested as part of the cargo tank 5-year pressure test performed by a U.S. DOT Registered Inspector.
2.3.1 Student Book  © 2004 Propane Education & Research Council
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29. PTOs & Pumps Figure 22a. Tractor PTO Output Shaft
Figure 22b. Connecting “Jack Shaft” Between Tractor and Trailer
2.3.1 Student Book  © 2004 Propane Education & Research Council
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30. PTOs & Pumps PTO SHAFT HAZARD WARNING:
DO NOT attempt to connect or adjust the PTO shaft section between the tractor and trailer with the engine running.
NEVER place any body part, clothing, hair, or hand-held object (within 3 feet of) a rotating PTO shaft.
2.3.1 Student Book  © 2004 Propane Education & Research Council
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31. PTOs & Pumps Figure 23. In-Cab Pneumatic PTO Control
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32. PTOs & Pumps Figure 24. Sliding Vane LP-Gas Pump
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33. PTOs & Pumps Figure 24. Sliding Vane LP-Gas Pump
2.3.1 Student Book  © 2004 Propane Education & Research Council
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34. PTOs & Pumps Never allow the pump to run dry.
Liquid LP-gas is the lubrication and cooling material that protects the pump from premature wear and failure.
2.3.1 Student Book  © 2004 Propane Education & Research Council
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35. Auxiliary Pump Inlet Figure 25. Auxiliary Pump Inlet
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36. Liquid Meters
Most transports are not equipped with a liquid meter. CTMVs in metered delivery service, however, have a liquid meter installed in the pump discharge line to account for the correct number of gallons delivered to customers.
To ensure accurate inventory records, deliveries of propane to bulk plants and industrial customers are adjusted so the invoice displays the volume of gas at 60° F.
Figure 26. State Weights & Measures Registration Decal on Meter Register
2.3.1 Student Book  © 2004 Propane Education & Research Council
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37. Transfer Hoses
Vapor Equalizing Hose – Typically attached to the plant transfer bulkhead, but on CTMVs in metered delivery service, may be carried on the transport
Use of the vapor equalizing hose prevents or minimizes the following:
excessive pump cavitation
excessive pressure build up in the customer storage containers
venting of relief valves on customer storage containers in hot weather or on ASME tanks that fill to the liquid space
2.3.1 Student Book  © 2004 Propane Education & Research Council
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38. Transfer Hoses Delivery Hose Assembly (Liquid) –
One of the most frequent causes of early failure of delivery hoses is damage from abrasion caused by vibrations of the hose.
When this condition is detected, there are two important steps to be taken at once. The hose must be inspected more frequently and the cause of the vibration should be determined and corrected. If wear is so extensive as to expose the hose reinforcing fabric, the hose cannot be used until it is repaired and pressure tested or replaced with a new hose.
2.3.1 Student Book  © 2004 Propane Education & Research Council
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39. Emergency Discharge Control Systems
U.S. DOT regulations require the installation of either off-truck remote emergency discharge control systems or passive shutdown systems.
MC 330, MC 331, and non-specification cargo tank motor vehicles …. must be retrofitted with required emergency discharge control equipment at their first scheduled pressure test after July 1, All required retrofits must be complete by July 1, There are three types of emergency discharge control systems used on transports:
Manually actuated systems
Off-truck remotely actuated systems
Passive shutdown systems
2.3.1 Student Book  © 2004 Propane Education & Research Council
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40. Emergency Discharge Control Systems
Manually Actuated Systems
Figure 27b. Emergency Shutdown Station—Rear Deck Location
Figure 27a. Emergency Shutdown Station—Front Trailer Location
2.3.1 Student Book  © 2004 Propane Education & Research Council
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41. Emergency Discharge Control Systems
Off-Truck Remotely Actuated System
Figure 28. Example of Off-Truck RF Device
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42. Emergency Discharge Control Systems
Passive Emergency Shutdown System – Passive emergency shutdown systems are systems that can stop the flow of product and stop the vehicle engine without human action within 20 seconds in the event of a complete delivery hose separation.
Figure 29a. Passive Shutdown System Control Box
Figure 29b. Discharge Line Sensor
2.3.1 Student Book  © 2004 Propane Education & Research Council
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43. Figure 30. Undercarriage Interlock Gate Open for Loading
Pull-away Prevention Devices
Safety Air Brake Interlocks – The purpose of the interlocks is to prevent accidents such as moving the vehicle from a loading or unloading bulkhead with the PTO engaged or the hoses connected.
Figure 30. Undercarriage Interlock Gate Open for Loading
2.3.1 Student Book  © 2004 Propane Education & Research Council
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44. Cargo Tank Labeling & Marking
U.S.Department of Transportation regulations require specific cargo tank markings, including:
Hazard Class Placards
Product Shipping Labels
Cargo Tank Inspection and Test Markings
Quench Tempered or Non-Quench Tempered Markings
Placards and shipping labels (Figures 31 and 32) are required on the front, back and both sides.
2.3.1 Student Book  © 2004 Propane Education & Research Council
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45. Cargo Tank Labeling & Marking
Figure 31. Propane Shipping Label
and Placard with LP-gas Identification Number
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46. Figure 32. Hazard Class Placards
Cargo Tank Labeling & Marking
*Some states may require decals stating, "WE STOP AT RAILROAD CROSSINGS," to be placed on the rear of the vehicle.
Figure 32. Hazard Class Placards
2.3.1 Student Book  © 2004 Propane Education & Research Council
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47. Cargo Tank Test and Inspections
Cargo Tank Labeling & Marking
Tests & Inspections – The month and year of the latest required annual cargo tank inspections and the test and inspections required every five years must be shown near the cargo tank data plate. All commercial motor vehicles must also pass an annual vehicle inspection. Documentation of the annual mechanical inspection may be in the form of a decal.
Cargo Tank Test and Inspections
Annual Inspections Year Test and Inspection
External visual inspection
(V inspection), and
Leak inspection (K inspection).
Hydrostatic pressure test
(P test), and
Internal inspection
(I inspection)
2.3.1 Student Book  © 2004 Propane Education & Research Council
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48. Time to See If You Got the Key Points of This Module…
Complete the Review on page 29.
See if you are ready for the Certification Exam by checking off the performance criteria on page 30.
2.3.1 Student Book  © 2004 Propane Education & Research Council
Pages 29 & 30