MODULE 7 Unload a Cargo Tank Motor Vehicle (CTMV)

Module 7 – Unload a Cargo Tank Motor Vehicle (CTMV) When a cargo transport delivers propane. When a bobtail must be emptied of liquid.

Module 7 – Unload a Cargo Tank Motor Vehicle (CTMV) Tasks include: Verify room in bulk storage tanks. Position the CTMV. Connect the liquid and vapor hoses, and check for leaks. Start the transfer. End the transfer. Carefully bleed down liquid trapped in the riser and hose. Disconnect and store the hoses.

LESSON 1 Characteristics of Bulkheads and Plant Piping

Lesson 1 – Characteristics of Bulkheads and Plant Piping Bulkhead components: – Liquid connections. – Vapor connections. – Breakaway system. May have hoses attached.

Breakaway Systems Predictable breakaway point. Means to limit flow of propane.

Emergency Shutdown System Not less than 25 feet or more than 100 feet from any liquid transfer point.

Lesson 2 Characteristics of CTMVs

Lesson 2 – Characteristics of CTMVs Gauges Valve operators

Liquid and Vapor Connections Cargo Transport Bobtail

Liquid and Vapor Connections Connections NOT used when unloading Cargo Transport Bobtail

Emergency Activation System Bobtail with WC ≤ 3500 gallons, in metered delivery service. Bobtail with WC > 3500 gallons, in metered delivery service. CTMV other than metered delivery service.

Lesson 3 Hazards and Precautions

Lesson 3 – Hazards and Precautions Remove ignition sources, flammable liquids and combustible materials to a safe distance. Observe precautions within Static Discharge Control Area. Wear appropriate PPE. Inspect hoses and fittings. Emergency evacuation procedures, and adequate egress locations.

Hazards and Precautions for All Propane Transfers When? Where? Metered delivery service. Other than metered. Definition of “qualified person”?

Valves and Hoses Inspect hoses before use. When moving hoses – Avoid dragging. – Carry valves by the body. – Aim valve outlet away from yourself and others. Know locations of ESVs.

Other Potential Hazards Auto Refrigeration – Details in Lessons 7, 8 & 10. Multiple storage tanks of different diameters.

When Equipment Malfunctions Occur Lock-out/Tag-out – May be unsafe to transfer propane Tag identifies – Who locked the device – Why it was locked – What must be done before the device can be returned to service

Lesson 4 Measure the Liquid Level in a Tank

Lesson 4 – Measure the Liquid Level in a Tank Float Gauge Rotary Gauge

Lesson 5 Determine the Amount of Propane to be Unloaded

Lesson 5 – Determine the Amount of Propane to be Unloaded

Verify the Contents of a Cargo Tank Check bill of lading to insure cargo tank contains propane. Verify presence of odorant. Check temperature and pressure readings. Record % liquid volume in cargo tank. % liquid volume x WC = gallons of liquid propane in cargo tank.

Determine the Available Capacity in Storage Tanks Determine maximum permitted filling level (MPFL) for each available tank Calculate gallons of liquid propane that can be added to each available tank: Record % liquid volume in each tank % available capacity = MPFL – current % volume Gallons available capacity = % available capacity x WC in gallons Add gallons that can be added to all available storage tanks

Example – 30,000 gallon tank MPFL = 80%. Current Level = 69%. Available capacity = 80% - 69% = 11%. Gal available capacity = 11% x 30,000 gal = 3,300 gallons.

Learning Activity – Calculating Available Capacity in Bulk Storage Tanks

Lesson 6 Unload a Bobtail Using the Bobtail Pump

Lesson 6 – Unload a Bobtail Using the Bobtail Pump

Position the Bobtail Level gauges visible. Shutoff valves accessible. 10 ft. from container. Set parking brake. Turn off electrical devices. Wheel chocks.

Connect the Hoses and Check for Leaks Connection depends on bulkhead configuration. Vapor equalization recommended.

Start the Transfer If required, set meter Open discharge valves – Open last valve slowly Engage PTO Monitor storage tank levels Stop immediately if: – Leak – Abnormal sounds from pump – EFV slugs

End the Transfer Stop bobtail pump when: Cargo tank reaches empty. All storage tanks reach MPFL. Close liquid and vapor valves on bulkhead and cargo tank.

Lesson 7 Safely Disconnect the Bobtail Liquid Hose

Lesson 7 – Safely Disconnect the Bobtail Liquid Hose Recognize hazards posed by auto refrigeration. Avoid the condition when bleeding down a riser. Recognize the condition when it occurs, and act to avoid the hazards.

Avoid Auto-Refrigeration When Bleeding Down a Riser

Avoid Auto-Refrigeration When Bleeding Down a Riser

Avoid Auto-Refrigeration When Bleeding Down a Riser

Avoid Auto-Refrigeration When Bleeding Down a Riser

Avoid Auto-Refrigeration When Bleeding Down a Riser

Avoid Auto-Refrigeration When Bleeding Down a Riser

How to Avoid the Hazard Be patient when bleeding trapped liquid. Chance of auto-refrigeration increases as wetted surface area decreases. Frost? - Close the valve or adapter and wait. Auto-refrigeration can occur without frost . Follow these precautions: – Always disconnect slowly. – Keep hands and face away from connection. – Wear PPE. – Don't point hose at yourself or anyone else.

Disconnect and Store the Hoses Loosen vapor connection - relieve pressure. When both connections fully depressurized: Disconnect bobtail hose end valve from bulkhead adapter. Disconnect vapor hose from bobtail vapor connection. If not permanently connected to bulkhead, disconnect vapor hose from bulkhead and store. Inspect bobtail hose as it is reeled in. Remove adapter and store. Replace caps. Complete forms as required.

Lesson 8 Empty the Bobtail Liquid Hose

Lesson 8 – Empty the Bobtail Liquid Hose If bobtail hose must be disconnected to permit servicing. May use scavenging system to transfer liquid into a container, or May be necessary to vent the hose to atmosphere. – Repeatedly open and close hose end valve – Auto-refrigeration difficult to avoid

Venting a Bobtail Hose Before opening hose end valve: – Shut off bobtail’s engine. – Shut off supply from cargo tank to hose reel. – Remove all ignition sources, flammable liquids and combustible materials to a safe distance.

Venting a Bobtail Hose Potential for auto-refrigeration is affected by: – How long hose end valve is left open during each interval –short is better. – Recovery time allowed between openings – more is better. – Surrounding air temperature and dew point – Sunlight shining on the hose – more is better.

Venting a Bobtail Hose

Venting a Bobtail Hose

Venting a Bobtail Hose Frost may not appear. May occur in center of hose reel.

Venting a Bobtail Hose Consider leaving the hose end valve open to allow vaporization to continue. – No ignition sources within 25 feet of the hose end valve. – With hose end valve outdoors, leave open to allow venting to continue. – Remain in attendance until venting is finished. – Do not rewind empty hose on reel.

Lesson 9 Unload a Cargo Transport Using the Transport Pump

Lesson 9 – Unload a Cargo Transport Using the Transport Pump

Position the Cargo Transport Level gauges visible. Shutoff valves accessible. 10 ft. from container. Tank level for accurate reading. Align the tractor and trailer . Set parking brake. Turn off electrical devices. Wheel chocks.

Connect the Hoses and Check for Leaks Connection depends on bulkhead configuration. With shutoff valves closed, remove caps. Inspect connectors and hoses. Connect hoses. Check each connection for leaks.

Start the Transfer Open valves on transport to equalize pressure Open remaining vapor and liquid valves – Open last liquid valve slowly Start pump Monitor storage tank levels Stop immediately if: – Leak – Abnormal sounds from pump – EFV slugs

End the Transfer Stop transport pump when: – Cargo tank reaches empty. – All storage tanks reach MPFL. Close liquid and vapor valves on bulkhead and cargo tank.

Lesson 10 Safely Disconnect the Transport Liquid Hose

Lesson 10 – Safely Disconnect the Transport Liquid Hose Recognize hazards posed by auto refrigeration. Avoid the condition when bleeding down a riser. Recognize the condition when it occurs, and act to avoid the hazards.

How Auto-Refrigeration Can Develop

How Auto-Refrigeration Can Develop

How Auto-Refrigeration Can Develop

How Auto-Refrigeration Can Develop

How Auto-Refrigeration Can Develop

Learning Activity

How to Avoid the Hazard Be patient when bleeding trapped liquid. Chance of auto-refrigeration increases as wetted surface area decreases. Frost? - Close the valve or adapter and wait. Auto-refrigeration can occur without frost. Follow these precautions: – Always disconnect slowly. – Keep hands and face away from connection. – Wear PPE. – Don't point hose at yourself or anyone else.

Disconnect and Store the Hoses Loosen vapor connection - relieve pressure. When both connections fully depressurized disconnect liquid and vapor hoses from transport and bulkhead. Replace caps. Store hoses. Complete forms as required.

Case Study – Handling Valves and Hoses

Summary Verify room in storage tanks to hold contents of CTMV. Position CTMV. Connect liquid and vapor hoses, and check for leaks. Start transfer, and monitor tank levels. End transfer when cargo tank is empty or storage tanks are full. Don’t let pump run dry. Carefully bleed down liquid trapped in riser and hose. Disconnect and store hoses.

Summary Avoid most common causes of accidents. – Venting trapped product too rapidly. auto-refrigeration. uncontrolled release of liquid propane. – Failure to remain in attendance during the entire transfer. – Failure to check for leaks and check hoses and fittings for damage or wear. – Failure to verify ESVs.

Module 7 Quiz