LPG Tank Drain and Evacuation
LPG Tank Drain and Evacuation
Special Tools
* CH-50934 - Hose Assembly, LPG Tank Transfer
* CH-50935 - Flare Stack, LPG Vapor Burn-Off
For equivalent regional tools, refer to Special Tools Tools and Equipment.
Danger: Do not remove any valves, bulkheads or fittings from a LPG tank unless the tank has been properly drained and evacuated completely. LPG is stored under pressure. When a valve or bulkhead is removed from a tank, any pressure is released at once, in a violent rush. The pressure inside a LPG tank can push a loosened bulkhead or valve out with enough force to cause injury. Release of LPG in an uncontrolled situation will create a flammable/explosive mixture of air and LPG, which could cause death, serious injury and property damage.
Warning
Never service a LPG fuel tank inside a building. Always perform the drain and evacuation procedure outside, with the vehicle and flare stack a minimum of 50 feet from any combustibles, hazardous atmosphere, buildings, structure and source of ignition. Always remove any possible sources of ignition when performing the evacuation. The person(s) or company performing any fuel transfer or service work on a LPG system is liable for their actions and must be properly trained, insured and licensed if required by the authority having jurisdiction.
The National Fire Protection Associations pamphlet No. 58 states in Chapter 1, General Provisions 1-5 Qualification of Personnel: Persons who transfer liquid LP Gas, who are employed to transport LP Gas, or whose primary duties fall within the
scope of this code shall be trained in proper handling procedures. Refresher training shall be provided at least every three years. The training shall be documented.
For more information, contact your local, state or national propane gas association and ask about certified employee training programs. Failure to follow this procedure could result in bodily injury or damage to the vehicle.
Warning
The person performing this procedure must be trained and familiar with the properties and characteristics of LPG gas; this person must stand watch of this procedure until it is complete and cannot leave the process unattended; if the person must leave the drain and evacuation process then all valves should be shut off and the process would require restarting upon return. Failure to follow this procedure may result in bodily injury and/or damage to the vehicle.
The safest way to empty a LPG tank is to:
1. Use the fuel in the tank.
2. Transfer the fuel to an empty tank.
3. Burn the fuel through a flare stack.
It is never recommended to release more than minimal amounts of LPG to the atmosphere.
Transferring Fuel from One Tank to Another
Warning
Always disconnect the vehicle's negative battery terminal prior to performing any service to a LPG tank or fuel line. Failure to follow this procedure could cause bodily injury or damage to the vehicle.
Warning
When transferring the fuel from one tank to another, position the vehicle and flare stack a minimum distance of 50 feet from any buildings, structures, or combustible materials and in a well ventilated area. Failure to follow this procedure could result in bodily injury and/or damage to the vehicle.
1. Remove the vehicle fuel tank shield.
2. Disconnect the negative vehicle battery cable. Refer to Battery Negative Cable Disconnection and Connection Service and Repair.
3. Be sure the LPG fuel tank drain valve (8) is closed on the vehicle's fuel tank (7), and that the drain valve and fill bleeder valve (spitter valve) on the receiving tank (2) are both closed. Remove the brass caps from the fuel tank drain valves on both tanks.
4. Connect CH-50934 - Hose Assembly, LPG Tank Transfer (6) from the vehicle tank liquid service valve to a receiving tank liquid service valve.
5. Slowly open the fuel tank drain valves on both tanks.
Note:
* If the receiving tank is empty and has no vapor pressure, the drain valve's excess flow protection will close and stop/decrease the flow. The drain valve on the vehicle tank is equipped with excess flow protection and will only allow a flow of 1.7 gpm (gallons per minute) If the flow exceeds this rate, the excess flow protection will close.
* Do not overfill the receiving tank. LPG tank maximum filling capacity is 80%.
* LPG tanks must be in a well ventilated area.
6. Open the receiving tank fill bleeder valve.
7. The drain valve may be opened for more flow, but if the flow rate is exceeded, the excess flow protection could close.
8. The LPG fuel transfer hose contains a sight glass with a ball that indicates the fuel flow. When the tank being evacuated is empty of liquid or the flow of liquid has stopped, turn off all tank valves, and remove the LPG fuel transfer hose assembly.
9. Connect the flare stack hose to the fill bleeder valve of the tank being evacuated.
10. Open the fill bleeder valve of the tank being evacuated and light the flare stack to burn the remaining fuel in the tank.
Danger: If the vehicle tank is opened by removing the LPDM or any valve before any frost or ice has dissipated, liquid fuel may remain in the bottom of the tank. Release of LPG in an uncontrolled situation will create a flammable/explosive mixture of air and LPG, which could cause serious injury, death and property damage.
11. If frost or ice appears on the bottom of the tank being evacuated, liquid fuel is in that area of the tank. The area of the tank with frost or ice may be sprayed with a water hose to help vaporize the fuel so that it may flow from the tank.
12. After the fuel tank service is complete, install the brass cap on the LPG fuel tank drain valve and bleeder valve.
13. Install the vehicle fuel tank shield.
Flaring Off (Burning) the Fuel From a Tank
Warning
Always disconnect the vehicle's negative battery terminal prior to performing any service to a LPG tank or fuel line. Failure to follow this procedure could cause bodily injury or damage to the vehicle.
Warning
While flaring off fuel, position the vehicle and flare stack a minimum distance of 50 feet from any buildings, structures, or combustible materials. Failure to follow this procedure could result in bodily injury and/or damage to the vehicle.
1. Remove the vehicle fuel tank shield.
2. Disconnect the negative vehicle battery cable and the LPDM connector from the fuel pump flow control module.
3. Be sure the LPG fuel drain valve is closed and remove the brass cap from the valve.
4. Connect one end of the CH-50934 - Hose Assembly, LPG Tank Transfer to the LPG fuel tank drain valve. Using an appropriate union, connect the other end of the fuel transfer hose to the hose of the CH-50935 - Flare Stack, LPG Vapor Burn-Off.
Note: Set up the flare stack as far from the vehicle as the hose will allow. Make sure that the flare stack stand is securely pounded into the ground, and that the flare stack will not tip.
5. Close the flare stack valve. Open the LPG fuel tank drain valve. Open the valve on the flare stack 1/4 turn, and light the flare stack.
Note: The drain valve on the vehicle tank is equipped with excess flow protection and will only allow a flow of 1.7 gpm (gallons per minute). If the flow exceeds this rate, the excess flow protection will close.
6. If the flare stack is equipped with a valve, slowly open the valve until the flow rate and the burn rate are maximized.
7. If the flare stack flame goes out due to improper fuel mixture, wind or any reason, the drain valve must be closed immediately. Wait a few minutes for any accumulation of fuel vapor to dilute into the atmosphere before attempting to restart or relight the flare stack.
8. A technician trained in this procedure must attend the process at all times and cannot leave the area without closing off all valves and discontinuing the evacuation process.
9. When the level of the liquid fuel in the tank drops below the drain valve, the remaining liquid fuel in the tank must vaporize before it will flow from the tank. A frost or ice line on the tank indicates liquid fuel is in the tank and the burning process is faster than the liquid in the tank can vaporize. The area of the tank with frost or ice may be sprayed with a water hose to help vaporize the fuel so that it may more easily flow from the tank.
Note: When burning LPG vapor, the flame from the flare stack may be colorless.
10. Close all valves to see if pressure builds up in the tank - this indicates some liquid fuel remains in the tank. Do not remove any valve, gauge or LPDM from the tank until it is completely empty of liquid and vapor fuel.
11. After the fuel tank service is complete, install the brass cap on the LPG fuel tank drain valve and bleeder valve.
12. Install the vehicle fuel tank shield.