Tank truck to marine vessel - Oil transfer
6. Static Discharge Protection
Table of Content
- About This Manual
- 1. Introduction
- 2. Regulations and Guidelines
- 3. Responsibilities
- 4. Oil Transfer Locations
- 5. Tank Trucks
- 6. Static Discharge Protection
- 7. Nozzles
- 8. Transfer Hoses
- 9. Receiving Vessels
- 10. Contingency Planning
- 11. Operating Procedures
- Appendix A: Fuel transfer safety checklist
- Appendix B: BC Coastal marina contingency plan
Static electricity remains one of the greatest dangers in handling petroleum products. All personnel must be properly trained and must carry out proper operating procedures.
For more information, see Chapter 2 in the CPPI Petroleum Products Professional Driver's Manual.
6.1 Bonding And Grounding
The delivering company should have detailed procedures for bonding and grounding depending on the operation and the fuel being transferred. If carrying out a transfer at a marine terminal then that terminal may have a bonding or isolating protocol that must be observed.
In the absence of company-specific requirements the following procedures should be used.
Two key points regarding bonding and grounding:
- Be fully bonded while the fuel is flowing.
- Make or break all bonding connections, with fill caps closed, clear of any potential vapor sources.
The steps to take are as follows:
- To neutralize the static discharge of both, ground the receiving tank (or the vessel if the tank is bonded to the vessel) and the tank truck to an earthing stud or other ground at the dock.
- If earthing points are not available then the vessel and truck are to be bonded together to equalize any difference in potential.
- Before the vessel's fill cap is opened, bond the nozzle to the vessel to ensure there is no difference in the electrical potential between them.
- If a nozzle bonding cable is not available then touch the nozzle to the cap or vessel structure to discharge any difference. During transfer the nozzle must be kept in contact with the fill fitting to bleed away any charge buildup due to fuel flow.
- When transfer is complete, allow a 30 second waiting period for any possible static charges, that have accumulated in the fuel, to equalize.
- Remove the nozzle and close the fill cap.
- Disconnect bonding cables in reverse order
6.2 Drip Collection
- Drip containers must be bonded to the fitting from which they are collecting the drip.
- Use metal pails only. Never use a plastic pail to collect leakage of flammable or combustible liquids.
- Plastic handles should be taken off metal pails to ensure an electrical bond takes place between the pail and the fitting.
- Any leaking fittings must be contained and then repaired before next use.
6.3 Splash Loading
Splash loading occurs when product is allowed to free-fall into a storage container, creating turbulence and static charge. Properly mounted fuel tanks are usually fitted with fill spouts that safely accept a normal nozzle tip without creating a splash loading hazard. Cargo tanks, however, often have a fill opening without an extended spout that can lead to splash loading.
Splash loading can be avoided by using an extended fill spout that reaches the bottom of the tank being filled. If splash loading cannot be avoided, the following precautions can help minimize the risk:
- Limit the flow rate to minimize turbulence
- Keep the nozzle in contact with the side of the container being filled to ensure a continuous electrical bond, and
- Do not lower any objects into the tank for at least 30 minutes after the flow has stopped.
6.4 Aviation Fuels
- Aviation fuels (Avgas and Jet fuels) are particularly susceptible to static charge buildup. Extra precautions are required.
- Because of the likely presence of a static charge on the liquid surface, wait at least 10 minutes before lowering any objects into, or taking a sample from a tank filled with aviation fuel.
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