IMPERIAL OIL - Approval for variance from the Liquid Fuels Handling Code

Liquid Fuels Handling Code (LFHC) Requirements that Would Not be Met:

5.6.1.3. Bulk plant tanks receiving product shall be equipped with an overfill protection

device for each storage tank that will automatically shut off the flow to the tank.

Why the Code Would Not be Met

Activation of the overfill protection device (automatic motor operated valve) could lead to an overpressure of the marine piping during offload. An overpressure scenario is a higher practical risk than the possibility of overfilling a tank due to the multiple safety processes that mitigate against the occurrence of a tank overfill.

Safety Assessment

Information provided by Waleed Hathat, P.Eng.:

The high-high level audible alarm and visible strobe that currently exist for the tanks will remain operational, allowing adequate time for site operators to shut down vessel pumps by emergency shut down signals and to manually close the valve.

The procedures in place during vessel arrival and product receipt greatly reduce the risk of a tank overfill scenario. Vessel receipts are staffed with two operators at the terminal and one operator at the dock. One terminal operator is an Imperial employee acting as the “Imperial person-in-charge” responsible for the following checks:

• Planning prior to every vessel arrival and receipt of product:
  • a physical dip of the tanks is completed to verify the automatic tank gauges re accurate; and
  • the tank space available is calculated to confirm there is adequate room in the tank

• Pre-discharge meeting takes place between Imperial Operations and Vessel Crew, which includes:
  • discussing the planned discharge sequence including the volume to be discharged into each tank, which is endorsed by the Vessel Chief Mate and Vessel Captain/Master;
  • confirming the emergency shutdown signals with vessel crew prior to discharge (stop, stop, stop);
  • establishing and testing radios for constant communication between Imperial Operators and Vessel Crew during product receipts; and
  • establishing plans for back-up communications by intrinsically safe cell phone; (there are three means of communication, this includes Radio (UHF), Cellphone and landline - terminal will not receive in the event there is no communication with the vessel)

• During product receipt:
  • tanks have a safe-fill level that Imperial uses as the maximum level of the tank for any planned product receipt, including calculation of “space available”;
  • beyond the safe-fill level, the tanks have a high-level alarm and a high-high level alarm (audible alarm and visible strobe activates at the site and at the dock, plus activation of the automatic motor operated valve being discussed). High-high level alarms are function tested quarterly.
  • product receipts are monitored in-person by site operators who are stationed at the dock and at the terminal; and
  • hourly field checks are performed by the Imperial person-in-charge, including tank gauges (vs expected final level), receipt rate (vs max receipt rate and current vessel discharge rate), and volume remaining to be discharged (for the receiving tank).
  • There are three means of communication. This includes Radio (UHF), Cellphone and landline. Terminal will not receive in the event there is no communication with the vessel