Proceedings magazine is a communication tool for the Coast Guard's Marine Safety & Security Council. Each quarterly magazine focuses on a specific theme of interest to the marine industry.
Issue link: http://uscgproceedings.epubxp.com/i/707823
67 Summer 2016 Proceedings www.uscg.mil/proceedings The facility PIC and the tank cleaning technician also heard the towing vessel's engines increasing in speed and tried to get the master's attention. The towing vessel master attempted to shut down the main diesel engines from the pilothouse, but was unsuccessful. He then requested his deckhands to manually shut down the engines by closing the fuel supply lines. The deckhands activated the emer- gency shut-downs for the main diesel engines located on the main deck; however, despite their efforts, the engines kept on running. and the tank cleaning technician opened all cargo tanks and hatches in preparation for residual cargo stripping using a vacuum truck and ventilation operations. After stripping operations commenced, flammable vapors escaped from all deck openings and hatches and started to accumulate on the deck of the barges as well as along the facility's shoreline. The flammable vapors escaped at a natural rate for approxi- mately six hours before the workers installed mechanical blowers. At approximately 8 p.m., another tank barge pulled up to dock at the facility to receive tank cleaning services on another day. The barge was about to moor next to the barges in service until the PIC guided them to the adjacent slip. After securing the barge, its towing vessel departed. At around the same time, the facility PIC and the tank clean- ing technician completed residual cargo stripping and initi- ated operations to ventilate the atmosphere inside the cargo tanks. They connected two shoreside air compressors to six portable pneumatic fans placed on each barge. Trouble Ahead, Trouble Inbound Between 8 and 8:30 p.m., the mechanical blowers started to fail. The tank cleaning technician attributed the failure to a loose air hose assembly connection. The facility PIC shut down both compressors to investigate the failure. At this time, another towing vessel arrived at the facility to drop off a radio technician and deckhand, mooring in between one of the tank barges in service and the tank barge that arrived earlier, awaiting service. As the radio technician and a deckhand disembarked the towing vessel, the deckhand overheard the towing vessel's master speaking on the radio — warning that the revolu- tions per minute of the vessel's port main diesel engine were increasing uncontrollably. Essential Procedures for Tank Cleaning Operations 1 1) Provide appropriate procedures and supervision: a. Develop a facility operations manual consistent with applicable regulations and guidance. b. Ensure facility and vessel PICs hold the required training and authorizations. c. Prior to oil transfers and tank cleaning operations, complete declaration of inspection. 2) Avoid the simultaneous presence of a flammable atmo- sphere and sources of ignition. a. To control the flammability of the tank atmosphere: ● Identify and continuously monitor the tank atmosphere. ● Flush and strip the cargo lines and tank bottom with water. ● Properly ventilate to reduce gas concentra- tions. ● Wash the tanks with water. 3) To control the presence of ignition sources: a. Minimize the number and duration of other vessels alongside the operation. b. Eliminate spark-producing tools and machinery. Endnote: 1. In completing its marine casualty investigation, Sector Mobile developed the Essential Procedures for Tank-Cleaning Operations. Because facility operators must pay special attention to numerous key factors when devel- oping operations manuals that include tank cleaning, the application of these procedures will help responsible, compliant tank cleaning facilities to holistically consider risk factors consistent with regulations and estab- lished best practices. See the related marine casualty report of investiga- tion under Coast Guard MISLE Activity #4576288. The fire.