New Provisional Rules From LR
Lloyds Register (LR) has developed Provisional Rules covering the duplication and performance of a ship's propulsion and steering systems, allowing for continued operations in the event of system failure.
Ships built and maintained in accordance with these new Rules will be eligible for the class notation, "EA." The Rules are consistent with LR's current Rules for machinery installations and anticipate the need of owners to have ships capable of continuous operation at sea.
The requirements go beyond provision of standby units and specify availability and functionality of propulsion and maneuvering systems with defined operating and emergency parameters.
"We have responded to the wishes of shipowners for performance standards for the segregation and duplication of key items," said Norman Rattenbury, senior surveyor in LR's Engineering Services Group. "The EA notation is of particular interest for owners of passenger cruise liners, ships carrying hazardous cargoes and those which operate in environmentally sensitive areas." The Rules detail requirements for: •Propulsion and steering machinery; •Electrical power supplies; •Essential services for operation of machinery; •Oil fuel storage and transfer; •Control arrangements; •Failure mode and effects analysis; •Testing and trials; •Maneuvering capability; and •Operating manuals.
The Rules require consideration of the effects of failure or malfunction in any system associated with propulsion and steering. A failure mode and effects analysis (FMEA) is required for propulsion systems, electrical power supplies, essential services, control systems and steering arrangements. This approach is consistent with marine safety assessment methods currently being applied within the shipping industry. The FMEA investigation is required to address the following: May, 1998 •Separation of machinery compartments; •Demonstration that a single failure in the propulsion and related auxiliary systems will not cause loss of all propulsion or steering capability; •Fire in a machinery space or control room; and •Flooding of any watertight compartment which could affect propulsion or steering capability.