Learning by tragedy
April 2012 marked the 100th anniversary of the best known ship disaster: the loss of the Titanic and the deaths of over 1 500 of her passengers and crew. The shipwreck was the catalyst for the adoption, in 1914, of the first Safety of Life at Sea (SOLAS) Convention. The SOLAS convention, which forms a central part of the IMO's (International Maritime Organization) activity, applies to all commercial international seagoing ships of 500 GT (gross tonnes) and above.
Improving equipment through standardization has been instrumental towards raising safety levels in the maritime environment. Shipping was one of the first industries to adopt international safety standards that are now widely implemented.
The IMO, acknowledging the IEC's expertise, established a formal relationship with it to collaborate in the field of electrical systems for ships. This work was entrusted to IEC TC 18: Electrical installations of ships and of mobile and fixed offshore units, whose origin dates back to 1927. At a meeting in 1986 the TC’s scope was extended to cover electrical installations on board fixed and mobile offshore oil and gas exploration units.
TC 18 prepares standards that chiefly concern factors promoting the safety of ships and of mobile and fixed offshore units and those promoting safety of life, in accordance with the SOLAS convention.
IEC SC 18A develops international standards for electric cables for ships and fixed offshore units.
Self-contained power generation and distribution
Electrical installations on ships and offshore units are indispensable for the operation of machinery, propulsion, navigation and communication equipment, as well as for the auxiliary systems that provide essential services such as lighting, running water, plumbing, refrigeration and food preparation.
Power on ships is supplied by generators mostly driven by the main engines and by auxiliary units.
TC 18 prepares standards to ensure all types of equipment and installations used on board ships and in mobile and fixed offshore installations are designed and built to operate safely and appropriately, a complex task as power and water do not mix.
Previously, the standards gave specific requirements for equipment such as switchboards, rotating electrical machines, transformers and galley (kitchen) equipment. Today, reference is, as far as possible, given to existing equipment standards issued by the TCs connected with relevant products, while only those additional or alternative features required for use in a ship or offshore environment are given in TC 18 standards.
A major project underway within TC 18 aims at reducing the number of standards and at updating others to reflect the fast-changing pace of current marine technology.
TC 18 standards cover all types of equipment and installations used on board ships and in mobile and fixed offshore installations.
IEC 60092, the current series of International Standards for electrical installations in ships, the first edition of which was published in 1957, is referenced in SOLAS.
Bigger, faster ships facing both old and new problems
The current types of ship will continue to exist but will do so in parallel with new, larger and more efficient container and passenger ships. However, in addition to new issues the newer ships still face age-old hazards.
One of these, fire, has always been a major threat to mariners: they have nowhere to escape to and no external aid is available. Today there is a growing understanding not only of the dangers of fire but also of the consequences of the spread of fire and of the risks associated with smoke. For these reasons, special attention is paid to characteristics such as flame retardation capability, fire resistance, smoke emission, toxicity, corrosivity and use of halogen-free materials for both electrical equipment and cables.
The increase in the size of vessels and of the installed electrical load is leading to the introduction of higher voltage systems for power consumers, propulsion and machinery auxiliaries.
The last category includes addressable fire alarm and low-level lighting systems, as well as passenger and crew address systems. Proper operation of on-board computer equipment may be affected by electromagnetic interference resulting from the higher voltage systems being introduced in ships.
Clean up your act
There is general consensus that international shipping needs to become cleaner.
Cutting emissions of sulphur oxide (SOx), nitrogen oxide (NOx) and particulate matter (PM) produced by ships’ generators in ports has become a priority worldwide and has led to the introduction of HVSC (High Voltage Shore Connection) systems. These allow ships to shut down their diesel engines and connect to a land-based grid while they are docked.
TC 18 issued a PAS (publicly available specification) for HVSC systems in 2009, giving requirements for such systems. This PAS was further developed into an International Standard prepared in cooperation with ISO (International Organization for Standardization) and IEEE(Institute of Electrical and Electronics Engineers). IEC/ISO/IEEE 80005-1, Utility connections in port – Part 1: High Voltage Shore Connection (HVSC) Systems – General requirements, was published in July 2012 (see article in this issue).
Electric propulsion offers further prospects for cleaner shipping. In addition to operational solutions such as slow steaming, which can cut fuel consumption and emissions by up to 40%, and design and engineering approaches such as improved hull shape, more efficient engines and even the type of paint used on hulls, the industry is also experiencing a shift towards electric and hybrid propulsion systems. This started in the cruise ship industry and has been made possible primarily due to the development of power electronics.
Hybrid solutions use a combination of diesel engines or gas turbines, generators, batteries and motors to drive the propulsion system; they will require improved and modified standards. A move to variable speed auxiliary drives is also being seen for the same reasons. The standard for electrical propulsion is now being updated and a revised standard is expected in 2013.
The application of fuel cells to marine propulsion is being studied by shipbuilding and marine engine manufacturers. The technology’s viability is already being tested on a 5 900 metric tonne Norwegian offshore supply ship.
Global cooperation relying on IEC standards
Shipping and offshore exploration are such complex and international industries, implementing practices and a variety of systems developed over decades, even centuries, that they involve many national and international bodies and organizations.
IEC standards for electrical installations for ships and mobile and fixed offshore units are implemented worldwide by naval architects, marine engineering design and consulting companies, and all industries involved in the shipbuilding and related sectors.
Rather than opting to develop their own standards, most of the industry's bureaus or registers of shipping, such as the ABS (American Bureau of Shipping), Bureau Veritas, DNV (Det Norske Veritas), Lloyd's Register, the Korean Register of Shipping and the Russian Maritime Register of Shipping, rely on IEC International Standards as their preferred choice.