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February 2014 Issue

IEEE Oceanic Engineering Society Standards Initiative
Kenneth G. Foote

Uses of technology in everyday life are largely underpinned by standards designed to ensure safety and security. This is certainly true of ocean engineering and oceanography. Working at sea is unavoidably costly and often hazardous. Safety and security are uppermost in the minds of those responsible for the lives of seafarers. At the same time, making good measurements is uppermost in the minds of oceanographers. The contribution of standards to these activities is vital.

At issue with respect to standards in ocean engineering and oceanography is the diversity of publication forums. These span official standards documents from international and national standards organizations, articles or papers in refereed journals and conference proceedings, and technical reports published by research institutions and manufacturers. Each has a relevance and period of applicability, but what, when, and where?

The IEEE Oceanic Engineering Society (OES) is attempting to compile and disseminate information on current standards, protocols, quality assurance procedures, and best practices in ocean engineering and oceanography through its website, www.oceanicengineering.org, under Technical Activities: OES Standards Initiative. Three items are registered to date.

The first is the equation of the state of seawater. Interest in the properties of seawater is ubiquitous in ocean engineering and oceanography. Density, sound speed, specific heat capacity at constant pressure and freezing-point temperature are examples of thermodynamic properties of seawater and ice of broad interest in engineering and science. These are now derivable from algorithms in “The international thermodynamic equation of seawater–2010: Calculation and use of thermodynamic properties,” commonly referred to as “TEOS-10.” This joint publication by the Intergovernmental Oceanographic Commission, Scientific Committee on Oceanic Research, and the International Association for the Physical Sciences of the Oceans supersedes the well-known “Algorithms for computation of fundamental properties of seawater,” which was published by UNESCO in 1983. TEOS-10 is available for free download through a link on the OES website.

The second registered item is offshore oil and gas industry standards. The offshore industry depends on so many standards that the International Association of Oil & Gas Producers has published a “Catalogue of international standards used in the petroleum and natural gas industries” in its Report no. 362 (February 2012). This lists many standards prepared for the industry by the International Organization for Standardization (ISO) and by the International Electrotechnical Commission (IEC).

Some ISO Technical Committees (TCs) involved in the writing of these standards include TC8 Ships & marine technology; TC12 Quantities, units, symbols, conversion factors; TC43 Acoustics; TC67 Materials, equipment & offshore structures for petroleum & natural gas industries; TC69 Applications of statistical methods; TC147 Water quality; TC156 Corrosion of metals and alloys; and TC164 Mechanical testing of metals, among others. Joint ISO-IEC standards are also included in the more than 2,000 standards listed in the catalog, which is available free of charge through a link given on the OES website.

The third registered item is active sonar calibration standards. Measurements for both quantification and imaging require calibration of the measuring device, sensor, or instrument. Calibration is the process through which the performance of sonar is measured, enabling monitoring over time. It also enables echo measurements, for example, to be expressed in absolute physical units of backscattering, allowing measurements to be compared or combined over time and across frequency, as in the acoustic characterization of an unknown target or its environment, for example, seafloor.

Another potential application is in the detection of seafloor change over time based on comparison of absolute measurements of backscatter in addition to comparison of highly processed images, which represents current practice. The standard-target method of sonar calibration is described on the OES website for its wide applicability to sonar and their coupled transducers or transducer arrays as configured for operational use.

The method is highly accurate, achieving or aspiring to achieve an accuracy of ±0.1 decibels with respect to the overall two-way transfer characteristic or function.

It is also rapid and cost-effective. Its total span in frequency using robust solid elastic spheres as standard targets is demonstrably 1 kilohertz to 1 megahertz.

On the OES website, the “American National Standard: Procedures for calibration of underwater electroacoustic transducers” (2012) is cited. A link to a free practical guide to the standard-target sonar-calibration method is given on the site. Other references are cited for use of the method for calibrating multibeam sonars, acoustic backscatter systems, and the kilohertz difference-frequency band of a parametric sonar.

The three items described here are examples of standards widely used in ocean engineering and oceanography. There are many other widely used standards waiting to be described and cited on the OES website. Progress has already benefitted from community input.

The continued engagement of the community in calling attention to current standards, protocols, quality assurance procedures and best practices for citation on the OES website is welcomed.

Dr. Kenneth G. Foote is a senior scientist at the Woods Hole Oceanographic Institution and IEEE Oceanic Engineering Society vice president for technical activities. His principal interests include acoustic scattering, marine resource quantification and sonar performance evaluation. In developing and transitioning acoustic scattering methods to operations at sea, he has worked from 77° North to 55° South.


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