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6 OCTOBER 2016 MATERIALS PERFORMANCE NACE INTERNATIONAL: VOL. 55, NO. 10 UP FRONT —Ben DuBose Microsubmarines Can Help Monitor Subsea Infrastructure Autonomous underwater vehicles (AUVs) called "microsubs" are becoming more pop- ular within the oil and gas industry, accord- ing to BP (London, United Kingdom), which posted a report on its research on using AUVs to record detailed photos and informa- tion about the underwater environment. "We're adapting a microsub to perform environmental surveying that would nor- mally be done at considerable cost using large-scale AUVs or remotely operated vehi- cles," says Joe Little, a technology principal on BP's digital innovation team. The report says these microsubs are only 500-mm long and cost as little as $7,000 each. BP is working with manufacturer Planet Ocean (Camberley, United Kingdom), the Marine Robotics Innovation Centre at the U.K.'s National Oceanography Centre (Southampton, United Kingdom), and the Scottish Association of Marine Science (Oban, United Kingdom) to optimize the micro sub technology before starting the first trial run in the North Sea in December 2016. The company plans to use the microsubs to patrol its subsea infrastructure, such as pipelines, to provide an early warning of any potential problems. If the trials are success- ful, BP plans to roll out a fleet of microsubs for environmental and operational monitor- ing and also crisis response planning. That process could start as soon as 2017. The miniature size of the microsubs could allow BP to explore previously inac- cessible areas such as shallow water, wrecks, and reefs, and they can be used to pinpoint pipeline corrosion or potential leaks. To learn more, visit bp.com. New Standard Published for Corrosion Testing in Oil and Gas Pipelines The British Standards Institution (BSI) (London, United Kingdom), the national U.K. standards body, has published a new stan- dard, BS 8701, for corrosion testing of pipe- lines used by the oil and gas industry. The BS 8701 standard describes a full ring ovaliza- tion test used to determine the susceptibility of line-pipe steels to cracking in sour service. The test method enables the measurement of corrosion and environmentally assisted cracking of pipelines, BSI says. Different factors must be taken into ac- count when testing pipes, including environ- ments, age of pipeline, materials used, coat- ings, and more. The types of corrosion must be accounted for as well, including both sweet corrosion (wet carbon dioxide [CO 2 ]) and sour corrosion (wet hydrogen sulfide [H 2 S]). Both scenarios exist in pipelines. One of the best ways to assess a pipe- line's susceptibility to cracking, BSI says, is by testing a full ring specimen of the line pipe in a sour environment—where a stress level is applied at two regions on the speci- men. Ultrasonic monitoring is then used to define crack initiation and propagation, BSI says, both during and after the specimen's exposure to the sour test solution. Addition- ally, a metallographic study can be devel- oped after the test to help classify any de- fects found by the ultrasonic survey. The new standard updates the 1996 HSE Guidance document OTI 95 635, which fea- tures the protocol for ensuring pipelines are properly tested to avoid environmental damage from pipeline failure. This is refer- enced in ANSI/NACE MR0175/ISO 15156, the flagship document for upstream mate- rial selection for sour service. For more information, visit bsigroup.com. CSB Issues Safety Alert on High-Temperature Hydrogen Attacks The U.S. Chemical Safety Board (CSB) (Washington, DC) issued a safety alert, "Pre- venting High Temperature Hydrogen Attack (HTHA)," that focuses on preventing acci- dents like the 2010 explosion and fire at Tesoro's refinery in Anacortes, Washington, that fatally injured seven workers. The CSB's investigation into the failure of a 40-year-old heat exchanger at the refinery determined that the explosion and fire was caused by the HTHA damage mechanism, which severely cracked and weakened the carbon steel (CS) heat exchanger over time, leading to a rupture. The CSB's safety alert is aimed at preventing accidents like this simulated model demonstration at U.S. refineries and chemical plants. Image courtesy of CSB. The CSB's report, released in May 2014, concluded that the standard used by indus- try to determine the vulnerability of equip- ment to HTHA is inadequate. To address its findings, the CSB made recommendations intended to prevent HTHA to the American Petroleum Institute (API) (Washington, DC), the industry group that issues guidance on HTHA. "The CSB is concerned that the risk of equipment failure due to HTHA may not be fully known or appreciated within the indus- try," says Vanessa Allen Sutherland, chair- person of the CSB. "Our goal is to help in- form and educate industry of potential risk in order to prevent future accidents and to protect workers and the public." The alert provides guidance to industry, including the need to identify all CS equip- ment in H service with the potential to harm workers or communities due to catastrophic failure; to verify actual operating conditions (H partial pressure and temperature) for the identified CS equipment; to replace CS pro- cess equipment that operates above 400 °F (204 °C) and >50 psia (345 kPa) of H partial pressure; and to use inherently safer materi- als, such as steels with higher chromium and molybdenum content. To learn more, visit csb.gov.