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Valve Techbook 2017

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8 | September 2017 | VALVE TECHBOOK: TECHNOLOGY continued evolution of standards designed to address safety including the International Electro- technical Commission (IEC) standards 61508 and 61511 along with International Standards Associ- ation (ISA) Standard 84.01. Recently a new revision of IEC 61511 was released. "As the standards come out and get applied, we see good things that come out of it; however, we also see areas where we might be able to improve those standards down the road," Statham added. Current standards don't adequately address the integration of individual components in an SSDS. For example in an emergency shutdown (ESD) sys- tem, you typically have a valve from one manufac- turer, an actuator from another manufacturer and controls from a third manufacturer. "Most customers rely on best practices to guide the integration but everyone seems to be doing something different, communication in this field is also a challenge, and we often don't have the same taxonomy for that matter," he said. For the upstream sector, Emerson is talking about high-integrity, pressure-protection systems (HIPPS) and ESD valves. "These two SIS subsystems are being applied in both drilling and production. HIPPS systems are applied in some overpressure cases where high pressure systems will potentially need to be brought to a safe state if there is an upset condition," Statham explained. The SIS is comprised of sensors, logic solvers and final elements. The sensors measure temperature, pressure and flow, and act as initiators sending a signal through the logic solver. The logic solver then sends a signal to the automated valve package to open or close the valve. Companies like Emerson now manufacture all of these components. "There is potential for improvements to these systems as we begin to look at them more holistically and not as individual parts," he emphasized. The automated valve also referred to as the final element often contributes the greatest portion of probability of failure on demand, and it's where the majority of failures occur. "This is largely due to the fact that the valve is a mechanical device and not instrumentation; it's in contact with the media and typically sitting static for long periods of time. The media can degradate the operational capability of the valve in many ways," he continued. "It's critical that these valves be tested to ensure they can be counted on to work when we need them, and a full stroke test is not always possible due to process demands. Some of the more recent advancements we've made are in the area of partial stroke testing. Utilizing the Fisher Digital Valve Controller enables our customers to partially stroke a valve 5% to 10% to verify the valve moves, and the actuator and solenoid are working, etc. This test does not shut the process down while still allowing a test to ensure the system is functional," Statham said. Another strong focus in the industry in general is the Internet of Things (IoT). "IoT offers new capabilities such as redun- dant monitoring of SSDS as well as remote diagnostics monitoring capabilities. The ability to perform partial and full-stroke testing on valves on an offshore platform via the internet and get all the diagnostic feed backremotely are areas where we're going to see more development in the future," Statham added. In-riser 20,000-psi, HP/HT shear-seal valve A new HP/HT in-riser shear and seal valve has been designed by Interventek Subsea Engineering. The "Safety shutdown systems continue to be a significant area of focus." —Shawn Statham, Emerson Automation Solutions Emerson has provided four HIPPS top-entry API 15000 FCT valves with Biffi actuators for an offshore platform in the North Sea. (Photo courtesy of Emerson Automation Solutions)

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