Among the many innovative projects to be presented at this year's Emerson Exchange is Denver-based URS Corp.'s partnership with Emerson Process Management and local business partner (LBP) Applied Control Equipment (ACE) to execute a series of turnkey, high-integrity pressure protection systems (HIPPS). The systems are used to isolate and protect gas processing equipment from high pipeline pressures, providing a more elegant and environmentally responsible alternative to the flares and pressure relief valves or rupture disks they replace.
But the engineering, sourcing, integration, testing, and documentation tasks involved in ensuring that a piecemeal HIPPS solution meets the necessary level three safety integrity level (SIL 3) requirements as specified in IEC 61511 and 61508 standards would have been no small undertaking, according to Al Schmidt, supervising I&C engineer for URS, who, together with colleague Richard Marchetti, URS consulting engineer, and Eric Schultz, control system specialist for ACE, will share their project experience with Exchange attendees in session 5-1561 on Tuesday morning at 9:00 a.m. and again Thursday at 1:15 p.m. The work that is subject of their presentation also is a finalist for this year's Plantweb Excellence award.
"Rather than coordinate all these activities, we found that we could write a single specification for the performance of the entire system, and that ACE, working with Emerson Process Management, could deliver a complete turnkey solution," Schmidt says. "This saved us a tremendous amount of time," adds Marchetti. "If we were to engineer this solution we would typically have to go out to three different suppliers to find IEC 61508 components for each discipline—measurement, control, and valves. But through our local business partner, Applied Controls, we were able to write only one purchase order, and not pursue certifications for any components required for the IEC61511 SIL verification report."
The finished HIPPS solution accounts for only 1% of the total DeltaV system I/O count at the facility, including three redundant pressure transmitters, two digital valve controllers, two solenoid valves, and four limit switches—all connected to a DeltaV SIS Smart Logic Solver and managed with Emerson's AMS Suite. But by turning things over to Emerson and ACE, URS reduced its own engineering time by two-thirds and, more importantly, shaved eight weeks off the project schedule and allowed the facility to start up as scheduled. Further, FIELDVUE ValveLink software provides diagnostics for partial stroke testing, allowing URS' customer to extend scheduled plant outages by verifying the availability of the HIPPS during normal plant operations.
"An integrated common platform for the process control system, safety instrumented system, and the HIPPS system provides a common access and interface to all aspects of plant controls, including partial stroke testing and documentation of test results," Schmidt says. "The PlantWeb system does everything in one package."