It’s not surprising that safety is a top priority for plant managers and operators, but minimizing risk in these environments is no simple task. Safety Instrumented Systems (SIS) are failsafes built into critical processes to maintain maximum operational integrity. These systems consist of independent sensors and control equipment in series in order to detect abnormal operating conditions. Should an issue arise, the SIS loop interrupts the process’s regular system and puts it into a safe state.
Each part of a SIS loop must be maintained and tested to ensure safety integrity levels (SILs) are met and sustained over time. All SIS loop control functions, known as safety instrumented functions (SIFs), have to meet a minimum SIL requirement as laid out in the IEC safety standards. Compliance with these safety standards means regularly checking equipment, performing necessary maintenance, and replacing instruments as needed.
Proof-testing is a crucial component of this safety lifecycle management. Essentially, proof-testing is testing your SIS equipment at regular intervals to ensure that everything is working correctly and ready to engage in the event of an emergency. Emerson’s built-in proof-testing functionality in our SIS loop devices makes performing this important task quicker and easier, saving our customers many hours of labor, reducing the need to interfere with daily operations, and minimizing risks to personnel.
Remote Proof-Testing: Partial Proof-Tests to Maintain SILs
Before remote proof-testing was possible, proof-testing was much more complicated and riskier for operators. Every test had to be comprehensive and involved workers physically entering the process environment, removing the instruments from the process (possibly causing shutdowns), and bringing them to a workshop for testing. Today, remote proof-testing means that operators can activate a proof-test from the safety of the control room and perform these tests as often as needed.
These remote tests are considered partial proof-tests because they cannot assess the full spectrum of functional elements that a comprehensive test includes, but they provide a strong complement to them. Utilizing this approach allows plants to maintain SILs and keep the probability of failure on demand (PFD) in check while significantly reducing the need for full-scale, in-person procedures.
What This Means for Your Safety Lifecycle Management
Digital and automation technology has made modern plants less hazardous and more streamlined than ever before. With the ability to perform partial proof-testing remotely, the time between required comprehensive proof-tests is considerably extended. These partial proof-tests bring the instrument’s PFD back to a percentage of the original level and maintain the instrument’s SIL. This cost-effective improvement to SIS loop operations has resulted in significant savings for our customers.
Emerson Proof-Testing Estimator
As your partner in operational improvement, Emerson is always seeking ways to make your process smoother, safer, and more efficient. Our cutting-edge proof-testing solutions help eliminate some of the complexity of proof-testing and make it easier for operators to manage the safety lifecycle.
In this spirit, we’ve built an online Proof-Testing Estimator tool to help you explore all your options for optimizing your safety loop via proof-testing devices. Its simple interface allows you to compare Emerson products with other manufacturers’ proof-testing products to find the best proof-testing interval to meet your needs. A direct device to device comparison is especially useful to see how undetected failures relate to proof-test intervals and proof-test coverage.
Learn more about our innovative proof-testing technology at the On-line Proof-testing Estimator Tool https://tools.rosemount.com/proof-test-estimator.
Or, visit our proof-testing expertise page for more in-depth information on how these modern capabilities can improve your process at www.Emerson.com/proof-testing.