SafetySIL Emergency Shutdown Block Valve System
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An Introduction to the SafetySIL Fault-tolerant, On-line Full-stroke Testing, Emergency Shutdown Block Valve System
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SafetySIL Emergency Shutdown Block Valve System
- 1. Revolutionizing the way the Process, Production & Pipeline Industries Deal with Safety Critical Systems SafetySafetySILSIL
- 2. SafetySafetySILSIL Revolutionizing the way the Oil Field Industries Deal with Safety Critical Systems WELCOME To the World’s First & Only On-Line, Fault-tolerant, Full-Stroke Testing Emergency Shutdown Block Valve System
- 3. Revolutionizing the way the Oilfield Industries Deal with Safety Critical Systems SafetySafetySILSIL INTRODUCING: THE SafetySafetySILSIL BLOCK VALVE SYSTEM U. S. Patent No. 6,058,956
- 4. Revolutionizing the way the Production Industries Deal with Safety Critical Systems U. S. Patent No. 6,058,956 SafetySafetySILSIL Both Valves Open dP Transmitter at Middle Normal Mode
- 5. Revolutionizing the way the Process Industries Deal with Safety Critical Systems U. S. Patent No. 6,058,956 SafetySafetySILSIL “B” Valve Closed dP Transmitter drawn downBernoulli Effect Pulls Down Dead Leg SIL Test – 1st Half Cycle
- 6. Revolutionizing the way the Production Industries Deal with Safety Critical Systems U. S. Patent No. 6,058,956 SafetySafetySILSIL Both Valves Open dP Transmitter at Middle Transitioning
- 7. Revolutionizing the way the Process Industries Deal with Safety Critical Systems U. S. Patent No. 6,058,956 SafetySafetySILSIL “A” Valve Closed dP Transmitter pulled upBernoulli Effect Pulls Down Dead Leg SIL Test – 2nd Half Cycle
- 8. Revolutionizing the way the Process Industries Deal with Safety Critical Systems U. S. Patent No. 6,058,956 SafetySafetySILSIL Both Valves Open dP Transmitter at Middle Return to Normal Mode
- 9. SafetySafetySILSIL Revolutionizing the way the Oil Field Industries Deal with Safety Critical Systems Applying the SafetySIL Regulatory Oversight Operator’s Risk Strategy Safety Integrity Level (SIL)
- 10. Revolutionizing the way the Process Industries Deal with Safety Critical Systems REQUIRES OPERATORS OF HAZARDOUS PROCESSES TO: • IDENTIFY AND MITIGATE ALL POTENTIALLY DANGEROUS EVENTS • DANGEROUS EVENTS IMPACT SAFETY, HEALTH, AND THE ENVIRONMENT THEY ARE REQUIRED THEN TO EITHER: • REDUCE THE CONSEQUENCES IF THESE EVENTS OCCUR • REDUCE THE PROBABILITY OF THEIR OCCURANCE TO A LEVEL DEEMED “ACCEPTABLE.” SafetySafetySILSIL FEDERAL & STATE REGULATORY OVERSIGHT
- 11. Revolutionizing the way the Process Industries Deal with Safety Critical Systems SafetySafetySILSIL OPERATORS RISK STRATEGY PROCESS HAZARD ANALYSIS (PHA) CONSISTS OF: • STUDYING THE PROCESS • REDUCING THE PROBALILITY OF A DANGEROUS EVENT • REDUCING THE RISK TO THE REQUIRED “ACCEPTABLE” LEVEL • SAFETY INSTRUMENTED SYSTEMS (SIS) ARE INSTALLED TO REDUCE RISK • SIS ARE ASSIGNED A SAFETY INTEGRITY LEVEL (SIL)
- 12. Revolutionizing the way the Process Industries Deal with Safety Critical Systems SafetySafetySILSIL SAFETY INTEGRITY LEVEL (SIL) BASED ON (3) CHARACTERISTICS OF THE PROCESS AND SIS: 1. SHUTDOWN DEMAND RATE 2. PROBABILITY TO FAIL UPON DEMAND (PFD) 3. TESTING FREQUENCY EACH OF THESE FACTORS CAN BE ADDRESSED TO INCREASE THE SIL OF A SIS
- 13. Revolutionizing the way the Process Industries Deal with Safety Critical Systems SafetySafetySILSIL INCREASING SIL ACTIVITIES THAT CAN RESULT IN A HIGHER SIL FOR A SIS: • RE-ENGINEERING PROCESS TO LOWER THE SHUTDOWN DEMAND RATE • INCREASE MEAN TIME BETWEEN FAILURE (MTBF) OF SIS EQUIPMENT • TEST SIS MORE FREQUENTLY
- 14. Revolutionizing the way the Process Industries Deal with Safety Critical Systems SafetySafetySILSIL SIL = Testing Frequency (PFD X Demand Rate) SIL RELATIONSHIP DEFINED TESTING FREQUENCY ↑= SIL ↑ PDF ↓ = SIL ↑ DEMAND RATE ↓= SIL ↑
- 15. Revolutionizing the way the Process Industries Deal with Safety Critical Systems SafetySafetySILSIL FREQUENCY TESTING EFFECTS SIL IN THE FOLLOWING WAYS: • ANY SYSTEM CAN MEET REQUIRED PFD IF IT IS TESTED FREQUENTLY ENOUGH • FREQUENT FUNCTION TESTING CAUSES PROCESS INTERUPTIONS • PROCESS INTERUPTIONS REDUCE PRODUCTION & REVENUE • PARTIAL STROKE TESTING DECREASES INTERUPTIONS, BUT ALSO DIAGNOSTIC COVERAGE
- 16. Revolutionizing the way the Process Industries Deal with Safety Critical Systems SafetySafetySILSIL SIL LEVELS DEFINED RANGES OF (4) LEVELS OF SAFETY INTEGRITY (IEC 61508): •SIL 1 : 0.1 – 0.01 Failures / YR (1% to 10% or RRF 10-100 YRS) •SIL 2 : 0.01 – 0.001 Failures / YR (0.1% to 1% or RRF 100-1,000 YRS) •SIL 3 : 0.001 – 0.0001 Failures / YR (0.01% to 0.1% of RRF 1,000-10,000 YRS) •SIL 4 : 0.0001 – 0.00001 Failures / YR (0.001% to 0.0001% or RRF 10,000-100,000 YRS) (Note: Administrative Procedures/Operator Actions are classed as SIL-1) (Interesting Note: Safety Integrity Level is the same as the number of zeros)
- 17. Revolutionizing the way the Process Industries Deal with Safety Critical Systems SafetySafetySILSIL CONTRIBUTIONS TO SIS FAILURES OF THE FINAL CONTROL ELEMENT (BLOCK VALVE): • MAJORITY OF DANGEROUS FAILURES CAUSED BY THE BLOCK VALVE • MAJORITY OF NUISANCE TRIPS CAUSED BY THE BLOCK VALVE • PRIMARY CHALLENGE IS FREQUENCY TESTING THE BLOCK VALVE • ACHIEVING NEAR 100% DIAGNOSTICS WOULD SHUT DOWN THE PROCESS • TESTING SYSTEMS CAN CAUSE COSTLY SPURIOUS/NUISANCE TRIPS Note: Dangerous Failures are classed under “Probability to Fail on Demand” (PDF), Nuisance (spurious) Trips are classed under “Mean Time To Fail Safe” (MTTFS)
- 18. Revolutionizing the way the Process Industries Deal with Safety Critical Systems SafetySafetySILSIL
- 19. Revolutionizing the way the Process Industries Deal with Safety Critical Systems SafetySafetySILSIL SIS SYSTEM DESIGN WHEN DESIGNING A SIS: • USE EQUIPMENT WITH A LARGE MTBF (DOESN’T FAIL OFTEN) • DESIGN FOR INCREASED TESTING FREQUENCY TO ACHIEVE THE PFD • MOST VULNERABLE PART OF THE SIS IS THE FINAL ELEMENT (THE BLOCK VALVE) LATEST SIS DESIGNS FOR BLOCK VALVES DO NOT SOLVE THE PROBLEM
- 20. Revolutionizing the way the Process Industries Deal with Safety Critical Systems SafetySafetySILSIL SIS BLOCK VALVE DESIGN TWO (2) BLOCK VALVES IN SERIES: • INCREASE SAFETY WITHOUT THE NEED TO TEST MORE FREQUENTLY • UNLIKELY THAT BOTH VALVE’S WILL HAVE FAILED AT THE SAME TIME • DOUBLES THE CHANCE FOR A SPURIOUS/NUISANCE TRIP • SIGNIFICANT POTENTIAL FOR LOST REVENUE, (COULD BE MORE COSTLY THAN OTHER ALTERNATIVES)
- 21. Revolutionizing the way the Process Industries Deal with Safety Critical Systems SafetySafetySILSIL SIS BLOCK VALVE DESIGN PARALLEL BYPASS AROUND THE BLOCK VALVE: • ALLOWS FOR ON-LINE FULL STROKE TESTING • INCREASES DIAGNOSTIC COVERAGE OF EACH TEST • HUMAN ERROR ON BYPASS CREATES POTENTIAL FOR DANGEROUS FAILURE • LIMITED TO SIL 1 RATING (BECAUSE OF THE HUMAN INTERACTION)
- 22. Revolutionizing the way the Process Industries Deal with Safety Critical Systems SafetySafetySILSIL SIS BLOCK VALVE TESTING PARTIAL STROKE TESTING: • BLOCK VALVE IS EXERCISED PARTIALLY CLOSED • TEST PERFORMED WITH MINIMAL PROCESS INTERUPTION • DECREASED DIAGNOSTIC COVERAGE VS. A FULL STROKE TEST • WIDELY ACCEPTED THAT PARTIAL STROKE WILL CATCH 60 – 80% OF FAILURES, BUT WHAT ABOUT THE OTHER 20 – 40%?
- 23. Revolutionizing the way the Process Industries Deal with Safety Critical Systems SafetySafetySILSIL SIS BLOCK VALVE TESTING
- 24. Revolutionizing the way the Process Industries Deal with Safety Critical Systems SafetySafetySILSIL This screen print from a large, international partial stroke testing manufacturer shows their opinion of Partial Stoke Technology!
- 25. Revolutionizing the way the Process Industries Deal with Safety Critical Systems SafetySafetySILSIL SIS BLOCK VALVE TESTING INDUSTRY NEEDS A BLOCK VALVE SYSTEM CAPABLE OF: • ON-LINE TESTING • FULL STROKE TEST • FAULT TOLERANT (NO SPURIOUS/NUISANCE TRIPS, REPAIRABLE ON-LINE) • SIL CAPABLE • NO PROCESS INTERUPTION, REGARDLESS OF THE TESTING FREQUENCY!!!
- 26. Revolutionizing the way the Process Industries Deal with Safety Critical Systems SafetySafetySILSIL
- 27. Revolutionizing the way the Process Industries Deal with Safety Critical Systems THE SafetySafetySILSIL WHY’S: SafetySafetySILSIL
- 28. Revolutionizing the way the Process Industries Deal with Safety Critical Systems SafetySafetySILSIL THE SafetySafetySILSIL WHY’S WHY DOES THE SafetySafetySILSIL INCREASE THE LEVEL OF PROTECTION: • ON-LINE, FULL STROKE TESTING • TESTING AS FREQUENTLY AS REQUIRED TO ACHIEVE ANY SIL, EVEN SIL 4 • NEARLY 100% DIAGNOSTICS, INCLUDING OPERATION OF PLC & I/O MODULES • NO PROCESS INTERUPTION, REGARDLESS OF THE TESTING FREQUENCY!!!
- 29. Revolutionizing the way the Process Industries Deal with Safety Critical Systems SafetySafetySILSIL THE SafetySafetySILSIL WHY’S WHY DOES THE SafetySafetySILSIL DECREASE NUISANCE TRIPS: • FAULT TOLERANT TESTING SYSTEM • TESTING WILL DETERMIME IF THERE IS ANY FAILED PART THAT WILL PREVENT EXPECTED OPERATION • FAILED PART CAN BE REPAIRED ON-LINE WITH NO PROCESS INTERUPTION • SPURIOUS/NUISANCE TRIP WILL NOT INTERUP PROCESS
- 30. Revolutionizing the way the Process Industries Deal with Safety Critical Systems SafetySafetySILSIL THE SafetySafetySILSIL WHY’S WHY DOES THE SafetySafetySILSIL SAVE YOUR OPERATIONS MONEY: • ELIMINATING SPURIOUS/NUISANCE TRIPS • A TYPICAL SPURIOUS TRIP RATE (STR) CAN BE 3 – 4 PER YEAR • PREVENTION OF JUST (1) SPURIOUS TRIP CAN PAY FOR THE SYSTEM • EACH ADDITIONAL SPURIOUS/NUISANCE TRIP PREVENTED IS PURE PROFIT!
- 31. Revolutionizing the way the Process Industries Deal with Safety Critical Systems SafetySafetySILSIL THE SafetySafetySILSIL WHY’S WHY DOES THE SafetySafetySILSIL DECREASE MAINTENANCE COSTS: • BLOCK VALVES CAN BE TESTED WHILE IN OPERATION • NO NEED TO REMOVE A VALVE UNTIL IT FAILS (RUN TO FAIL) • ON-LINE TESTING INSURES THE VALVE’S ARE FUNCTIONING AS EXPECTED • REDUCTION IN MAINTENANCE COSTS ARE PURE PROFIT!
- 32. Revolutionizing the way the Process Industries Deal with Safety Critical Systems SafetySafetySILSIL THE SafetySafetySILSIL WHY’S WHY DOES THE SafetySafetySILSIL DECREASE T-I-Cs: • COSTS UPWARDS OF $30K TO $35K TO MOVE ONE SAFETY FUNCTION FROM SIL-1 TO SIL-2, OR FROM SIL-2 TO SIL 3. (MOVING FROM SIL-1 TO SIL 3 CAN COST UP TO $70K. ONE SafetySafetySILSIL FUNCTION CAN PROVIDE SIL-4 • ELIMINATES NEED FOR MULTIPLE SIL-1 LAYERS OF PROTECTION • CAN USE LESS EXPENSIVE VALVES AND OTHER EQUIPMENT (LOWER MTBFS)
- 33. Revolutionizing the way the Process Industries Deal with Safety Critical Systems SafetySafetySILSIL THE ONLY: ON-LINE FULL STROKE TESTING FAULT TOLERANT SIL CAPABLE BLOCK VALVE SYSTEM THE REVOLUTION IN FAULT TOLERANT TECHNOLOGY!
- 34. Revolutionizing the way the Process, Oilfield & Pipeline Industries Deal with Safety Critical Systems SafetySafetySILSIL SafetySIL, LLC’s PARTNER IN PRODUCTION, FACTORY ACCEPTANCE TESTING AND FIELD SUPPORT FOR • INSTALLATION, • CONFIGURATION • MAINTENANCE • TRAINING
Notas del editor
- UNDER FEDERAL AND STATE REGULATORY OVERSIGHT, ALL OPERATORS OF HAZARDOUS PROCESSES MUST IDENTIFY AND MITIGATE ALL POTENTIALLY DANGEROUS EVENTS WHICH CAN IMPACT SAFETY, HEALTH AND THE ENVIRONMENT. THEY ARE REQUIRED THEN TO EITHER: REDUCE THE CONSEQUENCES IF THESE EVENTS OCCUR OR REDUCE THE PROBABILITY OF THEIR OCCURANCETO A LEVEL DEEMED “ACCEPTABLE.”
- THE PROCESS OF ACCOMPLISHING THIS CONSISTS OF STUDYING THE PROCESS, REVISING IT TO REDUCE THE PROBABLY OF A DANGEROUS EVENT OCCURING, AND THEN DESIGNING A ‘LAST DITCH’ SYSTEM THAT WILL REDUCE THE RISK TO THE REQUIRED ‘ACCEPTABLE’ LEVEL. THIS ‘LAST DITCH’ SAFETY INSTRUMENTED SYSTEM (SIS) WILL HAVE ASSIGNED TO IT A ‘SAFETY INTEGRITY LEVEL’ (SIL) WHICH SIGNIFIES THE LIKELIHOOD THAT THE SYSTEM WILL NOT WORK WHEN IT NEED SO SHUTDOWN THE PROCESS.
- THE SIL RATING IS BASED UPON THREE CHARACTERISTICS OF THE PROCESS AND THE SAFETY INSTRUMENTED SYSTEM: THE SHUTDOWN DEMAND RATE – A STATISTICAL REPRESENTATION OF HOW OFTEN THE PROCESS WILL ENTER A DANGEROUS STATE, THE PROBABILITY TO FAIL UPON DEMAND (PDF) – A NUMBER THAT REPRESENTS OF HOW OFTEN THE SIS WILL HAVE AN UNDETECTED (I.E. UNDIAGNOSED) INTERNAL FAILURE WHICH WILL PREVENT THE SIS FROM SHUTTING DOWN THE PROCESS WHEN IT SHOULD, AND THE TESTING FREQUENCY – THIS IS THE PERIOD BETWEEN THOSE TESTS THAT VERIFY THE SIS IS WORKING CORRECTLY. EACH OF THESE FACTORS CAN BE ADDRESSED TO INCREASE THE SAFETY INTEGRITY LEVEL OF A SAFETY INSTRUMENTED SYSTEM.
- THE FOLLOWING ACTIVITIES CAN RESULT IN A HIGHER SAFETY INTEGRITY LEVEL FOR A SAFETY INSTRUMENTED SYSTEM. THE SHUTDOWN DEMAND RATE CAN LOWERED THROUGH RE-ENGINEERING THE PROCESS, REDUCING THE OPPORTUNITIES FOR THE PROCESS TO ENTER A DANGEROUS STATE. THE LESS TIME THE PROCESS WILL SPEND IN A DANGEROUS STATE, THE LOWER THE DEMAND RATE. THE EQUIPMENT USED IN THE SIS CAN BE SELECTED TO INCREASE THE MEAN-TIME-BETWEEN-FAILURES, OR TO USE EQUIPMENT THAT HAS CERTIFIED INTERNAL DIAGNOSTICS WHICH CAN WARN IF THE DEVICE HAS AN INTERNAL FAILURE THAT WILL PREVENT IT FROM WORKING CORRECTLY. LESS OPPORTUNITY FOR THE SIS EQUIPMENT TO HAVE AN UNDETECTED FAILURE RESULTS IN A HIGHER SAFETY INTEGRITY LEVEL. THE SIS CAN BE TESTED MORE FREQUENTLY. THIS IS A FORM OF DIAGNOSTICS WHICH WILL DETECT EQUIPMENT FAILURES (ALLOWING IT TO BE REPAIRED) OR PROVING THE SYSTEM IS WORKING CORRECTLY.
- Stated Simply, the Safety Integrity Level is equal to the Testing Frequency (in times per year) divided by the Probability to Fail on Demand times the Demand Rate: SIL = Testing Frequency divided by the quantity (PFD X Demand Rate) As the Testing Frequency goes up, the SIL goes up. As the PFD down, the SIL goes up. As the Demand Rate goes down, the SIL goes up.
- Any Safety Instrumented System, using any collection of real-world hardware, will eventually allow a hazardous event to occur, if left too long without being tested, (and repaired if a fault is found). A given PFD, coincidently, includes a time window within which the system can be repaired, without lowering the Safety Integrity Level of the system. All of the above means that a system of actual hardware can only be said to meet a particular PFD if it is tested frequently enough. Said in the opposite way, any system can meet a particular PFD if it is tested frequently enough. But the problem with frequent function testing is with the interruptions they cause to the process, that is, interruptions to making product (i.e., making money).
- There are four ranges or levels of safety integrity that can be assigned to a system according the international standard IEC 61508. A system would have a SIL-1 rating if its predicted failure rate is between 0.1 and 0.01 failures per year. This means that it would probably have a failure once every 10 years to once every 100 years. (This last is sometimes called its Risk Reduction Factor). Note: well organized Administrative or Operational Procedures are limited to a SIL-1. The next Safety Integrity Levels of IEC 61508 is SIL-2: including those systems with between 0.01 and 0.001 failures per year (RRF of 100 to 1000 years). The next is SIL-3: between 0.001 and 0.0001 failures (RRF of 1000 to 10,000 years), and Lastly, is SIL-4: including those SISs with between 0.0001 and 0.00001 failures per year (RRF of 10,000 to 100,000 years).
- Its No Secret… Studies indicate that the majority of dangerous failures in a SIS are caused by the final control element, the block valve. Most of the other components that make up a safety function have on-board diagnostics which perform their testing while the system is functioning, or have some mechanical or procedural means of testing the component while the process is in operation. Not so with the block valve. Typically, if you try to completely close the block valve, you will shut down the process. The following slide shows the contribution of the block valve to the PDF, (and also its contribution to spurious, nuisance trips, designated by the term ‘Mean-Time-Between-Failures-safe or MTBFs).
- What we try to do, then, when designing a SIS for a particular layer of protection, is to use equipment that doesn’t fail very often (that is, has a large MTBF), and/or design the SIS so that it can be tested on-line at whatever testing frequency would be required to achieve the PFD. To summarize, the Probable Demand Rate, the PFD and the testing frequency all combine to form the Safety Integrity Level of the system, or SIL.
- To increase safety, sometimes a plant will install two block valves in series. This will increase safety significantly without having to test more frequently, because it is very unlikely that both valves will have failed at the same time. But the problem with this approach is that if there is a failure in either valve, the process is shut down when conditions don’t require it. This interrupts the process just as much as a full stroke test would have. Not good! Another approach sometimes used is to install a parallel bypass around the block valve, so that it can be tested on-line. However, we know from what was said earlier, the administrative procedure by which the bypass valve is opened, and the automated block valve is tested, only has a maximum SIL rating of 1. This doesn't increase the safety level any more than would an operational procedure to respond to, for instance, a process alarm.
- To increase safety, sometimes a plant will install two block valves in series. This will increase safety significantly without having to test more frequently, because it is very unlikely that both valves will have failed at the same time. But the problem with this approach is that if there is a failure in either valve, the process is shut down when conditions don’t require it. This interrupts the process just as much as a full stroke test would have. Not good! Another approach sometimes used is to install a parallel bypass around the block valve, so that it can be tested on-line. However, we know from what was said earlier, the administrative procedure by which the bypass valve is opened, and the automated block valve is tested, only has a maximum SIL rating of 1. This doesn't increase the safety level any more than would an operational procedure to respond to, for instance, a process alarm.
- Another common and increasingly more popular procedure is that of Partial Stroke testing. A procedure whereby a block valve is exercised from full open to, say 90% open then back to full open. Industry and regulatory powers have decided that this procedure, while not as good as a full stroke test, does offer some additional indication of the likelihood of the device operating as required when conditions demand. You can see in the following slide that the PFD avg on a system that performs a full stroke test once every three years and a partial stroke test every three months is greater than the same system that only initiates a full stroke test once per year. Still, it is widely accepted that Partial Stroke testing will catch 60% to 80% of the failures… But, what about the other 20% to 40%?
- What is needed is an on-line, full-stroke testing, fault tolerant, SIL capable block valve system. This system is the SafetySIL.
- Why does the SafetySIL significantly increase your level of protection against dangerous failures of the final control element? The SafetySIL can be tested on-line, and can be tested as frequently as required to achieve any Safety Integrity Level, SIL-4, or even the undefined SIL-5 (0.00001 to 0.000001). The SafetySIL doesn't only check the valve, it checks the entire Safety Function, from the operation of the valve plugs down in the process, through the correct operation of the valve stems, actuators, limit switches & solenoid valves, through the wiring that connects all of the field equipment to the safety PLC I/O modules, through the correct functioning of the I/O modules themselves, and finally, the correct configuration within the PLC that drives the SafetySIL. Especially since on-line, full-stroke testing can be performed at unheard of frequencies (every 10 hours for instance), your third-party certifier can specify any PFD, the system with the SafetySIL can achieve it. And because the system can be SIL Tested at whatever frequency required to achieve a Target PFD, one layer in a LoPA tree can achieve a RRF of 100,000 (SIL-4) replacing up to 3 protective layers in a single layer. This alone will save 10s of thousands of dollars in achieving a target PFD.
- Why will the SafetySIL significantly decrease the number of nuisance trips caused by a failure in the final control element? The SafetySIL is a fault tolerant system. As such, if a SIL Test detects a fault in any piece of equipment, the failed part can be repaired on-line while the process continues to operate. This includes: · the pipe manifold legs going to each valve (pluggage) · the valve bodies and plugs, · the actuating stems, · the actuators, · the air supply, · the solenoid valve body, · the solenoid valve coil, · the solenoid valve vent port, · the limit switches, the differential pressure transmitter (which would typically have its own internal diagnostics), · the impulse lines from the valve outlets to the differential pressure transmitter, · the ports for the impulse lines, · the terminals within the switch enclosures, · the wire and terminations, · the individual I/O modules (for fault tolerance, there needs to be a unique discrete I/O module for each valve). All of this equipment can be repaired on-line while the process is still operating. And, if the repairs are completed within the allowable repair window, the valve system can be brought back on-line and tested. If it passes the SIL test, the system is without fault and can resume normal operations. No single fault can cause a spurious trip of the process.
- Why does the SafetySIL save your operations much more than it costs? By eliminating nuisance trips. A typical process produces somewhere between $35,000 and $50,000 per hour of product. If a spurious trip occurs, it interrupts that process, and, if the source of the trip is not known, technicians will have to be called to troubleshoot the shutdown systems. The time it takes for the technicians to marshal their resources, find the fault, repair the component, retest the system, and assist operations in getting the process running again, could easily amount to 4 to 12 hours. At the lower amount of time and with the least amount of production, this accounts for the loss of $140,000 worth of production for each spurious trip. A typical Spurious Trip Rate (STR) for a chemical process is between 3 and 4 trips per year. Since a fault in the SafetySIL system does not cause a spurious trip, in fact prevents the spurious trip from occurring, the payback period for a SafetySIL is on the order of 3 months. Said another way, if the SafetySIL prevents just one spurious trip during its entire useful life, it has paid for itself. The rest of the spurious trips that are prevented are pure profit
- Why does SafetySIL significantly decrease your maintenance costs related to your final control elements. Because other block valves cannot be fully tested while they are in operation, these other valves must periodically be taken out of service, broken down, and refurbished to increase the probability they will operate correctly when called upon to shut down the process. Needless to say, many valves are in fact working correctly when they are taken out of service, but the plant management can't take a chance that they might have been defective. The SafetySIL on the other hand, can be run until a valve, or any of the other components, actually fails. Since it is fault tolerant, the failed component can be repaired on-line, without interrupting production. So, instead of refurbishing/repairing a block valve every three years or so “just in case”, you can run the SafetySIL for 5 years, or 7 years, or 10 years, allowing it to go until it fails, and only repairing it when it needs to be repaired, all on-line, while you are still making product. Because of the on-line testing, you can be sure that it will function when it needs to.
- Why does SafetySIL significantly decrease your maintenance costs related to your final control elements. Because other block valves cannot be fully tested while they are in operation, these other valves must periodically be taken out of service, broken down, and refurbished to increase the probability they will operate correctly when called upon to shut down the process. Needless to say, many valves are in fact working correctly when they are taken out of service, but the plant management can't take a chance that they might have been defective. The SafetySIL on the other hand, can be run until a valve, or any of the other components, actually fails. Since it is fault tolerant, the failed component can be repaired on-line, without interrupting production. So, instead of refurbishing/repairing a block valve every three years or so “just in case”, you can run the SafetySIL for 5 years, or 7 years, or 10 years, allowing it to go until it fails, and only repairing it when it needs to be repaired, all on-line, while you are still making product. Because of the on-line testing, you can be sure that it will function when it needs to.
- The ONLY On-line, Full-stroke testing, Fault tolerant, SIL capable Block Valve System The Revolution in Fault Tolerant Technology!
- The ONLY On-line, Full-stroke testing, Fault tolerant, SIL capable Block Valve System The Revolution in Fault Tolerant Technology!