Using HAZOP/LOPA to Create an Effective Mechanical Integrity Program Steven T. Maher, PE CSP & David J. Childs 949/282-0123 www.rmpcorp.com Download Presentation & Handout www.sems1.com/gcps/2017.htm
Steven T. Maher, PE CSP 37-Year Engineer 33 in Process Safety Consulting Specializing in Hazard Analysis and QRA Mechanical Engineering BS Duke University MS Carnegie-Mellon University Professional Engineer Mechanical & Chemical Engineering CCPS Technical Steering Committee mid-1980s Past-President Southern CA Society for Risk Analysis Landmark Efforts Platform Safety Shutdown System Effectiveness Study Torrance Refinery Safety Advisor for MHF Conversion Paper & Book Publications See www.rmpcorp.com
David J. Childs Mechanical Engineering BS University of California Santa Barbara HAZOP/LOPA experience within multiple industries Supported development of effective Mechanical Integrity programs Paper & Webinars See www.rmpcorp.com
Using HAZOP/LOPA to Create an Effective Mechanical Integrity Program Steven T. Maher, PE CSP & David J. Childs 949/282-0123 www.rmpcorp.com Download Presentation & Handout www.sems1.com/gcps/2017.htm
Key Topics MI Defined Significant Events Involving MI Faliure Why do a PHA? Using LOPA to Dig Further Pulling It Together Complementary Methodologies Select Statistics to Optimize the MI Program Summary Questions
MI Defined Saratoga News Photo
Evolution of SMS Guidelines & Regulations to Performance (Goal) Based Standards Onshore Process Safety (USA) Offshore Safety Management Systems (USA) Offshore Safety Management Systems (UK)
PSM Elements Employee Participation EP Process Safety Information CA PSI Process Hazard Analysis EP&R PHA Operating Procedures Training II PSM OP Contractors Pre-Startup Safety Review Mechanical Integrity MOC TRN Hot Work Permit Management of Change HWP CON Incident Investigation MI PSSR Emergency Planning & Response Compliance Audits (CA-IIPP)
What is MI? Key Premise (from CMA Process Safety Code of Management Practices) Process equipment that is properly designed, fabricated, installed and operated should provide reliable service if it is adequately inspected, tested and maintained over the life of the facility. MI Definition Maintaining the design function of structures and equipment MI is required by SEMS, RMP, PSM, & State ARP. A less-rigorous requirement for simpler RMP and State ARP Programs is called Preventive Maintenance (PM).
What is MI? Preventive Maintenance is a key component of Mechanical Integrity also Inspection, Testing, & Repair. MI can apply to any type of the device or structure; however, for regulated facilities; MI may apply to: Tanks, Pressure Vessels, and Piping BOP and Pressure Relief Systems Emergency Shutdown Systems Rotating Equipment Controls (including monitoring devices & sensors, alarms, & interlocks) (e.g., Gas Detector function & calibration) Any Device That Might be Listed as a Safeguard in a Hazards Analysis MI can be used for reliability; however, the focus of PSM, RMP, & SEMS is safety & environmental.
Significant Events Involving Mechanical Integrity Failure
Examples of Significant Events Flixborough - 1974 Cyclohexane vapor cloud generated Cracked reactor vessel Temporary bypass fabricated in plant Bypass failed Significant explosion 28 fatalities & 36 injuries June 2004 CCPS Process Safety Beacon
Examples of Significant Events Texas City - 2005 During startup of ISOM Unit, overflow of Distillation Tower and Blowdown Drum Valve left closed on liquid to drain from bottom of tower (procedural step omitted) Failure of high and high-high liquid level alarm No documented test methods Level transmitter indicated that liquid level was falling at ~9 feet (actual level 158 feet) Overflow of flammables ignited by idling truck resulting in 15 deaths and 180 injuries Siting Issues September 2004 CCPS Process Safety Beacon September 2009 CCPS Process Safety Beacon
Why do a PHA?
Hazard Analysis Tool Spectrum Checklist Each of these tools provides a different perspective & different insights. Allows Risk Quantification & Graphical Scenario Development HAZID JSA LOPA Bow-tie What-If/ Checklist API RP 14C Review CHAZOP ETA What-If FMECA HAZOP Risk-Graph FTA Less Effort Increased Effort, with Increased Insights
Using LOPA to Dig Further
Scenario-Based Analysis Objectives Increasing Frequency 3 5 2 1 Acceptable Unacceptable 4 RISK = PROBABILITY * CONSEQUENCES Probability = Likelihood of Occurrence Consequences = Effects of Occurrence For Engineered Systems: Risk = Σ F i * C i Increasing Consequences
Tandem Advances in Protection System Design Architectures & Analysis. Single-Element Analog Devices Electronic Sensing & Sig. Processing Voting Logic Protection System Design Evolution Reliability Criteria & Design Architecture Specifications SIL-1 (10-2 PFD AVG < 10-1 ) SIL-2 (10-3 PFD AVG < 10-2 ) SIL-3 (10-4 PFD AVG < 10-3 ) Safety Integrity Levels
Control/Protection System Spectrum BPCS & SIS/HIPS Increasing Reliability & Larger SIL (SIS-Only, ANSI/ISA-S84.01 & IEC-61508/61511) Smart Sensors Redundancy Voting Logic Electronic Sensing & Sig. Processing Diversity Single-Element Analog Devices Separation of Control & Protection High Pedigree Devices End Device Feedback Loops Decreased Cost Increased Redundancy, Diversity, Pedigree BPCS = Basic Process Control System, SIS = Safety Instrumented System, HIPS = High Integrity Protection System
LOPA Snapshot Risk Framework Risk(R) = Σ F i * C i Scenario Frequency Assessment as Absolute Value f ic = f ii * P ij EC * PFD ij * P ij CM Scenario Frequency Assessment as a Ratio Where: LOPA Ratio ( Safety) ICL(f ii ) Initiating Cause Likelihood (Frequency) PFD Probability of Failure on Demand TF Target Frequency EC Enabling Condition CM Conditional Modifier ICL PFD 1 TF PFD 2 Safety PFD3... ECi CMi
Pulling It Together
MI Program Elements Feedback Requirements Documentation Program Management Insp./Test. Maint./Repair Procedures Training
MI Implementation Spectrum Computerized Maintenance Management System (CMMS) Memory of Maint. Mgr. Multi-Industry Application Process Industry Focus Memory of Retiree Complex Functions Key Functions Post-It Notes Use of Maintenance Contractor Self-Standing Web-Based Written on Calendar Simple Scheduling Software Significant Training Requirements Intuitive Potential Effectiveness Challenges Increased Ability to Achieve Objectives
Complementary Methodologies
Complementary Methodologies API RP 581 Pressure Vessels and Piping Atmospheric Storage Tank Pressure Relief Devices Heat Exchanger Tube Bundles Effective Use of Standardized Maintenance Schedules
DMR Implementation Spectrum Enhanced Contemporary Best Practices Prioritized DMR Approach ipha MI-Centered Risk-Based Assessment Less Effort Increased Effort, with Increased Insights
Select Statistics to Optimize the MI Program
Monitored Repairable Components Operating State Failed State Availability 1.0 Time A( ) 0.5 Time
Monitored Repairable Components A( ) = Q( ) = A( ) + Q( ) = 1 Example For λ = 1E-6/hr, MTTR = 10 hr Q = 1E-5
Unmonitored Repairable Components Component Unavailability = Mean Time of Interest ( ) = Time Between Tests Mean Time of Unavailability = 2 Q =
Dynamics of Plant MI Issues Can Materialize Variance of inspection/testing intervals Variance of inspection/testing methods Impact of maintenance outage time on equipment reliability Repair prioritization and allowable outage time Feedback of reliability observations back into the MI Program Optimize MI Implementation By Understanding Statistics Concepts
Summary
PHA/MI Complementary Elements Using HAZOP/LOPA to Enhance the Effectiveness of the MI Program Ensuring that high-priority equipment gets the attention needed Optimizing inspection, testing, and preventive maintenance frequencies Identification of low-priority equipment, so that Plant Maintenance Department can focus on highpriority equipment Identification of over-application of SIS, where a BPCS component can provide adequate reliability with much lower recurring MI costs
Questions? Steven T. Maher, PE CSP Steve.Maher@RMPCorp.com David J. Childs David.Childs@RMPCorp.com 877/532-0806 www.rmpcorp.com