Using HAZOP/LOPA to Create an Effective Mechanical ... · Risk Management Professionals Using...

Risk Management Professionals

Using HAZOP/LOPA to Create an Effective

Mechanical Integrity Program

Steven T. Maher, PE CSP & David J. ChildsRisk Management Professionals

949/282-0123www.RMPCorp.com

Download Presentation & Handout – www.SEMS1.com/GCPS/2017.htm


Steven T. Maher, PE CSPRisk Management Professionals

• 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. ChildsRisk Management Professionals

• 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. ChildsRisk Management Professionals


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

PSM

EPPSI

PHA

OP

TRN

CON

PSSRMI

HWP

MOC

II

EP&R

CA

• Employee Participation• Process Safety Information• Process Hazard Analysis• Operating Procedures• Training• Contractors• Pre-Startup Safety Review• Mechanical Integrity• Hot Work Permit• Management of Change• Incident Investigation• 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

Risk Management Professionals ©

Examples of Significant EventsTexas 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?

Risk Management ProfessionalsRisk Management Professionals

Hazard Analysis Tool Spectrum

Each of these tools provides a different perspective & different insights. Allows Risk

Quantification & Graphical Scenario

Development

What-If HAZOP

ETA

Risk-Graph FTA

Checklist

FMECA

Less Effort Increased Effort, with Increased Insights

What-If/Checklist

API RP 14CReview

HAZID Bow-tieJSA

CHAZOP

LOPA


Using LOPA to Dig Further


Scenario-Based Analysis Objectives

• RISK = PROBABILITY * CONSEQUENCES– Probability =

Likelihood of Occurrence

– Consequences = Effects of Occurrence

• For Engineered Systems:– Risk = Σ Fi * Ci

Increasing Consequences

Incr

easi

ng F

requ

ency

2

3

4

5

1Acceptable

Unacceptable


Tandem Advances in Protection System Design Architectures & Analysis

Protection System Design Evolution

Reliability Criteria & Design Architecture Specifications

Safety Integrity Levels

.

SIL-1(10-2 ≤ PFDAVG < 10-1)

SIL-2(10-3 ≤ PFDAVG < 10-2)

SIL-3(10-4 ≤ PFDAVG < 10-3)

Voting LogicSingle-ElementAnalog Devices

ElectronicSensing &

Sig. Processing


Control/Protection System Spectrum – BPCS & SIS/HIPS

Redundancy

Diversity

End DeviceFeedback

Loops

Single-ElementAnalog Devices

ElectronicSensing &

Sig. Processing

Decreased Cost Increased Redundancy, Diversity, Pedigree

Separation ofControl &Protection

SmartSensors

High PedigreeDevices

Increasing Reliability & Larger SIL (SIS-Only, ANSI/ISA-S84.01 & IEC-61508/61511)

BPCS = Basic Process Control System, SIS = Safety Instrumented System,HIPS = High Integrity Protection System

Voting Logic


LOPA Snapshot

• Risk Framework– Risk(R) = Σ Fi * Ci

• Scenario Frequency Assessment as Absolute Value– fi

C = fiI * ∏Pij

EC * ∏PFDij * ∏PijCM

• Scenario Frequency Assessment as a Ratio

• Where:– ICL(fi

I) – Initiating Cause Likelihood (Frequency)– PFD – Probability of Failure on Demand– TF – Target Frequency– EC – Enabling Condition– CM – Conditional Modifier

CMiECiPFDPFDPFDICLTF

SafetyRatioLOPA Safety

...)(

321


Pulling It Together


MI Program Elements

Require-ments

ProgramManagement

Procedures

Training

Insp./Test.Maint./Repair

Documentation

Feedback


MI Implementation SpectrumComputerized Maintenance

Management System (CMMS)

ComplexFunctions

ProcessIndustryFocus

Potential Effectiveness Challenges Increased Ability to Achieve Objectives

Memory ofMaint. Mgr.

Multi-IndustryApplication

Self-Standing

SignificantTraining

Requirements

SimpleScheduling

Software

Use of MaintenanceContractor

Key Functions

Web-Based

Intuitive

Memory ofRetiree

Post-It Notes

Written onCalendar


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

EnhancedContemporary

BestPractices

PrioritizedDMR

ApproachiPHA

Less Effort Increased Effort, with Increased Insights

MI-CenteredRisk-BasedAssessment


Select Statistics to Optimize the MI Program


Monitored Repairable Components

Time

Time

A(∞)

Operating State

Failed State

Availability

1.0

0.5


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 high-priority 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 [email protected]

David J. [email protected]



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