create an effective mechanical integrity · pdf filecreate an effective mechanical integrity...

Steven T. Maher, PE CSPDavid J. Childs

1Risk Management Professionals – www.RMPCorp.com

29 March 2017

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 Risk Management Professionals

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

• QuestionsRisk Management Professionals

MI Defined

Saratoga News Photo



29 March 2017

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

EP

PSI

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



29 March 2017

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-GraphFTA

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

Fre

qu

ency

2

3

4

5

1

Acceptable

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



29 March 2017


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

– fiC = fi

I * ∏PijEC * ∏PFDij * ∏Pij

CM

• 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

CMiECiPFDPFDPFDICL

TFSafetyRatioLOPA 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



29 March 2017


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 (τ) = Time Between Tests

• Mean Time of Unavailability =

∗ λ ∗ λτ2

2

• Q =



29 March 2017


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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