Equipment Failure Modes

Documentation for equipment failure mode modeling in NeqSim for reliability and risk analysis.

Table of Contents

• Overview
• EquipmentFailureMode Class
• Failure Types
• Builder Pattern
• Reliability Data Sources
• Usage Examples
• Integration with Risk Analysis
• Related Documentation

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Overview

Location: neqsim.process.equipment.failure

The failure package provides classes for modeling equipment failure modes and their impact on process operations. This enables:

• Reliability analysis
• Risk assessment
• Availability calculations
• Monte Carlo simulation support
• Degraded operation modeling

Class	Description
EquipmentFailureMode	Defines how equipment can fail
ReliabilityDataSource	Source of reliability data (OREDA, etc.)

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EquipmentFailureMode Class

The EquipmentFailureMode class represents a specific way that equipment can fail, including the consequences and recovery characteristics.

Class Hierarchy

Serializable
└── EquipmentFailureMode
    ├── enum: FailureType
    └── static class: Builder

Key Features

• Failure Type Classification: Trip, degraded, partial, full failure
• Capacity Impact: Capacity factor after failure (0.0 to 1.0)
• Efficiency Impact: Efficiency degradation factor
• Recovery Modeling: MTTR, auto-recovery options
• Frequency Data: Failure frequency per year
• Builder Pattern: Fluent API for construction

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Failure Types

FailureType Enumeration

Type	Description	Typical Capacity
TRIP	Equipment stops completely	0.0
DEGRADED	Operates at reduced capacity	0.3 - 0.8
PARTIAL_FAILURE	Some functions lost	0.5 - 0.9
FULL_FAILURE	Equipment non-functional	0.0
MAINTENANCE	Planned shutdown	0.0
BYPASSED	Flow routed around equipment	0.0 (but flow continues)

Failure Type Examples

import neqsim.process.equipment.failure.EquipmentFailureMode;
import neqsim.process.equipment.failure.EquipmentFailureMode.FailureType;

// Complete trip - compressor shutdown
EquipmentFailureMode trip = EquipmentFailureMode.builder()
    .name("Compressor Trip")
    .type(FailureType.TRIP)
    .capacityFactor(0.0)      // No output
    .mttr(24.0)               // 24 hours to repair
    .build();

// Degraded operation - fouled heat exchanger
EquipmentFailureMode fouled = EquipmentFailureMode.builder()
    .name("Heat Exchanger Fouling")
    .type(FailureType.DEGRADED)
    .capacityFactor(0.7)      // 70% capacity
    .efficiencyFactor(0.85)   // 85% of normal efficiency
    .mttr(48.0)               // 48 hours to clean
    .build();

// Partial failure - one of two pumps fails
EquipmentFailureMode partial = EquipmentFailureMode.builder()
    .name("Pump A Failure")
    .type(FailureType.PARTIAL_FAILURE)
    .capacityFactor(0.5)      // 50% capacity (Pump B still running)
    .mttr(12.0)
    .build();

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Builder Pattern

Creating Failure Modes

The EquipmentFailureMode class uses the builder pattern for clear, readable construction:

EquipmentFailureMode failureMode = EquipmentFailureMode.builder()
    .name("Control System Failure")
    .description("Loss of DCS communication to field devices")
    .type(FailureType.TRIP)
    .capacityFactor(0.0)
    .efficiencyFactor(1.0)
    .mttr(4.0)                          // 4 hours MTTR
    .failureFrequency(0.5)              // 0.5 per year
    .requiresImmediateAction(true)
    .autoRecoverable(false)
    .build();

Builder Methods

Method	Description	Default
name(String)	Failure mode name	-
description(String)	Detailed description	””
type(FailureType)	Type of failure	TRIP
capacityFactor(double)	Capacity after failure (0-1)	0.0
efficiencyFactor(double)	Efficiency after failure (0-1)	1.0
mttr(double)	Mean time to repair (hours)	0.0
failureFrequency(double)	Failures per year	0.0
requiresImmediateAction(boolean)	Requires operator action	false
autoRecoverable(boolean)	Can recover automatically	false
autoRecoveryTime(double)	Time to auto-recover (seconds)	0.0

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Reliability Data Sources

ReliabilityDataSource Class

The ReliabilityDataSource class provides access to industry reliability databases:

import neqsim.process.equipment.failure.ReliabilityDataSource;

// Get OREDA data for centrifugal compressor
ReliabilityDataSource oreda = new ReliabilityDataSource("OREDA");

// Standard equipment types and their failure rates
// Centrifugal Compressor: ~2.5 failures/million hours
// Reciprocating Compressor: ~5.0 failures/million hours
// Centrifugal Pump: ~1.5 failures/million hours
// Gas Turbine: ~3.0 failures/million hours

Common Failure Rate Data

Equipment	Failure Rate (per 10⁶ hours)	MTTR (hours)	Source
Centrifugal Compressor	2.0 - 3.5	24 - 72	OREDA
Reciprocating Compressor	4.0 - 6.0	12 - 48	OREDA
Centrifugal Pump	1.0 - 2.0	8 - 24	OREDA
Heat Exchanger	0.5 - 1.5	24 - 168	OREDA
Control Valve	0.5 - 1.0	4 - 12	OREDA
Gas Turbine	2.5 - 4.0	48 - 168	OREDA
PSV	0.1 - 0.3	4 - 8	OREDA

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Usage Examples

Example 1: Compressor with Multiple Failure Modes

import neqsim.process.equipment.compressor.Compressor;
import neqsim.process.equipment.failure.EquipmentFailureMode;
import neqsim.process.equipment.failure.EquipmentFailureMode.FailureType;

// Create compressor
Compressor compressor = new Compressor("Export Compressor", gasStream);
compressor.setOutletPressure(150.0);

// Define failure modes
EquipmentFailureMode sealFailure = EquipmentFailureMode.builder()
    .name("Dry Gas Seal Failure")
    .description("Primary seal degradation requiring shutdown")
    .type(FailureType.TRIP)
    .capacityFactor(0.0)
    .mttr(72.0)  // 3 days to replace seals
    .failureFrequency(0.3)  // 0.3 per year
    .requiresImmediateAction(true)
    .build();

EquipmentFailureMode bearingWear = EquipmentFailureMode.builder()
    .name("Bearing Wear")
    .description("Bearing degradation causing vibration")
    .type(FailureType.DEGRADED)
    .capacityFactor(0.8)  // Can run at 80%
    .mttr(48.0)
    .failureFrequency(0.5)
    .build();

EquipmentFailureMode controlFault = EquipmentFailureMode.builder()
    .name("Control System Fault")
    .description("PLC communication error")
    .type(FailureType.TRIP)
    .capacityFactor(0.0)
    .mttr(4.0)
    .failureFrequency(1.0)
    .autoRecoverable(true)
    .autoRecoveryTime(300.0)  // 5 minutes
    .build();

// Apply failure mode to equipment
// compressor.setFailureMode(sealFailure);

Example 2: Heat Exchanger Degradation

import neqsim.process.equipment.heatexchanger.HeatExchanger;
import neqsim.process.equipment.failure.EquipmentFailureMode;

// Heat exchanger fouling modes
EquipmentFailureMode lightFouling = EquipmentFailureMode.builder()
    .name("Light Fouling")
    .type(FailureType.DEGRADED)
    .capacityFactor(0.9)
    .efficiencyFactor(0.85)
    .mttr(24.0)
    .failureFrequency(2.0)  // Common occurrence
    .build();

EquipmentFailureMode severeFouling = EquipmentFailureMode.builder()
    .name("Severe Fouling")
    .type(FailureType.DEGRADED)
    .capacityFactor(0.6)
    .efficiencyFactor(0.6)
    .mttr(72.0)  // Requires cleaning
    .failureFrequency(0.5)
    .build();

EquipmentFailureMode tubeLeakage = EquipmentFailureMode.builder()
    .name("Tube Leakage")
    .type(FailureType.TRIP)
    .capacityFactor(0.0)
    .mttr(168.0)  // 1 week for tube bundle replacement
    .failureFrequency(0.1)
    .requiresImmediateAction(true)
    .build();

Example 3: Separator Level Control Failure

import neqsim.process.equipment.separator.Separator;
import neqsim.process.equipment.failure.EquipmentFailureMode;

// Level control failures
EquipmentFailureMode levelTransmitterFail = EquipmentFailureMode.builder()
    .name("Level Transmitter Failure")
    .description("LT fails high causing overfill risk")
    .type(FailureType.PARTIAL_FAILURE)
    .capacityFactor(0.7)  // Operate with manual control
    .mttr(8.0)
    .failureFrequency(0.8)
    .requiresImmediateAction(true)
    .build();

EquipmentFailureMode levelValveStuck = EquipmentFailureMode.builder()
    .name("Level Control Valve Stuck")
    .description("LCV stuck in position")
    .type(FailureType.DEGRADED)
    .capacityFactor(0.5)
    .mttr(4.0)
    .failureFrequency(0.3)
    .autoRecoverable(false)
    .build();

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Integration with Risk Analysis

Calculating Equipment Availability

// Calculate availability from failure data
double failureRate = 2.5;  // per million hours
double mttr = 48.0;        // hours

double mttf = 1.0e6 / failureRate;  // Mean time to failure (hours)
double availability = mttf / (mttf + mttr);

System.out.println("MTTF: " + mttf + " hours");
System.out.println("Availability: " + (availability * 100) + "%");
// Output: MTTF: 400000 hours, Availability: 99.99%

Monte Carlo Simulation Integration

import java.util.Random;

// Simple Monte Carlo for production availability
Random random = new Random();
int simulations = 10000;
double totalUptime = 0.0;

double failureRatePerHour = 2.5 / 1.0e6;  // Convert to per hour
double mttrHours = 48.0;
double simulationHours = 8760.0;  // 1 year

for (int i = 0; i < simulations; i++) {
    double uptime = 0.0;
    double currentTime = 0.0;
    
    while (currentTime < simulationHours) {
        // Time to next failure (exponential distribution)
        double ttf = -Math.log(random.nextDouble()) / failureRatePerHour;
        
        if (currentTime + ttf > simulationHours) {
            uptime += simulationHours - currentTime;
            break;
        }
        
        uptime += ttf;
        currentTime += ttf + mttrHours;
    }
    
    totalUptime += uptime / simulationHours;
}

double averageAvailability = totalUptime / simulations;
System.out.println("Monte Carlo Availability: " + (averageAvailability * 100) + "%");

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Common Failure Mode Patterns

Compressor Failure Modes

Failure Mode	Type	Capacity	MTTR	Frequency
Dry gas seal failure	TRIP	0%	72h	0.3/yr
Bearing failure	TRIP	0%	48h	0.2/yr
Anti-surge valve stuck	DEGRADED	70%	8h	0.5/yr
Vibration high	DEGRADED	80%	24h	1.0/yr
Motor/driver failure	TRIP	0%	24h	0.5/yr

Pump Failure Modes

Failure Mode	Type	Capacity	MTTR	Frequency
Seal leakage	TRIP	0%	12h	0.8/yr
Impeller wear	DEGRADED	85%	24h	0.5/yr
Bearing failure	TRIP	0%	16h	0.3/yr
Cavitation damage	DEGRADED	70%	48h	0.2/yr

Separator Failure Modes

Failure Mode	Type	Capacity	MTTR	Frequency
Level control failure	DEGRADED	70%	4h	1.0/yr
Pressure control failure	DEGRADED	80%	4h	0.5/yr
Internals damage	TRIP	0%	168h	0.1/yr
Instrument failure	PARTIAL	90%	8h	2.0/yr

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Related Documentation

• Risk Simulation - Risk analysis framework
• SIS Integration - Safety system verification
• Process Equipment - Equipment overview
• Capacity Constraints - Operational limits

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API Reference

EquipmentFailureMode

// Builder creation
static Builder builder()

// Getters
String getName()
String getDescription()
FailureType getType()
double getCapacityFactor()
double getEfficiencyFactor()
double getMttr()
double getFailureFrequency()
boolean isRequiresImmediateAction()
boolean isAutoRecoverable()
double getAutoRecoveryTime()

FailureType Enum

enum FailureType {
    TRIP,
    DEGRADED,
    PARTIAL_FAILURE,
    FULL_FAILURE,
    MAINTENANCE,
    BYPASSED
}