Api580 a my self study notes

中国固有领土: 钓鱼岛

Risk-Based InspectionDownstream SegmentAPI RECOMMENDED PRACTICE 580SECOND EDITION, NOVEMBER 2009基于风险的检验-下游段

2014年内部培训

Facilitators:Charlie Chong/ Fion Zhang/

中国固有领土: 钓鱼岛

基于风险的检验-下游段

查理/菲帆

Charlie Chong/ Fion ZhangAPI 580

RBI 基于风险的检验风险评估和管理过程.这些风险主要通过设备检查管理,专注于

加压设备因材料变质导致溶液流失.

什么是基于风险检验 RBI?好的设备 → 使用环境导致损伤机理的启动 → 时间(非时间敏感-情况)导致损伤恶化 → 失效模式 → 故障情景 (一个或多个)前面三个能量化(失效概率), 后面两个个也能量化(故障结果)把失效概率与故障结果严峻性组合 → 风险 (风险 = 故障结果 x 失效概率)

RBI 终目标是什么? → 降低风险到可接受水平

如何降低风险? → 缓解活动

检验不能直接影响失效概率与故障结果, 如何在这里带来作用?

检验能提供失效概率需要的正确数据,减少不确定性, 从而减少设备风险!

Foreword

Foreword 诸言

This recommended practice (RP) is intended to provide guidance on developing a risk-based inspection (RBI) program for fixed equipment and piping in the hydrocarbon and chemical process industries. It includes:

— what is RBI, 什么是.RBI.— what are the key elements of RBI,什么是 RBI关键要素.— how to implement an RBI program,如何实现 RBI.— how to sustain an RBI program.如何维持 RBI.

It is based on the knowledge and experience of engineers, inspectors, risk analysts, and other personnel in the hydrocarbon and chemical industry.

This RP is intended to supplement API 510, API 570, and API 653. These API inspection codes and standards allow an owner/user latitude to plan an inspection strategy and increase or decrease the code designated inspection frequencies and activities based on the results of an RBI assessment. The assessment must systematically evaluate both the probability of failure (POF) and the associated consequence of failure (COF). The POF assessment should be evaluated by considering all credible damage mechanisms. Refer to the appropriate code for other RBI assessment requirements. This RP is intended to serve as a guide for users in properly performing such an RBI assessment.

API 580旨在补充 API 510, API 570, and API 653;宽容度来规划的检查策略, 允许业主/用户增加或减少规范指定的检验频率和活动

Contents

1 Purpose 1.1 General 1.2 RBI Benefits and Limitations 1.3 Using RBI as a Continuous Improvement Tool 1.4 RBI as an Integrated Management Tool

2 Scope 2.1 Industry Scope 2.2 Flexibility in Application 2.3 Mechanical Integrity Focused 2.4 Equipment Covered 2.5 Equipment Not Covered 2.6 Target Audience

3 Normative References 4 Terms, Definitions, Acronyms, and Abbreviations

4.1 Terms and Definitions 4.2 Acronyms and Abbreviations

5 Basic Risk Assessment Concepts 5.1 What is Risk? 5.2 Risk Management and Risk Reduction 5.3 The Evolution of Inspection Intervals/Due Dates 5.4 Overview of Risk Analysis 5.5 Inspection Optimization 5.6 Relative Risk vs Absolute Risk

6 Introduction to Risk-Based Inspection 6.1 Key Elements of an RBI Program 6.2 Consequence and Probability for RBI 6.3 Types of RBI Assessment 6.4 Precision vs Accuracy 6.5 Understanding How RBI Can Help to Manage Operating Risks 6.6 Management of Risks 6.7 Relationship Between RBI and Other Risk-Based and Safety Initiatives 6.8 Relationship with Jurisdictional Requirements

7 Planning the RBI Assessment 7.1 Getting Started 7.2 Establishing Objectives and Goals of an RBI Assessment 7.3 Initial Screening 7.4 Establish Operating Boundaries 7.5 Selecting a Type of RBI Assessment 7.6 Estimating Resources and Time Required

8 Data and Information Collection for RBI Assessment 8.1 General 8.2 RBI Data Needs 8.3 Data Quality 8.4 Codes and Standards—National and International 8.5 Sources of Site Specific Data and Information

9 Damage Mechanisms and Failure Modes 9.1 Introduction 9.2 Damage Mechanisms 9.3 Failure Modes 9.4 Accumulated Damage 9.5 Tabulating Results

10 Assessing Probability of Failure 10.1 Introduction to Probability Analysis 10.2 Units of Measure in the POF Analysis 10.3 Types of Probability Analysis 10.4 Determination of POF

11 Assessing Consequences of Failure 11.1 Introduction to Consequence Analysis 11.2 Types of Consequence Analysis 11.3 Units of Measure in Consequence Analysis 11.4 Volume of Fluid Released 11.5 Consequence Effect Categories 11.6 Determination of Consequence of Failure

12 Risk Determination, Assessment, and Management 12.1 Purpose 12.2 Determination of Risk 12.3 Risk Management Decisions and Acceptable Levels of Risk 12.4 Sensitivity Analysis 12.5 Assumptions 12.6 Risk Presentation 12.7 Establishing Acceptable Risk Thresholds 12.8 Risk Management

13 Risk Management with Inspection Activities 13.1 Managing Risk by Reducing Uncertainty Through Inspection 13.2 Identifying Risk Management Opportunities from RBI Results 13.3 Establishing an Inspection Strategy Based on Risk Assessment 13.4 Managing Risk with Inspection Activities 13.5 Managing Inspection Costs with RBI 13.6 Assessing Inspection Results and Determining Corrective Action 13.7 Achieving Lowest Life Cycle Costs with RBI

14 Other Risk Mitigation Activities 14.1 General 14.2 Equipment Replacement and Repair 14.3 Evaluating Flaws for Fitness-For-Service 14.4 Equipment Modification, Redesign, and Rerating 14.5 Emergency Isolation 14.6 Emergency Depressurizing/Deinventorying14.7 Modify Process 14.8 Establish Integrity Operating Windows 14.9 Reduce Inventory 14.10 Water Spray/Deluge 14.11 Water Curtain 14.12 Blast-resistant Construction 14.13 Others

15 Reassessment and Updating RBI Assessments 15.1 RBI Reassessments 15.2 Why Conduct an RBI Reassessment? 15.3 When to Conduct an RBI Reassessment

16 Roles, Responsibilities, Training, and Qualifications 16.1 Team Approach 16.2 Team Members, Roles, and Responsibilities 16.3 Training and Qualifications for RBI Application

17 RBI Documentation and Recordkeeping 17.1 General 17.2 RBI Methodology 17.3 RBI Personnel 17.4 Time Frame 17.5 Basis for the Assignment of Risk 17.6 Assumptions Made to Assess Risk 17.7 Risk Assessment Results 17.8 Mitigation and Follow-up 17.9 Applicable Codes, Standards, and Government Regulations

18 Summary of RBI Pitfalls 18.1 General 18.2 Planning 18.3 Data and Information Collection 18.4 Damage Mechanisms and Failure Modes 18.5 Assessing POF 18.6 Assessing Consequence of Failure 18.7 Risk Determination, Assessment, and Management 18.8 Risk Management with Inspection Activities 18.9 Other Risk Management Activities 18.10 Reassessment and Updating RBI Assessment 18.11 Roles, Responsibilities, Training, and Qualifications for RBI Team Members 18.12 RBI Documentation and Recordkeeping

Figures1 Management of Risk Using RBI.2 Risk Plot. 3 Continuum of RBI Approaches. 4 Risk-Based Inspection Planning Process. 5 Determination of Consequence of Failure. 6 Example of Calculating the Probability of a Specific Consequence. 7 Example Risk Matrix Using Probability and Consequence Categories to Display Risk Rankings. 8 Risk Plot when Using Quantitative or Numeric Risk Values.

Tables1 Three Levels of POF. 2 Six Levels of POF. 3 Six Level Table. 4 Three Level Safety, Health, and Environmental Consequence Categories. 5 Six Level Safety, Health, and Environmental Consequence Categories.


Introduction

This recommended practice (RP) provides information on using risk analysis to develop an effective inspection plan. The output of the inspection planning process conducted according to these guidelines should be an inspection plan for each equipment item analyzed that includes:

a) inspection methods that should be used,b) extent of inspection (percent of total

area to be examined or specific locations),

c) inspection interval or next inspection date (timing),

d) other risk mitigation activities,e) the residual level of risk after inspection

and other mitigation actions have been implemented.

Introduction

API 580利用风险分析,以制定有效的检查计划. 检查计划过程的输出应该是一个对每个被分析设备的详细检验计划, 其内容包括

a) 检查方法,b) 检查的范围(总面积的百分比或位置), c) 检查间隔或下一个检验日期(时间),d) 其他风险缓解活动,e) 检查与其他已经实施减排措施后的风险残

留量

RBI is synonymous 同义 with risk-prioritized inspection, risk-informed inspection and with inspection planning using risk

based methods.

1 Purpose目的.

Contents

1 Purpose 1.1 General 1.2 RBI Benefits and Limitations 1.3 Using RBI as a Continuous Improvement Tool 1.4 RBI as an Integrated Management Tool

1.1 General

The purpose of this document is to provide users with the basic elements for developing, implementing, and maintaining a risk-based inspection (RBI) program. It provides guidance to owners, operators, and designers of pressure-containing equipment for developing and implementing an inspection program. These guidelines include means for assessing an inspection program and its plan. The approach emphasizes safe and reliable operation through risk-prioritized inspection. A spectrum of complementary risk analysis approaches (qualitative through fully quantitative) can be considered as part of the inspection planning process. RBI guideline issues covered include an introduction to the concepts and principles of RBI for risk management; and individual sections that describe the steps in applying these principles within the framework of the RBI process include:

It provides guidance to (1) owners, (2) operators, and (3) designers of pressure-containing equipment for developing and implementing an inspection program.

guidance to ≠ Inspector ≠ Process Specialist≠ Corrosion & Material Specialist.

Principles within the framework of the RBI process include: 框架内的原则

a) understanding the design premise; 了解设计的前提b) planning the RBI assessment; 策划 RBI 评估c) data and information collection; 数据和信息收集d) identifying damage mechanisms and failure modes;

确定损伤机理和失效模式e) assessing probability of failure (POF); 失效概率评估f) assessing consequences of failure (COF); 失效后果评估g) risk determination, assessment, and management;风险确定,评估和管理h) risk management with inspection activities and process control;

通过,检验活动和过程控制的风险管理i) other risk mitigation activities;其他风险缓解活动j) reassessment and updating; 重新评估和更新k) roles, responsibilities, training, and qualifications;

角色,职责,培训和资格l) documentation and recordkeeping.文件和记录

RBI过程预期成果: The expected outcome from the application of the RBI process should be the linkage of risks with appropriate inspection, process control or other risk mitigation activities to manage the risks. 评估得到风险与下述的缓解方法来管理风险

appropriate inspection 适当的检查,

process control 过程控制 or

other risk mitigation activities 其他风险缓解活动.

(1) appropriate inspection 适当的检查, (2) process control

过程控制or other risk mitigation activities 其他风险缓解活动.

The RBI process 能够产生的 is capable of generating:

1. a ranking by relative risk of all equipment evaluated;所有设备的相对危险度评价的排名

2. a detailed description of the inspection plan to be employed for each equipment item, including:每个设备的详细检查计划

inspection method(s) that should be used [e.g. visual, ultrasonic (UT), radiography, wet florescent magnetic particle]; 合适的无损探伤方法

extent of application of the inspection method(s) (e.g. percent of total area examined or specific locations); 检验深度(面积/位置)

timing of inspections/examinations (inspection intervals/due dates); 间隔/时间

risk management achieved through implementation of the inspection plan;通过实施检查计划的实现管理风险

3. a description of any other risk mitigation activities [such as repairs, replacements or safety equipment upgrades, equipment redesign or maintenance, integrity operating windows (IOWs), and controls on operating conditions];任何其他风险缓解活动:如修理,更换,安全设备的更新,重新设计,维修设备,过程控制与作业范围 IOW维护.

4. the expected risk levels of all equipment after the inspection plan and other risk mitigation activities have been implemented; 预期遗留风险水平的认识

5. identification of risk drivers.识别风险激发因素

任何其他风险缓解活动: (1) 设备维修/ (2) 更新/ (3) 安全设备提升或更换, (4) 重新设计, (5) 维护, (6) 完整作业窗口, (7) 作业过程控制.

RBI过程预期成果(1) 所有设备的相对危险度评价的排名


RBI过程预期成果(2) 每个设备的详细检查计划

RBI过程预期成果3) 任何其他风险缓解活动.

任何其他风险缓解活动:如修理,更换,安全设备的更新,重新设计,维修设备,过程控制与作业范围 IOW维护.

RBI过程预期成果3) 任何其他风险缓解活动.

RBI过程预期成果

• (4) 遗留预期风险水平• (5) 识别风险激发因素

1.2 RBI Benefits and Limitations 优点和局限性

The primary work products of the RBI assessment and management approach are plans that address ways to manage risks on an equipment level. These equipment plans highlight risks from a (1) safety/ (2) health/ (3) environment perspective and/or from an (4) economic standpoint. RBI plans should include cost-effective actions along with a projected risk mitigation. Implementation of these plans provides one of the following: 计划应包括成本效益的行为与预计风险缓解并用

a) an overall reduction in risk for the facilities and equipment assessed,风险整体减少

b) an acceptance/understanding of the current risk.能接受的/理解当前风险

RBI plans should include (A) cost-effective actions along with a (B) projected risk mitigation.

a) an overall reduction in risk for the facilities and equipment assessed,风险整体减少

b) an acceptance/understanding of the current risk.能接受的/理解当前风险

RBI Benefits and Limitations

RISK Factors 风险因素?These equipment plans highlight risks from a safety/health/environment perspective and/or from an economic standpoint. 安全/健康/环境的角度和/或从经济的角度来看

a) an acceptance/understanding of the current risk.能接受的/理解当前风险

The RBI plans also identify equipment that does not require inspection or some other form of mitigation because of the acceptable level of risk associated with the equipment’s current operation. In this way, inspection and maintenance activities can be focused and more cost effective. This often results in a significant reduction in the amount of inspection data that is collected. This focus on a smaller set of data should result in more accurate information. In some cases, in addition to risk reductions and process safety improvements, RBI plans may result in cost reductions.

inspection and maintenance activities can be focused

equipment that does not require inspection or some other form of mitigation

筛选出可接受风险水平的设备,这些设备可以不用检验或缓解活动.这样检验与维护活动能可以集中在关键的设备. 信息的收集可以相应的减少,集中在一个较小的数据收集导致更准确的信息,排除不确定性. 除了降低风险和过程安全改善计划可能会导致在降低成本

RBI is based on sound, proven risk assessment and management principles. Nonetheless, RBI will not compensate for: 有效的 RBI 基于健全,成熟的风险评估和管理原则, 以下为阻碍点

c) inaccurate or missing information,错误或遗漏的信息d) inadequate designs or faulty equipment installation,设计不足或设备安装故障e) operating outside the acceptable IOW, 超出可接受操作窗口f) not effectively executing the plans,不能有效地执行计划g) lack of qualified personnel or teamwork,缺乏合格的人员或团队h) lack of sound engineering or operational judgment.缺乏合理的工程或运作判断

inaccurate or missing information,错误或遗漏的信息

inadequate designs or faulty equipment installation,设计不足或设备安装故障

operating outside the acceptable IOWs,超出可接受操作窗口

not effectively executing the plans,不能有效地执行计划

lack of qualified personnel or teamwork,缺乏合格的人员或团队

lack of sound engineering or operational judgment.缺乏合理的工程或运作判断

1.3 Using RBI as a Continuous Improvement Tool 作为持续改进工具

Utilization of RBI provides a vehicle for continuously improving the inspection of facilities and systematically reducing the risk associated with pressure boundary failures. As new data (such as inspection results and industry experiences with similar processes) becomes available or when changes occur (e.g. operating conditions), reassessment of the RBI program can be made that will provide a refreshed view of the risks. Risk management plans should then be adjusted appropriately.

RBI offers the added advantage of identifying gaps or shortcomings in the effectiveness of commercially available inspection technologies and applications. In cases where technology cannot adequately and/or cost-effectively mitigate risks, other risk mitigation approaches can be implemented. RBI should serve to guide the direction of inspection technology development, and hopefully promote a faster and broader deployment of emerging inspection technologies as well as proven inspection technologies that may be available but are underutilized.

RBI should serve to guide the direction of inspection technology development, and hopefully promote a faster and broader deployment of emerging inspection technologies

新检验技术的引导

RBI should serve to guide the direction of inspection technology development, and hopefully promote a faster and broader deployment of emerging inspection technologies as well as proven inspection technologies that may be available but are underutilized. 新检验技术的方向引导

proven inspection technologies that may be available but are underutilized 充分的发挥现有的检验方法

1.4 RBI as an Integrated Management Tool 配合其他工具综合管理工具RBI is a risk assessment and management tool that addresses an area of risk management not completely addressed in other organizational riskmanagement efforts such as process hazards analyses (PHA)工艺危害分析, IOWs 作业窗口完整性 or reliability centered maintenance (RCM) 可靠性为中心的维修. Integration of these risk management efforts, including RBI, is key to the success of a risk management program. RBI produces inspection and maintenance plans for equipment that identify the actions that should be taken to provide reliable and safe operation.

The RBI effort can provide input into an organization’s annual planning and budgeting that define the staffing and funds required to maintain equipment operation at acceptable levels of performance and risk. RBI needs to be integrated with a management system for defining and maintaining IOWs as well as a robust management of change (MOC) 健全的变革管理 process as a basis for managing and controlling damage mechanisms in fixed equipment.

综合管理工具配合其他工具综合管理工具例如;

process hazards analyses (PHA)工艺危害分析, Integrity operating window (IOW) 作业窗口完整性, reliability centered maintenance (RCM) 可靠性为中心的维修.

在健全的 management of change (MOC)变革作为在固定的设备管理和控制损

害的机制奠定了基础。

2 Scope 范围

Contents

2 Scope 2.1 Industry Scope 2.2 Flexibility in Application 2.3 Mechanical Integrity Focused 2.4 Equipment Covered 2.5 Equipment Not Covered 2.6 Target Audience


2.1 Industry ScopeAlthough the risk management principles and concepts that RBI is built on are universally applicable, this RP is specifically targeted at the application of RBI in the hydrocarbon and chemical process industry. 碳氢化合物(石油)和化工行业


this RP isspecifically targeted at the application of RBI in the hydrocarbon and chemical process industry. 适用于化工与石油天然气行业


2.2 Flexibility in Application 灵活应用Because of the broad diversity in organizations’ size, culture, federal and/or local regulatory requirements, this RP offers users the flexibility to apply the RBI methodology within the context of existing corporate risk management practices and to accommodate unique local circumstances.

The document is designed to provide a framework that clarifies the expected attributes of a quality risk assessment without imposing undue constraints on users. This RP is intended to promote consistency and quality in the identification, assessment, and management of risks pertaining to material deterioration, which could lead to loss of containment.

Many types of RBI methods exist and are currently being applied throughout industry. This document is not intended to single out one specific approach as the recommended method for conducting an RBI effort. The document instead is intended to identify and clarify the essential elements of an RBI analysis and program.


此规范并不打算挑出一个特定的方法而是在众多方法里更加确定和澄清分析和方案基本要素. 从而促进识别,评估和管理因材料退化可能导致设备溶液的流失相关风险的正确方法与一致性.


2.3 Mechanical Integrity Focused

The RBI process is focused on maintaining the mechanical integrity of pressure equipment items and minimizing the risk of loss of containment due to deterioration. RBI is not a substitute for a PHA or hazard and operability assessment (HAZOP). Typically, process hazards analyses PHA riskassessments focus on the process unit design and operating practices and their adequacy given the unit’s current or anticipated operating conditions. RBI complements the PHA by focusing on the mechanical integrity related damage mechanisms and risk management through inspection.

RBI also is complementary to Reliability Centered Maintenance RCM programs in that both programs are focused on understanding failure modes, addressing the modes and therefore improving the reliability of equipment and process facilities.


RBI 补足 HAZOP/PHA/RCM 综合管理工具, 其重点是维护承压设备的机械完整性大限度地减少因变质遏制溶液流失的风险

关键字眼: 机械完整性溶液流失


RBI 补足 HAZOP/PHA/RCM 作为综合管理工具, 其重点是维护承压设备的机械完整性


承压设备的机械完整性 :材料退化可能导致受压媒介流失

API 580

2.4 Equipment Covered 覆盖设备

The following types of equipment and associated components/internals are covered by this document.

a) Pressure Vessels- All pressure containing components. 压力容器-所有承压部件

b) Process Piping- Pipe and piping components.工艺管道,管道和管件

c) Storage Tanks- Atmospheric and pressurized.大气(常压)和加压储罐

d) Rotating Equipment- Pressure containing components. 旋转设备承压部件

e) Boilers and Heaters- Pressurized components.锅炉及加热器,加压组件

f) Heat exchangers (shells, floating heads, channels, and bundles).热交换器(筒体,浮动封头,格栅与管束)

g) Pressure-relief devices.压力释放装置.


Pressure Vessels- All pressure containing components. 压力容器 - 所有承压部件


Process Piping- Pipe and piping components.工艺管道，管道和管件


Storage Tanks- Atmospheric and pressurized.储罐,大气(常压)和加压


Rotating Equipment- Pressure containing components.旋转设备-承压部件


Boilers and Heaters - Pressurized components.锅炉及加热器,加压组件


Pressure-relief devices.压力释放装置


2.5 Equipment Not Covered 不覆盖设备The following equipment is not covered by this document:

a) instrument and control systems,仪表和控制系统b) electrical systems,电气系统c) structural systems,结构d) machinery components (except pump and compressor casings). However,

these systems and components may be covered by other types of RBI or risk assessment work processes such as RCM.机械部件(除泵和压缩机外壳)


不覆盖设备?


2.6 Target Audience 目标受众

The primary audience for this RP is inspection and engineering personnel who are responsible for the mechanical integrity and operability of equipment covered by this RP. However, while an organization’s inspection/materials engineering group may champion the RBI initiative, RBI is not exclusively an inspection activity. RBI requires the involvement of various segments of the organization such as engineering, maintenance and operations. Implementation of the resulting RBI product (e.g. inspection plans, replacement/upgrading recommendations, other mitigation activities, etc.) may rest with more than one segment of the organization. RBI requires the commitment and cooperation of the total operating organization.

In this context, while the primary audience may be inspection and materials engineering personnel, other stakeholders who are likely to be involved should be familiar with the concepts and principles embodied in the RBI methodology to the extent necessary for them to understand the risk assessmentprocess and to be able to accept the results.


虽然主要观众为负责设备的机械完整性和可操作性(1) 检验和(2) 工程技术(材料)人员.其他可能参与的相关者都应熟悉风险风险检验概念和原则.


other stakeholders who are likely to be involved


3 Normative References


Contents3 Normative References


Societies/Organizations:

1. ASME International, 3 Park Avenue, New York, New York 10016-5990, www.asme.org.

2. American Institute of Chemical Engineers, Center for Chemical Process Safety, 3 Park Avenue, 19th Floor, New York, New York 10016, www.aiche.org/ccps.

3. 3 U.S. Environmental Protection Agency, Ariel Rios Building, 1200 Pennsylvania Avenue, Washington, DC 20460, www.epa.gov.

4. 4 International Organization for Standardization, 1, ch. de la Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, www.iso.org.

5. 5 U.S. Department of Labor, Occupational Safety and Health Administration, 200 Constitution Avenue, NW, Washington, DC 20210, www.osha.gov.


• API Publication 510, Pressure Vessel Inspection Code: Inspection, Rating, Repair, and Alteration.

• API Publication 570, Piping Inspection Code: Inspection, Repair, Alteration, and Rerating of In-service Piping Systems

• API Recommended Practice 571, Damage Mechanisms Affecting Fixed Equipment in the Refining Industry

• API Standard 579-1/ASME 1 FFS-1, Fitness-For-Service• API Recommended Practice 581, Risk-Based Inspection Technology• API Standard 653, Tank Inspection, Repair, Alteration, and Reconstruction• API Recommended Practice 752, Management of Hazards Associated

With Location of Process Plant Buildings• API Recommended Practice 941, Steels for Hydrogen Service at Elevated

Temperatures and Pressures in Petroleum Refineries and Petrochemical Plants


• AICHE 2, Dow’s Fire and Explosion Index Hazard Classification Guide, 1994• ASME PVRC Project 99-IP-01, A Comparison of Criteria For Acceptance of

Risk, February 16, 2000• EPA 58 FR 54190 (40 CFR Part 68) 3, Risk Management Plan (RMP)

Regulations• ISO Guide 73 4, Risk Management Vocabulary• OSHA 29 CFR 1910.119 5, Process Safety Management of Highly

Hazardous Chemicals


4 Terms, definitions, acronyms and abbreviations


Contents

4 Terms, Definitions, Acronyms, and Abbreviations 4.1 Terms and Definitions 4.2 Acronyms and Abbreviations


4.1 Terms and DefinitionsFor purposes of this RP, the following terms, definitions, acronyms, and abbreviations shall apply.

4.1.1absolute riskAn ideal and accurate description and quantification of risk.准确的描述和量化风险4.1.2acceptable riskA level of risk that is acceptable to the owner-user.用户可以接受的风险水平4.1.3as low as reasonably practical ALARPA concept of minimization that postulates that attributes (such as risk) can only be reduced to a certain minimum under current technology and with reasonable cost.根据目前的技术和合理成本只能被减小到一定的小的特性(如风险)

1.2 RBI Benefits and Limitations 优点和局限性……… an acceptance/understanding of the current risk.

能接受的/理解当前风险


http://www.hse.gov.uk/foi/internalops/hid_circs/permissioning/spc_perm_37/

ALARP


4.1.4components 组成整件部分的组件Parts that make up a piece of equipment or equipment item. For example a pressure boundary may consist of components (pipe, elbows, nipples, heads, shells, nozzles, stiffening rings, skirts, supports, etc.) that are bolted or welded into assembles to make up equipment items.4.1.5Consequence 后果An outcome from an event. There may be one or more consequences from an event. Consequences may range from positive to negative. However, consequences are always negative for safety aspects. Consequences may be expressed qualitatively or quantitatively. 可以定性或定量来表达4.1.6corrosion specialist 防腐专家A person who is knowledgeable and experienced in the specific process chemistries, corrosion degradation mechanisms, materials selection, corrosion mitigation methods, corrosion monitoring techniques, and their impact on pressure equipment.


4.1.7cost-effective 经济有效An activity that is both effective in resolving an issue (e.g. some form of mitigation) and is a financially sound use of resources.4.1.8damage (or deterioration) mechanism 损坏机理A process that induces micro and/or macro material changes over time that are harmful to the material condition or mechanical properties. Damage mechanisms are usually incremental, cumulative, and, in some instances, unrecoverable. Common damage mechanisms include corrosion, stress corrosion cracking, creep, erosion, fatigue, fracture, and thermal aging. 可能是微观和/或宏材料变动


4.1.9damage (or deterioration) mode 损坏模式(状态)The physical manifestation of damage (e.g. wall thinning, pitting, cracking, rupture). 损伤机理带来的物理表现的损坏4.1.10damage tolerance 损伤容限The amount of deterioration that a component can withstand without failing. 组件能承受损伤而不导致失效的容限.


4.1.11design premise 设计的前提Assumptions made during the design (e.g. design life and corrosion allowance needed).例如设计寿命和腐蚀裕量4.1.12deterioration退化The reduction in the ability of a component to provide its intended purpose of containment of fluids. This can be caused by various damage mechanisms (e.g. thinning, cracking, mechanical). Damage or degradation may be used in place of deterioration.4.1.13equipment 设备An individual item that is part of a system. Examples include pressure vessels, relief devices, piping, boilers, and heaters.


4.1.14event 事件Occurrence of a particular set of circumstances. The event may be certain or uncertain. The event can be singular or multiple. The probability of an event occurring within a given period of time can be estimated.组特定的情况下发生的 (确定/不确定,单数或多个)状况.给定的时间内发生的事件的概率可估算


4.1.15event tree 事件树An analytical tool that organizes and characterizes potential occurrences in a logical and graphical manner. The event tree begins with the identification of potential initiating events. Subsequent possible events (including activation of safety functions) resulting from the initiating events are then displayed as the second level of the event tree. This process is continued to develop pathways or scenarios from the initiating events to potential outcomes.4.1.16 external event 外部事件Events resulting from forces of nature, acts of God, sabotage, or events such as neighboring fires or explosions, terrorism, neighboring hazardous material releases, electrical power failures, forces of nature, and intrusions of external transportation vehicles, such as aircraft, ships, trains, trucks, or automobiles. External events are usually beyond the direct or indirect control of persons employed at or by the facility.


intrusions of external transportation vehicles, such as aircraft, ships, trains, trucks, or automobiles.


4.1.17Facility 设施(地点)Any location containing equipment and/or components to be addressed under this RP.4.1.18Failure 失效( 导致终止或不终止)- 未发现 / 发现失效Termination of the ability of a system, structure, equipment or component to perform its required function of containment of fluid (i.e. loss of containment). (1) Failures may be unannounced and undetected at the instant of occurrence (unannounced failure). For example, a slow leak under insulation may not be detected until a pool of fluid forms on the ground or someone notices a drip or wisp of vapor. A small leak may not be noticed until the next inspection (unannounced failure), e.g. slow leakage from buried piping or small leak in a heat exchanger tube; or they may be (2)announced and detected by any number of methods at the instance of occurrence (announced failure), e.g. rupture of a pipe in a process plant or sudden decrease in pressure in the system.


4.1.18Failure ………………

1. Failures may be unannounced and undetected or they may be 2. announced and detected by any number of methods at the instance of

occurrence (announced failure)


4.1.19failure mode 失效模式The manner of failure. For RBI, the failure of concern is loss of containment of pressurized equipment items. Examples of failure modes are small hole, crack, and rupture. 此规范关注的失效是加压设备的溶液的流失.失效模式的例子有小孔,裂纹,破裂.


For RBI, the failure of concern is loss of containment of pressurized equipment items.


4.1.20Fitness-For-Service assessment 适用性评价A methodology whereby damage or flaws/imperfections contained within a component or equipment item are assessed in order to determine acceptability for continued service. 确定可接受的持续服务4.1.21Hazard 危害A physical condition or a release of a hazardous material that could result from component failure and result in human injury or death, loss or damage, or environmental degradation. Hazard is the source of harm. Components that are used to transport, store, or process a hazardous material can be a source of hazard. Human error and external events may also create a hazard. 导致环境恶化或人身伤害隐患(隐患是伤害之源)


4.1.22hazard and operability study HAZOP study 隐患和可操作性研究A HAZOP study is a form of failure modes and effects analysis (FMEA). HAZOP studies, which were originally developed for the process industry, use systematic techniques to identify hazards and operability issues throughout an entire facility. It is particularly useful in identifying unforeseen hazards designed into facilities due to lack of information, or introduced into existing facilities due to changes in process conditions or operating procedures. The basic objectives of the techniques are:

1. to produce a full description of the facility or process, including the intended design conditions;生产设施或过程，包括预期的设计条件的完整说明;

2. to systematically review every part of the facility or process to discover how deviations from the intention of the design can occur;系统地审查工厂或过程每一个部分, 找出设计意图的偏差是如何发生;

3. to decide whether these deviations can lead to hazards or operability issues;决定这些偏差是否会导致危险或可操作性问题

4. to assess effectiveness of safeguards.评估保障的有效性


4.1.23Inspection 检查Activities performed to verify that materials, fabrication, erection, examinations, testing, repairs, etc., conform to applicable code, engineering, and/or owner’s written procedure requirements. It includes the planning, implementation, and evaluation of the results of inspection activities. The external, internal, or on-stream assessment (or any combination of the three) of the condition of pressure equipment.4.1.24 integrity operating window IOW 完整过程变量窗口Established limits for process variables that can affect the integrity of the equipment if the process operation deviates from the established limits for a predetermined amount of time.4.1.25Likelihood 可能性Probability.


4.1.26management of change MOC 变革管理A documented management system for review and approval of changes in process, equipment or piping systems prior to implementation of the change.


4.1.27Mitigation 缓解Limitation of any negative (1) consequence or reduction in (2) probability of a particular event.4.1.28Probability 可能性Extent to which an event is likely to occur within the time frame under consideration. The mathematical definition of probability is “a real number in the scale 0 to 1 attached to a random event.” Probability can be related to a long-run relative frequency of occurrence or to a degree of belief that an event will occur. For a high degree of belief, the probability is near one (1). Frequency rather than probability may be used in describing risk. Degrees of belief about probability can be chosen as classes or ranks like “rare/ unlikely/ moderate/ likely/ almost certain” or “incredible/ improbable/ remote/ occasional/ probable/frequent.” 事件可能在考虑的时间框架内发生的程度


4.1.29process unit 工艺设备A group of systems arranged in a specific fashion to produce a product or service. Examples of processes include power generation, acid production, fuel oil production, and ethylene production.


System within a Process unit


Reformer PFD

Facility →Process units → Systems → Equipments


PHARMACEUTICALS PFD


Facility →Process units → Systems → Equipments


4.1.53System 系统A collection of equipment assembled for a specific function within a process unit. Examples of systems include service water system, distillation systems, and separation systems.

Facility → Process units → Systems →Equipments


4.1.30qualitative risk analysis 定性风险分析An analysis that uses broad categorizations for probabilities and consequences of failure. Methods that use primarily engineering judgment and experience as the basis for the determination of probabilities and consequences of failure. The results of qualitative risk analyses are dependent on the background and expertise of the analysts and the objectives of the analysis.

FMEA and HAZOP are examples of qualitative risk analysis techniques that become QRA (quantitative risk analysis) methods when consequence and failure probability values are estimated along with the respective descriptive input.

定性风险分析的结果依赖于分析师的背景和专业知识和分析的目标. 在 FMEA / HAZOP 分析时后果和失效概率值如被估计, 这定性的风险分析技术可以作为QRA分析的方法.


Methods that use primarily engineering judgment and experience as the basisfor the determination of probabilities and consequences of failure.


定性风险分析的结果依赖于分析师的背景和专业知识和分析的目标. 在FMEA / HAZOP 分析时后果和失效概率值如被估计, 这定性的风险分析技术可以作为QRA(定量)分析的方法.(?)


4.1.31quantitative risk analysis QRA 定量风险分析An analysis that quantifies the probabilities and consequences of the probabledamage mechanisms and that:

identifies and delineates the combinations of events that, if they occur, may lead to a severe event or any other undesired consequence;识别并描述事件的组,如果它们发生可能引发一个严重的事件或任何其它不期望的后果

estimates the probability of occurrence for each combination;估计每个组合发生的概率

estimates the consequences.估计后果

The events?The likelihoods of each event?The consequences of each event?


QRA generally: 方法

integrates information about facility design, operating practices, operating history, component reliability, human actions, the physical progression of incidents, and potential environmental and health effects;

uses logic and probabilistic models depicting combinations of events and the progression of incidents to provide both qualitative and quantitative insights into the level of risks;

analysis logic models consisting of event trees and fault trees to estimate the frequency of each incident sequence.


QRA-uses logic and probabilistic models depicting combinations of events and the progression of incidents to provide both qualitative and quantitative insights into the level of risks; analysis logic models consisting of event trees and fault trees to estimate the frequency of each incident sequence.


4.1.32 Reassessment 重新估价The process of integrating inspection data or other changes into the risk analysis.4.1.33relative risk 相对风险The comparative risk of a facility, process unit, system, equipment item or component to other facilities, process units, systems, equipment items, or components, respectively.4.1.34residual risk 剩余风险The risk remaining after risk mitigation.


4.1.35Risk 风险-事件的概率及其后果Combination of the probability of an event and its consequence. In some situations, risk is a deviation from the expected. When probability and consequence are expressed numerically, risk is the product.4.1.36risk acceptance 风险接受- 依风险准据而定A decision to accept a risk. Risk acceptance depends on risk criteria.


Risk 风险-事件的概率及其后果


4.1.37risk analysis 风险分析Systematic use of information to identify sources and to estimate the risk. Risk analysis provides a basis for risk evaluation, risk mitigation and risk acceptance. Information can include historical data, theoretical analysis, informed opinions, and concerns of stakeholders.利益相关者的关注


concerns of stakeholders?


concerns of stakeholders?Himba women


concerns of stakeholders?


4.1.38risk assessment 风险评估Overall process of (1) risk analysis and (2) risk evaluation.4.1.39risk avoidance 风险规避Decision not to become involved in, or action to withdraw from a risk situation. The decision may be taken based on the result of risk evaluation.4.1.40risk-based inspection RBI 基于风险的检验A risk assessment and management process that is focused on loss of containment of pressurized equipment in processing facilities, due to material deterioration. These risks are managed primarily through equipment inspection.风险评估和管理过程.这些风险主要通过设备检查管理


4.1.41risk communication 风险沟通Exchange or sharing of information about risk between the decision maker and other stakeholders. The information may relate to the existence, nature, form, probability, severity, acceptability, mitigation, or other aspects of risk.决策者和其他利益相关者之间对风险信息的交换或共享.4.1.42risk criteria 风险标准Terms of reference by which the significance of risk is assessed. Risk criteria may include associated cost and benefits, legal and statutory requirements, socio-economic and environmental aspects, concerns of stakeholders, priorities and other inputs to the assessment.


4.1.43risk driver 风险驱动An item affecting either the (1) probability, (2) consequence, or both such that it constitutes a significant portion of the risk.4.1.44risk estimation 风险评估Process used to assign values to the probability and consequence of a risk. Risk estimation may consider (1) cost, (2) benefits, (3) stakeholder concerns, and (4) other variables, as appropriate for risk evaluation.

Other variables ? (Safety/health/environment/economic standpoints)


risk criteria 风险标准Terms of reference by which the significance of risk is assessed. Risk criteria

may include; associated cost and benefits,相关的成本和收益 legal and statutory requirements,法律和法定要求 socio-economic and 社会经济 environmental aspects, 环境方面 concerns of stakeholders, 利益相关者的关注 priorities and other inputs to the assessment.优先事项和其他评估数据要求.

Safety/health (?)


4.1.45risk evaluation 风险评估Process used to compare the estimated risk against given risk criteria to determine the significance of the risk. Risk evaluation may be used to assist in the acceptance or mitigation decision.4.1.46risk identification 风险识别Process to find, list, and characterize elements of risk. Elements may include: (1) source, (2) event, (3) consequence, (4) probability. Risk identification may also identify (5) stakeholder concerns.4.1.47risk management 风险管理Coordinated activities to direct and control an organization with regard to risk. Risk management typically includes risk assessment, risk mitigation, risk acceptance, and risk communication.


4.1.48risk mitigation 风险缓解Process of selection and implementation of measures to modify risk. The term risk mitigation is sometimes used for measures themselves.4.1.49risk reduction 降低风险Actions taken to lessen the probability, negative consequences, or both associated with a particular risk.4.1.50semi-quantitative analysis 半定量分析A semi-quantitative analysis includes aspects of both qualitative and quantitative analyses.


Source 源Thing or activity with a potential for consequence. Source in a safety context is a hazard.潜在隐患的源头4.1.52Stakeholder 利益相关者Any individual, group or organization that may affect, be affected by, or perceive itself to be affected by the risk.


4.1.53System 系统A collection of equipment assembled for a specific function within a process unit. Examples of systems include service water system, distillation systems, and separation systems.

Facility → Process units → Systems → Equipments

4.1.54Turnaround 周转(周期)A period of down time to perform inspection, maintenance, or modifications and prepare process equipment for the next operating cycle.停机进行检查, 维修或改装, 并准备为下一个操作周期。


System within a Process unit – 3 phase separator


4.1.55toxic chemical 有毒化学品Any chemical that presents a physical or health hazard or an environmental hazard according to the appropriate material safety datasheet. These chemicals (when ingested, inhaled, or absorbed through the skin) can cause damage to living tissue, impairment of the central nervous system, severe illness, or in extreme cases, death. These chemicals may also result in adverse effects to the environment (measured as ecotoxicity and related to persistence and bioaccumulation potential).


4.1.56unmitigated risk 未缓和前风险The risk prior to mitigation activities.


4.2 Acronyms and AbbreviationsACC American Chemistry Council.AIChE American Institute of Chemical Engineers.ALARP as low as reasonably practical.ANSI American National Standards Institute.ASME American Society of Mechanical Engineers.ASNT American Society of Nondestructive Testing.ASTM American Society of Testing and Materials.BLEVE boiling liquid expanding vapor explosion.CCPS Center for Chemical Process Safety.COF consequence of failure.EPA Environmental Protection Agency.FMEA failure modes and effects analysis.HAZOP hazard and operability assessment.IOW integrity operating window.ISO International Organization for Standardization.LOPA layers of protection analysis.MOC management of change.MSD material selection diagrams.


NACE National Association of Corrosion Engineers.NDE nondestructive examination.NFPA National Fire Protection Association.OSHA Occupational Safety and Health Administration.PHA process hazards analysis.PMI positive material identification.POF probability of failure.PSM process safety management.PTASCC polythionic acid stress corrosion cracking.PVRC Pressure Vessel Research Council.QA/QC quality assurance/quality control.QRA quantitative risk assessment.RBI risk-based inspection.RCM reliability centered maintenance.RMP risk management plan.SIL safety integrity level.TEMA Tubular Exchangers Manufacturers Association.TNO The Netherlands Organization for Applied Scientific Research.UT ultrasonic testing.


5 Basic Risk Assessment Concepts


Sub-Contents

5 Basic Risk Assessment Concepts 5.1 What is Risk? 5.2 Risk Management and Risk Reduction 5.3 The Evolution of Inspection Intervals/Due Dates 5.4 Overview of Risk Analysis 5.5 Inspection Optimization 5.6 Relative Risk vs Absolute Risk


5.1 What is Risk? 什么是风险Risk is something that we as individuals live with on a day-to-day basis. Knowingly or unknowingly, people are constantly making decisions based on risk. Simple decisions such as driving to work or walking across a busy street involve risk. More important decisions such as buying a house, investing money, and getting married all imply an acceptance of risk. Life is not risk-free and even the most cautious, risk-adverse individuals inherently take risks. Some people take more risks than others (knowingly or unknowingly), e.g. sky divers, mountain climbers, coal miners, and people who drive while intoxicated.

For example, in driving a car, people accept the probability that they could be killed or seriously injured. The reason this risk is accepted is that people consider the probability of being killed or seriously injured to be sufficiently low as to make the risk acceptable. Influencing the decision are the type of car, the safety features installed, traffic volume and speed, and other factors such as the availability, risks and affordability of other alternatives (e.g. mass transit).


Risk is the combination of the probability of some event occurring during a time period of interest and the consequences, (generally negative) associated with the event. 风险是在指定时间段某些事件发生的(1)概率和(2)后果(一般为负面)组合.风险 = 概率×后果

In mathematical terms, risk can be calculated by the equation:

Risk = Probability × ConsequenceLikelihood is sometimes used as a synonym for probability, however probability is used throughout this document for consistency. Effective risk assessment should be a rational, logical, structured process, which contains at least two key steps. First to determine how big the risk is; and second, to determine whether the risk is acceptable.


5.2 Risk Management and Risk Reduction 风险管理和减少风险Once the risk is known and the magnitude of the risk is established, it is time for

risk management. At first, it may seem that risk management and risk reduction are synonymous. However, risk reduction is only part of risk management.

Risk reduction is the act of mitigating a known risk that is deemed to be too high to a lower, more acceptable level of risk with some form of risk reduction activity.

Risk management, on the other hand, is a process to assess risks, to determine if risk reduction is required and to develop a plan to maintain risks at an acceptable level. By using risk management, some risks may be identified as acceptable so that no risk reduction (mitigation) is required.


5.3 The Evolution of Inspection Intervals/Due Dates 检验间隔/到期日期的演变

In process plants, inspection and testing programs and process monitoring are established to detect and evaluate deterioration due to the effects of in-service operation. The effectiveness of inspection programs varies widely, ranging from (1) reactive programs, which concentrate on known areas of concern, to (2) broad proactive programs covering a variety of equipment. One extreme of this would be the;

(2a) “don’t fix it unless its broken” approach. The other extreme would be (2b) complete inspection of all equipment items on a frequent basis.

Setting the intervals/due dates between inspections has evolved over time. With the need to periodically verify equipment integrity, organizations initially resorted to time-based or “calendar-based” intervals/due dates.


检验程序可以分为两大类:

反应式: 集中在已知关注的领域,

广泛积极式:

‾ 除非坏了不解决‾ 基于设定间隔检验全部设备


With advances in inspection approaches, and better understanding of the type and rate of deterioration, inspection intervals/due dates became more dependent on the equipment condition (i.e. condition-based inspection), rather than what might have been an arbitrary calendar date. Codes and standards such as API 510, API 570, and API 653 evolved to an inspection philosophy with elements such as: 跟着检验方法的改进与进化, 依照设备的状态设定检验间隔(即基于状态的检查)被上述规范采纳. 检验哲理的元素包括;

a) inspection intervals/due dates based on some percentage of equipment life (such as half life), 设备残余寿命-半衰期设定检验间隔

b) on-stream inspection in lieu of internal inspection based on low deterioration rates, 低恶化率设备,外部在役检验替代内部开罐检验

c) internal inspection requirements for damage mechanisms related to process environment induced cracking, 依照损伤机理设定检验要求例如环境腐蚀开裂.

d) consequence based inspection intervals/due dates. 基于后果的检查

½ (one half) the remaining life of the vessel or 10 years, whichever is less.Internal & On-stream Inspection

High Risk

When an internal inspection or on-stream is performed or at shorter intervals at the owner or user’s option.

External InspectionHigh Risk

At least every 5 years.Internal & On-Stream Inspection

Air Receiver

At least every 3 years.Internal & On-Stream Inspection

Portable Test Separator

¾ (three quarter) remaining corrosion-rate life or 15 years whichever is less.

Internal & On-stream Inspection

Low Risk

When an internal inspection or on-stream is performed or at shorter intervals at the owner or user’s option.

External InspectionLow Risk

E&P Vessel

Five years for typical process services; and Ten years for clean (non-fouling) and non-corrosive services.

Pressure relief devices

½ (one half) the remaining life of the vessel or 10 years, whichever is less.Internal & On-stream Inspection

five (5) years or the required internal/on-stream inspection whichever is less.

External Inspection

Non- E&P Vessel API510


RBI represents the next generation of inspection approaches and interval/due date setting, recognizing that the ultimate goal of inspection is the safety and reliability of operating facilities. RBI, as a risk-based approach, focuses attention specifically on the equipment and associated damage mechanisms representing the most risk to the facility. In focusing on risks and their mitigation, RBI provides a better linkage between the mechanisms that lead to equipment failure (loss of containment) and the inspection approaches that will effectively reduce the associated risks. Though there can be many definitions for failure of pressure equipment, in this document, failure is defined as loss of containment. 失效被定义为溶液的流失


in this document, failure is defined as loss of containment. 失效被定义为溶液的流失


5.4 Overview of Risk Analysis 风险分析的概述

The complexity of a risk analysis is a function of the number of factors that can affect the risk and there is a continuous spectrum of methods available to assess risk. The methods range from a strictly relative ranking to rigorous calculation. The methods generally represent a range of precision for the resulting risk analysis (see 6.4). Any particular analysis may not yield usable results due to a lack of data, low-quality data or the use of an approach that does not adequately differentiate the risks represented by the equipment items. Further, analysis results may not be realistic. Therefore, the risk analysis should be validated before decisions are made based on the analysis results.


Any particular analysis may not yield usable results due to;

(1) a lack of data,

(2) low-quality data or

(3) the use of an approach that does not adequately differentiate the risks represented by the equipment items.


A logical progression for a risk analysis is: 风险分析的逻辑进展

a) collect and validate the necessary data and information (see Section 8);收集和验证的必要的数据和信息

b) identify damage mechanisms and, optionally, determine the damagemode(s) for each mechanism (e.g. general metal loss, local metal loss,pitting) (see Section 9);识别损伤机理和任选地确定每个损伤机理的破坏模式(例如一般的金属损失,局部金属损失,点蚀)

c) determine damage susceptibility and rates (see Section 9);确定损害的易感性和速度.

d) determine the POF over a defined time frame for each damage mechanism (see Section 10); 确定每个损伤机理的时间范围的失效概率


e) determine credible failure mode (s) [e.g. small leak, large leak, rupture (see Section 10)]; 确定可信的失效模式(例如小量泄漏, 大量泄漏, 破裂)

f) identify credible consequence scenarios that will result from the failure mode(s) (see Section 11);从故障模式(多)引发可信的后果场景(多个场景)

g) determine the probability of each consequence scenario, considering the POF and the probability that a specific consequence scenario will result from the failure (see Section 11);确定每个后果场景的失效概率

h) determine the risk, including a sensitivity analysis, and review risk analysis results for consistency/reasonableness (see Section 12).确定风险,包括敏感性分析

Data → Damage Mechanism→Damage Modes→ Failure Modes→Consequence Scenario


A logical progression for


Data → Damage Mechanism→Damage Modes→ Failure Modes→Consequence Scenario


5.5 Inspection Optimization 检验优化

When the risk associated with individual equipment items is determined and the relative effectiveness of different inspection techniques and process monitoring in reducing risk is estimated or quantified, adequate information is available for planning, optimizing, and implementing an RBI program. Figure 1 presents stylized curves showing the reduction in risk that can be expected when the degree and frequency of inspection are increased.

The upper curve in Figure 1 represents a typical inspection program. Where there is no inspection, there may be a higher level of risk, as indicated on the y-axis in the figure. With an initial investment in inspection activities, risk generally is significantly reduced.


A point is reached where additional inspection activity begins to show a diminishing return and, eventually, may produce very little additional risk reduction.

If excessive inspection is applied, the level of risk may even go up. This is because invasive inspections in certain cases may cause additional deterioration (e.g. moisture ingress in equipment with polythionic acid; inspection damage to protective coatings or glass-lined vessels). This situation is represented by the dotted line at the end of the upper curve.


Conventional

Inspection Optimization


If excessive inspection is applied, the level of risk may even go up.

typical inspection programUpper curve


A complete RBI program provides a consistent methodology for assessing the optimum combination of methods and frequencies of inspection. Each available inspection method can be analyzed and its relative effectiveness in reducing failure probability can be estimated. Given this information and the cost of each procedure, an optimization program can be developed. The key to developing such a procedure is the ability to assess the risk associated with each item of equipment and then to determine the most appropriate inspection techniques for that piece of equipment. A conceptual result of this methodology is illustrated by the lower curve in Figure 1. The lower curve indicates that with the application of an effective RBI program, lower risks can be achieved with the same level of inspection activity. This is because, through RBI, inspection activities are focused on higher risk items and away from lower risk items.


focused on higher risk items and away from lower risk items and a more appropriate inspection techniques.

RBI Inspection lower risks can be achieved with the same level of inspection activity (Lower curve)

Lower risk


RBI Inspection vs conventional inspection;the most appropriate inspection techniquesfocused on higher risk items


残余风险


As shown in Figure 1, risk cannot be reduced to zero solely by inspectionefforts. The residual risk factors for loss of containment include, but are not limited to issues such as the following: 残余风险的因素

a) human error,人为误差b) natural disasters,c) external events (e.g. collisions or falling objects),外部事件d) secondary effects from nearby units, 临近设二次效应e) consequential effects from associated equipment in the same unit,

在相同单元相关联的设备间接影响f) deliberate acts (e.g. sabotage),蓄意行为g) fundamental limitations of inspection methods,检查方法基本限制h) design errors,设计错误i) unknown or unanticipated mechanisms of damage.

未知或无法预料的损坏机理

Many of these factors are strongly influenced by the process safetymanagement (PSM) system in place at the facility.上述受到工艺安全管理PSM 的强烈影响


deliberate acts (e.g. sabotage),蓄意行为


5.6 Relative Risk vs Absolute Risk 相对风险与绝对风险

The complexity of risk calculations is a function of the number of factors that can affect the risk. Calculating absolute risk can be very time and cost consuming and often can not be done with a high degree of accuracy, due to having too many uncertainties. Many variables are involved with loss of containment in hydrocarbon and chemical facilities and the determination of absolute risk numbers is often not even possible and not cost effective.

因太多的不确定性导致计算”绝对风险”不准确与不符合成本效益


RBI is focused on a systematic determination of relative risks 运用系统化的确定相对风险. In this way, facilities, units, systems, equipment, or components can be ranked based on their relative risk.

This serves to focus the risk management efforts on the higher ranked risks and allow decisions to be made on the usefulness of risk management efforts on lower ranked risks. If a quantitative RBI study is conducted rigorously and properly, the resultant risk number should be a fair approximation of the actual risk of loss of containment due to deterioration.

Numeric relative risk values determined in qualitative and semi-quantitative assessments using appropriate sensitivity analysis methods also may be used effectively to evaluate risk acceptance.


API 580 RBIRBI is focused on a systematic determination of relative risks 系统化的确定相对风险.


6 Introduction to Risk-Based Inspection 基于风险的检验介绍


to Risk-Based Inspection


Contents

6 Introduction to Risk-Based Inspection 6.1 Key Elements of an RBI Program 6.2 Consequence and Probability for RBI 6.3 Types of RBI Assessment 6.4 Precision vs Accuracy 6.5 Understanding How RBI Can Help to Manage Operating Risks 6.6 Management of Risks 6.7 Relationship Between RBI and Other Risk-Based and Safety Initiatives6.8 Relationship with Jurisdictional Requirements


6.1 Key Elements of an RBI ProgramKey elements that should exist in any RBI program include:

a) management systems for maintaining documentation, personnel qualifications, data requirements, consistency of the program and analysis updates;

b) documented method for POF determination;c) documented method for COF determination;d) documented methodology for managing risk through inspection,

process control and other mitigation activities.

However, all the elements outlined in Section 1 should be adequatelyaddressed in all RBI applications, in accordance with the recommendedpractices in this document.


a) 保持文件管理系统管理;人员资格的要求,数据,程序和一致性分析的更新;

b) 失效概率测定方法的记录;c) 失效后果测定方法的记录;d) 通过检验风险管理,过程控制和其他缓

解措施的记录.


6.2 Consequence and Probability for RBI 后果与概率

The objective of RBI is to determine what incident could occur (consequence) in the event of an equipment failure, and how likely (probability) it is that the incident could happen. For example, if a pressure vessel subject to damage from corrosion under insulation develops a leak, a variety of consequences could occur. Some of the possible consequences are:

a) form a vapor cloud that could ignite causing injury and equipment damage;b) release of a toxic chemical that could cause health problems;c) result in a spill and cause environmental damage;d) force a unit shutdown and have an adverse economic impact;e) have minimal safety, health, environmental, and/or economic impact.


a) 形成蒸气云可能会引燃造成伤害和设备损坏;b) 释放有毒的化学物质,可能引发健康问题;c) 导致泄漏造成环境的破坏;d) 导致停机给经济带来不利的影响;e) 低限度对;安全,健康,环境,和/或经济的影响.

LEAK

Failure Mode-Leak

Scenario-a, b, c, d, e


Combining the probability of one or more of these events with its consequences will determine the risk to the operation. Some failures may occur relatively frequently without significant adverse safety, environmental or economic impacts. Similarly, some failures have potentially serious consequences, but if the probability of the incident is low, the risk may not warrant immediate or extensive action. However, if the probability and consequence combination (risk) is high enough to be unacceptable, then a mitigation action to reduce the probability and/or the consequence of the event is appropriate.

If high risk:reduce (1) the probability and/or (2) the consequence


relatively frequently without significant adverse safety, environmental or economic impacts.

potentially serious consequences, but if the probability of the incident is low,

probability and consequence combination (risk) is high

risk to the operation


Traditionally, organizations have focused solely on the consequences or the POF without systematic efforts tying the two together. They have not considered how likely it is that an undesirable incident will occur in combination with the consequence. Only by considering both factors can effective risk-based decision-making take place. Typically, risk acceptability criteria are defined, recognizing that not every failure will lead to an undesirable incident with serious consequence (e.g. water leaks) and that some serious consequence incidents have very low probabilities (e.g. rupture of a clean propane vessel).

Risk = Probability × Consequence


Understanding the two-dimensional aspect of risk allows new insight into the use of risk for inspection prioritization and planning. Figure 2 displays the risk associated with the operation of a number of equipment items in a process plant. Both the probability and COF have been determined for 10 equipment items, and the results have been plotted.

The points represent the risk associated with each equipment item. Ordering by risk produces a risk-based ranking of the equipment items to be inspected. From this list, an inspection plan can be developed that focuses attention on the areas of highest risk. An “ISO-risk” line is shown on Figure 2. An ISO-risk line represents a constant risk level, as shown across the matrix in Figure 2.

All items that fall on or very near the ISO-risk line are roughly equivalent in their level of risk. A user defined acceptable risk level could be plotted as an ISO-risk line. In this way the acceptable risk line would separate the unacceptable from the acceptable risk items. Often a risk plot is drawn using log-log scales for a better understanding of the relative risks of the items assessed.

Charlie Chong/ Fion ZhangAPI 580 Key: ISO: constant risk level line


6.3 Types of RBI Assessment


6.3 Types of RBI Assessment 评估的类型(定性/定量/半定量)Various types of RBI assessment may be conducted at several levels. The choice of approach is dependent on multiple variables such as:

a) objective of the study,研究的目的b) number of facilities and equipment items to study,设施和设备研究数c) available resources,可用资源d) assessment time frame,评估的时间框架e) complexity of facilities and processes,设施和过程的复杂性f) nature and quality of available data, 现有数据性质和质量g) the amount of risk discrimination needed. 需要的风险偏差量


The RBI procedure can be applied qualitatively, quantitatively or by using aspects of both (i.e. semi-quantitatively). Each approach provides a systematic way to screen for risk, identify areas of potential concern, and develop a prioritized list for more in depth inspection or analysis. Each develops a risk ranking measure to be used for evaluating separately the POF and the potential COF. These two values are then combined to estimate risk of failure.

定性/定量/半定量:每一种方法都提供了一个系统的方法来筛选风险, 找出可能引起关注点与优先级列表进行更深入的检查或分析


The chosen approach may be selected at the beginning of the analysis process and carried through to completion, or the approach may be changed (i.e. the analysis may become more or less quantitative) as the analysis progresses. However, consistency of approach will be vital to comparing results from one assessment to the next.

If the risk determined using any approach is below the acceptance criterion specified by the management of the organization conducting the analysis, no further analysis, inspection or mitigation steps are typically required within the analysis time frame as long as the conditions and assumptions used in the analysis remain valid. The spectrum of risk analysis should be considered to be a continuum with qualitative and quantitative approaches being the two extremes of the continuum and everything in between being a semi-quantitative approach (see 6.3.4 and Figure 3). Use of expert opinion will typically be included in most risk assessments regardless of type or level.

所选择的方法可以在分析过程的从开始到完成或中间转换为另个方法,分析结果可以为定性/定量/半定量. 然而使用方法的一致性对后续评估数据对比是关键的.


所选择的方法可以在分析过程的从开始到完成或中间转换为另个方法, 分析结果可以为定性/定量/半定量.

定量定性半定量


6.3.1 Qualitative Approach 定性的方法This approach requires data inputs based on descriptive information using engineering judgment and experience as the basis for the analysis of probability and COF. 使用基于(1) 工程判断和 (2) 经验的描述性信息作为后果 COF与概率分析 POF.定性分析结果的准确性取决于风险分析师和团队成员的背景和专业知识.

Inputs are often given in data ranges instead of discrete values. Results are typically given in qualitative terms such as high, medium, and low, although numerical values may also be associated with these categories. The value of this type of analysis is that it enables completion of a risk assessment in the absence of detailed quantitative data. The accuracy of results from a qualitative analysis is dependent on the background and expertise of the risk analysts and team members. Although the qualitative approach is less precise than more quantitative approaches it is effective in screening out units and equipment with low risk. The qualitative approach may be used for any aspect of inspection plan development; however, the conservatism generally inherent in the more qualitative approach should be considered when making final mitigation and inspection plan decisions.


Qualitative Approach-This approach requires data inputs based on descriptive information using engineering judgment and experience as the basis for the analysis of probability and COF.


6.3.2 Quantitative Approach 定量方法Fully QRA integrates into a uniform methodology the relevant information

about facility design, operating practices, operating history, component reliability, human actions, the physical progression of accidents, and potential environmental and health effects. 集成到一个统一的分析相关信息方法

about facility design,设施设计 operating practices,操作手法 operating history,操作历史 component reliability,元件的可靠性 human actions, 人类参与 the physical progression of accidents, and意外的物理进展 potential environmental and health effects. 潜在的环境和健康影响


QRA uses logic models depicting combinations of events that could result in severe accidents and physical models depicting the progression of accidents and the transport of a hazardous material to the environment. The models are evaluated probabilistically to provide both qualitative and quantitative insights about the level of risk and to identify the design, site, or operational characteristics that are the most important to risk. QRA is distinguished from the qualitative approach by the analysis depth and integration of detailed assessments.

定量方法通过更加深入分析和整合详细评估,从定性的方法区别开来

analysis

QRA


QRA logic models generally consist of event trees and fault trees. Event trees delineate initiating events and combinations of system successes and failures, while fault trees depict ways in which the system failures represented in the event trees can occur. These models are analyzed to estimate the probability of each accident sequence.逻辑模型一般包括 (1) 事件树和 (2) 故障树

Results using this approach are typically presented as risk numbers (e.g. cost per year). QRA refers to a prescriptive methodology that has resulted from the application of risk analysis techniques at many different types of facilities, including hydrocarbon and chemical process facilities. For all intents and purposes, it is a traditional risk analysis.

An RBI analysis shares many of the techniques and data requirements with a QRA. If a QRA has been prepared for a process unit, the RBI consequence analysis can borrow extensively from this effort.


QRA logic models generally consist of event trees and fault trees.


The traditional QRA is generally comprised of five tasks:传统的定量风险评估一般包括五项任务：

1. systems identification, 系统辨识2. hazards identification, 危害识别3. probability assessment,概率评估4. consequence analysis,后果分析5. risk results. 风险结果

The systems definition, hazard identification and consequence analysis are integrally linked.

Hazard identification in an RBI analysis generally focuses on identifiable failure mechanisms in the equipment (inspectable causes) but does not explicitly deal with other potential failure scenarios resulting from events such as power failures or human errors. A QRA deals with total risk, not just risk associated with equipment damage. 分析一般集中在识别设备失效机理. QRA针对总风险, 不仅仅与设备损坏相关的风险


QRA deals with total risk, not just risk associated with equipment damage.针对总风险, 不仅仅与设备损坏相关的风险


The QRA typically involves a much more detailed evaluation than an RBIanalysis. The following data are typically analyzed:定量风险评估通常涉及一个更详细的评价

a) existing HAZOP or PHA results, 现有的HAZOP或PHA结果b) dike and drainage design, 堤及排水设计c) hazard detection systems,危险探测系统d) fire protection systems,消防系统e) release statistics,解放统计f) injury statistics,伤害统计g) population distributions,人口分布h) topography,地形学i) weather conditions,天气情况j) land use.土地使用

A QRA is generally performed by experienced risk analysts. There areopportunities to link the detailed QRA with an RBI study.一般由经验丰富的风险分析进行


6.3.3 Semi-quantitative Approach 半定量方法-从定性和定量的评估方法Semi-quantitative is a term that describes any approach that has aspects derived from both the qualitative and quantitative approaches. It is geared to obtain the major benefits of the previous two approaches (e.g. speed of the qualitative and rigor of the quantitative) 采取定性的速度与定量的严谨.


Typically, most of the data used in a quantitative approach is needed for this approach but in less detail. The models also may not be as rigorous as those used for the quantitative approach. The results are usually given in consequence and probability categories or as risk numbers but numerical values may be associated with each category to permit the calculation of risk and the application of appropriate risk acceptance criteria.

风险结果可以用以下表达: (1) 风险等级 (2) 风险报数或 (3) 风险等级报数


6.3.4 Continuum of Approaches 连续统方法(复合方法)

In practice, an RBI study typically uses aspects of qualitative, quantitative andsemi-quantitative approaches. These RBI approaches are not considered ascompeting but rather as complementary. For example,

a high level qualitative approach could be used at a unit level to select the unit within a facility that provides the highest risk for further analysis.设施里的处理单元运用定性的方法

Systems and equipment within the unit then may be screened using a qualitative approach with.然后单元内的(1)系统和(2)设备使用定性的方法筛选

a more quantitative approach used for the higher risk items.上述筛选到的高风险的设备个别的进行更定量方法

Another example could be to use a qualitative consequence analysiscombined with a semi-quantitative probability analysis.另一个例子可以使用定性分析结果相结合的半定量概率分析


When performing risk analysis across different equipment, a single site or multiple sites, the user is cautioned about comparing specific results unless the same or very similar RBI methodologies and assumptions were applied.

The user is also cautioned against drawing conclusions about different results when different methodologies are used to evaluate the same piece of equipment.

The RBI process, shown in the simplified block diagram in Figure 4, depicts the essential elements of inspection planning based on risk analysis. This diagram is applicable to Figure 3 regardless of which RBI approach is applied, i.e. each of the essential elements shown in Figure 4 are necessary for a complete RBI program regardless of approach (qualitative, semi-quantitative, or quantitative).

分析结果共享与对比, 值得注意:不同的设备(所在地)分析或不同的方法被用来分析同一台设备时, 所得到的分析结果, 除非相同或非常相似的方法和假设被运用可能有明显差异.


基于风险分析的检查规划基本要素


6.4 Precision vs Accuracy 精度与准确度

It is important to understand the difference between precision and accuracy when it comes to risk analysis.

Accuracy is a function of the analysis methodology, the quality of the data and consistency of application while 准确度受控于; 分析方法,数据的质量,应用程序的一致性. (计算结果偏离实际)

precision is a function of the selected metrics and computational methods. 精确度受控于; 选定指标与计算方法 (计算数据一致性)


methodology,data quality,consistency

Metrics, computation methods

Accuracy precision


Risk presented as a precise numeric value (as in a quantitative analysis) implies a greater level of accuracy when compared to a risk matrix (as in a qualitative analysis). However, the implied linkage of precision and accuracy may not exist because of the element of uncertainty that is inherent with probabilities and consequences. The basis for predicted damage and rates, the level of confidence in inspection data and the technique used to perform the inspection are all factors that should be considered. 概率和后果固有的不

确定性因素导致精度和准确度连锁性可能不存在


In practice, there are often many extraneous factors that will affect the estimate of damage rate (probability) as well as the magnitude of a failure (consequence) that cannot be fully taken into account with a fixed model. Therefore, it may be beneficial to use quantitative and qualitative methods in a complementary fashion to produce the most effective and efficient assessment.

概率和后果固有的不确定性因素导致精度和准确度连锁性可能不存在. 使用定量和定性互补的综合方式来达到有效与高效的分析法.


Therefore, it may be beneficial to use quantitative and qualitative methods in a complementary fashion to produce the most effective and efficient assessment.定量和定性互补方式为佳 !


定量和定性互补方式为佳 !


Quantitative analysis uses logic models to calculate probabilities and consequences of failure. Logic models used to characterize materials damage of equipment and to determine the COFs typically can have significant variability and therefore could introduce error and inaccuracy impacting the quality of the risk assessment. Therefore, it is important that results from these logic models are validated by expert judgment. The accuracy of any type of RBI analysis depends on using a sound methodology, quality data, and knowledgeable personnel and is important to any type of RBI methodology selected for application.

定量分析采用逻辑模型通常有显著误差,引入错误和不准确数据而影响的风险评估的质量- 任何类型的基于风险检验的分析的准确度取决于使用合理的方法,数据质量,和熟悉情况的人员


Quantitative analysis uses logic models to calculate probabilities and consequences of failure. ………….Therefore, it is important that results from these logic models are validated by expert judgment.


6.5 Understanding How RBI Can Help to Manage Operating Risks 认识 RBI 如何管理操作风险

The mechanical integrity and functional performance of equipment depends on the suitability of the equipment to operate safely and reliably under the normal and abnormal (upset) operating conditions to which the equipment is exposed. In performing an RBI assessment, the susceptibility of equipment to damage by one or more mechanisms (e.g. corrosion, fatigue and cracking) is established. The susceptibility of each equipment item should be clearly defined for the current and projected operating conditions including such factors as:

a) normal operation, 正常操作b) upset conditions, 非正常操作c) normal start-up and shutdown, 正常启动和关机d) idle or out-of-service time,闲置或非操作时间e) emergency shutdown and subsequent start-up.紧急停机和后续开机

明确每台设备在以上操作/状况下,对一个或多个损伤机理的易感性.


Process variables that should be considered for each operating condition include, but are not limited to:应该考虑为每个操作条件过程变量包括

a) process fluid, contaminants and aggressive components; 工艺流体,污染物和侵略性成分

b) pressures, including cyclic and transient conditions;压力,包括周期和瞬态条件

c) temperatures, including cyclic and transient conditions; 温度,包括周期和瞬态条件

d) flow rates;流量e) desired unit run length between scheduled shutdowns (turnarounds).

周转期


The suitability and current condition of the equipment within the established IOW will determine the POF (see Section 10) of the equipment from one or more damage mechanisms. This probability, when coupled with the associated COF (see Section 11) will determine the operating risk associated with the equipment item (see Section 12), and therefore the need for mitigation, if any, such as inspection, metallurgy change or change in operating conditions (see Section 13 and Section 14).

在允许的工艺操作条件下, 不同的损伤机理造成的失效结果与相应的概率将确定设备风险.如果有的话通过(1) 检验, (2) 冶金变化或 (3) 改变操作条件来降低相关风险.


Since risk is dynamic (i.e. changes with time) it is vital that any RBI process that is developed or selected for application have the ability to be easily updated (including changes in the inspection plan) when changes occur or new information is discovered.风险是动态的; 相应的分析与检验计划也必要易于更新.


Those changes might include such things as: 更新项

a) new data from inspection activities (i.e. changes in rates of deterioration are noted in external, internal, or on-stream inspections);从检查活动的新数据,

b) changes in operation, operating variables or operation outside of the IOW;操作中的变化,操作变量,

c) changes in the process fluids, however small; 任何改变工艺流体d) changes in process equipment, including additions;改变工艺设(包括增加),e) equipment leaks or failures.设备泄漏或故障,

Any and all of this type of information must be communicated on a timely basisso that changes in the inspection plan can be made, as necessary.信息必须及时传达,检验计划可根据需要更改


6.6 Management of Risks 风险管理6.6.1 Risk Management Through Inspection通过检验风险管理

The objective of RBI is to direct management’s decision process of prioritizing resources to manage risk.

RBI的目的是引导管理层对管理风险的资源运用优先次序决策.

Inspection influences the uncertainty of the risk associated with pressure equipment primarily by improving knowledge of the deterioration state and predictability of the POF. Although inspection does not reduce risk directly, it is a risk management activity (provider of new information) that may lead to risk reduction.

检验虽然不能直接的降低风险,然而能提供对受压;

1. 设备的劣化状态的了解和2. 增加故障概率POF可预测性

从而导致降低风险.


The objective of RBI is to direct management’s decision process of prioritizing resources to manage risk. RBI 的目的是引导管理层对管理风险的资源运用优先次序决策.


Impending failure of pressure equipment is not avoided by inspection activities unless the inspection precipitates risk mitigation activities that change the POF. In-service inspection is primarily concerned with the detection and monitoring of deterioration.

在役检查主要关注点是发现和监测设备退化. 检查活动并不能避免压力设备即将出现的故障,除非检查活动导致风险缓解从而改变故障概率.


The POF due to such deterioration is a function of four factors:设备退化影响故障概率的因素有四个

a) deterioration type and mechanism,退化类型和机理,b) rate of deterioration,劣化率,c) probability of identifying and detecting deterioration and predicting future

deterioration states with inspection techniques, 所使用的检查方法, 识别和检测恶化并预测未来的恶化状态的概率,

d) tolerance of the equipment to the type of deterioration. 设备对相关劣化容忍性,


1. 退化类型和机制2. 劣化率3. 所使用的检查方法可探性4. 设备对相关劣化容忍性.


6.6.2 Using RBI to Establish Inspection Plans and Priorities 建立检验计划和优先事项

The primary product of an RBI effort should be an inspection plan for each equipment item evaluated. RBI is a logical and structured process for planning and evaluating inspection activities for pressure equipment. The inspection plan should detail the unmitigated risk related to the current operation. For risks considered unacceptable, the plan should contain the mitigation actions that are recommended to reduce the unmitigated risk to acceptable levels.

检验计划应详细说明当前操作中的设备可能存在的未缓和风险. 对于存在不可接受的风险的设备, 该计划应包含减缓行动以减少风险到可接受的水平


For those equipment items where inspection is a cost-effective means of risk management, the plans should describe the type, scope and timing of inspection/examination recommended. Ranking of the equipment by the unmitigated risk level allows users to assign priorities to the various inspection/examination tasks. The level of the unmitigated risk should be used to evaluate the urgency for performing the inspection.

该计划应说明检验/检查建议的类型, 范围和时间. 设备风险等级/顺序应该被用于评估检查的紧迫性.


该计划应说明检验/检查建议的类型, 范围和时间. 设备风险等级/顺序应该被用于评估检查的紧迫性.


6.6.3 Evaluation and Fitness-For-Service Analysis 评估与适用性分析

Evaluation of the results of the inspection and examination activities and conducting an assessment of fitness for continued service are also key parts of the RBI process. Although the reduction in uncertainty provided by the inspection process can help to better quantify the calculated risk, without evaluation of inspection results and assessment of equipment Fitness-For-Service after the inspection, effective risk reduction may not be accomplished.

The Fitness-For-Service assessment is often accomplished through the knowledge and expertise of the inspector and engineers involved when deterioration is within known acceptable limits, but on occasion will require an engineering analysis such as those contained in API 579-1/ASME FFS-1.

适用性分析一般上是由牵涉的检查员和工程师运用相关知识和专业技能完成, 然而很多时候需要更加详细的工程分析来完成此项工作(例如API 579-1/ASME FFS-1)


6.6.4 Other Risk Management 其他风险管理

Some risks cannot be adequately managed by inspection alone. Exampleswhere inspection may not be sufficient to manage risks to acceptable levelsare:一些风险不能单独被检查得到充分管理

a) equipment nearing retirement; 设备即将退休b) failure mechanisms (such as brittle fracture, fatigue) where avoidance of

failure primarily depends on design and operating within a defined pressure/temperature envelope;失效机理(如脆性断裂,疲劳) 失效主要取决于设备的设计和操作.

c) consequence-dominated risks.结果支配风险

In such cases, non-inspection mitigation actions (such as equipment repair,replacement or upgrade, equipment redesign or maintenance of strict controlson operating conditions) may be the only appropriate measures that can betaken to reduce risk to acceptable levels. See Section 14 for methods of riskmitigation other than inspection.


non-inspection mitigation 非检查缓解

In such cases, non-inspection mitigation actions such as;

1. equipment repair,设备维修2. replacement or upgrade,更换或升级3. equipment redesign or重新设计4. maintenance of strict controls on operating conditions 严格控制操作条件

may be the only appropriate measures that can be taken to reduce risk toacceptable levels. See Section 14 for methods of risk mitigation other thaninspection.


6.7 Relationship Between RBI and Other Risk-Based and Safety Initiatives RBI和其他基于风险的安全举措之间的关系

6.7.1 General 综合The risk-based inspection methodology is intended to complement other risk-based and safety initiatives. The output from several of these initiatives can provide input to the RBI effort, and RBI outputs may be used to improve safety and risk-based initiatives already implemented by organizations. Examples of some of these other initiatives are:

LOPACCPS risk assessment techniques

SILASME risk assessment publications

safeguarding analysisACC responsible care

PHAEPA risk management programs

RCMOSHA PSM programs


The relationship between RBI and several initiatives is described in 6.7.2 through 6.7.4.

RBI旨在补充其他基于风险和安全步骤(方法). 这些其他举措的输出也可以作为RBI 信息输入. RBI 输出可用于提高其他已经实施基于风险的举措的安全性.


RBI和其他基于风险的安全举措之间的关系- 旨在补充其他基于风险和安全举措.


6.7.2 PHAA Process Hazard Analysis (PHA) uses a systemized approach to identify and analyze hazards in a process unit. The RBI study can include a review of the output from any PHA that has been conducted on the unit being evaluated.

Hazards associated with potential equipment failure due to in-service degradation identified in the PHA can be specifically addressed in the RBI analysis. Potential hazards identified in a PHA will often affect the POF side of the risk equation. The hazard may result from a series of events that could cause a process upset, or it could be the result of process design or instrumentation deficiencies. In either case, the hazard may increase the POF, in which case the RBI assessment could reflect the same.

PHA 往往会影响风险方程的POF侧Risk = Probability × Consequence


Some hazards identified affect the consequence side of the risk equation. For example, the potential failure of an isolation valve could increase the inventory of material available for release in the event of a leak. The consequence calculation in the RBI procedure could be modified to reflect this added hazard. Likewise, the results of an RBI assessment can significantly enhance the overall value of a PHA and help to avoid duplicate effort by two separate teams looking at the risk of failure.


6.7.3 PSM Process Safety Management 工艺安全管理

An effective PSM system can significantly reduce risk levels in a process plant (refer to OSHA 29 CFR 1910.119 and API 750). RBI may include methodologies to assess the effectiveness of the management systems in maintaining mechanical integrity. The results of such a management systems evaluation are factored into the risk determinations. Several of the features of an effective PSM program provide input for an RBI study. Extensive data on the equipment and the process are required in the RBI analysis, and output from PHA and incident investigation reports increases the validity of the study. In turn, the RBI program can improve the mechanical integrity aspect of the PSM program.


An effective PSM program includes a well-structured and effective pressure equipment inspection program. The RBI system will improve the focus of the inspection plan, resulting in a strengthened PSM program.RBI 程序可以提高PSM程序的机械完整性方面

Operating with a comprehensive inspection program should reduce the risks of releases from a facility and should provide benefits in complying with safety-related initiatives.


6.7.4 Equipment Reliability 设备可靠性

Equipment reliability programs can provide input to the probability analysis portion of an RBI program. Specifically, reliability records can be used to develop equipment failure probabilities and leak frequencies. Equipment reliability is especially important if leaks can be caused by secondary failures, such as loss of utilities.

Reliability efforts, such as reliability centered maintenance (RCM), can be linked with RBI, resulting in an integrated program to reduce downtime in an operating unit. At facilities with an effective RBI program, the RCM program can typically focus on the reliability aspects of equipment other than pressure equipment, and perhaps just focus on the reliability aspects of pressure equipment that do not pertain to loss of containment (e.g. tray damage and valve reliability).


6.8 Relationship with Jurisdictional Requirements 与司法要求的关系

Codes and legal requirements vary from one jurisdiction to another. In some cases, jurisdictional requirements mandate specific actions such as the type of inspections and intervals between inspections. In jurisdictions that permit the application of the API inspection codes and standards, RBI should be an acceptable method for establishing inspection plans and setting inspection due dates. All users should review their jurisdictional code and legal requirements for acceptability of using RBI for inspection planning purposes. The fact that some jurisdictions may have some prescriptive time-based rules on inspection intervals do not preclude the user from gaining significant benefits from the application of RBI, as long as jurisdictional requirements are met and as long as the local regulations do not specifically prohibit the use of RBI planning.


Those benefits can include:

a) application of RBI can provide evidence of sound risk management and integrity monitoring programs that can be used as a basis for advocating adoption of RBI by jurisdictions,

b) application of RBI can provide evidence of fulfilling requirements of meeting specific industry standards as well as other types of asset integrity programs,

c) application of RBI can provide a basis for reducing risk further than what may be achieved through time-based inspection rules.


7 Planning the RBI Assessment评估计划


Contents

7 Planning the RBI Assessment 7.1 Getting Started 7.2 Establishing Objectives and Goals of an RBI Assessment 7.3 Initial Screening 7.4 Establish Operating Boundaries 7.5 Selecting a Type of RBI Assessment 7.6 Estimating Resources and Time Required


7.1 Getting Started 开始This section helps a user determine the scope and the priorities for an RBI assessment. Screening is done to focus the effort. Boundary limits are identified to determine what is vital to include in the assessment. The organizing process of aligning priorities, screening risks, and identifying boundaries improves the efficiency and effectiveness of conducting the RBI assessment and its end-results in managing risk. An RBI assessment is a team-based process. At the beginning of the exercise, it is important to answer the following questions.分析作业前需要确定的几点


What codes and standards are applicable?

How the RBI assessment will be carried out?

What data is to be used in the assessment?

Why the assessment is being done?

Which facilities, assets, and components will be included?

What is the plan period?Who is responsible and accountable for what actions?

How the results will be used?What are their roles in the RBI process?

How long the assessment will remain in effect and when it will be updated?

Who is on the RBI team?

When the assessment will be completed?

What knowledge and skills are required for the assessment?


At the conclusion of the planning portion of the development of the RBI program, the following should have been completed: 以下为整个计划必须完成的前期规划点

a) establish the objectives of the risk analysis, 建立风险分析的目标b) identify the physical boundaries, 识别物理边界c) identify the operating boundaries, 确定操作范围d) develop screening questions and criteria consistent with the objectives of the

analysis and identified physical and operating boundaries.根据上述三点, 开发筛选问题和一致准据


识别物理边界


确定操作范围


Once this portion of the RBI planning process has been completed, the data and information required for collection should be identified (see Section 8). Note that it may be necessary to revise the objectives, boundaries, screening questions, etc., based upon the availability and quality of the data and information.

当上述的事项认明后, 需要收集的数据和资料应相应的确定与开始收集.需要注意的是, 上述的变数可能按照需要做修改.


7.2 Establishing Objectives and Goals of an RBI Assessment 确立目标和目的

7.2.1 General 明确7.2.2 Understand Risks 认识风险7.2.3 Define Risk Criteria 风险准据定义7.2.4 Management of Risks 风险管理7.2.5 Reduce Costs 降低成本7.2.6 Meet Safety and Environmental Management Requirements 环保要求7.2.7 Identify Mitigation Alternatives 确定缓解的替代7.2.8 New Project Risk Assessment 新的项目风险评估7.2.9 Facilities End of Life Strategies 临近终使用期策略


7.2 Establishing Objectives and Goals of an RBI Assessment 确立目标和目的

7.2.1 General 明确An RBI assessment should be undertaken with clear objectives and goals that are fully understood by all members of the RBI team and by management. Some examples are listed in 7.2.2 to 7.2.9.

7.2.2 Understand Risks 认识风险An objective of the RBI assessment may be to better understand the risks involved in the operation of a plant or process unit and to understand the effects that inspection, maintenance and mitigation actions have on the risks.From the understanding of risks, an inspection program may be designed that optimizes the use of inspection and plant maintenance resources.从认识风险,设计一份检验计划来完善检验工作和利用实际的工厂维护资源.


7.2.3 Define Risk Criteria 定义风险准据An RBI assessment will determine the risk associated with the items assessed. The RBI team and management may wish to judge whether the individual equipment item and cumulative risks are acceptable. Establishing risk criteriato judge acceptability of risk could be an objective of the RBI assessment if such criteria do not exist already within the user’s company. 制定风险数据来判断风险的可接受性

7.2.4 Management of Risks 风险管理When the risks are identified, inspection actions and/or other mitigation that have a positive effect in reducing risk to an acceptable level may be undertaken. These actions may be significantly different from the inspection actions undertaken during a statutory or certification type inspection program. The results of managing and reducing risk are improved safety, avoided losses of containment, and avoided commercial losses. 当风险被识别后, (1) 检测和/或(2) 其他缓解活动, 将进行来降低风险到可接受的水平. 这些工作/活动或许显著不同法定或认证检验要求.


7.2.5 Reduce Costs 降低成本Reducing inspection costs is usually not the primary objective of an RBIassessment, but it is frequently a side effect of optimization. When theinspection program is optimized based on an understanding of risk, one ormore of the following cost reduction benefits may be realized:减少检查费用通常不是首要目标但它是经常优化的副作用

a) ineffective, unnecessary or inappropriate inspection activities may be eliminated;无效的,不必要的或不适当的视察活动可能被淘汰

b) inspection of low-risk items may be eliminated or reduced;低风险的项目进行检查也可以消除或减少

c) on-line or noninvasive inspection methods may be substituted for invasive methods that require equipment shutdown; 在职非介入检验代替介入检验, 这样能避免停机.

d) more effective infrequent inspections may be substituted for less effective frequent inspections.更有效的低频繁代替低效频繁检验


7.2.6 Meet Safety and Environmental Management Requirements 符合安全标准和环境管理要求Managing risks by using RBI assessment can be useful in implementing an effective inspection program that meets performance-based safety and environmental requirements. RBI focuses efforts on areas where the greatest risks exist. RBI provides a systematic method to guide a user in the selection of equipment items to be included and the frequency, scope, and extent of inspection activities to be conducted to meet performance objectives. 在实施有效的检查计划也带来符合基于性能的安全性及环保要求.


7.2.7 Identify Mitigation Alternatives 缓解选择识别The RBI assessment may identify risks that may be managed by actionsother than inspection. Some of these mitigation actions may include but arenot limited to:可以通过其他行动替代检查来管理风险相有;

a) modification of the process to eliminate conditions driving the risk; 工艺修改.(降低POF/COF)

b) modification of operating procedures to avoid situations driving the risk; 修改操作程序.(降低POF/COF)

c) chemical treatment of the process to reduce deterioration rates/susceptibilities;化学处理(降低POF)

d) change metallurgy of components to reduce POF;改变组件的冶金降低故障概率POF


e) removal of unnecessary insulation to reduce probability of corrosion under insulation; 去除不必要的保温层以减少腐蚀的概率(降低POF)

f) reduce or limit available inventories to reduce COF; 减少或限制设备编制(库存)降低COF

g) upgrade safety, detection or loss limiting systems;提升安全性,检测或流失限制系统(降低COF)

h) change process fluids to less flammable or toxic fluids;改变工艺流体不易燃或有毒液体(降低COF)

i) change component design to reduce POF;更改组件的设计达到降低POFj) process control and adherence to IOW.

过程控制和严守操作工艺界限.(降低POF/COF)


The data within the RBI assessment can be useful in determining the optimum economic strategy to reduce risk. The strategy may be different at different times in a plant’s life cycle. For example, it is usually more economical to modify the process or change metallurgy when a plant is being designed than when it is operating. 缓解策略在不同的周期而别(如运作/设计阶段)


The RBI assessment may identify risks that may be managed by actions other than inspection. …..

HOW INSPECTION MANAGEED RISK?

一句老话: 质量不是检出的!


7.2.8 New Project Risk Assessment 新建项目风险评估An RBI assessment made on new equipment or a new project, while in the design stage, may yield important information on potential risks. This may allow potential risks to be minimized by design and have a risk-based inspection plan in place prior to actual installation.新的项目风险评估有利于通过设计小化潜在的风险


New Project Risk Assessment


7.2.9 Facilities End of Life Strategies 设施使用寿命后期策略

Facilities approaching the end of their economic or operating service life are a special case where application of RBI can be very useful. The end of life case for plant operation is about gaining the maximum remaining economic benefitfrom an asset without undue personnel, environmental or financial risk.

End of life strategies focus the inspection efforts directly on high-risk areas where the inspections will provide a reduction of risk during the remaining life of the plant. Inspection activities that do not impact risk during the remaininglife are usually eliminated or reduced. 不影响风险的检验活动减少或删除而关注

高风险项目

End of life inspection RBI strategies may be developed in association with a Fitness-For-Service assessment of damaged components using methods described in API 579-1/ASME FFS-1. It is important to revisit the RBI assessment if the remaining plant life is extended after the remaining life strategy has been developed and implemented. 可以结合适用性评估作为更加有效的策略.


7.3 Initial Screening 初步筛选7.3.1 GeneralThe screening process focuses the analysis on the most important group of equipment items so that time and resources are more effectively utilized.焦点设备项目重要的一组

7.3.2 Establish Physical Boundaries of an RBI Assessment 物理界限Boundaries for physical assets included in the assessment are established consistent with the overall objectives. The level of data to be reviewed and the resources available to accomplish the objectives directly impact the extent of physical assets that can be assessed.来完成目标的数据水平和可用的资源影响物理界限

The scope of an RBI assessment may vary between an entire refinery or plant and a single component within a single piece of equipment. Typically, RBI is done on multiple pieces of equipment (e.g. an entire process unit) rather than on a single component. 评估范围可从全厂或小至设备的某组件. 一般来说评估范围为多个设备(例如,整个处理单元)


Typically, RBI is done on multiple pieces of equipment (e.g. an entire process unit) rather than on a single component.一般来说评估范围为多个设备 (例如,整个处理单元)


Screening Levels

1. Facilities

2. Process Units

3. Systems

4. Equipments


Facility-Plant


http://www.energyimages.com/refineryschematic.jpg

Facility-Units



process units



System – Sour Water Striper



System – CS Vessel 230psig, 230ºC , c=3mm


Equipment -Sour Water Striper Column, Condenser & CS Vessel


7.3.3 Facilities Screening 设备筛选At the facility level, RBI may be applied to all types of plants including but notlimited to:

a) oil and gas production facilities,石油和天然气生产设施b) oil and gas processing and transportation terminals,

石油和天然气加工和运输终端c) refineries,炼油厂d) petrochemical and chemical plants,石化和化工厂e) pipelines and pipeline stations,管道和管道站f) liquified natural gas plants.液化天然气工厂


石油和天然气生产设施


石油和天然气加工和运输终端


炼油厂


石化和化工厂


管道和管道站


液化天然气工厂


Examples of key questions to answer at the facility level are listed as follows.

a) Is the facility located in a regulatory jurisdiction that will accept modifications to statutory inspection intervals based on RBI? 基于风险分析方法被法定接受吗?

b) Is the management of the facility willing to invest in the resources necessary to achieve the benefits of RBI? 设施管理层愿意投资吗?

c) Does the facility have sufficient resources and expertise available to conduct the RBI assessment?是否有足够的资源和专门知识来进行评估?


facility level


设施水平需要回答的关键问题:(1) 基于风险分析方法被法定接受吗?


(2) 设施管理层愿意投资吗?


(3) 是否有足够的资源和专门知识来进行评估?


Screening at the facility level may be done by a simplified qualitative RBI assessment. Screening at the facility level could also be done by:设施水平可能通过一个简化的定性评估完成. 帅选因素有

a) asset or product value,资产或产品价值b) history of problems/failures at each facility, 在每个设施的问题/故障历史c) PSM (process safety management) /non-PSM facilities, PSM /非PSM设施d) age of facilities,设施的年龄e) proximity to the public,靠近公共设施f) proximity to environmentally sensitive areas.邻近环境敏感地区


Schematic overview of a refinery

炼油厂的总体示意图

http://www.globalspec.com/reference/79004/203279/chapter-3-fuels-from-petroleum-and-heavy-oil


Flow diagram of a typical oil refinery 典型炼油厂流程图


7.3.4 Process Units Screening 工艺装置(处理单元)筛选

If the scope of the RBI assessment is a multi-unit facility, the first step in the application of RBI is screening of entire process units to rank relative risk. The screening points out areas that are higher in priority and suggests which process units to begin with. It also provides insight about the level of assessment that may be required for operating systems and equipment items in the various units. Priorities may be assigned based on one of the following: 帅选全部处理单元, 按照优先级别(相对风险)排名. 优先级别可以根据以下被分配

a) relative risk of the process units,处理单元的相对风险b) relative economic impact of the process units, 处理单元的相对经济影响c) relative COF of the process units, 处理单元的相对的COFd) relative reliability of the process units, 处理单元相对可靠性e) turnaround schedule, 周转时间表f) experience with similar process units. 与同类处理单元经历


Examples of key questions to answer at the process unit level are similar to the questions at the facility level.

a) Does the process unit have a significant impact on the operation of the facility? 评估对设施的运作有显著影响吗?

b) Are there significant risks involved in the operation of the process unit and would the effect of risk reduction be measurable? 能显著降低风险量吗?

c) Do process unit operators see that some benefit may be gained through the application of RBI? 操作者会感受到益处吗?

d) Does the process unit have sufficient resources and expertise available to conduct the RBI assessment? 有充足的资源和专业知识执行评估吗?

e) What is the failure history in this unit? 设施故障历史记录?


Crude Oil instillation 原油蒸馏


Catalytic Reforming 催化转化


Process Units


7.3.5 Systems within Process Unit Screening 处理单元细分下系统筛选

It is often advantageous to group equipment within a process unit into systems, loops, or circuits where common environmental operating conditions exist based on process chemistry, pressure and temperature, metallurgy, equipment design and operating history. By dividing a process unit into systems, the equipment can be screened together saving time compared to treating each piece of equipment separately. In case the risks of each piece of equipment in the system show a common sensitivity to changes in process conditions, then a screening can establish one single IOW with common variables and ranges for the entire system.

Block flow or process flow diagrams for the unit may be used to identify the systems including information about metallurgy, process conditions, credible damage mechanisms and historical problems.

在工艺单元(处理单元);以相同工艺化学, 压力和温度, 冶金, 装备设计和操作历史等, 细分为工艺系统 / 环路有助于节省分析工作.

Charlie Chong/ Fion Zhang

http://en.wikipedia.org/wiki/HydrodesulfurizationHydrodesulfurization加氢脱硫过程

以设备细分为系统 – Condenser System


以相同工艺化学, 压力和温度细分为系统 300psig


以冶金细分为系统 – Carbon Steel


Delayed Coker 延迟焦化装置 – Coke Drum System


Catalytic Reforming 催化转化 – Fire Heater System


When a process unit is identified for an RBI assessment and overall optimization is the goal, it is usually best to include all systems within the unit. Practical considerations such as resource availability may require that the RBI assessment is limited to one or more systems within the unit. 虽然当一个处理单元被确定为RBI评估和整体优化为评估目标, 通常好覆盖处理单元内全部系统.实际的考虑因素可能考虑到可用资源, 评估仅只能限于单元内的一个或多个系统

Selection of systems may be based on the following:择的系统可以基于以下

a) relative risk of the systems, 系统的相对风险b) relative COF of systems, 系统相对COFc) relative reliability of systems, 系统相对可靠性d) expected benefit from applying RBI to a system, 预期效果e) sensitivities of risk to changes in process conditions.

工艺条件变化的风险敏感度，


7.3.6 Equipment Item Screening 设备筛选

In most plants, a large percentage of the total unit risk will be concentrated in a relatively small percentage of the equipment items. These potential high-risk items should receive greater attention in the risk assessment. Screening of equipment items is sometimes conducted to identify the higher risk items to carry forward to more detailed risk assessment. An RBI assessment may be applied to all pressure containing equipment such as: 在很多设施, 很大的总风险比例一般上都集中在一小部分的设备. 筛选识别风险较高的设备进行更详细的风险评估. 被评估的受压设备有;

control valves (pressure boundary). 控制阀 * furnaces and boilers, 炉和锅炉

pressure-relief devices, 压力释放装置heat exchangers, 换热器

compressors (pressure boundary), 压缩机*reactors, 反应器

pumps (pressure boundary), 泵*pressure vessels, 压力容器

tanks, 罐piping, 管系

* (压力边界)


Selection of equipment types to be included is based on meeting the objectives discussed in 7.2. The following issues may be considered in screening the equipment to be included. 设备筛选考虑因素有

a) Will the integrity of safeguard equipment be compromised by damage mechanisms? 设备的完整性会被损坏机理破坏吗?

b) Which types of equipment have had the most reliability problems?哪种设备有可靠性问题?

c) Which pieces of equipment have the highest COF if there is a pressure boundary failure? 压力边界失效哪个设备会有高的COF?

d) Which pieces of equipment are subject to the most deterioration that could affect pressure boundary containment? 哪个设备退化的快导致溶液流失?

e) Which pieces of equipment have lower design safety margins and/or lower corrosion allowances that may affect pressure boundary containment considerations? 哪个设备具较低的设计安全裕度与腐蚀余量导致溶液流失(压力边界围堵)?


A horizontal, recirculatingthermosyphon reboiler循环热虹吸重沸器

Boiler feedwater deaerator锅炉给水除氧器

http://en.wikipedia.org/wiki/User:Mbeychok/MRB%27s_image_gallery


7.3.7 Utilities, Emergency and Off-plot Systems 后勤,应急与外场系统

Whether or not utilities, emergency and off-plot systems should be included depends on the planned use of the RBI assessment and the currentinspection requirements of the facility. Possible reasons for inclusion of off-plot and utilities are listed below as follows.

a) The RBI assessment is being done for an overall optimization of inspection resources and environmental and business COF are included.整体优化(检验/环境/企业影响)

b) There is a specific reliability problem in a utility system. An example would be a cooling water system with corrosion and fouling problems. An RBI approach could assist in developing the most effective combination of inspection, mitigation, monitoring, and treatment for the entire facility.在后勤系统中特定的可靠性问题,RBI作为可信解决方案


c) Reliability of the process unit is a major objective of the RBI analysis.工艺设备的可靠性是RBI分析的一个主要目标

When emergency systems (e.g. flare systems, emergency shutdown systems)are included in the RBI assessment, their service conditions during both routine operations and upset should be considered.急系统评估,应当考虑,设备日常与倾覆运转


7.4 Establish Operating Boundaries 制定操作范围7.4.1 General 总则Similar to physical boundaries, operating boundaries for the RBI study are established consistent with the study objectives, level of data to be reviewed and resources. The purpose of establishing operational boundaries is to identify key process parameters that may impact deterioration. The RBI assessment normally includes review of both POF and COF for normal operating conditions. Start-up and shutdown conditions as well as emergency and non-routine conditions should also be reviewed for their potential effect on POF and COF.

制定操作范围的目的是识别可能会影响恶化的关键工艺参数. 在启动/关机以及紧急和非常规条件下操作对 POF/COF 潜在影响也是审查项.


The operating conditions, including any sensitivity analysis, used for the RBI assessment should be recorded as the operating limits for the assessment.Operating within the boundaries is fundamental to the validity of the RBI studyas well as good operating practice. It is vital to establish and monitor key process parameters that may affect equipment integrity to determine whether operations are maintained within boundaries (i.e. IOWs).

操作条件, 包括任何的敏感性分析作为 RBI分析参数, 应记录为操作限制. 在这限制下操作也是风险评估的有效性基础, 以及有效性良好的运行实践


7.4.2 Start-up and Shutdown 启动和关机Process conditions during start-up and shutdown can have a significant effect on the risk of a plant especially when they are more severe (likely to cause accelerated deterioration) than normal conditions, and as such should be considered for all equipment covered by the RBI assessment. A good example is polythionic acid stress corrosion cracking (PTASCC). The POF for susceptible equipment is controlled by whether mitigation measures are applied during shutdown procedures to avoid PTASCC. Start-up lines are often included within the process piping and their service conditions during start-up and subsequent operation should be considered.

启动和关机过程中的工艺条件, 可能对设备加速劣化从而对风险有显著负面影响. 这也是RBI评估应考虑的范围.


7.4.3 Normal, Upset, and Cyclic Operation 正常,颠覆,循环操作

The normal operating conditions may be most easily provided if there is a process flow model or mass balance available for the plant or process unit. However, the normal operating conditions found on documentation should be verified by unit operations personnel as it is not uncommon to find discrepancies between design and operating conditions that could impact the RBI results substantially.

流程模型和物量配平衡的数据一般能很方便的作为平常操作参数的来源,然而这文档数据与现实数据可能存在偏差.这些文档数据应当由生产操作人员核实以导致RBI错误的评估.


the normal operating conditions found on documentation should be verified by unit operations personnel as it is not uncommon to find discrepancies between design and operating conditions that could impact the RBI results substantially.


The following data should be provided: 下列为必须提供的数据

a) operating temperature and pressure including variation ranges,操作温度和压力以及的变化范围

b) process fluid composition including variation with feed composition ranges,过程流体成分变化,包括原料成分波动范围

c) flow rates including variation ranges, 流速包括波动d) presence of moisture or other contaminant species. 含水量与其他污染物

Changes in the process, such as pressure, temperature or fluid composition,resulting from unit abnormal or upset conditions should be considered in theRBI assessment.非正常或颠覆情况导致的工艺参数变化(比如:压力,温度,流体成分,等)也应当作

为评估考虑范围


The RBI assessment on systems with cyclic operation, such as reactor regeneration systems, should consider the complete cyclic range of conditions. Cyclic or intermittent conditions could impact the POF due to some damage mechanisms (e.g. mechanical fatigue, thermal fatigue, corrosion-fatigue, and corrosion under insulation). Examples include pressure swing absorption vessels, catalytic reforming unit regeneration piping systems, deaerator vessels, and insulated equipment that normally operates at higher temperatures but is subjected to periods of inactivity. 再生系统循环操作带来的操作参数范变动也是考虑项.


7.4.4 Operating Time Period 操作时间段

The unit run lengths of the selected process units/equipment is an important limit to consider. The RBI assessment may include the entire operational life, or may be for a selected period. For example, process units are occasionally shut down for maintenance activities and the associated run length may depend on the condition of the equipment in the unit. An RBI analysis may focus on the current run period or may include the current and next-projected run period. The time period may also influence the types of decisions and inspection plans that result from the study, such as inspection, repair, replace, operating, and so on. Projected operational changes are also important as part of the basis for the operational time period.

对于间断性工作与中间维修的设备, 评估可包括在整个运行寿命,或者可以为选定的间隔(当前运作至周转的时间间隔,或更长的间隔时段).


7.5 Selecting a Type of RBI Assessment 选择RBI评估的类型Selection of the type of RBI assessment will be dependent on a variety of

factors, such as:依赖于多种因素

a) is the assessment at a facility, process unit, system, equipment item, or component level;评估的级别; 设施, 处理单元, 系统, 设备项目或组件

b) objective of the assessment;评估的目的c) availability and quality of data;可用性和数据的质量d) resource availability;资源可用性e) perceived or previously evaluated risks;意识或之前的风险评估f) time constraints.时间限制


A strategy should be developed, matching the type of assessment to the expected or evaluated risk. For example, processing units that are expected to have lower risk may only require simple, fairly conservative methods to adequately accomplish the RBI objectives. Whereas, process units which have a higher expected risk may require more detailed methods. Another example would be to evaluate all equipment items in a process unit qualitatively and then evaluate the higher risk items identified more quantitatively. See 6.3 for more on types of RBI assessment.

评估策略应符合分析目的与预期风险; 例如, 风险较低的处理单元可能只需要简单的，相当保守的方法.然而, 有较高预期风险的处理单元需要更详细的方法.

另一个例子是将所有单元设备项目首先做定性评估, 然后确定的高风险项目再对

高风险项目更加的详细的定量评估


评估策略应符合分析目的与预期风险; 例如, 风险较低的处理单元可能只需要简单的，相当保守的方法.然而, 有较高预期风险的处理单元需要更详细的方法.

另一个例子是将所有单元设备项目首先做定性评估, 然后确定的高风险项目再对高风险项目更加的详细的定量评估


7.6 Estimating Resources and Time Required 估算资源及所需时间

The resources and time required to implement an RBI assessment will vary widely between organizations depending on a number of factors including:不同组织之间有很大的差别. 依赖许多因素如

a) implementation strategy/plans,实施策略/计划b) knowledge and training of implementers, 实施者的培训/知识c) availability and quality of necessary data and information,

必要数据/信息的可获取性与质量d) availability and cost of resources needed for implementation,

实施资源可获取性e) amount of equipment included in each level of RBI analysis,设备的数量f) degree of complexity of RBI analysis selected,所选分析的复杂度g) degree of precision required. 精确度要求


The estimate of scope and cost involved in completing an RBI assessment might include the following: 用于完成评估的范围和费用的估算

a) number of facilities, units, equipment items, and components to be evaluated;被评估的设备, 单元, 设备及元件数量,

b) time and resources required to gather data for the items to be evaluated; 收集数据所需要的时间与资源,

c) training time for implementers; 人员培训时间,d) time and resources required for RBI assessment of data and information;

分析资料的时间与资源,e) time and resources to evaluate RBI assessment results and develop

inspection, maintenance, and mitigation plan.评估分析结果,制定检查, 维护和缓解计划的时间与资源.


8 Data and Information Collection for RBI Assessment 数据和信息收集


Contents

8 Data and Information Collection for RBI Assessment 8.1 General 8.2 RBI Data Needs 8.3 Data Quality 8.4 Codes and Standards—National and International 8.5 Sources of Site Specific Data and Information


8.1 General 总则

Utilizing the objectives, boundaries, level of approach and resources identified in Section 7, the objective of this section is to provide an overview of the data that may be necessary to develop an RBI plan. The data collected will provide the information needed to assess potential damage mechanisms, potential failure modes and scenarios of failure that are discussed in Section 9. Additionally, it will provide much of the data used in Section 10 to assess probabilities, the data used in Section 11 to assess consequences and data used in Section 13 to assist in inspection planning.


收集的数据作为评估潜在的损害机制, 故障概率与失效后果所需要的信息按照第七章描述的,设定的目标,范围,处理深度,可用资源收取所应当需要的数据.数据用来作为;

第九章: 分析,损坏机理,失效模式/情景第十章: 分析失效概率第十一章: 分析失效后果第十三章: 策划检验计划


Examples of data sources include: 数据源的例子包括

a) design and construction records; 设计和施工记录b) inspection and maintenance records; 检查和维修记录c) operating and process technology records; 操作和工艺技术记录d) hazards analysis and MOC records; 危害分析和建设部记录e) materials selection records; corrosion engineering records & library/database;

材料选择记录f) cost and project engineering records. 成本和项目工程记录

The precision of the data should be consistent with the RBI method used. The individual or team should understand the precision of the data needed for the analysis before gathering it.

数据的精度应和所用的RBI方法要求一致.


It may be advantageous to combine risk analysis data gathering with otherisk/hazard analysis data gathering (see 6.7) as much of the data may be thesame. (PHA, RCM, QRA)

数据收集时, 可以考虑结合其他风险/危害分析的数据收集


8.2 RBI Data NeedsAn RBI study may use a qualitative, semi-quantitative and/or quantitative approach (see 6.3). A fundamental difference among these approaches is the amount and detail of input, calculations and output. 不同的评估方法需要不同的数据, 这些方法之间的根本区别是; 输入,计算和输出的(1)数量和(2)细节 .

For each RBI approach it is important to document all bases for the study and assumptions from the onset and to apply a consistent rationale. Any deviations from prescribed, standard procedures should be documented.

基点, 假设作为评估的宗旨, 从开始,到运用应当保持一致.任何从新规定,标准/程序的偏差应做记录.


Documentation of unique equipment and piping identifiers is a good starting point for any level of study. The equipment should also correspond to a unique group or location such as a particular process unit at a particular plant site. 每个被评估设备应当有自个唯一的识别号.


不同的评估方法需要不同的数据, 这些方法之间的根本区别是; 输入, 计算和输出的: (1) 数量和 (2) 细节.

基点-假设作为评估的宗旨,从开始,到运用应当保持一致.任何从新规定,标准程序的偏差应做记录.


9. damage mechanisms, rates, and severity; 损伤机制,速度和严重性

10.personnel densities; 人员密度

11.coating, cladding, and insulation data; 涂层,覆层和保温数据

12.business interruption cost; 业务中断成本

13.equipment replacement costs;设备更换成本

14.environmental remediation costs.环境整治费用

1. type of equipment; 设备的类型

2. materials of construction; 结构材料

3. inspection, repair and replacement records; 检查,修理和更换记录

4. process fluid compositions;过程流体成分

5. inventory of fluids; 流体盘点

6. operating conditions; 操作条件

7. safety systems; 安全系统

8. detection systems; 探测系统

Typical data needed for an RBI analysis may include but is not limited to:分析典型数据


8.2.1 Data Needs for Qualitative RBI 定性数据需求

A more qualitative approach typically does not require all of the data mentioned in 8.2. Further, items required only need to be categorized into broad ranges or classified versus a reference point. It is important to establish a set of rules to assure consistency in categorization or classification.

(较)定性的方法通常不要求上述所有提到的数据.牵涉的设备只需要分为广义范围或以参考点给以分类

Generally, a qualitative analysis using broad ranges requires a higher level of judgment, skill and understanding from the user than a more quantitative approach. Ranges and summary fields may evaluate circumstances with widely varying conditions requiring the user to carefully consider the impact of input on risk results. Therefore, despite its simplicity, it is important to have knowledgeable and skilled persons perform the qualitative RBI analysis.

通常, 使用范围广泛的定性分析, 要求更明确的判断/技能和用户对设备的了解. 因此,尽管它的简单,进行了定性分析需要更加有知识和技能的人.


通常, 使用范围广泛的定性分析, 要求更明确的判断/技能和用户对设备的了解. 因此, 尽管它的简单,进行了定性分析需要更加有知识和技能的人.


8.2.2 Data Needs for Quantitative RBI 定量分析数据要求

QRA uses logic models depicting combinations of events that could result in severe accidents and physical models depicting the progression of accidents and the transport of a hazardous material to the environment. The models are evaluated probabilistically to provide both qualitative and quantitative insights about the level of risk and to identify the design, site, or operational characteristics that are the most important to risk. Hence, more detailed information and data are needed for a fully quantitative RBI in order to provide input for the models.

定量风险分析, 使用逻辑模型来描述可能导致严重事故发生的组合. 该模型是以概率性评估来提供定性和定量的共同洞察问题. 识别设计, 场地或操作特性对风险的影响. 因此, 需要更详细的信息和数据


8.2.3 Data Needs for Semi-quantitative RBI 进行半定量评估数据需求The semi-quantitative analysis typically requires the same type of data as a quantitative analysis but generally not as detailed. For example, the fluid volumes may be estimated. Although the precision of the analysis may be less, the time required for data gathering and analysis will be less too; however that does not mean that the analysis will be less accurate (see 6.4).

半定量分析通常需要作为定量分析相同类型的数据, 但一般不用那么的详细.虽然分析的精度可能较少, 相应所需的数据收集和分析的时间将减少, 但是, 这并不意味着该分析将是不准确的.


8.3 Data Quality 数据质量

The data quality has a direct relation to the relative accuracy of the RBI analysis. Although the data requirements are quite different for the varioustypes of RBI analysis, quality of input data is equally important no matter whatapproach to RBI is selected. It is beneficial to the accuracy and quality of an RBI analysis to assure that the data input are up to date and validated by knowledgeable persons (see Section 16).

确保证数据输入的是新的和有知识的人进行数据验证.

As is true in any inspection program, data validation is essential for a number of reasons. Among the reasons for inspection data quality errors are:检查数据质量误差,其中的原因有

a) outdated drawings and documentation,过时的图纸和文档b) inspection error, 检查误差c) clerical and data transcription errors, 文书及数据抄写错误d) measurement equipment accuracy. 测量设备的精度


Another potential source of scatter and error in the analysis is assumptions on equipment history. For example if baseline inspections were not performed or documented, nominal thickness may be used for the original thickness. This assumption can significantly impact the calculated corrosion rate early in the equipment life.

The effect may be to mask a high corrosion rate or to inflate a low corrosion rate. A similar situation exists when the remaining life of a piece of equipment with a low corrosion rate requires inspection more frequently.

The measurement error may result in the calculated corrosion rate appearing artificially high or low. It is important that those making assumptions understand the potential impact of their assumptions on the risk calculation.

数据偏差和误差分析, 的另一个潜在来源是对设备历史错误的假设如没有进行设备基线调查导致错误的腐蚀率计算.


This validation step stresses the need for a knowledgeable individualcomparing data from the inspections to the expected damage mechanism and rates. This person may also compare the results with previous measurements on that system, similar systems at the site or within the company or published data. Statistics may be useful in this review.

This review should also factor in any changes or upsets in the process. As mentioned previously, this data validation step is necessary for the quality of any inspection program, not just RBI.

Unfortunately, when this data validation step has not been a priority before RBI, the time required to do it gets included with the time and resources necessary to do a good job on RBI, leaving the wrong impression with some managers believing that RBI is more time consuming and expensive than it should be.数据验证, 是确保任何检查程序质量的必要步骤, 而不是仅限于风险分析检验. 往往这数据验证牵涉到的时间与费用, 错误的只在 RBI 体现, 导致有的管理者感觉RBI 更耗时且昂贵的管理方法.


8.4 Codes and Standards—National and International规范与标准- 国家和国际

In the data collection stage, an assessment of what codes and standards are currently in use for in-service inspection and evaluation, or were in use during the equipment design, is generally necessary. The selection and type of codesand standards used by a facility can have a significant impact on RBI results.

确定使用标准与规范的是重要的. 选用的标准与规范对评估的结果有显著地影响.

Charlie C

hong/ Fion Zhang


8.5 Sources of Site-specific Data and Information 场地特定的数据和信息来源

Information for RBI can be found in many places within a facility. It is important to stress that the precision of the data should match the complexity of the RBI method used (see 6.4). The risk analysis and RBI team should understand the sensitivity of the data needed for the program before gathering any data. It may be advantageous to combine RBI data gathering with other risk/hazard analysis data gathering (e.g. PHA, RCM, QRA) as much of the data overlaps.

数据的精度应和所用的RBI方法一致. 在做数据收集时, 可以考虑结合其他风险/危害分析的数据收集. 如: PHA, RCM, QRA


Potential sources of specific information include but are not limited to: 具体信息的潜在来源包括;

a) design and construction records/drawings: 设计和施工记录/图

P&IDs, process flow diagrams, material selection diagrams (MSDs), etc., 仪表工艺图/工艺流程图/材料选择图

piping isometric drawings, 管线三维图 engineering specification sheets,工程规格表 materials of construction records,施工材料记录 construction QA/QC records, 建设QAQC记录 codes and standards used,规范和使用标准 protective instrument systems,防护仪器系统


Potential sources of specific information include but are not limited to: 具体信息的潜在来源包括;

a) design and construction records/drawings: 设计和施工记录/图

P&ID, process flow diagrams, material selection diagrams (MSDs), etc., 仪表工艺图/工艺流程图/材料选择图

piping isometric drawings, 管线三维图 engineering specification sheets, 工程规格表 materials of construction records, 施工材料记录 construction QA/QC records, 建设QAQC记录 codes and standards used, 规范和使用标准 protective instrument systems, 防护仪器系统


leak detection and monitoring systems, 泄漏检测和监控系统 isolation systems, 隔离系统 inventory records, 库存记录 emergency depressurizing and relief systems, 紧急减压系统及减压系统 safety systems, 安全系统 fire-proofing and fire-fighting systems, 防火和灭火系统 layout; 布置图


b) inspection records:检查记录

schedules and frequency, 时间表和频率 amount and types of inspection, 检查次数和类型 repairs and alterations, 修复与更改 positive material identification (PMI) records, 材料鉴定记录 inspection results; 检查结果

c) process data, 工艺过程数据

fluid composition analysis including contaminants or trace components,流体成分分析包括污染物或痕量组分

distributed control system data, 分布式控制系统数据 operating procedures, 操作程序 start-up and shutdown procedures, 启动和关闭程序 emergency procedures, 应急程序 operating logs and process records, 操作日志和过程记录 PSM, PHA, RCM, and QRA data or reports; 其他安全/风险分析法数据记录


d) MOC records; 设备变动管理记录

e) off-site data and information - if consequence may affect off-site areas; 影响设施的外场信息与数据

f) failure data: 故障数据

generic failure frequency data-industry or in-house,一般的故障频率(数据行业或内部)

industry specific failure data, 行业特定的故障数据 plant and equipment specific failure data, 设施与设备的具体故障数据 reliability and condition monitoring records, 可靠性和状态监测记录 leak data; 泄露数据

g) site conditions: 现场条件

climate/weather records, 气候/天气记录 seismic activity records; 地震活动记录


seismic activity records


h) equipment replacement costs: 设备更换费用

project cost reports, 工程造价的报告 industry databases; 行业数据库

i) hazards data: 危害数据

PSM studies, PHA studies, QRA studies, other site specific risk or hazard studies; 其他风险或危害的研究

j) incident investigations. 事故调查


9 Damage Mechanisms and Failure Modes 损伤机理和失效模式


Contents

9 Damage Mechanisms and Failure Modes 9.1 Introduction 9.2 Damage Mechanisms 9.3 Failure Modes 9.4 Accumulated Damage 9.5 Tabulating Results


9.1 Introduction 概述

This section provides guidance in identifying credible damage mechanisms and failure modes of pressure boundary metallic components that should be included in an RBI analysis. Guidance is also provided in other documents.Damage mechanisms in the hydrocarbon process industry are addressed in API 571. ASME PCC-3 also has some useful information and appendices on damage mechanisms. See 16.2.4 for the type of person with knowledge in materials and corrosion that should be involved in the process.

本节提供指导确定可信的损伤机理和失效模式.其他行业文章也提供这方面的指导,参考文件有;API571ASME PCC-3 Inspection Planning Using Risk-Based Methods


Damage mechanisms include corrosion, cracking, mechanical and metallurgicaldamage. Understanding damage mechanisms is important for:了解损伤的机制是重要的因为有助于以下活动;

a) the analysis of the POF; 失效概率的分析b) the selection of appropriate inspection intervals/due dates, locations and

techniques; 适当的安排检查间隔/到期日期, 位置和选择对应的检验技术c) the ability to make decisions (e.g. modifications to process, materials

selection, monitoring, etc.) that can eliminate or reduce the probability of a specific damage mechanism. 提供足够的信息做可消除或减少特定损伤机制的可能性的决策.


Failure modes identify how the damaged component will fail (e.g. by leakage or by rupture). 失效模式确定损坏的组件将如何失败 (例如, 由泄漏或破裂) Understanding failure modes is important for three reasons: 了解故障模式有三个重要原因(有助于)a) the analysis of the COF, 失效后果的分析b) the ability to make run-or-repair decisions, “运行-或-修复”决策的能力c) the selection of repair techniques. 维修方法的选择


http://dc102.4shared.com/doc/FpEz1KBm/preview.html


9.1.1 Identification of Damage Mechanisms 损伤机理的鉴定

Identification of the credible damage mechanisms and failure modes for equipment included in a risk analysis is essential to the quality and the effectiveness of the risk analysis. The RBI team should consult with a corrosion specialist to define the equipment damage mechanisms, damage modes (optional), and potential failure modes. A sequential approach is as follows.

应咨询腐蚀专家以确定设备损坏机理, 破坏模式(可选), 和潜在的失效模式.做法顺序如下


a) As indicated in Section 7, identify the internal and external operating and environmental conditions, age, design and operational loading. Data used and assumptions made should be validated and documented. Processconditions as well as anticipated process changes should be considered. Identifying trace constituents (ppm) in addition to the primary constituents in a process can be very important as trace constituents can have a significant affect on the damage mechanisms.

识别内部和外部的操作和环境条件,龄期, 设计和运行负荷. 应考虑工艺条件以及预期的变化, 除了主要成分应识别微量成分. 这微量成分可能对损伤机制显著影响.


b) Considering the materials, methods and details of fabrication, develop a list of the credible damage mechanisms that may have been present in past operation, be presently active, or may become active. 开发(1)可能已经存在(2) 在过去的操作中曾经发生或 (3)可能变得活跃, 可信的损害机制的列表

c) Under certain circumstances it may be preferable to list a specific damage mechanism and then list the various damage modes or ways that the damage mechanism may manifest itself. For example, the damage mechanism “corrosion under insulation” may precipitate a damage mode of either generalized corrosion or localized corrosion. Generalized corrosion could result in a large burst while localized corrosion might be more likely to result in a pinhole type leak. All credible failure modes for each damage mechanism or damage mode should be considered.列出具体的损伤机理能造成的多个失效模式列表(比如保温层下腐蚀, 可能带来局部腐蚀或广义腐蚀, 分别得造成针孔型泄漏和大爆裂.

Damage Mechanism→ Damage Modes → Failure Modes→ Failure Scenarios


Damage Mechanism→ Damage Modes → Failure Modes→ Failure Scenarios

Example:

CUI→ Pitting or General Corrosion → Leaks or Bursts → Low COF (water) or High COF (flammable fluid)


d) It is often possible to have two or more damage mechanisms at work on the same piece of equipment or piping component at the same time. Anexample of this could be stress corrosion cracking in combination with generalized or localized corrosion (thinning or pitting).往往是可能有两个或更多的损伤机制, 同时活跃在同一台设备或管道组成件. 如广义/局部腐蚀与应力开裂同时在同个部件活跃.


9.2 Damage Mechanisms 损伤机理

Understanding equipment operation and the interaction with the process environment (both internal and external) and mechanical environment is key to identifying damage mechanisms. Process specialists can provide useful input (such as the spectrum of process conditions, injection points etc.) to aid corrosion specialists in the identification of credible damage mechanisms and rates. For example, understanding that localized thinning may be caused by the method of fluid injection and agitation may be as important as knowing the corrosion mechanism.


Understanding equipment operation and the interaction with the process environment (both internal and external) and mechanical environment is key to identifying damage mechanisms.

了解设备的操作和使用过程中环境(包括内部和外部)的相互作用和机械环境是确认损伤机理的关键点.在这方面, 工艺流程专家能提供有用的信息给以腐蚀专家,可靠的鉴定损伤机理和速率.


equipment operation and the interaction with the process environment


9.3 Failure Modes 失效模式

Once a credible damage mechanisms has been identified, the associated failure mode should also be identified. For example, local thinning could lead to a pinhole leak in the pressure containing boundary. There may be more than one credible failure mode for each damage mechanism. For example, cracking could lead to a through-wall crack with (1) a leak before break scenario or (2) could lead to a catastrophic rupture.

The failure mode will depend on the type of cracking, the geometric orientation of the cracking, the properties of the material of construction, the component thickness, the temperature, and the stress level. Examples of failure modes include: 一旦一个可靠的损伤机制被确定, 相关的故障模式(或多个)也应查明. 故障模式的例子包括

a) pinhole leak,针孔泄漏b) small to moderate leak,小到中等泄漏c) large leak,大量泄漏d) ductile rupture,韧性开口e) brittle fracture.脆性断裂


The risk analysis may, at the discretion of the owner, also include failures other than loss of containment, such as loss of function, tray damage, demister pad failures, coalesce element failures, liquid distribution hardware failures, andheat exchanger tube leaks.

风险分析可在用户的选择下: 除了溶液流失, 还可包括其他故障, 如功能丧失, 托盘的损坏, 除雾器垫故障, 凝聚元件故障, 液体分配系统的硬件故障, 和热交换管的泄

漏


9.4 Accumulated Damage 累积损伤

Damage rates may vary as damage mechanisms progress (i.e. various mechanisms may accelerate or slow or stop completely). In some cases, damage by one mechanism may progress to a point at which a different mechanism takes over and begins to dominate the rate of damage.An evaluation of damage mechanisms and failure modes should include the cumulative effect of each mechanism and/or mode.

损伤机理和失效模式的评价应包括每种机制和/或模式的累积效应


9.5 Tabulating Results 结果制表

The results of a damage mechanisms and failure modes analysis for RBI should indicate:损伤机理和失效模式分析的结果应说明

a) a list of credible damage mechanisms: 可的靠损伤机理列表example: external corrosion; 例如- 外部腐蚀

b) a list of credible damage modes resulting from the damage mechanisms (in 9.5 a): 损伤机理导致的损坏模式example 1: localized thinning,局部变薄example 2: general thinning; 广义变薄

note: Step (b) is optional. Failure modes may be determined directlywithout this intermediate step if desired. 这中间步骤 (b) 是可选的, 如果需要故障模式可以直接确定就可忽略.


c) a ranking of credible failure modes resulting from the damage modes in 9.5 a) and 9.5 b): 顺序排名可靠的失效模式

1. example 1: localized thinning: 局部变薄

- failure mode 1: pinhole leak, - failure mode 2: small leak;

2. example 2: general thinning: 广义变薄

- failure mode 1: pinhole leak, - failure mode 2: small leak, - failure mode 3: large leak, - failure mode 4: rupture.


10 Assessing Probability of Failure (POF) 失效概率评估


Contents

10 Assessing Probability of Failure 10.1 Introduction to Probability Analysis 10.2 Units of Measure in the POF Analysis 10.3 Types of Probability Analysis 10.4 Determination of POF


10.1 Introduction to Probability Analysis 概率分析介绍The probability analysis in an RBI program is performed to estimate the probability of a specific adverse consequence resulting from a loss of containment that occurs due to a damage mechanism(s).

RBI 程序的概率分析是评估一个特点的因一或多个损伤机理, 造成受压设备溶液流失的逆向结果.

The probability that a specific consequence will occur is the product of the POF and the probability of the scenario under consideration assuming that the failure has occurred. This section provides guidance only on determining the POF. Guidance on determining the probability of specific consequences is provided in Section 12. 将发生的特定结果的概率依故障概率与发生故障后正在审议的方案中

的概率

Key words: Probability of specific consequence, POF, probability of the scenario.


POFThe probability of the scenario under consideration

The probability of specific consequence

The probability that a specific consequence will occur is the product of the POF and the probability of the scenario

under consideration


http://www.wermac.org/others/ndt_pressure_testing.html


The probability of the scenario under consideration

POF



The probability of the scenario under consideration

POF


There could be many scenario


Guidance on determining the probability of specific consequences is provided in Section 12.


The POF analysis should address all damage mechanisms to which the equipment being studied is or can be susceptible. Further, it should address the situation where equipment is or can be susceptible to multiple damage mechanisms (e.g. thinning and creep). The analysis should be credible 可信, repeatable 能重复 and documented 必须记录. It should be noted that damage mechanisms are not the only causes of loss of containment. Other causes of loss of containment could include but are not limited to: 但应注意的是, 损伤机理并不是唯一导致溶液流失的原因, 其他原因有

a) seismic activity, 地震活动b) weather extremes, 极端天气c) overpressure due to pressure-relief device failure, 过压,由于减压装置故障d) operator error, 操作失误e) inadvertent substitution of materials of construction, 施工材料无意取代f) design error, 设计错误g) sabotage. 破坏活动

These and other causes of loss of containment may have an impact on thePOF and may be (but typically are not) included in the POF analysis for RBI.


有一定影响但通常不包括在RBI分析

seismic activity


weather extremes


overpressure (under pressure) due to pressure-relief device failure,


operator error


design error


sabotage


http://en.wikipedia.org/wiki/Military_use_of_children

sabotage


10.2 Units of Measure in the POF Analysis 故障概率分析,的计量单位POF is typically expressed in terms of frequency. Frequency is expressed as a number of events occurring during a specific time frame. For probability analysis, the time frame is typically expressed as a fixed interval (e.g. one year) and the frequency is expressed as events per interval (e.g. 0.0002 failures per year). The time frame may also be expressed as an occasion (e.g. one run length) and the frequency would be events per occasion (e.g. 0.03 failures per run).

Time Frame 期限 : (1) fixed interval 固定时间间隔 (2) Occasion 时机 (per run etc.)

故障概率 (POF) 一般上是以频率表示,频率是在特定的时间范围内发生的事件的数次.


For a qualitative analysis, the POF may be categorized (e.g. high, medium and low, or one through five). However, even in this case, it is appropriate to associate an event frequency with each probability category to provide guidance to the individuals who are responsible for determining the probability. If this is done, the change from one category to the next could be one or more orders of magnitude or other appropriate demarcations that will provide adequate discrimination. 个别类别 (高低等)的相应特定概率(数次)关联, 有助于, 有效, 可信的故障频率计量的分配与变动.

http://www.skybrary.aero/index.php/Risk_Assessment


Two examples of this are listed in Table 1 and Table 2.

Table 1—Three Levels of POF


Table 2—Six Levels of POF


10.3 Types of Probability Analysis 概率分析的类型10.3.1 General 概要

The following paragraphs discuss different approaches to the determination of probability. For the purposes of the discussion, these approaches have been categorized as “qualitative” or “quantitative.” However, it should be recognized that “qualitative” and “quantitative” are the end points of a continuum rather than distinctive approaches (see Figure 3). Most probability assessments use a blend of qualitative and quantitative approaches. 大多数概率评估使用混合, 定性和定量方法

The methodology used for the assessment should be structured such that a sensitivity analysis or other approach may be used to assure that realistic, though conservative, probability values are obtained (see 12.4).用于评估的方法,应该灵活操作; 灵敏度分析或其它的方法也可以并用, 以确保获得真实的, 尽管保守的概率值.


10.3.2 Qualitative POF Analysis 故障概率定性分析

A qualitative method involves identification of the units, systems or equipment, the materials of construction and the corrosive components of the processes. On the basis of knowledge of the operating history, future inspection and maintenance plans and possible materials deterioration, POF can be assessed separately for each unit, system, equipment grouping or individual equipment item. Engineering judgment is the basis for this assessment. A POF category can then be assigned for each unit, system, grouping or equipment item. Depending on the methodology employed, the categories may be described with words (such as high, medium, or low) or may have numerical descriptors (such as 0.1 to 0.01 times per year). 定性分析考虑包括识别单元,系统或设备,建材和腐蚀. 工程判断是评估依据. 计量单位可以为描述性如, 高/中/低或数值描述如 0.1~0.01次数/年


10.3.3 Quantitative POF Analysis 故障概率定量分析

There are several approaches to a quantitative probability analysis. One example is to take a probabilistic approach where specific failure data or expert solicitations are used to calculate a POF. These failure data may be obtained on the specific equipment item in question or on similar equipment items. This probability may be expressed as a distribution rather than a single deterministicvalue.概率方法计算方法, 故障数据可在特定有问题的设备项目或类似设备项目获得. 得到的概率可以为一个分布来表示, 而不是一个单一的确定性概率值


Another approach is used when inaccurate or insufficient failure data exists on the specific item of interest. In this case, general industry, company or manufacturer failure data are used. A methodology should be applied to assess the applicability of these general data. As appropriate, these failure data should be adjusted and made specific to the equipment being analyzed by increasing or decreasing the predicted failure frequencies based on equipment specific information. In this way, general failure data are used to generate an adjusted failure frequency that is applied to equipment for a specific application. Such modifications to general values may be made for each equipment item to account for the potential deterioration that may occur in the particular service and the type and effectiveness of inspection and/or monitoring performed. Knowledgeable personnel should make these modifications on a case-bycase basis.

当不准确或不足的故障数据时, 另一种方法是使用一般行业,公司或制造商的故障数据.在适当情况下, 这些故障数据应按照正在分析的具体的设备进行调整. 这数据调整工作应当是由有相关知识的人员进行.


故障概率定量分析有两种数据来源;

明确的设备故障数据概率方法计算; 故障数据可在特定有问题的设备项目或类似设备项目获得. 分析到的概率可以一个分布来表示, 而不是单一的确定性概率值

一般行业,公司或制造商的故障数据当不准确或不足的故障数据时, 另一种方法是使用一般行业,公司或制造商的故障数据.在适当情况下, 这些故障数据应按照正在分析的具体的设备进行调整. 这数据调整工作应当是由有相关知识的人员进行.

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