Functional Safety Terms and Acronyms Glossary - exida - This list of functional safety terms and acronyms has been compiled from a number of sources listed at the end including the IEC 61508, IEC 61511 (ISA84.01) standards. It is meant to provide a general reference for engineers practicing safety lifecycle engineering in the process industry. As such it provides both safety and related non-safety term definitions in a clear useable form. It specifically highlights the most important terms and acronyms from the safety lifecycle standards with working level definitions. The reader is encouraged to pursue IEC 61508 or IEC 61511 for additional definitions and for additional information on applying the safety lifecycle to the process industry.

Safety and related Acronyms From the Laboratory Safety Institute

Other Safety Instrumented Systems Links

The following links are compliments of Emerson Process Management

6.11 Basic Fundamentals Of Safety Instrumented Systems -  This section of a training course explains the basic concepts, definitions and commonly used terms in Safety Instrumented Systems and provide a basic understanding of SIS related concepts.
Selecting Transmitters for Safety Instrumented Systems
7.11 When SIL Suitability is Required for Final Control Elements- Riyaz Ali - Final control elements (control valves or safety shut down valves) are the key components of any closed loop control system, whether used for a basic process control system (BPCS) or for a safety instrumented system (SIS). Financial constraints derive different constructions of valves suitable for throttling vs. on-off applications. However, due to past accidents, reliability has become a key criterion for valve selection process. Many of process industries based on their plant specific experience are tempted to use control valves for safety shut down applications, specifically smaller size valves, which may not be cost-prohibitive. This article provides clarity on when to assign the SIL suitability for valves used in different scenarios (process control vs. safety shut down) and establish criterion to assign safety integrity level (SIL) applicability for “final element”.

SIS/IEC 61508 Frequently Asked Questions
If you go to the following SIS link you can register and download the following very useful documents which cover; 
Basic safety concepts
What is risk? / Reducing risk/ Safety standards
Building your SIS
Physical design/Functional design/ Verification & validation/ Installation & commissioning
Using your SIS
Operations & maintenance/ Modifications/ Decommissioning
The intelligent advantage
Smart SIS

The following Links are compliments of Pilz
Guide to Programmable Safety Systems - A comprehensive guide from Pilz
How functional safety helps to save lives -In this article Ron Bell explains functional safety and looks ahead to the revision of the IEC 61508standard that is due for publication in 2010.This article by Jeanne Erdmann was first published in the January 2008 edition of the IEC's E-TECH. http://www.iec.ch 
The Golden Rules of Risk Assessment - Frank Schrever - At its worst, the risk assessment is a bureaucratic time-waster that does nothing to make workplaces safer. On the other hand, following five golden rules mean risk assessments can be both functional and lifesaving. From Pilz and Manufacturers Monthly. 

The following Links are compliments of  Moore Industries-Pacific, Inc.
The Ups and Downs of Alarms -read about alarms in a Safety Instrumented Systems  environment -Garry Prentice-Moore Industries International -Intech Magazine
Safety Instrumented Systems: The "Logic" of Single Loop Logic Solvers - What can the "new generation" of safety-certified Single Loop Logic Solvers do for you? 
Networked Safety- Mainstream or Marketing? Discussing the advantages and potential caveats of networked safety systems, and specifically the Fieldbus Foundation’s FF-SIF safety protocol, this article offers expert testimony and answers key questions about the technologies. Moore Industries’ Director of Technology, Charles Larson, contributes to the debate noting the considerable benefits of networked safety - from  Automation World
Emphasis on Safety - Rob Stockham, Moore Industries-Europe General Manager and safety expert, looks at the latest method being employed by the UK nuclear industry to access control systems in safety-related and safety-critical applications in power stations
Using HART To Improve Safe Failure Fraction in Protective Measures - Peter Russell -  Evaluation International (EI) is a technology club for large scale users of instruments for measurement and control, their Members wished to show, by the use of simulation testing (and other reliability data not part of this testing), that the combination of a Moore Industries HIM converter, a Moore Industries STA trip-amplifier and a Yokogawa EJX110A pressure transmitter would be suitable for use up to Safety Integrity Level 2 (SIL2). The key to this is the use of diagnostics via HART.

The following excellent papers have been generously provided to ICEWeb with the permission of World Renowned SIS expert Dr Angela E. Summers, Ph.D. President, SIS-TECH Solutions, LLC, 12621 Featherwood Dr., Suite 120, Houston, TX 77034 USA Phone: 281-922-8324 , Fax: 281-922-4362. For more papers and excellent links etc go to  http://www.SIS-TECH.com

SIF Proof Testing Yields Process Sector Reliability Data - William H. Hearn, Patrick Skweres, A. D. Arnold, and Angela E. Summers, Ph.D. - ANSI/ISA 84 requires periodic proof testing of SIFs to demonstrate the correct operation of the loop elements along with sufficient historical documentation to support analysis of discrepancies and validation of the SIF integrity and reliability. The analysis of proof test records is an important element of the quality assurance process necessary to support continued use of installed equipment. The CCPS Process Equipment Reliability Database (PERD) project has developed failure data taxonomies which provide a structure to capture data to support chemical process data collection and analysis. SIS-TECH® has been distributing a device failure rate database for more than 10 years. This paper describes how SIS-TECH® will collect device performance data under a quality plan during periodic SIF proof testing. This data will be contributed to PERD for review and analysis so that SIL Solver® failure rates can be validated against operating environment data.
Overfill Protective Systems - Complex Problem, Simple Solution - Angela E. Summers, Ph.D - Overfills have resulted in significant process safety incidents. Longford (Australia, 1998), Texas City (United States, 2005), and Buncefield (United Kingdom, 2005) can be traced to loss of level control leading to high level and ultimately to loss of containment. A tower at Longford and a fractionating column at Texas City were overfilled, allowing liquid to pass to downstream equipment that was not designed to receive it. The Buncefield incident occurred when a terminal tank was overfilled releasing hydrocarbons through its conservation vents. The causes of overfill are easy to identify; however, the risk analysis is complicated by the combination of manual and automated actions often necessary to control level and to respond to abnormal level events. This paper provides a summary of the Longford, Texas City, and Buncefield incidents from an overfill perspective and highlights 5 common factors that contributed to making these incidents possible. Fortunately, while overfill can be a complex problem, the risk reduction strategy is surprisingly simple.
Lessons Learned While Auditing Automation Systems for PSM Compliance - Angela E. Summers, Ph.D - While reliance on instrumentation has increased at an incredible pace, resources allocated to design and manage the equipment have declined in many companies, leading to more burden and expectations being placed on fewer and fewer people. Quality instrumented system performance relies on a rigorous management system that minimizes human error and equipment failure potential. This paper focuses on safety instrumented systems and applicable process safety management requirements. Observations from assessments and audits are provided, illustrating poor performing instrumented systems, inadequate operating and maintenance procedures, recordkeeping and retention practices, and out-of-date documentation.
Consistent Consequence Severity Estimation -Angela Summers, PhD, PE William Vogtmann and Steven Smolen - Most risk analysis methods rely on a qualitative judgment of consequence severity, overstatement creates excessive risk reduction requirements, understatement results in inadequate risk reduction. This paper provides justification for developing semi-quantitative look-up tables to support a LOPA team's assessment of consequence severity.
Safety Management is a Virtue - Angela E. Summers, Ph.D - This paper discusses various challenges to sustaining safe operation of process equipment. Each challenge is introduced using a Chinese fortune cookie to remind the reader that the barriers against progress are not new but have existed from many years. In most cases, the solutions are also well known and generally require deployment of robust equipment, proven techniques, and competent resources.
IEC 61508 Product Approvals - Veering Off Course - Upon close examination it appears that the product approval process of IEC 61508(1) has veered seriously off course, possibly rendering many safety instrumented system (SIS) applications less reliable than expected or required.
A Process Engineering View of Safe Automation -This step-by-step procedure applies instrumented safety systems (ISS) to continuously reduce process risk.
Quality Assurance in Safe Automation - A perfect process would have no hazards, but perfection is impossible in the real world. Nearly all process units have inherent risk associated with their design and operation. Safe operation is maintained with a risk reduction strategy relying on a wide variety of safety systems. This article focuses on the most common safety systems for managing process deviations during planned operating modes – instrumented safety systems (ISSs), such as safety alarms, safety controls, and safety instrumented systems (SIS). Rigorous quality assurance is necessary to achieve real-world risk reduction, so this article follows the Plan, Do, Check, and Act process to discuss quality assurance and its application to ISS.
Guidelines for Safe and Reliable Instrumented Protective Systems (IPS) - Written with guidance from members of the CCPS’s Guidelines for Safe and Reliable Instrumented Protective Systems subcommittee, author and safety standards expert Dr. Angela Summers explores the decision making processes necessary for the management of the protection systems commonly applied throughout the process industry. Based on the framework defined in the harmonized ANSI/ISA 84.01/IEC 61511 standards, this book provides readers with much-requested guidance in an easy to understand discussion that addresses IPS planning, risk assessment, design, engineering, installation, commissioning, validation, operation, and maintenance activities.
Achieve  Continuous Safety Improvement - This technical paper gives an insight of how to achieve continuous safety improvement.
Continuous Improvement in SIS - Discusses safety culture, Protective Management Systems and how to achieve continuous improvement.
The Evolution of Plant Automation - Most owner/operators continue the practice of implementing separate, and often diverse, platforms for the BPCS and SIS, this paper discusses the reasons behind this.
IEC 61511 and the Capital Project Process - A Protective Management Systems Approach
Random, Systematic, and Common Cause Failure: How do you manage them? - This paper provides an overview of random, systematic, and common cause failures and clarifies the differences in their management within IEC 61511.
Partial Stroke Testing of Block Valves - Chapter, “Partial Stroke Testing of Block Valves”, Instrument Engineers Handbook, Volume 4, Chapter 6.9 - For many operating companies, one of the most difficult parts of complying with the standards is the testing interval often required for final elements, such as emergency isolation valves or emergency block valves, this excellent chapter covers this in detail.
Safety Instrumented Systems - Published in Perry’s Handbook of Chemical Engineering 2007 - Covers Hazard and Risk Analysis, Design Basis,  Requirements Specifications, Engineering, Installation, Commissioning and Validation along with Operating Basis.
The Evolution of the Cookbook - This paper provides examples of simple “cookbook” approaches and illustrates how architectures must evolve when addressing higher integrity levels and/or process reliability.
User Approval of SIS Device -This paper explains the concept of user approval as documented in ANSI/ISA 84.00.01-2004, ANSI/ISA TR84.00.04, and the Center for ChemicalProcess Safety book, Guidelines for Safe and Reliable Instrumented Protective Systems.
Software Implemented Safety Logic - This paper discusses some of the requirements for implementing safety logic via software based systems.
Bridging the Safe Automation Gap Part 1 - Part 1 discusses safe automation on a broad perspective examining safety culture, organization and hazards analysis issues. 
Bridging the Safe Automation Gap Part 2 -Part 2 focuses on instrumented systems and discusses specification, implementation, operation, maintenance, and management of change. 
To Err is Human -It must be recognized in our designs that given the right conditions that all things succumb to human error.
Fault Management Analysis - Examining a device based on repairable or replaceable components may be your best bet for designing failure out of your SIS
Partial-Stroke Testing of Block Valves - This paper discusses the various ways that you can partial stroke test block valves and illustrates the probability of failure on demand calculations. 
Common Cause and Common Sense Designing Failure Out of Your SIS -Angela E. Summers, Ph.D. and Glenn Raney-  The paper will focus on how to identify potential common cause events through the application of industry or internal design standards or through the use of qualitative assessment techniques. 
Improve Facility SIS Performance and Reliability - Angela E. Summers, Ph.D., P.E, President, SIS-TECH Solutions, LP and Bryan A. Zachary, Operations Manager
Introduction to Layer of Protection Analysis -This paper provides an overview of the LOPA process, highlighting the key considerations
High Integrity Protective Systems for Reactive Processes - This paper discusses how to assess, design, and implement HIPS to effectively manage potential overpressure of equipment used for reactive processes.
Perspectives on ANSI/ISA 84.00.01-2004 (IEC61511)-An Emerging International Consensus Standard - Angela E. Summers, Ph.D., P.E., President, SIS-TECH Solutions, LP
Bhopal: Could it Happen Again? - Angela E. Summers, Ph.D., P.E., President, SIS-TECH Solutions, LP
Estimation and Evaluation of Common Cause Failures in SIS - Angela E. Summers, Ph.D., Kimberly A. Ford, and Glenn Raney
Safety Requirements Specification in a Capital Project Environment
Is your SIS "grandfathered" under ANSI/ISA S84.01-2004? - Kimberly A. Ford and Angela E. Summers, Ph.D., P.E.
Avoid Bad Engineering Practices in Safety Instrumented System Design - Angela E. Summers, Ph.D., P.E., President, SIS-TECH Solutions, LLC - As industry races toward compliance, it must work hard to prevent the creation and acceptance of bad engineering practices, which threaten the economics of plant operation and erode the effectiveness of SIS designs. 
Techniques for Assigning a Target Integrity Level - Angela E. Summers, Ph.D.
Using instrumented systems for overpressure protection - Dr. Angela E. Summers, PE, SIS-TECH Solutions, LLC
Viewpoint on ISA TR84.0.02 - Simplified Methods and Fault Tree Analysis - Angela E. Summers, Ph.D., P.E.- Simplified equations and fault tree analysis are two techniques that can be used to verify safety integrity level. The two methods do yield different results but both provide acceptable approximations. 
6.11 Consistent Consequence Severity Estimation - Angela Summers, PhD, PE William Vogtmann and Steven Smolen - Most risk analysis methods rely on a qualitative judgment of consequence severity, regardless of the analysis rigor applied to the estimation of hazardous event frequency. Since the risk analysis is dependent on the estimated frequency and consequence severity of the hazardous event, the error associated with the consequence severity estimate directly impacts the estimated risk and ultimately the risk reduction requirements. Overstatement of the consequence severity creates excessive risk reduction requirements. Understatement results in inadequate risk reduction. Consistency in the Layers of Protection Analysis (LOPA) can be substantially improved by implementing consequence estimation tools that assist team members in understanding theflammability, explosivity, or toxicity of process chemical releases. This paper provides justification for developing semi-quantitative look-up tables to support the team assessment of consequence severity. Just as the frequency and risk reduction tables have greatly improved consistency in the estimate of the hazardous event frequency, consequence severity tables can significantly increase confidence in the severity estimate.
6.11The Interrelationship of Risk Criteria and Conditional Modifiers - Angela E. Summers, Ph.D. PE and William H. Hearn, PE - This paper begins with a brief introduction to risk analysis concepts to provide a foundation for a discussion of the typical analysis boundaries and associated risk criteria. Then, it discusses how the analysis boundary and risk criteria affect the consideration of protection layers, enabling conditions, and conditional modifiers.
1.12 Centralised or Distributed Process Safety - Picking the Best Safety System Architecture cuts Risk and Cost while Simplifying Implementation and Maintenance - Dr. Angela Summers - Process plant safety systems can either be centralized, distributed, or a combination of both. Each approach has its advantages and challenges, with selection of the best option dependent on a variety of factors. This article will examine various safety system architectures and will show process plant users how to pick the best solution to fit their specific needs - from ISAand InTech

The following Links are from Exida
Statistical Signature Analysis: Modeling Complex λD(t) from Proof Test Data and the Effects on Computing PFDavg - Julia V. Bukowski - To compute PFDavg, we must first have a model for λD(t), the failure rate of the equipment in the dangerous failure mode. A dangerous failure occurs when equipment designed for prevention or mitigation of an unsafe condition cannot properly respond to the unsafe condition, i.e., the equipment fails on demand. For example, consider a PRV, which, in normal operation, is closed. Should it fail in the "stuck-shut" mode, it would be in a state of dangerous failure as it would be unable to respond to an overpressure event if one occurred.
Final Elements and the IEC 61508 and IEC 61511 Functional Safety Standards Book - This book reviews and explains the application of the IEC 61508 and IEC 61511 functional safety standards as they apply to final control elements. The overall safety lifecycle and reliability requirements are reviewed with special focus on the challenges encountered when dealing with complex electro-mechanical subsystems. Throughout the book requirements for designing and implementing reliable and effective safety instrumented functions are covered in a clear step by step manner.
61508 and 61511; What Is an Operations Company Supposed to Do? - Eric Scharpf - The typical first reaction from the process operations side of the table when confronted with a new standard is, "How much will this cost and how much extra paperwork will it involve?".... IEC 61508 and 61511, the standards covering the design and use of a safety instrumented system to reduce process plant accidents, are no exception to this initial reaction.
Accurate Failure Metrics for Mechanical Instruments -Dr. William M. Goble -Probabilistic calculations done to verify the integrity of a Safety Instrumented System design require failure rate data and failure mode data of all equipment including the mechanical devices.
Assessment Levels for Safety Equipment - Dr. William M. Goble - The end user must carefully choose all instrumentation equipment used in Safety Instrumented System (SIS) applications. All such equipment must be carefully justified... IEC 61511, Functional Safety for the Process Industries, requires that equipment used in safety instrumented systems be chosen based on either IEC 61507 certification to the appropriate SIL level or justification based on "prior use" criteria.
Common Cause Simulation - Dr. William M. Goble - Fault tolerant systems have been designed for safety critical applications including the protection of potentially dangerous industrial processes.
Development of a Mechanical Component Failure Database -Dr. William Goble & Julia Bukowski - In this paper, they present a methodology to derive component failure rate data for mechanical components used in automation systems based on warranty and field failure rate data as well as expert opinion.
Estimating The Beta Factor - Dr. William M. Goble - A Safety Instrumented System (SIS) is often designed to help protect an industrial process against potentially dangerous hazards. These systems often use redundant equipment to achieve the needed levels of protection. If the design was done to meet requirements of IEC 61511 or IEC 61508, probabilistic evaluation is done to verify that the design achieves risk reduction goals.
Evolution of European Standards - Rainer Faller - Slide show presentation of his Rockwell Automation 2002 speech
FMEDA - Accurate Product Failure Metrics - John C. Grebe and Dr. William Goble - The letters FMEDA form an acronym for "Failure Modes Effects and Diagnostic Analysis." The name was given by one of the authors in 1994 to describe a systematic analysis technique that had been in development since 1998 to obtain subsystem / product level failure rates, failure modes and diagnostic capability.
Getting Failure Rate Data - Dr. William M. Goble - Safety verification calculations for each safety instrumented function are a key concept in functional safety standards like ISA 84.01 and IEC 61511.
IEC 61508 Overview - exida - IEC 61508 is an international standard for the “functional safety” of electrical, electronic, and programmable electronic equipment. This standard started in the mid 1980s when the International Electrotechnical Committee Advisory Committee of Safety (IEC ACOS) set up a task force to consider standardization issues raised by the use of programmable electronic systems (PES). At that time, many regulatory bodies forbade the use of any software-based equipment in safety critical applications. Work began within IEC SC65A/Working Group 10 on a standard for PES used in safety-related systems. This group merged with Working Group 9 where a standard on software safety was in progress. The combined group treated safety as a system issue.
IEC61511 Standard For Functional Safety - exida - IEC 61511 has been developed as a Process Sector implementation of the international standard IEC 61508: "Functional safety of electrical / electronic / programmable electronic safety-related systems."
Implementing IEC61508 In The Process Industries - Dr. Eric W. Scharpf & Dr. William M. Goble - IEC 61508 and its process-specific companion IEC 61511 are providing new codification to safety instrumented systems and their application to the process industry.
Mechanical Database Verification Report -Julia Bukowski - The purpose of this document is to report on exida's successful efforts to validate statistically certain random equipment failure rate data used in a mechanical parts failure rate and failure mode database and, by extension, to validate the techniques used to derive the data. To accomplish this, a Failure Modes, Effects, and Diagnostic Analysis (FMEDA) is initially used to predict the useful- life failure rate for the fail-to-open condition of a particular pressure relief valve (PRV) using the failure rates from the mechanical parts database. Next, this prediction is statistically tested against three independent data sets consisting of proof test data for PRV provided by Fortune 500 operating companies. The data sets all meet the intent of the quality assurance of proof test data as documented by the Center for Chemical Process Safety (CCPS) Process Equipment Reliability Database (PERD) initiative.
Mechanical Failure Rate Data for Low Demand Applications - exida - The use of IEC 61508 [1] and IEC 61511 [2] has increased rapidly in the past several years. Along with the adoption of the standards has come an increase in the need for accurate reliability data for devices used in Safety Instrumented Systems (SIS), both electronic and mechanical. While the methodology of determining failure rates for electronic equipment is fairly well accepted and applied, the same can not be said for mechanical equipment. Several methods are currently being utilized for generating failure rates for mechanical components. These methods vary in their approach and often lead to dramatically different failure rates which can lead to significant differences when calculating the reliability of a safety instrumented function (SIF). Some methods can result in dangerously optimistic failure rate numbers.
Mechanical FMEDA Presentation - Slide show presentation by Dr. William M. Goble
Modeling & Analyzing The Effects Of Periodic Inspection On The Performance Of Safety-Critical Systems - Julia V. Bukowski - This paper presents a method for incorporating into Markov models of safety-critical systems, periodic inspections and repairs which occur deterministically in time.
Open IEC 61508 Certification of Products -Rainer Faller & Dr. William Goble -IEC 61508 has been in use for several years since the final parts were released in 2000. Although written from the perspective of a bespoke system, it is more commonly used to certify products for a given SIL level. Valid product certification schemes must involve the assessment of specific product design details as well as an assessment of the safety management system of the product manufacturer and the personnel competency of those professionals involved in the product creation.
Partial Valve Stroke Testing - Iwan van Beurden - The objective of a Safety Instrumented System (SIS) is to reduce the risk associated with a particular process to a level lower than or equal to the tolerable risk level.
PFDavg Calculations For Redundant Systems With Incomplete Testing - Harry Cheddie - A common definition of a Safety Instrumented Function (SIF) as defined in Functional Safety Standards is "Function to be implemented by a Safety Instrumented System (SIS) to mitigate or prevent a specific hazardous event."
PLC vs Safety PLC - Dr. William M. Goble - Safety Programmable Logic Controllers (PLCs) are special purpose machines that are used to provide critical control and safety applications for automation users. These controllers are normally an integral part of a safety instrumented system (SIS) which are used to detect potentially dangerous process situations.
Project Experience with IEC 61508 and its Consequence - Rainer Faller -  This paper reports on the experiences with implementation of IEC 61508 in recent projects with European, North American and Japanese system vendors. The paper describes problems identified in implementing the standard and proposes a knowledge tool and a combination of software verification methods to mitigate these issues.
Real Time Operating Systems for IEC 61508 - Mike Medoff - In today’s world many potentially dangerous pieces of equipment are controlled by embedded software. This equipment includes cars, trains, airplanes, oil refineries, chemical processing plants, nuclear power plants and medical devices. As embedded software becomes more pervasive so too do the risks associated with it. As a result, the issue of software safety has become a very hot topic in recent years. The leading international standard in this area is IEC 61508: Functional safety of electrical/electronic/ programmable electronic safety-related systems. This standard is generic and not specific to any industry, but has already spun off a number of industry specific derived standards, and can be applied to any industry that does not have its own standard in place. Several industry specific standards such as EN50128 (Railway), DO-178B (Aerospace), IEC 60880 (Nuclear) and IEC 601-1-4 (Medical Equipment), are already in place. Debra Herrmann (Herrmann, 1999) has found a total of 19 standards related to software safety and reliability cut across industrial sectors and technologies. These standards’ popularity is on the rise, and more and more embedded products are being developed that conform to these standards. Since an increasing number of embedded products also use an embedded real time operating system (RTOS), it has become inevitable that products with an RTOS are being designed to conform to such standards. This creates an important question for designers: how is my RTOS going to effect my certification? This article will attempt to explore the challenges and advantages of using an RTOS in products that will undergo certification.
SIL Verification - Dr. William M. Goble - The safety lifecycle (SLC) is one of the fundamental concepts presented in the ANSI/ISA 84.01 and IEC 61508 functional safety standards.
Software - Stress Vs. Strength - Dr. William M. Goble - Considering the components used in the current control systems, hardware failure cause have been widely studied.
Software Safety Technique - Dr. William M. Goble - There is a strong trend toward the use of programmable electronics in safety instrumented systems. yet some users still avoid software-based systems.
State-Of-The-Art Safety Verification - Dr. Eric W. Scharpf & Dr. William M. Goble -The past few years have brought significant changes to the control safety field in both technology (i.e., fieldbus) and regulation (i.e., IEC 61508).
What Does Proven In Use Imply? - Rachel Amkreutz & Iwan van Beurden - The functional safety standards, IEC 61508, IEC 61511, and ANSI/ISA 84.01 each specify the Safety Integrity Level performance parameter of Safety Instrumented Functions.
What is PFDavg.? - Dr. William M. Goble - IEC 61508 requires probabilistic evaluation of each set of equipment used to reduce risk in a safety related system.
The Grandfather Clause and Existing Equipment - Dr. William Goble - International safety standards permit users to utilise a ‘Proven in Prior Use’ methodology to justify  SIS equipment ie., A Grandfather Clause ; but can users take on the responsibility? - Following a recent internally initiated audit of your facility’s SIS, you realized your systems do not meet the “grandfather clause” requirements described in ANSI/ISA 84.01.00. Now you face the task of bringing those systems into conformance with international safety standards. One of the questions your SIS team raised is, “Do our installed transmitters meet the ‘prior use’ requirements described in Section 11.5.3 of IEC 61511-1 – Requirements for the selection of components and subsystems based on prior use?” From the ISA and InTech.
6.11 Three Important Factors in Evaluating your SIL Certified Device - William A. Schwartz and Monica L. Hochleitner - A device’s Architectural Constraints determine immediately which level of Redundancy (HFT) is appropriate for use in a Safety Function with a given SIL requirement. The interpretation of a device’s PFDavg is more complex. It does not determine the product’s Safety Integrity Level (SIL). It determines the device’s contribution to the PFDavg of the Safety Function. As such, the device’s PFDavg must be considered together with the PFDavg’s of other devices with which it will be used, to determine the SIL of the Safety Function. This article addresses these two characteristics separately.
6.11A Brief Discussion over Safety Costs in New Enterprises - Alejandro Esparza and Monica Levy Hochleitner - The starting point of a new industrial plant concerning the levels of reliability required to keep the process under a defined tolerable risk is a challenge most contractors company face. During the embryonic phases, in the bidding process and for budget purposes, a pre-defined Safety Instrumented System (SIS) design must be provided to the contractor, sometimes even before the process conceptual design is well defined. The consequences of such situation, in which no risk analysis have been considered, not only disregards the Safety Lifecycle template suggested by the recent versions of the functional safety standards applied to the process industry, IEC 61511 [1] and ANSI/ISA 84.01 [2] but also implies in unpredictable outcomes. By means of actual examples, where the customers names will be suppressed for confidentiality matters, this paper will present and briefly discuss the pros and cons of some actual applications, the achieved safety of the resulting design and the impact of investments during implementation and operation phases of the enterprise.
6.11Accurate Modeling of Shared Components in High Reliability Applications - This paper addresses how to model and evaluate the Risk Reduction Factor (RRF) of Safety Instrumented Systems when one or more of the components in the SIS can cause the dangerous condition or hazard that the SIS is designed to protect against
6.11Field Failure Data – the Good, the Bad and the Ugly - This paper presents some common field failure analysis techniques, shows some of the limitations of the methods and describes important attributes of a good field failure data collection system
6.11Functional Safety in the Life Science Industries - David Hatch, Iwan van Beurden and Eric W Scharpf - This article presents an overview of functional safety within the life science industry based on international standards.
6.11Position Paper on IEC61508 2010 - Definitions regarding minimum hardware fault tolerance / Architectural Constraints. 
6.11Setting the Standard - How Process Plants can benefit through Proper and Careful Adoption of the IEC 61511 Safety Standard - Dr Peter Clarke -  Process industry safety standard IEC 61511 and its parent, functional safety standard IEC 61508, have been in existence for several years now, and have enjoyed widespread acceptance as an effective method for managing high levels of industrial risk. Despite this success, some may view these standards as another complex, onerous burden imposed by regulators, with little tangible benefit to the end user. However, as we will explore in this article, the reality is far different.
6.11You Asked: Alarm Management - Setting a new Standard for Performance, Safety, and Reliability with ISA-18.2 - Alarm Management affects both the bottom line and plant safety. A well functioning alarm system can help a process run closer to its ideal operating point – leading to higher yields, reduced production costs, increased throughput, and higher quality, all of which add up to higher profi ts. Poor alarm management, on the other hand, is one of the leading causes of unplanned downtime and has been a major contributor to some of the worst industrial safety accidents on record.
6.11 Saved by the Bell: Using Alarm Management to make Your Plant Safer - Recent industrial accidents at Texas City, Buncefield (UK) and Institute, WV have highlighted the connection between poor alarm management and process safety incidents. At Texas City key level alarms failed to notify the operator of the unsafe and abnormal conditions that existed within the tower and blowdown drum. The resulting explosion and fire killed 15 people and injured 180 more. The tank overflow and resultant fire at the Buncefield Oil Depot resulted in a £1 billion (1.6 billion USD) loss. It could have been prevented if the tank’s high level safety switch, per design, had notified the operator of the high level condition or had automatically shut off the incoming flow. At the Bayer facility (Institute, WV) improper procedures, worker fatigue, and lack of operator training on a new control system caused the residue treater to be overcharged with Methomyl - leading to an explosion and chemical release. Accidents like these demonstrate what can happen when an alarm system and operator response fail as a layer of protection in a hazardous process. They also provided the motivation for the new ISA-18.2 standard "Management of Alarm Systems for the Process Industries", which provides a framework for the successful design, implementation, operation and management of alarm systems in a process plant. It offers guidance on how alarm management can be used to help a plant operate more safely. ISA-18.2 can also be used to bring together the disciplines of alarm management and safety system design, which must work more closely to prevent future accidents.
6.11Alarm Management and ISA 18 - A Journey, not a Destination - Todd Stauffer,Nicholas P. Sands and Donald G. Dunn - Poor alarm management is one of the leading causes of unplanned downtime, contributing to over $20B in lost production every year, and of major industrial incidents such as the one in Texas City. Developing good alarm management practices is not a discrete activity, but more of a continuous process (i.e., it is more of a journey than a destination). This paper will describe the new ISA-18.2 standard -"Management of Alarm Systems for the Process Industries"[1]. This standard provides a framework and methodology for the successful design, implementation, operation and management of alarm systems and will allow end-users to address one of the fundamental conclusions of Bransby and Jenkinson that "Poor performance costs money in lost production and plant damage and weakens a very important line of defense against hazards to people." [3] Following a lifecycle model will help users systematically address all phases of the journey to good alarm management. This paper will provide an overview of the new standard and the key activities that are contained in each step of the lifecycle.
6.11Get a life(cycle)! Connecting Alarm Management and Safety Instrumented Systems - Todd Stauffer, Nicholas P. Sands and Donald G. Dunn - Alarms and operator response are one of the first layers of defense in preventing a plant upset from escalating into an abnormal situation. The new ISA 18.2 standard [1] on alarm management recommends following a lifecycle approach similar to the existing ISA84/IEC 61511 standard on functional safety. This paper will highlight where these lifecycles interact and overlap, as well as how to address them holistically. Specific examples within ISA 18 will illustrate where the output of one lifecycle is used as input to the other, such as when alarms identified as a safeguards during a process hazards analysis (PHA) are used as an input to alarm identification and rationalization. The paper will also provide recommendations on how to integrate the safety and alarm management lifecycles.

The following Links are from HIMA Australia
Integration today - Integration solutions - For years people have been discussing the subject of “integration” in automation technology. There are a variety of solutions available for the integration of safety and control systems. Provided the right decision is made you can take advantage of all the opportunities and potential synergies of integration, long-term.
  Summary of Offshore Health and Safety Performance Report 2007-08 - The Offshore Health and Safety Performance Report 2007-08 was produced by the National Offshore Petroleum Safety Authority (NOPSA), with the aim to "move beyond the view of safety as compliance with codes and standards and towards an overall improved safety culture within an organisation. The report contains statistics, trends and observations of health and safety within the Australian offshore petroleum industry for the financial year 2007-08. Areas of concern highlighted include equipment design, risk awareness and management, procedures, ageing equipment, supervision and a shortage of skilled personnel.
Next Generation Safety Controller Maximizes Availability for Demanding Process Applications - The nemesis of all continuous processes is unplanned stoppage resulting from controls malfunction, equipment failure, or operator error. System availability can be improved significantly through the use of redundant control architectures – especially those that allow hot-swapping or on-the-fly program changes. Modern process safety solutions provide comprehensive diagnostics that help users to recognize safety-critical situations and act quickly and accordingly to avoid unnecessary system shutdowns. This paper from ARC highlights why companies should invest in process safety.
NOPSA competence findings in line with AS61511 - The Australian National Offshore Petroleum Safety Authority recently recommended that oil and gas facility operators implement formal staff competency management systems to ensure that basic skills requirements for safe plant operation are met.
Functional Safety: A Practical Approach for End-Users and System Integrators- Tino Vande Capelle,Dr. M.J.M. Houtermans - The object of this paper is to demonstrate through a practical example how an end-user should deal with functional safety while designing a safety instrumented function and implementing it in a safety instrumented system.
Modern 2oo4-Processing Architecture for Safety Systems-Prof. Dr.-Ing. habil. Josef Börcsök -This paper provides an overview of two out of four system architecture and associated considerations. 
Safety Bus Systems -Prof. Dr.-Ing. habil. Josef Börcsök - Modern distributed control systems are connected via bus systems, which need effective and uninterrupted communication between all subscribers. Therefore it is necessary for these communications to be fault tolerant and safe. For safety related systems, additional safety layers are required to fulfil these requirements.
Introduction in Safety Bus Systems-Prof. Dr.-Ing. habil. Josef Börcsök - This paper discusses how modern distributed control systems are connected via bus systems, and need effective and uninterrupted communication between all bus stations. Therefore it is necessary that these communications are fault tolerant and safe. 
Safety Critical Software-Prof. Dr.-Ing. habil. Josef Börcsök -This paper discusses the methodical analysis of hardware architectures used in safety-related applications. It provides an excursus on a safe computer system’s software technology and specifies the overview in greater detail.
Safety Systems -Prof. Dr.-Ing. habil. Josef Börcsök - This technical paper gives an excellent overview of Safety Systems covering development history, the fundamental considerations required, fault avoidance basis and measurement, fault control basis, along with external influences such as environmental demands, electromagnetic, mechanical and climatic considerations.
Comparison of PFD calculation -Prof. Dr.-Ing. habil. Josef Börcsök - This paper discusses the compares calculation methods.
Sharing Control & Safety Instruments-Are your Layers Overlapping?-Dirk Schreier - Since its release as an Australian standard in July of 2004, AS61511 is rapidly being accepted and applied on Safety Instrumented Systems throughout the process industry. Principles such as independence between control and protective instruments have existed for many years; however they continue to often be overlooked even with the introduction of this standard.
Risk Prevention and Mitigation-Where does gas detection fit in?-Dirk Schreier - It is quite common in today's process industry to see the terms fire and gas (F&G). These terms have been used hand in hand for many years and are also combined when referring to applications involving safety-instrumented systems. This article challenges the thinking behind this concept and demonstrates that although fire systems and gas detection systems both reduce risk; their methods are actually quite different.
Legal Implications in Australia for Companies and Individuals under “Industrial Manslaughter”-Dean McNair - There has been a lot of discussion in Australia recently over proposed new occupational health and safety (OH&S) legislation which will include the provision to prosecute corporations and individuals under industrial manslaughter laws. State and territory governments are enacting these new laws in response to workplace deaths in the hope that it will force company directors and senior executives to improve the safety cultures within their organisations.
Safety standard IEC 61508 - Consequences for automation technology and implementation at HIMA -This white paper provides an overview of IEC 61508 and how HIMA have addressed it's requirements.
SIL Assessments -Identification of Safety Instrumented Functions-Dirk Schreier - Since its release as an Australian standard in July of 2004, AS61511 is rapidly being accepted and applied on Safety Instrumented Systems throughout the process industry. AS61511 is a performance based standard with a risk-based approach to safety. Performance based standards are by nature very open to interpretation, and therefore allow for more than just one analysis technique. Some of the techniques currently applied in industry have some shortfalls in achieving the objective of the standard. This article looks at some common problems encountered during the analysis phase of the AS61511 safety lifecycle.
Communication with SafeEthernet -Franz Handermann- The application of SafeEthernet paves the way for the open automation- and network systems of the future.
Safety Considerations
Dr. Josef Börcsök,-Statistical evaluation of HIMA systems in the context of IEC 61508. This article contains the first comprehensive description of IEC 61508-compliant calculation of errors in safety-related systems in general and describes how relevant values for the H41q/H51q systems currently available from HIMA can be calculated. 
Critical Aspects of Safety, Availability and Communication in the control of a subsea gas pipeline- Requirements and Solutions - This is a large zipped file of 2.5 Meg so will take a while to download,  however it is worth it as shows safety related satellite communication.
Transporting gas - with safety first!-Automation of an ethylene pipeline.
Complete Burner Automation with Safety Controllers-A new solution for simple single and multi burner arrangements through to complex BMS applications, e.g. for power plants, waste incineration plants or processing plants. - Looking for more on Burner Management Systems? ICEweb's comprehensive BMS page has it!
Integrated safety controllers with safeethernet - By combining the world's fastest safety controllers "HIMatrix" with the world's fastest safety bus "safeethernet", HIMA is creating a hitherto unknown level of flexibility for safety-related automation. This flexibility is the basis for the development of new potential. The current system limits of safety-related automation concepts are disappearing, paving the way for truly application-based safety solutions. This creates new potential for increasing productivity and reducing the total costs for safety technology.
Comprehensive safety solutions for the South Pars gasfield exploration-ESD, F&G and HIPPS systems from HIMA ensure maximum safety and plant availability.

The following links are from ACM Automation 
HAZOP Budgeting Tool - How long will my HAZOP take? - Experience in facilitating HAZOP studies has provided us with some practical insight into how to budget your time effectively. Here is a 3-step approach for budgeting for your next HAZOP
Achieving High SIL Ratings with Partial Stroke Testing of Valves - Operating companies can substantially increase their SIL (safety integrity level) loop rating if they adopt a rigorous maintenance and testing program on their valves. By combining partial stroke testing of valves with more frequent inspection, companies can achieve higher SIL rating without spending for additional hardware.

SIL Determination Techniques Report, this excellent document covers;

• SIL Determination and the Safety Life Cycle
• SIL determination Techniques
• ALARP and Tolerable Risk Concept
• Semi-Quantitative Method – Fault Tree and Event Tree Analysis
• Safety Layer Matrix
• Calibrated Risk Graph
• Layer of Protection Analysis (LOPA)
• Evaluating the SIL Determination Options
• Process Industry Observations
• SIL Program Benefits

The following links are from www.fabig.com 
Fire & Explosion Hazard Management - The aim of the fire and explosion hazard management strategy is to reduce the risks from fires and explosions to as low as reasonably practicable (ALARP). The Oil and Gas UK guidance [1] and COMAH regulations [2] identify the following aims:
• Identify, analyse and understand all fire and explosion hazards and associated effects.
• The risk corresponding to fire and explosion hazards identified above should be as low as reasonably practicable.
• A suitable order of priority, and a suitable combination, of prevention, detection, control and mitigation systems for fire and explosion hazards should be implemented and supported throughout the life cycle of the offshore platform. In other words risks should be reduced to ALARP using inherently safe design principles.
• The above prevention, detection, control and mitigation systems should have performance measures proportionate to the required risk reduction.
• The design, operation and maintenance of the above prevention, detection, control and mitigation systems should be carried out by competent staff.
• Any changes that may occur throughout the lifecycle of the installation, and that may affect the likelihood and / or consequence of any fire or explosion hazard event (and therefore may make the risk on the installation deviate from an ALARP state) should be identified and assessed.  The prevention, detection, control and mitigation systems should be modified and updated as necessary to take into account any such changes. 
Fire & Explosion Hazard Management  - Technical How-To-Do Guidance - This useful list details references to many useful documents.
Fire & Explosion Hazard Management - Standards & Approved Codes of Practice - A comprehensive list of standards

The following links are from the 61508 Association 
Toolbox Talks - This excellent link gives you the essential toolbox tips in just a few sheets that will help your team to all be “singing from the same hymn sheet” which covers:
• Directors
• Senior Management
• Purchaser
• Project Manager
• Project Engineer
• Inspection and QA
• Operations
• Maintenance
• Service Engineer
• What is Functional Safety Management
• Proven in use / Prior use claims
• Functional Safety Management cross-reference between IEC61508 and IEC61511

What is a Functional Safety System? A short description.
What is Conformity assessment? - Conformity Assessment is defined as "activity that provides demonstration that specified requirements relating to a product, process, system, person or body are fulfilled."
What is CASS? - Accredited Certification for Safety Systems -  to IEC 61508 and Related Standards - CASS is a scheme for assessing the compliance of safety related systems with the requirements of IEC 61508 and associated standards. It provides a systematic approach to be used by certification bodies and others when assessing compliance at all stages from the specification of safety requirements through the design, development and manufacture of system components to integration, commissioning, operation and maintenance. At each stage CASS takes the conformity assessor through the logical steps of defining the scope of the assessment, the target of evaluation, the requirements to be met and the process of demonstrating and recording conformity.
Legacy Systems - Basic Principles for Safety - Engineered systems are relied upon for safety in a wide range of work environments. There is however, a general lack of awareness of the exact role played by such systems, and whether adequate safety is, in fact, being achieved. This is particularly true of systems that have been in place for many years. This document describes how to assess the capability of so called Legacy Systems, focussing on how electrical, electronic, or programmable devices achieve adequate safety in conjunction with other technologies such as mechanical systems and operational expectations.
SIL-Loops to the Rescue - Poor Process Design shouldn’t have to Hide behind Safety Loops - Clive de Salis -You’ve probably never thought of it this way but it really is true: To have an SIL-rated loop is a failure. An SIL-3 safety loop means that the layers of safety that we as chemical engineers have put in place in the process design are inadequate to such an extent that the risk of the fatality is 1000 timesthe wrong side of tolerable. The failure, herefore, is a failure of the chemical engineer to design a process that has sufficient layers of safety to not require an SIL-rated loop.
SIL Certs can Seriously Impair Plant Safety - Clive de Salis -  Process operators are investing in certificates and experts - that the IEC standards do not require - at the expense of actual functional safety management. IEC61508 and particularly the process industry application of it in IEC61511 is gaining ground strongly for high integrity safety instrumented systems. However, the majority of industry is still naively asking for certification that the standard does not require, and has never needed, whilst ignoring its basic essentials. How long can this really go on for?
The 61508 Association provides additional articles to promote the benefits of IEC 61508 and accredited certification.

6.11 The following links are from www.silsupport.com (some excellent papers here!)

Achieving ALARP with Safety Instrumented Systems - C.R. Timms - This paper sets out a methodology for setting tolerable risk levels, for various methods of Safety Integrity Level (SIL) determination, to meet the principles as low as reasonably practicable (ALARP). It makes proposals on how to deal with the tolerable risk concept for safety instrumented systems (SIS) protecting against single hazards.
Alarm Rationalisation - C.R. Timms - Anyone who has been involved in the application of IEC 61508 (1) and the Safety Integrity Level (SIL) determination for Safety Instrumented Functions (SIF) will appreciate the amount of effort and tenacity that is required to undertake the task. However, the SIL determination of Safety Instrumented Functions, or trip functions as they are often called, is only the tip of an iceberg when we come to consider what is involved in reviewing or configuring a typical alarm system.
Hazards Equal Trips or Alarms or Both -  C.R. Timms - This paper details various methods of criticality assessment which have been successfully applied to set the appropriate priority, identify the critical alarms that need to be upgraded to trips and to rationalise those of no value. It will also cover the use of software tools which can significantly reduce the effort involved in this process.
EC 61508 - Is it Pain or Gain?  - C.R. Timms - IEC 61508 provides designers and operators with the first generic internationally accepted benchmark standard for determining the Safety Integrity Level (SIL), the design requirements and test intervals for Safety Instrumented Functions (SIF). It covers every aspect of the full lifecycle management requirements for Safety Instrumented Systems (SIS). Before the introduction of IEC 61508, the most widely accepted standard was ANSI/ISA SP84.01, but it is most likely that ISA SP84-01 will be superseded in 2003 by the publication of IEC 61511 which is the process sector specific version of IEC 61508. The IEC 61508 standard provides a lifecycle road map for any SIS, yet is widely regarded as difficult to use and costly to implement. Numerous articles, presentations and training courses have addressed details of the standard but to date there has been little practical application advice available. This situation is now changing; by utilising experienced practitioners and appropriate software tools users of the standard can assure asset integrity whilst reducing the capital costof new projects and the maintenance costs for existing facilities.
IEC 61511 - An aid to Control of Major Hazards Regulations (COMAH) and Safety Case Regulations - C.R. Timms - It is accepted that the management of safety, like most other business management, is now a risk based approach and that is the basis of the SMS within COMAH and SCR. This is also the approach of the IEC 61511 (Functional Safety: Safety Instrumented Systems for the Process Industry Sector) standard and this paper will outline the synergy between the two Regulations and IEC 61511.
Live Changeout of SIS - C.R. Timms - Replacement of SIS Logic Solvers Whilst the Process Remains Operational - Clive Timms - With increasing global demand for oil and gas driving prices higher and higher, the focus of oil and gas producers is to maintain and maximise production from every available facility. Older unreliable facilities are being upgraded and this often includes the replacement of Safety Instrumented Systems (SIS) such as emergency shutdown (ESD) systems, process shutdown (PSD) systems, Emergency Depressurisation (EDP) systems and fire and gas (F&G) systems due to obsolescence or reliability issues. Traditionally, the replacement of such safety critical systems is undertaken during a plant shutdown opportunity to ensure that process integrity was maintained and the replacement systems could be fully commissioned and validated without the presence of the process hazards. However, in this era of high oil and gas demand we are now seeing more and more SIS replacement projects being undertaken whilst the process is still fully operational, and this can lead to potential compromises during commissioning and validation of functionality.
Software tools for SIS Lifecycle support - C.R. Timms - Since the publication of IEC 61508 and IEC 61511 there has been a steady increase in the number of PC based software tools developed to aid compliance. These come with a wide range of both capability and price, but carefully selected tools are considered the most appropriate way forward for ensuring lifecycle support of safety instrumented systems (SIS). Software tools are not just the realm of the design engineer, and this paper draws on experiences to demonstrate the benefits that can be realised by SIS engineering practitioners and end users. This paper also discusses configuration aids for programmable logic controllers (PLC) but it does not cover PLC software or computer aided design (CAD) software.

Other Very Useful Safety Instrumented Systems Links

Fire Safe Actuators - A paper detailing an innovative concept from valued sponsor Samson Controls Pty Ltd

Recommendations on the Design and Operation of Fuel Storage Sites -This 52 page report sets out recommendations to improve safety in the design and operation of fuel storage sites.

SIS Links -TUV provides links to more Safety Instrumented Systems Information

1.12  New Tank Over Fill and Spill Protection Standard - As a direct result of the Buncefield explosion, the American Petroleum Institute's Recommended Practice 2350 is being revised and updated to help prevent future incidents. It should be noted that there are similar storage terminals spread across Canada and the world. Many are currently in the process of updating to these standards. Of particular interest, are storage facilities fed by a pipeline, or from a ship, as the potential spill risk is greater than those fed by truck or rail. The API 2350 4th edition will require most petroleum storage tanks over 5000 liters to have an independent level alarm for critical high level. Past practices of taking a high level or overfill alarm off the main tank level gauge (commonly a radar level device) are no longer allowed. A back up device is now required that can be a second transmitter (continuous level indication) or more cost effectively a point level switch. Depending on the overfill prevention category of the vessel, these switches may be mechanical or electronic. While there are several potential alarm points, here we are discussing the independent alarm required for the "High-High" alert - from Magnetrol

12.11A Culture of Safety - Industry Moves to Make Sure Accidents DON'T Happen - Amy W. Richardson - In response to some major disasters in the 1970s and ‘80s, in which control system failures were contributing factors, a new culture of industrial process automation safety was born. As part of this movement, end-users, industry associations, and equipment suppliers alike moved to more closely consider control and safety applications with the aim of minimizing common modes of failure. For decades, it was common to build certain protections into the Basic Process Control System (BPCS) to prevent failures. However, the new approach focused on separation between control and safety applications to reduce failures. In the ‘90s, the ISA-SP84 Committee settled on the term Safety Instrumented System (SIS) to describe an independent automated safety system. Today, if the layers of safety measures built into a modern process control systems were peeled back, one would likely find the SIS at the outermost level, providing the last preventive layer of protection against undetected and detected equipment failures that lead to unsafe process conditions - from www.flowcontrolnetwork.com 

6.11An introduction to Functional Safety and IEC 61508 - This application note is intended to provide a brief introduction to the IEC 61508 standard, and to illustrate how it is applied - from MTL

6.11 Reliability with Respect to Safety Instrumented Systems - Bonne Hoekstra - The term Safety Instrumented System (SIS) has been introduced in the international standard IEC 61511 and covers the equipment from sensors, logic solver and final elements that is needed to realise the Safety Integrity Functions (SIF), another IEC term. Reliability with respect to these systems is defined by its ability to command an output to a safe state on a process demand and to function within a required time span without causing a spurious action (e.g. nuisance process trip). The first term has to do with safety integrity as meant by IEC 61508; the second is often presented as process availability, in short availability. The latter is not formally defined in international standards. Systematic failures as well as the human factor are also mentioned in this standard, however they will not be considered in this context for the sake of clearness - from Yokogawa.

4.11 A Map to the Latest Safety Standards - James R. Koelsch - Safety standards and their terminology continue to multiply and evolve, generating a confusing sea of letters and numerals that few can navigate. This guide should help novices to chart a course - from Automation World.

4.11 Webcast: Functional Safety - What It Is, Why It's Important, and How to Comply - In this 1 hour presentation industry experts Kevin Connelly and Thomas Maier from Underwriters Laboratories define functional safety, why it is important, and the common functional safety standards you need to know. For functional safety compliance, manufacturers must consider their systems as a whole, and the environment with which they interact. A functional safety assessment determines whether your systems meet the standards and requirements created to protect against potential risks. You will have to register to view this webcast.

Don't Gamble with Control Safety and Reliability - Understand the benefits and limitations of safety instrumented systems - Arthur Zatarain - As a wise singer once crooned, you have to “know when to hold ’em and know when to fold ’em.” But Kenny “The Gambler” Rogers merely had to beat long-shot odds to win at his game. Outside the casino, designers of industrial control systems don’t have the luxury of being right only 51% of the time. For many manufacturing and process systems, a control system failure — even for a second — simply isn’t an option. Hence, it’s important that control systems deliver safe and reliable performance, even when things go wrong - from PlantServices.com.

Selecting Transmitters for Safety Instrumented Systems - Stephen R. Brown and Mark Menezes -  Users design safety systems to mitigate the risk of identified process hazards within tolerable levels, using application-specific risk models, defined user inspection schedules, and safety data for the devices under consideration. Some suppliers provide safety data for their devices. However, supplier data, even when validated by a third party, reflects laboratory results, and can be an order of magnitude too aggressive for field devices. “Proven-in-use” data includes real-world failure causes; however it tends to be conservative, since it must cover the whole range of the category, from 20-year-old pneumatics to the latest smart technology. Moreover, proven-in-use data is often aggregated for a given technology: for example, “pressure transmitter = dangerous failure rate of once in 50 years”. This aggregate data often does not isolate failure causes, so it does not allow users to take credit for improvements in technology or user practices intended to minimize the impact of specific failures. The net result to the user can be over design, over-testing, increased spurious trips and needless capital expenditures - from IDC

Center for Chemical Process Safety - The Global Community Committed to Process Safety - CCPS is a not-for-profit, corporate membership organization within AIChE that identifies and addresses process safety needs within the chemical, pharmaceutical, and petroleum industries. CCPS brings together manufacturers, government agencies, consultants, academia and insurers to lead the way in improving industrial process safety.

An Introduction to Inherently Safer Design - Inherently safer design (ISD) is a philosophy for addressing safety issues in the design and operation of chemical processes and manufacturing plants. When considering ISD, the designer tries to manage process risk by eliminating or significantly reducing hazards. Thanks to Centre for Chemical Process Safety.

Recommended Guidelines for the application of IEC 61508 and IEC 61511 in the petroleum activities on the Norwegian Continental Shelf - This very comprehensive 55 page guideline from the Norwegian Oil Industry association is very useful.

Introduction & background to IEC 61508  - Ron Bell - Over the past 25 years there have been a number of initiatives worldwide to develop guidelines and standards to enable the safe exploitation of programmable electronic systems used for safety applications. In the context of industrial applications (to distinguish from aerospace and military applications) a major initiative has been focussed on IEC 61508 and this standard is emerging as a key international standard in many industrial sectors. This paper looks at the background to the development of IEC 61508, considers some of the key features and indicates some of the issues that are being considered in the current revision of the standard - Thanks to crpit.com

6.11 Note New Edition- PDS Method Handbook 2010 Edition - Reliability Prediction Method for Safety Instrumented Systems - The “PDS Method Handbook” gives a description of the PDS method, including the mathematical details. It has also been the objective to make it comprehensible to the non-expert. The IEC-standards 61508 (”Functional safety of safety-related systems”) and IEC 61511 (Functional safety — Safety instrumented systems for the process industry sector) provide useful information and guidance on safety requirements regarding the use of Safety Instrumented Systems (SIS). In the latest "PDS Method Handbook" the notation has been further updated in order to be in line with the IEC standard. The objective has been to “keep the best of the PDS method and at the same time to adapt the method to terms and requirements in IEC”. New features of this 2010 Edition of the PDS Method Handbook include:

• A general review and up

• Date of the methodology and the formulas, including a more in depth discussion of the assumptions underlying the formulas

• An update of the model for common cause failures (CCF) in multiple redundant systems

• A discussion on the use of the method for continuously (high demand mode) operating systems

• Some new and revised terminology

An electronic version (in PDF-format) of the first three chapters of the PDS Method Handbook can be viewed here.

Equipment, Don't Fail Me Now - Calculating failure probabilities works better with systematic approach - Peter Morgan -  Specialists in control and instrumentation were once confident to rely on their own experience and good design practice to design protection systems. Now they must adhere to a quantitative approach to designing systems deemed safety systems. Even the ubiquitous burner management system (BMS) is by virtue of its function, a safety instrumented system (SIS), and you should design it according to ISA 84.01 as well as the applicable National Fire Protection Agency standard. One step in this approach is calculating the target probability of failure on demand (PFD) for the system - From ISA and InTech

An Integrated Approach to Safety: Defense in Depth -  Ensuring safety requires reducing the risk of incidents, faults and failures that can disrupt normal operations. This effort goes far beyond simply installing fail-safe controllers or a safety instrumented system. In fact, to mitigate the risk of serious incidents that can cause injury to personnel, equipment and the environment, it is important to consider safety from all aspects of a plant’s operation - From Honeywell

Certified Functional Safety Expert Governance Board -The CFSE is now administered by the CFSE Governance Board which is in turn supported by a broad consortium of companies including Honeywell, Pilz, Siemens, TUV, exida and other leading safety related firms.

6.11 Personnel Functional Safety Certification - Not All Programs Are Created Equal - As production runs ever closer to equipment and facility operating limits and new plants come on line in expanding and developing economies, the pressure to design and operate systems more safely and economically is increasing. A key to meeting this goal is having competent people who are knowledgeable and experienced in applying the IEC 61508 and IEC 61511 / ISA 84 functional safety standards. To develop and measure an individual’s safety engineering competence, several personnel functional safety certification programs have been created. This paper discusses why these programs are needed and the benefits they deliver to individuals and companies alike. It will also review the characteristics and differences of the various certification programs on the market today, things to watch out for, and some important questions to ask when selecting a certification program- from CFSE.

1.11 ANSI/ISA-TR96.05.01, Partial Stroke Testing of Automated Block Valves - The technical report provides guidance on various criteria to consider when determining whether partial stroke testing would be beneficial and on the different methods used.Use of this technical report involves familiarity with the operation of automated block valves and with the quantitative analysis of its average probability of failure on demand (PFD_AVG).  Users of ANSI/ISA-TR96.05.01 will include:
- owner/operators who use automated block valves in operating environments requiring partial stroke testing;
- designers who identify automated block valve applications where it is apparent more frequent and stringent proof testing is required;
- operations and maintenance personnel who need to understand the process and results of partial stroke testing.

10.11 Automatic Shutdown Industry Example Systems & Methodology - David Ransome - Covers the Safety Lifecycle, Hazard and Risk assessment, Safety Instrumented Functions & Safety Requirements Specifications, Safety Integrity Levels, Safety Instrumented Function, Design of Safety Instrumented System, Sensors, Logic Solvers, Final Elements along with applications for Rail Tanker, Ship Offloading, Pipeline Transfer and Jetty Transfer Systems, This presentation is reasonably useful, it is a shame that it does not come with the audio as well though - from eemua

Valve System Controls for Safety - A matrix that substantially increases the level of safety in the process industries while significantly reducing the number of nuisance trips - Improved safety brings more nuisance trips, which means lost production. The single block valve is the weak point of the 2oo2D architecture and Parallel valve   technology can provide 95% diagnostic coverage- G. Paul Baker and ISA InTech

Converting Relay-Based Logic Solver to Triple Modular Redundancy Means Safer plants at Less Cost - Keyur Vora and Ranjan Bhattacharya - When a leading Indian petrochemical plant noticed interlock operations and actuation happening six times a year due to shutdowns, they knew it was time for a change. Problems with trips in the oxidation reactor lead to huge costs in production and  quality losses. Finally plant officials looked at upgrading the relay-based interlock system with triple modular redundancy (TMR) to enhance reliability and availability and reduce nuisance trips. From ISA and InTech.

How to Specify Solenoid Valves for a Particular Safety Integrity Level - S.A. Nagy - Selection must be done with care and understanding of safety and reliability standards to avoid the risks associated with an  operational failure of a critical plant system - thanks to chem.info

Smart Instruments in Safety Instrumented Systems - Tom Nobes - The U.K.'s largest nuclear site operator implements IEC61508 and finds the quality of instrument firmware to be variable, but improving. Thanks to ISA.

Vessel overflow protection systems seem so simple, so straightforward—that is until one of them fails to work properly and your plant is the six o’clock news -  The underlying concept required of an automated  overfill protection system seems so simple: If the level of a vessel reaches a pre-determined maximum, then stop the flow of liquid filling the vessel. Satisfying such a simple requirement occurs in toilets, clothes  washers, and dishwashers every day, so what is the big deal? The big deal is the liquid in toilets, washers, and dishwashers is water, not a highly flammable, possibly toxic, fuel or chemical. In addition, remember  if the overfill protection system fails and there is even a minor incident, government investigators are going to want to see evidence you applied the principles of IEC 61511. Thanks to InTec

HSE (UK) Safety Instrumented System documents

'The Strategy for Workplace Health and Safety in Great Britain to 2010 and beyond' http://www.hse.gov.uk/aboutus/hsc/strategy.htm

Development of a Business Excellence Model of Safety Culture - Michael S Wright, Philip Brabazon, Alison Tipping and Medha Talwalkar -  This report gives the results of a study carried out by Entec UK Ltd to provide a comprehensive review of research on how to assess and develop safety culture, and thereafter produce a safety culture improvement matrix (SCIM).

Root Causes Analysis - Literature review - This report contains the findings of a literature search, outlining the principles, structure and method of application of each identified root causes analysis technique.

Best Practice for Risk Based Inspection as a part of Plant Integrity Management - J B Wintle, B W Kenzie Mr G J Amphlett and S Smalley -This report discusses the best practice for the application of Risk Based Inspection (RBI) as part of plant integrity management, and its inspection strategy for the inspection of pressure equipment and systems that are subject to the requirements for in-service examination under the Pressure Systems Safety Regulations 2000 (PSSR). It can also apply to equipment and systems containing hazardous materials that are inspected as a means to comply with the Control of Major Accident Hazards Regulations (COMAH).

A Review of Experience from Two Offshore Design Projects - D Piper -  This report describes the outcome of a review of experience from two recent offshore design projects, primarily from a safety perspective, to identify key issues and any lessons that may be learnt for future projects.

Application of QRA in Operational Safety Issues - Andrew Franks, Richard Whitehead, Phil Crossthwaite and Louise Smail - This study has performed research into the use of risk in Health and Safety Executive's (HSE) operational decisions in the context of the COMAH regulation 4. The research focussed on the use of regulatory guidance, risk matrices and Quantitative Risk Analysis (QRA) to demonstrate compliance with the ALARP principle. Each approach has its strengths and weaknesses, for any particular situation. Cost Benefit Analysis (CBA) when used in conjunction with QRA is able to provide an economic justification as to whether risk reduction measures should be implemented.

A Methodology for the Assignment of Safety Integrity Levels (SILs) to Safety-Related Control functions Implemented by Safety-Related Electrical, Electronic and Programmable Electronic Control Systems of Machines - Mark Charlwood,  Shane Turner and Nicola Worsell - This contract research report describes the development by the authors, with funding from HSE, of a methodology for the assignment of required Safety Integrity Levels (SILs) of safety related electrical control systems of machinery. The rationale behind the methodology and how to use it in practice are also explained in some detail. The methodology has been developed and accepted for inclusion in an informative annex of the International Electrotechnical Committee standard IEC 62061: "Safety of Machinery Functional Safety of Electrical, Electronic and Programmable Electronic Control Systems for Machinery"

Risk Based Inspection - A Case Study Evaluation of Onshore Process Plant - W Geary - A survey of approximately 50 UK organisations carried out by HSL in 1999 showed that approximately half were using an approach to plant inspection based on risk. It was clear however, that a wide range of systems were in use including commercial software packages and in-house systems specific to individual plants. Given the disparate nature of some of these systems and the likelihood that RBI assessments might produce very different results depending on which methodology was used, HSE took the view that a study should be undertaken using a number of example cases to tease out the differences between the systems. This is the subject of the current investigation.

INDG218, 'A Guide to Risk Assessment Requirements' http://www.hse.gov.uk/pubns/raindex.htm

INDG163, 'Five Steps to Risk Assessment'
http://www.hse.gov.uk/pubns/raindex.htm

RR216, 'A methodology for the assignment of safety integrity levels (SILs) to safety-related control functions implemented by safety-related electrical, electronic and programmable electronic control systems of machines'
http://www.hse.gov.uk/research/rrhtm/rr216.htm

INDG316, 'Procedures for daily inspection and testing of mechanical power presses and press brakes'
http://www.hse.gov.uk/pubns/engindex.htm

INDG375, 'Power presses: a summary of guidance on maintenance and thorough examination'
http://www.hse.gov.uk/pubns/puwerind.htm

INDG229, 'Using work equipment safely'
http://www.hse.gov.uk/pubns/puwerind.htm

INDG270, 'Supplying New Machinery: a Short Guide'
http://www.hse.gov.uk/pubns/puwerind.htm

INDG271, 'Buying New Machinery: a Short Guide'
http://www.hse.gov.uk/pubns/puwerind.htm

INDG291, 'Simple guide to the Provision and use of Work Equipment Regulations 1998'
http://www.hse.gov.uk/pubns/puwerind.htm

RR125, 'Evaluation of the implementation of the use of work equipment directive and the amending directive to the use of work equipment directive in the UK'
http://www.hse.gov.uk/research/rrhtm/rr125.htm

HSC13, 'Health and Safety Regulation: a Short Guide'
http://www.hse.gov.uk/pubns/regindex.htm

INDG275, 'Managing Health and Safety: Five Steps to Success'
http://www.hse.gov.uk/pubns/manindex.htm

INDG343, 'Directors' Responsibilities for Health and Safety'
http://www.hse.gov.uk/pubns/manindex.htm

'Directors' Responsibilities for Health and Safety (INDG343): Frequently Asked Questions'
http://www.hse.gov.uk/pubns/manindex.htm

HIMA Australia offer a number of training courses in Australia - Details can be found here.

Wish to learn more about Manufacturing and Automation Safety or Burner Management? ICEweb has these topics well covered on our MAS and BM pages.