1  Introduction

1.1 What is "Human Factors"?

As illustrated in Figure 1-1, like engineering, Human Factors is a combination of science, concepts, and principles. Human Factors draws on several scientific disciplines. These include psychology, ergonomics, anthropometrics, and physiology. The Human Factors approach uses these disciplines to help people understand how and why they behave and perform as they do, and how best to support them to perform tasks. The science adds to the knowledge gained from operational experience.

Figure 1-1 Human Factors science, concepts and principles

Human Factors also provides a set of principles and concepts that can be used to guide day-to-day decisions. The decisions focus on how best to support successful human performance. This approach helps people to understand tasks from the perspective of the person doing the work and provides ideas on how to support people to perform better. It advocates an orientation (a way of thinking) towards making improvements that support human performance and the prevention of error. It recognizes people's capabilities and commitment, and it aims to maximize people's roles in safe and productive operations, and to build their ability to cope mentally and emotionally with stressful and demanding tasks, i.e., psychological resilience.

Human Factors covers a very wide range of topics including, training, work planning, and fatigue. Many of these topics come under existing management systems, such as the operation of rotating shift schedule systems, and training systems. Human Factors provides knowledge, tools, and insights that can be integrated into an organization's existing systems of work and operational management, safety assessments, incident investigations, and day-to-day operational decision-making. In this book, the terms 'incident' and 'accident' will be used interchangeably.

1.2 Purpose of this handbook

1.2.1 Purpose and scope

This handbook provides practical advice and examples of good practice that can be applied to design, process operations, start-ups and shut-downs, maintenance, and emergency response. It is a comprehensive but simple to understand handbook aimed at people responsible for the process operations.

The handbook:

• Provides examples of practical application, principles, and tools. It also provides an understanding of the fundamentals of Human Factors, so the reader can develop their own approach.
• Provides an explanation of how people think and behave, why people make mistakes, and how to help people perform process operational tasks successfully. This includes how to support human performance through procedures and job aids, training and learning, effective task planning, high reliability communications, fatigue risk management, development of error management skills, and preparing people to perform emergency response tasks.
• Briefly covers the Human Factors of change management and managing contractors. It also offers help on how to learn from errors, and how to use indicators of human performance to improve support to people.

1.2.2 Other guidance

How does this handbook fit with other guidance documents?

Safety culture, leadership, and process safety management are covered in other CCPS publications, as shown by the book front covers. Most chemical process businesses have a set of process safety management systems in place already. The advice in this handbook can be integrated into these process safety management systems.

Human Factors methods, such as error analysis and Human Reliability Assessment, typically applied during a "Hazard Identification and Risk Analysis", are not covered in this handbook. CCPS books on "Bow Ties in Risk Management" and "Guidelines for Integrating Process Safety into Engineering Projects" are available if further information is needed. This handbook does outline forms of error assessment that can be used by everyone involved in task planning and task management.

This handbook can be read in conjunction with other CCPS guidance on safety culture and process safety management, including:

• Essential Practices for Creating, Strengthening, and Sustaining Process Safety Culture [8].
• Process Safety Leadership from the Boardroom to the Frontline [9].
• Guidelines for Risk Based Process Safety [5] [10].
• Recognizing and Responding to Normalization of Deviance [11].
• Human Factors Methods for Improving Performance in the Process Industries [12].
• Investigating Process Safety Incidents [13].

Some of the elements within "Guidelines for Risk Based Process Safety" are relevant to this handbook. Therefore, they have been referenced at various points throughout the handbook as additional information where this would be helpful to the reader.

1.2.3 Who should read this handbook?

This handbook is intended for everyone involved with defining, planning, instructing, and managing process operations, maintenance, and emergency response. This includes:

• Frontline supervisors.
• Designers.
• Operations and maintenance managers.
• Plant superintendents.
• Process engineers.
• Project managers.
• Construction managers.
• Process safety and health and safety personnel with the role of coaching higher-level managers on Human Factors aspects.

The handbook is intended for people who understand process operations and have some process safety management experience.

1.2.4 A note on language and terminology

The explanation of some topics has been intentionally simplified and phrased in normal everyday language, rather than in scientific terms. This has been done in order to make the document more accessible, readable and more usable in the practical domain, and also with the aim of making it more understandable for an international audience.

For example, the term 'mistake' is used in this book to refer to both mistakes and other kinds of error, even though human factors specialists commonly understand the term 'mistake' to mean a specific kind of error that is to do with judgement and decision-making, as distinct from other kinds of error such as 'slips and lapses'. The term 'mistake' is used generally in the book, but where specific types of error are being discussed then the specific appropriate terms are used where that aids clarity.

A more complete explanation of the traditional terminology of 'human error' commonly used by Human Factors specialists is given in Appendix 0.

1.3 Why Human Factors?

1.3.1 Major accidents associated with human performance

Human performance is a factor in almost every major process accident. The costs of major process accidents are well known: major injury, destruction of facilities, environmental damage, immense costs, reputational loss, closure.

BP's Texas City 2005 refinery explosion: 15 fatalities, 170 injured.

The compensation totalled billions of US dollars. Repairs and lost profits cost over US $1billion.

See section B.1

In those cases where obvious signs of poor Human Factors were found, stakeholder confidence in the company was greatly reduced and employee morale was destroyed.

The United States Chemical Safety and Hazard Investigation Board (CSB) investigation of the Texas City accident cited that previous accidents have shown that Human Factors plays a role in industrial accidents [14]. The Texas City event includes several examples of Human Factors. People had worked without rest for many weeks or worked excessively long days. In some cases, it was known that process instrumentation was unreliable or that critical information such as Piping and Instrumentation Diagrams were out of date, and that training on new control systems had not been provided.

This kind of evidence greatly undermines stakeholder trust in an organization and can cause loss of the "license to operate".

1.3.2 It is more than common sense

Human Factors is more than common sense. People may make mistakes for many reasons. Many factors influence how people perform. Process operations can be complex and involve many difficult tasks. Technology is constantly changing.

"Work as done"

versus

"Work as imagined"

People who plan work and develop operating procedures should not be remote from the actual task. They need to understand how the tasks are carried out in the field. Authors should have a complete knowledge of the surrounding environment or operational requirements.

Time constraints and attention demands impact frontline managers and supervisors. These demands can prevent frontline managers and supervisors from spending time to understand how people are performing, and what is influencing their performance. Issues should not be overlooked or considered in a superficial way.

Businesses must prioritize and balance production, operations, maintenance, and budget. Human Factors appreciation can direct focus to human performance support. It can also aid in...