Accident Theories for Accident Prevention
Summary
TLDRIn this presentation, Azman Abdul Rahman explores theories and models developed by safety experts to understand and prevent accidents. Key topics include the classification of accidents and incidents, the accident triangle ratio, and the causes of accidents. The presentation delves into the domino theory of accident causation and the importance of root cause analysis in preventing recurrence. The speaker emphasizes the application of these theories to workplace safety programs, suggesting a combination of theories and models for effective problem-solving.
Takeaways
- 📚 Accidents and incidents are two different concepts: Accidents result in injury or damage, while incidents have the potential but do not cause actual harm.
- 🔍 Unsafe acts and conditions are significant contributors to workplace accidents, with acts like horseplay and conditions like slippery floors posing risks.
- 📊 The accident triangle, introduced by Heinrich, illustrates the relationship between minor injuries, serious injuries, and near misses, suggesting that reducing minor incidents can lead to fewer major accidents.
- 👷♂️ Unsafe acts are often caused by human error, which can be influenced by factors like training, attitudes, and fatigue.
- 🏗️ Unsafe conditions can result from inadequate housekeeping, improper storage, or defective equipment, and are often a consequence of human actions.
- 🔑 Root cause analysis is crucial for preventing accidents by identifying and addressing the underlying causes rather than just the immediate symptoms.
- 💡 Maslow's Hierarchy of Needs provides insight into human motivation and behavior, which is important for managing safety in the workplace.
- 🌐 The iceberg model demonstrates that direct costs of accidents are often just the tip, with indirect costs like legal fees and lost business potentially much higher.
- 🛠️ Equipment suitability, proper handling of substances, and safe operating procedures are key components of a safe workplace.
- 🔄 Theories of accident causation, such as the domino theory and multiple factors theory, offer different perspectives on why accidents occur and how they can be prevented.
Q & A
What is the main purpose of the presentation by Azman Abdul Rahman?
-The main purpose of the presentation is to provide an understanding of various theories and models developed by safety experts to prevent accidents by addressing unsafe acts and conditions.
How are accidents and incidents differentiated according to the presentation?
-Accidents are unplanned and unexpected events that result in loss, injury, or damage, while incidents are similar events that have the potential to cause harm but do not actually result in injury or damage.
What is the significance of the accident triangle ratio introduced by Heinrich?
-Heinrich's accident triangle ratio suggests that for every 300 near misses, there will be 29 minor injuries and one major injury, indicating the importance of addressing minor accidents to prevent major ones.
What is the role of unsafe acts and conditions in causing accidents as per the presentation?
-Unsafe acts are actions by people that are not safe, such as horseplay or not using PPE, while unsafe conditions are workplace conditions that could cause injury or damage, like missing machine guards or slippery floors.
How does the presentation describe the relationship between near-misses and accidents?
-The presentation describes near-misses as incidents that have the potential to cause injury or damage but do not, and that they are precursors to accidents, which do result in injury or damage.
What is the iceberg model mentioned in the presentation, and how does it relate to accident costs?
-The iceberg model represents the costs of accidents, with direct costs being the visible tip and indirect costs being the larger, hidden portion beneath the surface, which can be significantly higher.
According to the presentation, what are the four main factors that contribute to workplace injuries?
-The four main factors contributing to workplace injuries are environment, equipment and materials, system and procedure, and worker factors such as training, skills, and attitudes.
What is the domino theory of accident causation as presented by Heinrich?
-Heinrich's domino theory suggests that accidents result from a chain of sequential events, and by removing one of the dominoes, typically an unsafe act, the chain can be broken to prevent accidents.
How does Bird's update of the domino theory differ from Heinrich's original model?
-Bird's update introduces the concept of management failure as a leading cause of accidents, emphasizing the role of inadequate systems, standards, and compliance by management in the chain of events leading to accidents.
What is the difference between root cause and basic cause in the context of accident analysis?
-Root cause is the most fundamental cause that, if corrected, can prevent the recurrence of an error, such as poor safety management or lack of training. Basic cause refers to the underlying reasons for unsafe acts or conditions.
Why is root cause analysis important in accident prevention programs?
-Root cause analysis is important because it identifies the fundamental causes of accidents, allowing for corrective actions that can prevent recurrence, rather than just addressing symptoms.
Outlines
📚 Introduction to Accident Theories and Models
Azman Abdul Rahman introduces various theories and models developed by safety experts to understand how accidents occur. These theories form the basis for accident prevention programs aimed at preventing unsafe acts and conditions. The presentation will cover the classification of accidents and incidents, the accident triangle ratio, causes of accidents, accident causation theories, and root cause analysis. The importance of applying these theories in workplace accident prevention is emphasized, suggesting that a combination of theories and models may offer the best approach to problem-solving. The difference between accidents and incidents is clarified, with accidents resulting in injury or damage and incidents having the potential but not causing harm.
🔍 Accident Classification and Heinrich's Theory
The script discusses how accidents can be classified by the extent of injury or property damage. Unsafe acts and conditions are identified as common causes of accidents. A near-miss is defined as an incident with potential for harm but no actual injury or damage. The concept of property damage due to negligence or acts of nature is introduced. The accident triangle, introduced by Herbert William Heinrich in 1931, illustrates the relationship between serious injuries, minor injuries, and no injuries in accidents. Heinrich's study suggests that for every 300 near-misses, there will be 29 minor injuries and one major injury, implying that reducing minor accidents can lead to a decrease in major accidents. Frank E Bird later refined the theory, proposing a different ratio based on a larger dataset.
🧠 Human Factors in Accident Causation
The script emphasizes that accidents are caused by a combination of factors, including unsafe acts and conditions. Heinrich's studies indicate that 88% of accidents are due to unsafe actions, 10% due to unsafe conditions, and only 2% by uncontrolled factors. The shift in safety management from engineering to managing human error is highlighted, with human behavior becoming a crucial aspect of workplace safety. Abraham Maslow's Hierarchy of Needs is introduced as a model to understand human motivation, which includes physiological, security, belonging, esteem, and self-actualization needs. Employers are advised to be aware of contributing factors in their workplace, such as equipment suitability, substance handling, safe operating procedures, and environmental conditions.
🏥 The Domino Theory and Accident Prevention
Herbert W. Heinrich's domino theory is presented, which suggests that accidents result from a chain of sequential events. The theory identifies injury, accident, unsafe act/condition, and person's fault as the dominoes that lead to an accident. The theory emphasizes the importance of preventing unsafe acts and conditions to avoid accidents. Bird and Loftus later updated the domino theory, adding management failure as a leading cause of accidents and suggesting that effective safety programs can prevent them. The script provides an example of how the updated domino model can be applied to analyze an accident involving a stamping machine, highlighting the importance of management's role in accident prevention.
🔬 Root Cause Analysis in Accident Investigation
The final paragraph discusses root cause analysis as a systematic process for identifying the underlying causes of problems or events and developing action plans to address them. It differentiates between basic or root causes, contributing causes, and direct causes, explaining that focusing only on the latter two may not prevent recurrence. Root cause analysis aims to answer key questions about what happened, how, and why, and what needs correction. The tools necessary for conducting root cause analysis are mentioned, and the presentation concludes with a hope that the information will aid in developing effective workplace accident prevention programs.
Mindmap
Keywords
💡Accident
💡Incident
💡Unsafe Acts and Conditions
💡Accident Triangle
💡Root Cause Analysis
💡Human Error
💡Maslow's Hierarchy of Needs
💡Iceberg Model
💡Domino Theory
💡Prevention Program
Highlights
The presentation discusses theories and models developed by safety experts to understand how accidents happen and prevent them.
Accident prevention programs aim to prevent unsafe acts and conditions, which are foundational to safety.
Understanding the classification of accidents and incidents is crucial for effective prevention strategies.
The accident triangle ratio, introduced by Heinrich, suggests a relationship between near-misses, minor injuries, and major injuries.
Unsafe acts and conditions are identified as primary causes of workplace accidents.
The concept of near-misses, or incidents with potential for injury but no actual harm, is explored.
Property damage and lost time injury (LTI) are discussed as consequences of accidents in the workplace.
The domino theory by Heinrich explains accidents as a chain of sequential events, emphasizing the prevention of unsafe acts.
Frank E Bird's amended accident triangle shows a different ratio, focusing on property damage and incidents without injury.
Human error in accident causation has become a significant area of study, with human behavior models like Maslow's Hierarchy of Needs being applied.
The iceberg model illustrates the direct and indirect costs of workplace accidents, highlighting the financial impact.
Single factor theory and multiple factors theory are compared in terms of their effectiveness in accident prevention.
Root cause analysis is defined and its importance in preventing accident recurrence is emphasized.
The presentation concludes with a call to action for developing effective workplace accident prevention programs.
A combination of theories and models may provide a better approach to solving safety problems in the workplace.
The importance of understanding the difference between root cause and basic cause of an accident is discussed for effective investigation.
Transcripts
Hello and welcome, my name is Azman Abdul Rahman. In this presentation we look at some
of the theories and models that were developed by safety expert to help better understanding
on how accidents happen. This theories provided the foundation for accident prevention program
aimed at preventing accident, by preventing unsafe acts and unsafe conditions.
By the end of this presentation you should be able to understand
how accident and incident are classified; what are the accident triangle ratio of
different types of accident; what are the cause involved in accident;
the theory of accident causation a theory that explains how accident happens; and the last one
is root cause analysis, it helps to understand difference between root cause and basic cause
of an accident. All of these theories are very useful when conducting accident investigation.
You can also apply these theories to your workplace accident prevention program.
A combination of theories and model may be the better approach towards problem solution.
Accident and incident are the two words that are easy to confuse
but they are not exactly the same. Let's begin by defining exactly what accident and incident is.
Accident can be defined as an unplanned and unexpected event that cause loss of life
injury property damage interruption of normal activities or damage to environment.
Incident is unplanned and unexpected event that has potential to cause injury,
illness or property damage, sometimes they are called near-miss. So both events are unplanned,
both can present injury or damage, the difference is in accident the event results in injury,
however in incident the event does not but it has potential to cause injury. Basically by definition
all accidents begin with an incident but not all incidents result in an accident.
In this example you will see the relationship between incident and accident. Bricks
and a hole in a walkway are hazard. Riding a bicycle just beside the brick is an incident.
Riding a bicycle in the hole will cause an accident.
Both are events, already happen. One has no result and the other caused an accident.
There are several ways to classify an accident, this includes classification by the extent
of injury cause or by the level or cause of the damage to property.
Unsafe acts are things that people do that are obviously just not safe.
Some examples are horseplay not using PPE, using damage tools, violating safety rules.
Unsafe conditions are a condition in the workplace that is likely to cause injury or property damage,
such as missing machine guards, damage equipment, slippery floor and improper storage of material.
A near-miss is any form of incident that has the potential to cause
but does not actually result in injury or property damage or any interruption to normal operation.
Near misses also may be referred to as close call or near accident.
Property damage is damage or destruction of real or personal property caused by negligence,
willful destruction or act of nature.
Accident is any unplanned or unexpected event which causes injury or property damage.
Accident may involve lost time injury or
LTI, simply means that number of days the workers cannot work due to the injury. LTI also includes
number of days the workers unable to perform his or her normal duties after returned to work.
Accident triangle shows a relationship between the number of accidents resulting in serious injury,
minor injuries or no injuries. The relationship was first introduced in 1931 by Herbert William
Heinrich. Heinrich was a pioneer in the field of workplace safety and health.
From the study of 75 000 accident reports data he suggested for every 300 near misses there
will be 29 minor injuries and one major injury. He concluded that by reducing the number of
minor accidents companies will see a fall in the number of major accidents.
The triangle was widely used in the industrial safety and health program
and was described as a foundation of safety and health philosophy.
The theory was developed further by Frank E Bird in 1966 based on the analysis of 1.7 million
accident reports. He produced an amended triangle that showed a relationship of
one serious injury accident to 10 minor injury accidents to 30 property damage
caused by accidents to 600 incident or near-misses without injury. Bird shows a
relationship between the number of reported incident and the number of major accidents,
and claimed that the majority of accident could be prevented by taking proper control.
Whenever an accident occurs someone always asks how did it happen ? Accident do not just happen,
they are caused. Causes of accident can be unsafe act, unsafe condition or a combination of both.
If you are going to prevent accident we must know what causes the unsafe act and unsafe condition.
Studies by Heinrich shows that 88% of all accidents are caused by unsafe action
or unsafe practices, such as reaching into a running machine, operating a machine without
guards, using defective tools or equipment, or horseplay during work. 10% are caused
by unsafe condition such as poor housekeeping, improper storage, defective or broken equipment,
machine with no guards and so on. However unsafe condition exists as a result of personal
action of a person. And only two percent are caused by uncontrolled factors or act of nature.
Over the period of time safety management approach has shifted from
engineering to managing human to prevent human error. Recently a lot of study has
been conducted about the role of human error in accident causation.
Study of human behavior has become important aspect in managing safety at workplace. One of
the good model for understanding what motivates human is Abraham Maslow's Hierarchy of Needs.
Maslow first introduced this concept in 1943. This theory explained that people are motivated by five
basic categories of needs; they are physiological security belonging esteem and self-actualization.
Needs lower down in the hierarchy must be satisfied before
individuals can attend to the higher needs.
Accidents do not just happen, they are caused.
Accidents do not have single cause. The accidents are usually the result of a combination of factors
which may vary from situation to situation. There is a lot of possibilities for what
can contribute or cause a workplace injury. They can be grouped into four,
that is environment, equipment and materials, system and procedure or error of worker.
Employers should aware of these contributing factors that may exist in their workplace.
Equipment, are equipment and tools suitable for the task,
are substances used in the workplace being handled stored and disposed of properly.
System and procedure, are their safe operating procedure,
are there any rules and force, are instruction and training provided for each workers.
Environment, does the work environment such as facility layout, walking surfaces,
ventilation, lighting create any hazard, are they comply with local environmental law.
Worker, are they trained and skilled in performing the work, what are the workers
attitudes towards their work, are they focused when doing their work, are they overtired.
Any accident at work result in both direct and
indirect costs which are represented by the iceberg model. Direct caused tend
to be the one that we think off first, they include medical costs and wage replacement.
Indirect costs are hidden costs, they account for more of the overall cost of an accident. They can
be 8 to 36 times higher than direct cost depending on various factors following the accident.
Indirect injury costs include but are not limited to legal cost, repair or replacement of damaged
materials or equipment, product delay, loss of future business and so on. All this causes can
have an impact on company business. By avoiding accident, company can save money and time.
You can estimate the magnitude of the accident by comparing the number of accidents with the
lost work days. You should also include in your report any course incurred during the accident
For decades people been asking this question : why do accidents happen ? Over the years several
theories of accident causation were introduced that tried to explain why accidents occur.
Single factor theory assumed that an accident is the result of single course. Further, if that
single course can be identified and eliminated the incident will not be repeated. The reality is that
accidents always have more than one contributing factors. The multiple factors theory says that
an accident occurs when a number of factors act together cause an accident. Determining the cause
leading to an accident can be quite difficult as there are so many factors to consider. An accident
causation model is a systematic method of finding what type of failure or area cause accident
and so action can be taken to address this failure, before they have the chance to occur.
This example shows a comparison between single and multiple model of accident causation.
In this scenario a forklift accidentally hit a worker while walking at a warehouse.
According to the single model the only cause is forklift operator fault for not being careful,
the solution is to take a disciplinary action.
When using the multiple model several causes of accident can be identified, among them are
does the forklift operator properly trained on operating the forklift, does the operator
authorize to operate the forklift, is there any safe operating procedure for operating a forklift,
thus the forklift is in good condition and safe to drive, does the environmental condition
such as lighting or ventilation at the warehouse create hazard, and so on.
In 1931 Herbert W Heinrich presented a model known as the domino theory. This theory
stated that the accident results from a chain of sequential events, just like a line of dominoes
falling over. When one of the dominoes falls it triggers the next one and the next one and so on.
The sequence is, injury such as cut, fracture. Injury is caused by
accident, the event that results in injury due to the unsafe act or unsafe condition,
due to the fault of the person that is negative traits that lead to unsafe acts,
caused by their negative traits that inherited from social environment. According to Heinrich
the accident is avoided by removing one of the dominoes normally the middle one or unsafe acts.
This theory provided foundation for accident prevention
measure aim at preventing unsafe act and unsafe condition.
The first update of the domino theory was presented by Bird and Loftus in 1976.
Using the same number of domino the elements are lack of control, refers to inadequate system
standard and compliance by the management, this lead to the basic courses that includes
human factors such as incompetent, and also job factor such as inadequate work standard.
Immediate causes are unsafe act and unsafe condition, they are symptoms of incident.
Accident is undesired events such as contact with hazardous substances, contact with hot object. And
loss is the result of accident, it can be loss to human, property and environment.
Bird stated that management failure is another leading cause
of accident at work. Management should implement
an effective safety and health program that able to prevent accidents and avoid injury.
This example applied the bird domino model. In this scenario a worker had an accident
while operating a stamping machine. Let's analyze each sequence of events.
Worker hand caught between moving object while trying to reach something in the machine,
as the result the worker's hand crushed and suffers from major injury. Why the worker's
hand crashed? because the workers put his hand inside the machine while it is in motion. How
can the workers can enter dangerous part of the machine? because the safety sensors
that supposed to protect the workers is not functioning. Why the sensor is not functioning?
because there is no one assigned to repair the machine safety sensor
and the management did not perform routine check of the machine safety.
For the control measures, the management can control at the immediate courses that
is remind the worker not to put his hand into the machine, and at the same time put a warning sign.
However this is not an effective control as the worker may forget and repeating to the unsafe act.
The best way is at the first domino that is repair or replace the sensor
and make sure it is functioning and tested daily before letting the worker operate the machine.
From here we can concluded that if the safety sensor is repaired at the early stage
that is controlled from the management, accident will not happen and injury can be avoided.
Causes of accident can be classified into three. The basic or root cause is the most
fundamental cause that can be corrected to prevent recurrence of the error, such as
poor safety management rules not enforce lack of training and so on, they are underlying causes.
Contributing causes are even or conditions that increase probability or severity of the accident,
such as equipment failure missing guard and so on. Direct causes is an immediate event
usually the result of one or more unsafe act or unsafe condition such as ignoring safety rules,
horseplay, and so on. They are the symptoms showing signs of poor safety management system.
Corrective action that focusing only on contributing and direct causes of an accident
may eliminate the symptom of a problem, but not the actual underlying problem itself.
This may lead to recurrence of similar issue or problem in the future.
Root cause analysis is defined as a systematic process for
identifying the root causes of problem or event and an action plan for responding to them.
A root cause analysis answered these questions : what happened? how did it happen?
why it happened? and what need to be corrected. By conducting a root cause
analysis employer may be able to completely prevent the same incident from recurring.
Following are the tools necessary to conduct root cause analysis. Employers
should use a combination of the tools to get an optimum result.
This concludes my today's presentation. I hope this will be useful in developing
your workplace accident prevention program. Thank you and see you again.
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