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Topic 52: Human Factors in Process Safety

faizakhatri's picture


It has been well understood by safety professionals that human factors greatly contribute to the success or failure of Process safety programs in the process industries as well as represent the area needing the most emphasis to Reduce risk. But in the recent past, most of industry has been preoccupied in initiating the development of process safety
Management programs and conducting PHA studies to measure hazards from process deviation from design intent or Design shortcomings, and has not developed special initiatives to comprehensively address human factors.
To address this issue we need to fully understand the Human Factors & Human Errors, both terms are often misunderstood or considered as Same. So we need to understand their behaviour and categorize them in to following
Active Failure
Passive Failure
Proficiency Failure


Faiza Khatri
M.Sc oil and gas engineering



Alabi Ochu Abdulraheem's picture

Nearly all accidents results from human error and this is because humans govern and accomplish all of the activities necessary to control the risk of accidents. Not only do humans cause accidents (unintentionally) by making errors directly related to the process itself, but they also cause errors by creating deficiencies in the design and the implementation of management systems. Process safety is all about controlling risk of failures and errors while controlling risk is primarily about reducing the risk of human error. In order to achieve process safety, all elements of Risk-Based Process Safety (RBPS) and alternative standards for process safety have to be considered. Each of these elements in turn helps to reduce the chance of human error or helps to limit the impact of human error. Each of process safety standards has some weakness in the control of human error.
Williams B, Revonda T, “Human Factors Elements Missing from Process Safety Management” American Institute of Chemical Engineers, 2010
Name: Alabi Ochu Abdulraheem
Reg no: 51231595

Craig Donaldson's picture

It is all about improving the interface between the system and humans in order to increase profitability by improving efficiency and reduce the number and severity of injuries resulting from operating incidents. The figure below is a human factor analysis and implementation model created to ensure a systematic process can be followed to produce a better man-machine interface.




If you can alter the safety culture, training and competence of your employees while focussing on improving the operating procedures and management structure then the amount of incidents caused by human errors will be greatly reduced. One of the biggest changes which could be implemented would be improvements to the operating environment such as providing proper lighting, handrails, seating and monitors so that operators can stay focused on the task.

Of course human errors can never be fully stopped so improvements plans can be put in place to mitigate he effects of human errors. Can anyone comment on the most common human factor which comes into play and how we should plan to mitigate it?


Attwood, D., and Fennell, D., "Cost-Effective Human Factors Techniques for Process Safety," Paper Presented at CCPS International Conference and Workshop, Toronto, 2001.

Alabi Ochu Abdulraheem's picture

The UK Health and Safety Executive (HSE) has recognised the
importance of human factors and now requires operators of major accident hazard
facilities to identify the potential for human failures  using safety critical tasks and carry out an
assessment of performance influencing factors. Most companies comply to this by
carrying out some form of process hazards analysis during initial process
design or periodic assessments of existing facilities, using techniques such as
HAZOP studies.

Human-HAZOP (Hazard and operability) studies identify the
potential for human failures during safety critical operating or maintenance
activities and also make recommendations to optimise the factors influencing human

The key stages in the Human-HAZOP methodology are shown

with risk of major accident

key steps in activity

credible human failures at each step

potential for recovery

consequences and risk control measures

Optimise performance influencing
factors for task


Name: Alabi Ochu Abdulraheem

Reg no: 51231595

Aleksandr Poljakov's picture


I completely agree with the guys above,
as human factors play a big role in process safety, and contribute both to both
success and failure of the operation. However, I feel that there is a need to
talk about the reason that makes human factors and errors so important.

Swiss cheese model shows us that there
are many barriers place to try and control and combat the risk. The barriers
are also there to try and control human factors that may cause failure of the
process system.  There is a need to
realise, that the human factor plays such an important role due to the system
safety itself. Theoretically, creating barriers strong enough to eliminate any
errors and create closed system would completely eliminate human factors in
process safety.

Aleksandr Poljakov, MSc Oil and Gas Engineering


sreehariprabhu's picture

As my friends posted, i too agree that human factors is a main factor in process safety. It is very important that we consider the human factors since a negligence during work by a single personnel can lead to a major accident. So it is necessary that every personnel knows his duties and to make sure that he does it well. While we consider human factors, it is important that we consider the type of job he is handling. A person should not be over strained  or allowed to do a job more than the time he can carry it out. If he works overtime, he may become tired and stressed which may lead to an accident due to his careless activity. Therefore, tasks must be organized according to ergonomic principles.

It also depends on each individual depending upon his skills, competency, personality, attitude and ability to perceive risk. Eventhough the personality cannot be varied, skills and competency can be enhanced. Thus, managing human failures is essential to prevent major accidents,
occupational accidents and ill health, all of which can cost businesses
money, reputation and potentially their continued existence.

Sreehari Ramachandra Prabhu

charlesggeorge's picture



I like  to add some of the point with your opinion.
There is a lot of examples of major accidents that caused by the human factor.
This is because of their negligence and irresponsible in their duty or sometimes
there may mislead the datas.This can be from the design stage to the operation
stage of a system. Best example is of gulf of Mexico oil spill.
 Motivation,Complexity,Distraction,Fatigue,Confusion &
also Communication are some of the Controlling  factors helps prevent
accidents due to human factors.

Charles George 

Msc in Oil and Gas Engg 


Savitha Haneef's picture

My project for one module was the Ergonomics or human factors consideration in the design of offshore control rooms. As it is a highly stressful job the human factors are to be considered at all stages of the design process and all those concerned (especially operator comments) to improve the efficiency,safety and the operator well being.I am aware I am limiting human factors to one example.

Ergonomics is a study of human characteristics which affects the design of systems , equipments and jobs.It is based on engineering, anatomy,physiology and psychology.I was surprised by the amount of ergonomics consideration that goes into each and every stage of tthe design. It touches all the parameters like the human-machine interface, environmental design , communications etc. Anthropometric guidelines are followed which reduces the stress on the operators. Shift handovers are carefully considered,  as you all know it is the key contributor to many significant accidents like the piper alpha.Absolute safety is not possible. Even with all this consideartions errors are tend to happen as it is human nature. But ergonomics definitely helps in improving the safety 

Savitha Haneef

MSC Safety & Reliability Engineering

Oluwatosin A. Oyebade's picture

I'd like to start by differentiating between human factor and human errors and then look into different methodsof reducing human error.

Human factor deals with the interface between human and other components of a complex system. Human errors on the other hand is undesirable human decision or behaviour with a potential to diminish performance efficiency and safety of a system.

Ergonomics as Haneef rightly pointed out above is an excellent approach in aiding reduction in human error. It can be broken down into 2 categories:

a) Microergonomic Approach: This looks into the link between human, machine and the physical environment by focusing on materials handling, Designs of equipments, Workstation and Handtool.

b) Macroergonomic Approach: which looks into the total people-technolog system level and is acquainted with effect of high-tech systems on human systems at various levels such as personnel, managerial and even organizational stages. These human errors can be in 3 major forms:

  • Situation based: i.e those connected with work environment in time and space.
  • Human based: in terms of failure due to emotional states, lack of motivation and poor work ethics.
  • Management based: which could result from leadership failures, communication breakdown or inactivity in perople and system training.

In process safet, the person that invent, control and run the systems are likened to the human factors and their activities are influenced by; the  organisations they work for, the techniques employed when working, the equipments used for their work and the environments in which they work and these different interface have tendencies for malfunction to occur hence the need for human factors to be addressed as a part of process harzard analsis.

Oluwatosin Oyebade

Msc Oil and Gas  Engineering.

Richard Sedafor's picture

i agree with the posts above addressing the element of human factor in process safety. As Haneef has said, each stage of the process of design of systems must be done with a lot of human considerations if the final system will be very safe to use. Even these may be done human errors can occur.

Human errors are simply mistakes done by those in charge of systems or personnel. A typical example is the failure of the USD 125 million Mars Orbital which failed partly due to the bad communication of readings relayed by the orbital and read by the NASA officials. One part of the project team had used English units while another part had used metric units. [1]. Again,the explosion at Mobil's refinery at Torrance can be attributed greatly to human error.[2]

Human errors have resulted the loss of millions and the death of thousands. Therefore the question is how can Human errors be reduced?

1. Strict adherance to government Process safety regulations such as the UK Control of Major Accident Hazards (COMAH) regulations

2. Continues training of Staff







faizakhatri's picture

Inline with the class mate’s comments I conclude that for safety processes reduction of human factor is necessary in the analysis of initial data for designing for any plant included a wide range of human factors tools and that sought to assess the ergonomics factor which can be directly interface Human behaviour toward design of the facilities and operating systems of process plants and reduce occurrence of human to identify human factor weakness and control below methods can help:
• Risk Reviews ( included, HIRA, PHA/HAZOP management system)
• Incident Investigation/Root Cause Analysis
• Compliance with safety standard  such as OSHAS,OSHA
• Safety Audits

Faiza khatri

M.Sc oil and gas engineering


Aleksandr Poljakov's picture

Human factors play an important role in
the system and all the possible errors need to be thought of. One of the most
widely used techniques to understand and calculate possible human errors is
Human Reliability Analysis. It allows calculating the reliability of the system
and probability of human errors. The data from the analysis can be used in
combination with reliability of the plant and equipment, as well as its’
probability of failure. Combination of the two above helps to create
reliability analysis for wider system. However, there are certain risks associated
with using this method – first and the most important one is that the data
gathered in the analysis is not always correct; it is not consistent and may
lead to errors in the calculations.

Ref: Jason Good  & Ann Blandford, Incorporating Human
Factors Concerns Into The Design And Safety Engineering Of Complex Control Systems,

Poljakov, MSc Oil and gas Engineering

Aleksandr Poljakov's picture

I would also like to mention some techniques
that are used to prevent accidents in process environment. There are quite a
few techniques that are used; most of them are based on the human psychology.
The processes identify which equipment or material used is hard to use and can
cause potential problems when people operate it. The varieties of approaches
used, however, have different approaches, as the data gathered and methods used
can differ significantly. The methods used to predict human errors are far less
accurate than the theoretical calculations of system reliability. In my
opinion, they can also be bias, as it depends on the person conducting research
evaluation and analysis.

Aleksandr Poljakov, MSc Oil and gas Engineering

t01sik12's picture

Process safety is about controlling risks of failure and errors: controlling risk is reducing the risk on human error. Nearly all  accidents results from human error. This is because humans are in charged and accomplish all of the activities necessary to control the risks of accident. Human factors are those aspects of the process that could may it more likely for human error to come in play which in turn causes an accidental discharge.

In order to control or reduces the risk of a complex process for human error:

1) Analyse the Problem and determine weakness in the process.

2) Control risk factor day to day.

3) Understand the risk.

it is also important to note that hazard identification and risk assessment helps to identify weakness in human factor practices and implementation.



Samuel Kanu

Msc Subsea Engineering

Tianchi You's picture

Nowadays, as safety is becoming more and more important among all the occupations, human factors have been taken seriously to decrease the level of risk behind potential hazards which may result in devastation. However, even though all the companies are emphasising the importance of safety all the time, there are still accidents happened every year in everywhere around the world. As we know that it can not make sure that the 100% safety, but there are still some human factors may cause problems in my opinion:

  • They may forget of the responsibility on their shoulder (Definitely not everyone, but sometimes some people probably notice that but do not obey the rules of their work, for example what if the bus driver got drunk last night and had a headache and then went to drive the bus, who knows maybe there is happened somewhere which is lack of supervison and management)
  • The environment such as weather, the condition of equipment , the mood of the worker may all influence the safey
  • As the safety problems may happen, I think the companies can organize some practise for emergency, which may help people to become much more familiar if there is sth really happened.

As I said ,human factors play an important role in influencing safety but I do not know whether it can be predicted. Like the fatal accident rate formula, is there any formula can calculate the rate of human activity on safety??


Tianchi You


Oil&gas engineering

Yaw Akyampon Boakye-Ansah's picture


The human is the
engineer of his own life's activities. All activities are coordinated by humans
even those computed by machines and computers. Humans feed data into these
machines to produce results and information. Thus, the failure in processes
reflects the limitation of human capacity.

Unusually though,
certain factors affect reliability apart from design limitations and lack
of knowledge on certain aspects of a process. To list the major disasters ever
recorded in the world, it can almost always be linked to one or more humans who
failed to honour their duties or totally neglected them. Sometimes though,
these processes are affected because the human elements had picked up certain
tendencies which are intrinsically not safe but they went ahead otherwise to
fulfill their desires.

There have been
quantified studies on how human failure to follow procedure affect quality and
thus pose a hazard to end users of the process.

"99% of
accidental losses (except for natural disasters) begin with a
human error (supported by data from more than
1500 investigations)" is a bold claim by William Bridges &
Revonda Tew for American Institute of Chemical Engineers. To be able to control
this, people must be trained to do what is right and they should have a resolve
to not cut corners to accomplish any work.

A prescriptive
approach is not required but some processes may well require them so as to
reduce the risk of exposure to hazard except if it can be proved that the
proposed process is intrinsically safer and will yield safer and more efficient
results than proposed approaches. "No job is too important not to be done

Yaw A. Boakye-Ansah


Richard Milne's picture

Human factors are possibly the most important part of safety engineering. As has been mentioned by several people already, everything we do (especially offshore) is run by people and hinges on people doing their job well. Everyone from the rigger on the back deck of a vessel through to the captain can have a bad day, and could be in a compromising situation.

The job of an Engineer is primarily to ensure safety, and so he should leave nothing to chance. Failsafes should be put in place for normal everyday operations (like vessel navigaton which has 3 seperate systems that can be used) so that someone who is having a bad day will not cause a large incident. For non-routine operations, such as heavy lifts, the best solution is to have lots of observation. An example of this happened when I was offshore and the deck crew were carrying out a lift of 110 tonnes. All of the guys had forgotten to cangethe cranes masterlink from the one used preciously (rated at 35te), and it wasn't until just before the crane wire became taught that this was noticed. This had to go down as a near miss.

This type of human factor can happen to anyone at anytime, and it is the engineers job to ensure that proper procedures are put in place to help any crew. An Engineer should ALWAYS assume that the person doing the job is doing it for the first time when writing a procedure. This should ensure that no steps are missed out and everyone will have a way to check the operation.   

Liu Yishan's picture

The human factor in process is the main cause of incidents in industry. There are a few researches studying the behaviour of man in the organizational environment to better understand their motivations and identify the causes of errors. The human error is not a cause, but a symptom of failure in modern view.
- Human error is a symptom of a trouble deeper inside the system.
- Safety is not inherent in systems. The systems themselves are contradictions between multiple goals that people must pursue simultaneously. People have to create safety.
- Human error is systematically connected to features of people tools, tasks and operating environment. Progress on safety comes from understanding and influencing these connections.
The theory interprets human factor in process safety in detail. It can reduce the human error in incidents by understanding the behaviour of human.


Aleksandr Poljakov's picture

I agree with Liu that human errors can cause
unexpected accidents to occur in the process environment. However, I would say
that the most accident occur due to poor system design, poor risk assessment or
lack of involvement and commitment from senior management. This is why many
H&S cases end up prosecuting senior management rather than a person that
actually caused an error. Some of the accidents can take place due to the
nature of the company itself and the way things are done in the environment.
For instance, people may be used to cutting corners and undertaking risky
operations, just because it became a cultural attribute of the company.

Aleksandr Poljakov, MSc Oil and Gas Engineering 

Aleksandr Poljakov's picture


Aleksandr Poljakov's picture

There is also a need to identify what
part of the safety engineering do the human errors belong to. Reliability of
equipment, for instance, is well-known, human errors are unknown. Human errors
can be both known unknowns, when we know that a person might act in
unpredictable manner, certain measures can be taken, barriers can be placed to
avoid the accident. It also, in my opinion belongs to the unknown unknowns,
when a person does something extraordinary and unconventional which may result
in the incident. This sort of accident can never be predicted or mitigated in
any way as we don’t know what are the unknowns that can cause an accident are.

Aleksandr Poljakov, MSc Oil and Gas Engineering 

Brenda Amanda's picture

I will agree with the preceding
posts. The human factor cannot be eliminated from the equation. Unless robots
and other machines were to completely take over the industry, but even so, we
would then discuss the failure mechanisms and probabilities of these machinery
and equipment.

The accidents caused by humans in
the work place, whether in the oil and gas industry or elsewhere can only be
reduced in frequency and magnitude.

One of the guaranteed ways of
achieving better safety standards is to have regular assessments of the systems
in place and how familiar workers are with them and to what degree and extent
the systems are adhered to. Assessments help to identify existing gaps in the
existing safety mechanisms and appropriate staff training given to close or
reduce these gaps or safety standards themselves upgraded.

Manuel Maldonado's picture

I agree with most of the comments in this forum because I can see the importance of considering human factors as a key part of the Process Safety Management. However, without repeating what has been said I would like to start from indicating the main goal of Process Safety Management and people involvement and finally to give my opinion on which factors need to be considered within this process which have not been considered within the elements of the process.

The main goal of Process safety is to ensure all process facilities are operated safely in order to avoid any hazardous material releases or hydrocarbons which can cause fires, or explosions. This management process is related to the use of procedures, standards and management practices which used in an integral and structured manner allow achieving the main goal.

As per definition the Process Safety Management involved people in all its areas. This also considering that process facilities are designed, operated and managed by people, the human factor becomes a key part of the process. Therefore, all procedures, standards and management practices are designed for controlling risks or avoiding errors which intrinsically aims at preventing or reducing human errors during process operations.

The Process Safety Management has considered the basic or general human factors within categories being the cause of a failure or incident, such as process safety culture, work force involvement, operating procedures, training and performance, operating readiness, conduct operations. These categories consider conditions of the interface person - process, and that is how the guidance for Process Safety Management has been developed. However, now a day it is necessary to go further into that development and consider the conditions of the person while interacting with the process. Human factors such as Fitness for duty, attention and motivation, staffing issues, task design and communication issues have been highlighted as some of the main causes for failures or accidents. This then will consider a person not as a piece of the process but rathen as a human.  

Human are involved in all the steps in process. We can say human is the main component of process. People are involed in process design, operation and maitenance. Therefore human error and human nature has a key role in process safety. We know that many well-know accidents are due to human errors.

Human errors can be classified into three. Omission error, Commission error, Extraneous act. Action which are not performed are omissionn errors, action which are performed incorrrectly are commission errors and performance of non-required action is called extraneous act. This classification donot depand on cause or mechanism. Human errors based on mechanism are slip, mistakes due to lack of experience etc. So from this it is clear that, human factors can cause many accidents and so it should to assessed and managed properly. 


Reference; tec_hniques.pdf


Kelvin Arazu's picture

Process safety is about controlling risk of failures and errors; controlling risk is primarily about reducing the risk of human error.

The human error in this context includes:

Error of omission: this is seen when someone skips a required or necessary step.

Errors of Commissioning: this is seen when someone performs the step wrong, this occur unintentionally.

Unintentional error they occur because the worker believes his or her way is a better way.

Intentional errors can usually be thought of as errors in judgement. The worker who commits an intentional error is well aware of the risk. As they often believe they know a better way to accomplish a task or they believe there are already too many layers of protection (with the assumption that bypassing one will not cause any harm).

While all elements of Risk-Based Process Safety (RBPS) and alternative standards for process safety (such as US OSHA's standard for Process Safety Management [PSM], Process Safety Code [PSC]) have many elements, and each of these in turn helps to reduce the chance of human error. Hence I will recommend that all organizations should exert considerable control of the errors.

[1] William B., Revonda Tew: Human Factors Elements Missing from Process Safety Management (PSM) Knoxville, TN USA, 2010. 


Human factors as a discipline plays an
important role in process safety by applying scientific knowledge and
principles as well as well as lessons taken from previous incidents &
operational experience to optimize system performances, reliability and human
wellbeing.  The application of human
factors can reduce the likelihood of human error hence increase productivity
and quality. The goal of improving process safety can be met by improving human
factors before an incident occurs. Human factors engineering focuses on the
application of human factors knowledge to the design and construction of
socio-technical systems. The objective of HFE is to ensure that systems are
designed in a way that optimizes human contribution to production and minimizes
potential for design induced risks to health, personal or process safety or
environmental performance.

Majority of oil and gas operating companies
recognize that HFE has an important contribution to make to ensure the quality,
safety and fitness for purpose of equipment and facilities used in the oil and
gas industry. This custom by oil and gas companies adopts a practical,
cost-effective and balanced approach to applying HFE on oil and gas projects. It
involves three elements for controlling HFE related risks:

Compliance with relevant technical

Specific design analysis and
design validation.

Organization and competence to
deliver appropriate standards of quality control.

The process allows projects to demonstrate
that considerations have been given to reducing HFE risks and potential for
human error to a level that can be shown to be As Low As Reasonably Practicable
(ALARP) through engineering and design.





Okechukwu Chukelu (51231798)

Oghenekevwe Ovbije's picture

Irrespective of the safety measures put in place by regulating bodies or managing systems, the most important factor to achieve accident free operations depends on the compliance of the personnel’s involved or assigned to carry out the desired tasks.

Cooperation and compliance from staff can be achieved from continuous awareness of safety practises, routine drills, and updates on accidents or incidents that have occurred because of non compliance of safety regulations.

For my 6 months industrial training, I worked with a firm that considered the safety of their staff above the business, they organised functions like Health Safety and Environment (HSE) day. It was a good medium to discuss safety related issues and understand the importance to comply with safety rules because at the end of it, “nothing that causes us harm is worth doing” and safety is all about us.

Bassey Kufre Peter's picture

I agree with my course mates that human error is major factor in process safety, as we cannot totally eliminate accident due to human error but we can put in place mitigation measures to reduce this error to as Low As Reasonably Practicable. This can be achieved through constant training and retraining of personnel on new technologies that are employed in the industry and also on the need and implications to adhere to guidelines/regulations in implementing their work. We should also ensure that individuals have the required qualification for before sensitive role that could cause fatalities before the role is assigned to them.

Bassey, Kufre Peter
M.Sc-Subsea Engineering-2012/2013
University of Aberdeen.

Andy Reid's picture

There is an interesting difference to distinguish between human error and procedural error.

Human error is when a person fails to follow correct procedure, drops an object or otherwise deviates from the correct protocols in place, resulting in an accident.

Conversely, procedural error is when a person follows all the correct procedures and protocols but the procedure itself is erroneous. An example being if a test procedure specifies pressuring up a vessel at a rate of 30bar / minute. This rapid pressurisation may cause rupture, but this wouldn't be human error on the part of the technicians who are pressuring up the vessel.

This error IS caused by a human - it's caused by the procedure writer/checker/approver who didn't comply to the relevant specifications and who missed this detail, but would this still fall under the bracket of a "human error"?

Should these two instances be treated differently or is there a distinction without a difference?


Andy Reid


SanjayVyas's picture

The design of equipment determines the interaction between the worker and the equipment. The New Approach or CE Marking Directives of the European Community specify the essential requirements to the safety and health of equipment. These essential requirements include requirements for the interaction between personnel and the equipment.

The following factors related to equipment design can affect the human performance.

1.      Accessibility. -       Can the equipment and its components be physically accessed without unnecessary physical stress?

-       Are anthropometric extremes taken into account?

In the design of accessibility and clearance, the anthropometric extremes have to be taken into account. These extremes are dependent on the location of operation of the facility. Accessibility is addressed on multiple levels and as a part of equipment design, the aspects related to Equipment access, Platform access, Access Inside Equipment and Access to Skid Mounted Equipment should be considered carefully.

2.      Physical Activity.

-       Which physical activities are required in the operation and maintenance of the equipment?

-       Can these activities be executed without unnecessary physical stress?

The equipment design determines the required physical activity. The following points should be taken into account:

-       Any component that is too heavy to lift by hand in accordance with local regulations requires a lifting lug. The regulations differ per country and in accordance with lifting situation. For repeatedly operated components with a weight above the lifting limit such as filter and manway covers, mobile hoisting equipment is required through fixed, overhead lifting facilities.

-       The opening or closing of valves, manual gear operators, levers, or chain operations may require excessive force or repeated activity. This may be impacted by the location and accessibility of the component

3.      Information Transfer and Labelling.

-       Is the critical information for the safe operation of the equipment locally and remotely visible?

-       Are the hazards warnings correctly labelled and are these labels visible?

The transfer of information of equipment identification, hazards, and operational procedure is an essential step in the prevention of human error. Signs and labels are indispensable in the transfer of operation to operations and maintenance personnel.

4.      Process Control and Safeguarding Design.

-       Which process control decisions are expected from the operator?

-       Which alarms are to be interpreted by the operator?

The design of the process control and safeguarding systems determines the required actions by operations personnel and therefore the likelihood of human error.

Sanjay Vyas- Student ID - 51234203

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