Explaining the Fundamental Contributing Factor Theory Accident Model

No single theory has been developed which can				happening.
be applied to determine what decision a safety				Another view that is just as critical in preventing
manager must take under all specific risk profiles				accidents is that the design, configuration and
and all variable circumstance. What is required,				layout of structures and assemblies be maintained
being the closest to a theory that tells one which				to prevent such deviation to contribute to
decision to make, are the criteria to be used for				accidents happening. In practice a number of
decision making. In order to develop appropriate				cases have been recorded where the design or
decision making criteria one needs to understand				layout are not maintained, it contributed to serious
the specific risk profiles, the variable				accidents occurring.
circumstances and the alignment of the maturity				Imperfect Procedures
levels of the management style with that of the				The developing and implementing of appropriate
organisation and the skill levels of the work force.				procedures will not in itself result in an accident
One must establish what the appropriate criteria				free work environment, however it is a known
are for various risk profiles are and then utilize the				fact that where appropriate procedures have
criteria intelligently. Despite this there can be no				been implemented the number of accidents are
guarantee that utilising a set of criteria will result in				significantly less than workplaces where this is not
the correct decision, however it will provide the				the case.
confidence that the decision maker have the best				According to Vincoli (1993) procedures should be
probability of making the most appropriate				developed to assist personnel to safely operate
decision. One way in which the probability of				hazardous systems. He continues that procedures
success can be improved, can be to utilise a				may include the use of personal protective
scientific model as a basis to formulate decision				equipment in hazardous conditions. There are a
making criteria.				number of regulatory requirements and Act of
Most safety decisions are made to prevent				parliament that also identifies the use of personal
accidents or reduce their impact. In order to				protective equipment as a means of minimising
improve accident prevention decision making				the risk to workers under certain circumstances.
criteria it may be beneficial to base these types				In most instances where the implementation of
of decisions on a scientific accident model. It is for				procedures fails to prevent accidents it has been
this reason that fundamental contributing factor				identified than that the procedure did not take
theory accident model is described in this article.				cognisance of variable conditions. In addition to this
In order to clarify the interaction of the various				the buy-in from the workforce to follow a specific
failure modes present in the model, a graphic				procedure is reduced where consultation have not
representation is represented in a figure that can				taken place during the development process.
be accessed by following a link at the end of this				Unsuitable Task Directives
article.				A task directive is a detailed explanation of the
In the graphic representation the fundamental				steps to be followed to enable a worker to safely
contributing factors are represented as individual				conduct the tasks making up a job. In the
solid plates rotating at individual, varying speeds on				absence of a task directive the complexities of a
a common axis. Each plate in the model				task is left to the discretion of the worker. This
represents a fundamental contributing factor				often, results in tasks being conducted without
associated with a potential accident. The solid				the impact of the specific order being considered.
parts of the plates represent a perfect condition				For this reason all high-risk tasks should be
in each of the elements. The randomly positioned				supported with a suitable task directive.
holes in the plates represent failure modes of the				In order to explain the lack of suitable task
fundamental contributing factors. The fundamental				directives one should consider that the supervisor
contributing factors identified to be present in				issuing the task directive normally has a totally
most accidents are:o Energy sources out of				different frame of reference than the worker
control,o Management system failure,o Training				receiving the directive.
deficiency,o Latent design defects,o Inappropriate				The correct way to establish a proper task
maintenance,o Imperfect procedures,o Unsuitable				directive is as follows:o Put the worker at ease.o
task directives,o Substandard physical conditions,o				Tell the worker about the task to be performed.o
Unsafe acts,o Barrier failures.				Explain the context of the task, including the
If at any time all the theoretical holes are aligned,				impact it may have on other workers busy on
or arranged so that a line of sight passes through				the same job.o Explain the task detail steps to
all the plates, an accident will result. In practice this				the worker, emphasising the high risk activities
means that an unsafe act or any of the other				and the standard control measures to reduce the
factors alone cannot cause an accident. The				risks of the task.o Request the worker to repeat
unsafe act forms part of a system of interactive				the steps of the task, including the safety
failures where all the fundamental contributing				precautions to be followed.o Correct any
factors have a defect lined up in the				deviations and again confirm understanding.o
four-dimensional space-time continuum. This may				Instruct worker when and where to start the
explain why defects in any of the fundamental				task.
contributing factor areas may exist for a long				The above steps in issuing a task directive is not
time without an accident resulting.				exhaustive, but is deemed to be the minimum
The following section gives a more in depth				requirement for issuing s task directive.
description of each of the fundamental				Substandard Physical Conditions
contributing factors contained in the model.				The physical environment, and especially sudden
Energy Source / Hazardous Materials				changes to that environment, should be identified
According to Haddon (1967) damage is caused to				by the worker on the workplace. Changes in the
the body of a living being when the amount of				conditions should be dealt with by the workers on
energy applied to the body is in excess of the				discovery. The actual situation at the time of
corresponding injury threshold of the body. This				conducting at risk activities is important, not the
implies that when the energy of the impact is				usual conditions, according to A Guide to Accident
greater than the capacity of the body to absorb				Investigation by the Canadian Centre for
it, injuries will result. The more the threshold is				Occupational Health & Safety to prevent
exceeded the more serious the injury will be.				accidents.
Over the years a significant number of studies				Once an accident happened, investigators may
have been launched to establish the links between				want to establish, for example, how the conditions
the energy of the impact and the subsequent				at the time of the accident differed from the
injuries on the person. Most of these studies have				so-called normal conditions at the scene in order
been conducted for and on behalf of the motor				to establish contributing factors with the aim of
industry worldwide. The results of these studies				preventing future accidents.
have already significantly influenced design of				It is important that investigators understand that
motor vehicles in the interest of safety.				task directives, procedures and maintenance
A number of commonly occurring energy sources				programmes are normally based on so called
have been identified in the literature. For the				standard conditions. Should the physical conditions
purposes of the industrial environment the				vary from the expected, the task directives,
following can be utilized as a guideline:o Mechanical				procedures and maintenance programmes may
energyo Electrical energyo Thermal energyo				become inappropriate to prevent accidents.
Chemical and Bio-chemical energyo				Unsafe Acts
Electromagnetic energyo Potential (gravitational)				Research about accidents indicates that upwards
energyo Kinetic energyo Acoustic energy				of 85% of all accidents can be attributed to the
Various elements present prior to an accident				so called human factor. The safety manager
may trigger the release of large amounts of				should not confuse the human factor with unsafe
energy or hazardous materials. During				acts. Human factors include behaviours as well as
investigations or preventative design it is				unsafe acts. A full discussion on behaviour is dealt
important to establish the energy source or				with else ware in this chapter. The unsafe act is
hazardous materials that may be causing the				the one contributing factor that most authors use
injury as a result of the actual or potential				to try and explain the reason for accidents, but it
exceeding of the threshold limit of the exposed				is also the most controversial and misunderstood
person's body.				factor. Acts or omissions are often utilised to
Safety Management System Failure				apportion blame and prosecute individuals under
A safety management system is an integral part				some law. It is normally focused on the acts of
of the overall management system that				the injured or persons in the immediate vicinity of
specifically facilitates the management of the				the accident, and in so doing moves the focus
occupational health and safety risks associated				away from more remote but equally important
with the business of the organization. This includes				unsafe acts.
the organizational structure, planning activities,				It is important to try to establish all the so called
responsibilities, practices, procedures, processes				unsafe acts and or omissions in all the aspects of
and resources for developing, implementing,				the at risk activity. Should an unsafe act or
achieving, reviewing and maintaining the				mission be identified it must be the aim to
organization's occupational health and safety policy.				prevent such act or omission in the future by
The role of safety management system failure				understanding the reason for it rather than utilising
should be critically reviewed during the accident				it to apportion blame for the accident.
investigation. The main objective of safety				Barrier Failure
management systems is to effectively manage				Barriers consist basically of two types namely
the identified significant risks by ensuring that				physical and time barriers. The purpose of physical
control measures for these risks are constantly in				barriers is to physically prevent the energy source
place. This implies that an appropriate risk				to come into contact with persons in the event
assessment was conducted and that the resulting				of other failures. When assessing the
risk profiles are utilised to direct prevention				effectiveness of physical barriers it is important to
activities. As the Safety Management system				establish the capability of the barrier to arrest the
forms the foundation of the safety management				energy source in such a way that the energy will
activities it will have to be designed to an				be dissipated so that the threshold limit of the
appropriate level of complexity to cater for the				person potentially in contact with the energy
risk profile of the organization to ensure that it				would not be exceeded. Physical barriers include
does not contribute to the failure mode and				barriers that would absorb the energy of an
accidents occur as a result.				impact that exceeds the threshold limit of the
Training Deficiency				body. Often such barriers are destroyed during
Organizations should have effective procedures to				the impact. It is this destruction of the barrier that
ensure the competence of employees in order to				absorbs the energy and prevents injuries. Such a
allow the employees to safety carry out their				destruction of a barrier does not means that the
allocated duties. Personnel should be trained to be				barrier failed, as long as the energy level has been
competent to perform all jobs. The accident				reduced to tolerable levels the barrier did the
prevention training should focus on high risk tasks				work it was designed to do.
that could impact on occupational safety in the				Often it is not possible to install a physical barrier
workplace. To assess the level of competence				and in these cases a time barrier may be just the
the employees should be evaluated in terms of				answer. A time barrier aims to ensure the
their appropriate education, training and/or				absence of persons during a final event. A time
experience to conduct the high risk tasks.				barrier is typically the removal of the workforce
A lack of appropriate training has been identified				from the affected area. In a mining environment
by most safety professionals as a major				the workers are normally removed from the
contributor to the unacceptably high accident rate				mine before the blast is initiated. The workers are
in the industrial environment. To address this				then only allowed back once the dangerous
problem the industry agreed to the inclusion of				gasses have dissipated. A time barrier can only be
various sections in different act that governs				successfully implemented where appropriate levels
industrial safety. A factor that one should be				of discipline are normal practise in the workforce.
careful about when prescribing training to prevent				Behaviour
accidents are that training programmes are				The unpredictability of the fundamental
normally developed for standard condition and				contributing factors aligning in a four dimensional
very seldom take cognisance of the varying				space time continuum can be ascribed to the
sub-normal conditions usually present at the time				unpredictability of the behaviour of the various
of accidents.				role-players. The fact that very little, if any,
Latent Design Defects				attention is paid to the alignment of individual
The design of equipment or factory layout and				values, with that of corporate safety values,
design is recognised as an important factor to				could be the most significant reason for this
ensure that the work environment is inherently				unpredictability. There are a number of
safe.				commercially available behaviour intervention
Most existing accident investigation models imply				techniques that could be utilised to alleviate this
that, in any given situation, latent design defects				problem.
will affect the likelihood that an accident will occur.				A full description of the concepts and particulars
Some models call it ergonomics and others				necessary to implement an appropriate behaviour
construction failure, structural defects or assembly				based programme are outside the scope of this
faults. Irrespective of what it is called, most				article.
authors agree that latent design defects play an				Conclusion
important part in any accident.				Despite the fact that theories and concepts are a
Often latent design defects could have been				very valuable basis in safety management, the
identified prior to purchasing of the parts or				practical success lies in the effective translation of
equipment but missed as the safety professional				these theories and concepts into actions related
does not form part of the approval process for				to the goals and objectives and aligning of the
the acquisition of new parts or equipment.				actions with the risk profile.
Inappropriate Maintenance				Theories could be utilised to evaluate past
Most modern accident investigation models have				experience and adapt future implementation
underplayed the contribution of inappropriate				practises taking these experiences into account.
maintenance to accidents. Vincoli (1993) identifies				As long as the evaluation takes the variability of
maintenance as a factor in accidents but focuses				the conditions in account a solid analysis is possible.
on the contribution that maintenance personnel				Irrespective of what accident model is used to
can make in identifying potential hazards and risk.				investigate accidents it is important to adjust the
One (correct) interpretation of maintenance are				model dimensions to the site specific risk profile
the replacement of worn components on				where the accident occurred to gain the
equipment with suitable components prior to such				maximum benefit from using the model.
worn components contribute to an accident

Arkon Safety

Explaining the Fundamental Contributing Factor Theory Accident Model