RISK ASSESSMENT
Risk assessment is the process of evaluating a hazard to determine the level of action required to reduce a risk to an acceptable level. When evaluating the risks imposed by a hazard one should consider both the likelihood and consequences of the event happening. Judging how likely it is that something will happen or what its potential consequences might be is like predicting the future. You cannot be really sure; you can only make a “best estimate” on the basis of the information available.
Because it is so unpredictable it is better to be conservative in your judgment.
LIKELIHOOD
This is defined as the chance of an event actually occurring. In the context of risk management, the event referred to is an event which may cause injury or harm to a person. When making an assessment of likelihood, you must establish which of the following categories most closely describes the likelihood of the hazardous event occurring.
Very Likely Could happen frequently
Likely Could happen occasionally
Unlikely Could happen, but only rarely
Highly Unlikely Could happen but probably never will
When evaluating the likelihood of an accident, a factor that will modify the likelihood category is exposure. Exposure is a measure of how often or how long a person is actually exposed to a hazard. Some examples are:
Very Rare Once per year or less
Rare A few times per year
Unusual Once per month
Occasional Once per week
Frequent Daily
Continuous Constant
It is a common mistake to place too much emphasis on the mitigating effects of a low exposure level. Just because a person is not exposed to a hazard very often, does not always mean we can take fewer precautions. The certainty or likelihood of an accident happening is more important than how often a person is expected to a hazard.
Example:
A power press is a common machine in a workshop. In essence, the stored energy in a rotating flywheel is instantaneously connected to a crankshaft, via a key. The crankshaft drives a ram from its resting position at the top of its stroke, down to the bottom of its stroke, where it punches a hole in a piece of metal called a blank. When the ram has completed its punching operation on the blank, it returns to its resting-place at the top of the stroke. The operator removes the blank and replaces it with a new blank.
The design of the machine is such that if a fault develops in the key, the press will unexpectedly operate and complete a stroke. If at this point in time the operator has his fingers under the ram whilst changing the blank, the normal result is a severe crush or amputation injury. The operator would expect to have his fingers in the danger zone for only a split second each time the press cycles. There are no guards or devices that can prevent the machine from cycling once a key fault has developed. Good maintenance will reduce the number of key faults happening but they can never eliminate them totally. For this example, let's assume that maintenance has reduced the risk of the press malfunctioning to once in 5 million operations.
(this is not an unrealistic figure)
At first glance, it seems we need do nothing further to reduce the risk. Closer examination will reveal that operators of presses often exceed 60 operations per minute. Using 60 operations per minute for this example and 1 fault every 5 million operations we fined that:
60 operations/min x 60 min/hour x 8 hrs/day x 5 days/week x 34.72 weeks = 5 million operations.
This indicates that a press operator is at risk of having an accident every 34.72 weeks. The exposure to risk is “very rare” however the “likelihood” of the accident happening is almost certain if a key fault develops. Control measures must be put it a place to reduce the likelihood of this accident occurring because is unacceptable for an organization to have a serious accident every 34 weeks.
The location of a hazard can affect the likelihood of the accident happening. For example, an exposed V belt drive located adjacent to a walkway where persons could easily come into contact with the nip points would have a higher likelihood rating than if the same drive 3 arrangement were located in a position form which persons were located in a position from which persons were excluded.
When we assess “likelihood” it should be remembered we are only assessing the possibility of an accident happening. As part of our assessment of likelihood, we must take into consideration how often and for how long the person is at risk, however, this is of lesser importance than the certainty of an accident occurring.
CONSEQUENCES
Consequence is a measure of the expected severity should an accident occur. When assessing the consequences of an accident, the most severe category one could reasonably expect to result from that accident should be selected.
The consequences of an event can be categorized as follows:
FATAL - Death
MAJOR - Normally irreversible injury or damage to
requiring extended time off work to effect the best recovery
MINOR - Typically a reversible injury or damage to
INJURIES health needing several days away from work to recover. Recovery would be full and permanent
NEGLIGIBLE - Would require first aid and may need the
INJURIES remainder of the work period or shift off before being able to return to work
If the position of the danger adds to the consequences in the event of an accident happening then the added consequences must be taken into consideration and the consequence rating increased.
When making a risk assessment all aspects of likelihood and consequences should be taken into consideration. The interrelated parameters of likelihood and consequences can easily be presented on the simple matrix shown below.
BASIC RISK ASSESSMENT
If we consider the likelihood of an accident whilst driving a car and the consequences, statistically it is highly unlikely that we will have an accident and the worst consequence would be a fatality. From the matrix below we can see that the risk is in the medium range which means that we make efforts to reduce the risk of an accident by such means as driver training, road management, and vehicle design.
Events or situations assessed as very likely with fatal consequences are most serious (HIGH risk); those assessed as highly unlikely with negligible injuries are the least serious (LOW risk).
When developing risk control strategies any item with a high rating should be addressed first. Using the above matrix it would be normal to develop a list of hazards with highly rated hazards at the top of the list. Management would then be expected to determine at what point it would be reasonable to take no further action.
RISK MANAGEMENT WORKSHEETS
There are no standard formats used to record the data in connection with risk management assessments. The examples given are only for reference and may need modification to suit the nature of individual projects.
Always use a Risk Management Worksheet for systematic recording.
PLANT RISK MANAGEMENT WORKSHEET
RISK CONTROL
Control: the measures we take to eliminate or reduce the risk to an acceptable level.
When a risk assessment has identified a hazard as having unacceptable risks we have to put in place control measures to eliminate the risk or reduce the risk to an acceptable level.
HIERARCHY OF CONTROL
Hierarchy of control: the order in which controls should be considered when selecting methods of controlling a risk.
Control measures can be sorted into a number of categories with the most effective listed at the top, the list of categories is collectively known as a “hierarchy of control”.
When selecting appropriate measures to control a risk we should select a control measure from as high on the hierarchy of control list as practicable. The hierarchy of Control list usually comprises:
Elimination
Substitution
Isolation
Engineering Controls
Administrative Controls
Provide Personal Safety Devices
ELIMINATION
The most satisfactory method of dealing with a hazard is to eliminate it. Once the hazard has been eliminated the potential for harm has gone.
Example: The dangers associated with transporting an explosive called Info are known and documented. Info is made by simply mixing ammonium nitrate with fuel oil (diesel). Both constituents are safe in isolation but when mixed they become unstable. The dangers of long-distance transport can be removed by not mixing the component parts until they are on site. By this simple expedient we have eliminated the hazard.
SUBSTITUTION
This involves substituting a dangerous process or substance with one that is not as dangerous. This may not be as satisfactory as elimination as there may still be a risk (even if it is reduced).
Example: many chemicals can be substituted for other safer chemicals which perform in the same manner but do not have the same dangers eg. Water-based paints rather than those that contain lead.
SEPARATION
Separate or isolate the hazard from people. This method has its problems in that the hazard has not been removed. The guard or separation device is always at risk of being removed or circumvented.
Example: A guard is placed over a piece of moving machinery. If the guard is removed for maintenance and not replaced people are again at risk.
ADMINISTRATION
Administrative solutions usually involve modification of the likelihood of an accident happening. This can be done by reducing the number of people exposed to the danger and providing training to those people who are exposed to the hazard.
Example: the dangers of electricity are well known and only trained and licensed people are allowed to work on electrical equipment. We can appreciate that the electrician is still at risk, but their training is such that the risk is reduced to an acceptable level.
Administrative solutions also include danger signs and written systems of work such as those working in confined spaces and lockout spaces and lockout procedures.
PERSONAL PROTECTIVE EQUIPMENT
Provision of personal protective equipment should only be considered when all other control methods are impractical, or to increase control when used with another method higher up in the Hierarchy of Control.
Example: To remove the possibility of a person dropping something on their foot in a workshop situation would be impracticable as it would involve securing every movable object large enough to do damage if it fell on a person’s foot. The practical solution is to provide every person at risk with safety footwear.
Controls are not mutually exclusive, several in the hierarchy may be needed to obtain the level of control necessary.
APPLY HIERARCHY OF CONTROL
It is crucial to apply the control measure from as high on the hierarchy of control list as practicable. If we go back to the power press example in “Risk Assessment” mentioned earlier we can examine the steps we should take to control the risk of an operator having an accident whilst loading the press. The contribution to the industry of the power press is so great that to eliminate them completely from the working environment would not be practicable. Since power presses were first invented in the early part of this century, designers have not been able to eliminate the hazard of an unexpected stroke. Based on the evidence and current knowledge, elimination of the hazard is not practicable.
We could then look for substitution to reduce the risk. We could substitute a power press for a hydraulic press or a drilling machine. Both of these alternatives are too slow to be viable alternatives in most cases.
Separating the operator and the hazard is possible in most cases if we use an automatic feed and a guard to eliminate persons from the danger area. This method is effective, but will not be applicable to all cases.
The administration should be our next alternative. This would involve training the operator to remove the work-piece and place a new blank in the machine without putting their fingers in a position where they could be crushed in the event of a malfunction of the press eg. By using a push stick or similar.
Personal safety devices may not always be applicable. In fact, it should be the aim of the organization to remove the necessity for personal safety devices.
Accepting a solution too low on the Hierarchy of control list is a common failing which must be avoided.
MONITORING AND REVIEW
The review is an important aspect of any risk management process. It is essential to review what has been done to ensure that the controls put in place are effective and that they have not introduced new hazards.
Example: An agricultural machine was found to be hazardous and a guard was subsequently fitted around the moving parts. this guard excluded persons from the danger area, however, due to the nature of the environment it was found that chaff built up behind the guard. If a review had not been carried out of the new guard after it had been in service for a short while, the chaff in conjunction with the moving parts may have caused a fire.
The lesson to be learned here is that however food the initial risk management process was, there is always the possibility that something will be overlooked and not addressed in the initial stages. The review system allows further modifications to be carried out.
CONCLUSION
Hazard identification, risk assessment, control, and review is not a task that is completed and then forgotten about. Hazard identification should be properly documented even in the simplest of situations. Sample worksheets to assist in this process are very useful. Risk assessment should include a careful assessment of both likelihood and consequence. Control measures should conform to the recommendations of the hierarchy of control. The risk management process is an ongoing activity which should include regular reviews of all aspects of an organizations activities including the purchase of new plant and consumables, the safety of existing plant, systems of work including administrative initiatives such as evacuation, fire, and violence in the workplace strategies.
THE PROCESS OF RISK MANAGEMENT
The process of risk management involves the four steps shown in the following diagram – the four steps are undertaken in a cycle until an acceptable level of risk is achieved.
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