Risk assessment is the process of assessing all of the risks associated with each of the hazards identified during the risk identification process.
|ChecklistRisk assessment procedureEvaluate the probability or likelihood of an accident occurring.Calculate or estimate the severity of the potential consequences.Based on these two factors, assign the risks priority for risk control through the use of a risk rating.
Set a time scale for acting on the risk assessment results.
Record the results.
Aids to risk assessment
There are many activities which can be undertaken to assist with the risk assessment process. These include:
undertaking visual inspections of the work and its associated environment or conducting workplace walkthroughs
carrying out scientific or technical evaluations
analysing accident, incident and near miss data
acquiring information from designers, manufacturers and suppliers.
|TipSome of these activities may have been undertaken during the hazard identification stage of the OHS program, in which case any records, reports and results should be analysed to assist with risk assessment.|
Step 1: evaluate likelihood
Evaluating likelihood just means working out how likely it is that a potential risk will actually happen. The method of determining likelihood may vary according to the type of workplace and operations involved. A basic system of evaluating likelihood is outlined below.
The following scale may be used as a model for rating likelihood using appropriate terminology and a basic numerical range of one to 10:
certain or imminent (10)
highly likely (8)
may happen (4)
highly unlikely (1).
|TipIn considering likelihood, it is important to review any information which was gathered during the risk identification stage.|
|ChecklistInformation to considerRisk identification checklists (which will indicate the factors taken into consideration).
Risk identification record forms (which will provide valuable information on circumstances surrounding the risk together with comments of the identification team or individual).
Your organisation’s accident, incident and first aid records (which should reveal trends or frequencies of injury).
Accident investigation reports.
Your organisation’s workers compensation records.
Plant maintenance and breakdown records (eg service books).
Work systems and procedures documentation.
OHS policies – both general and specific.
Employee training records.
Operators’ manuals and equipment instruction booklets.
National accident, injury and workers compensation statistics (which provide information on the numbers and frequencies of accidents related to type, activity and industry sector).
|ChecklistFactors to considerFrequency of occurrence – ie the number of times the situation occurs (eg how many times a day a construction worker is exposed to the hazard of manually handling 45 kg cement bags).
Frequency of exposure – ie the number of people exposed to the hazard (eg how many construction workers at the site lift and carry 45 kg bags around).
Any special characteristics of the people involved (eg a person who has had a prior back injury may be more likely to sustain another injury; a person who is already sensitised to solvents may be more likely to sustain health effects than another worker).
The position of the hazard – are there issues such as distance from the hazard which may influence the likelihood of injury?
Distractions such as time pressures or workplace conditions which may influence careful undertaking of a task (eg hectic activity in a hospital emergency area when a nurse is taking a blood sample could impact on the likelihood of a needlestick injury).
Duration of exposure – how long is the person exposed to the hazard?
Quantities of materials or multiple exposure points involved.
Environmental conditions – are there conditions which may increase the likelihood of an incident occurring (eg water in the vicinity of an electrical hazard)?
Competence of people involved (eg does the worker have adequate training and experience?).
Condition of equipment – defective equipment is more likely to be involved in an accident (eg a cracked guard on the power take-off shaft of a tractor may actually increase the likelihood of accidents rather than preventing them).
Current controls – how effective are any control measures already provided? Are they being used? Control measures may not be used due to issues such as:
lack of training or supervision
failure to replace controls following cleaning, maintenance or repair work
difficulty or awkwardness in using or working with controls
complexity of controls.
Step 2: estimate severity
Estimating severity means working out how much harm will be done if the risk is realised. The severity of a potential injury, illness, damage or loss is also rated. Again, the method chosen to determine severity will depend on the unique needs and circumstances of the workplace. A basic system is outlined below.
Rate the severity
The following scale may be used as a model for rating severity using appropriate terminology and a basic numerical range of one to 10:
multiple deaths (10)
single death (8)
major injury (6)
lost time injury (4)
minor injury (2)
delay only (1).
|ChecklistFactors influencing severitythe number of people who may be affected in one incident
special characteristics of individuals which place them at increased risk (such as lack of experience or medical conditions)
concentrations of substances
volumes of materials
speeds of projectiles and moving parts
heights and distances
forces and energy values
Step 3: assign an overall risk rating
Once the likelihood and severity have been ranked or rated, these conclusions are used to rate the risks in priority order for control. Again, the method and terminology used in cross-referencing the likelihood and severity may vary. The simplest means of doing this is to rate the priority of the risks as follows:
trivial (“Low” priority)
adequately controlled (“Medium” priority)
not adequately controlled (“High” priority).
For example, a risk which is “highly likely” to occur and may result in “major injury” would probably be rated as a “High” priority for control.
|TipSometimes you may find that a decision cannot be reached using a general risk assessment because the hazard is one for which special expertise or further information is required. It may be necessary, for example, to undertake some form of testing (such as workplace monitoring or health surveillance of employees) to make a precise determination on the risk. It may also be necessary to seek expert advice.|
The likelihood/severity matrix
On the table below, the severity rating and the likelihood rating numbers are multiplied to give a risk rating from 1 to 100. The higher the number, the greater the need for action to be taken to control the risk – that is, the higher the priority for risk control.
|The likelihood/severity matrix|
|Severity →XLikelihood ↓||Multiple deaths (10)||Single death(8)||Major injury(6)||Lost time injury(4)||Minor injury(2)||Delay only(1)|
|Certain or imminent (10)||100||80||60||40||20||10|
Interpreting results from the matrix
The following guidelines may be used as a “rule of thumb”.
“Low” priority (trivial) risks are those with risk ratings of 6 and under.
“Medium” priority (adequately controlled) risks are those rated as unlikely or highly unlikely.
“High” priority (inadequately controlled) risks are those rated as certain or imminent or highly likely – further control measures will be required.
“High” priority hazards are also those with ratings of 24 or above – these will require consideration of whether to suspend or start the operation until control measures are introduced.
The control measures provided for risk which are rated as likely or may happen must be examined against current standards to determine whether the risk is adequately controlled or not adequately controlled (“Medium” or “High” priority).
Step 4: set a time scale for action
The risk ratings determined during risk assessment enable decisions to be taken on the amount of effort to be expended in controlling risks associated with particular hazards. However, any risk that is “certain or imminent” or “highly likely” to cause harm must be attended to and the risk reduced even if the severity is low.
Those risks identified as not adequately controlled can now be itemised in a prioritised list for action using the risk rating numbers as a guide to those which will require urgent attention (and possibly suspension of operations), and those which can be listed for action some time in the future.
One method of dealing with risk is to put time limit bands against the risk rating score, such as:
“scores of 12 to 24 must be attended to within 12 months”
“scores of 25 to 40 must be attended to within three months – interim controls will be put in place immediately”
“scores of 41 to 100 must be attended to immediately – activities will be suspended until controls are in place”.
|TipIn setting these timescales, remember that the control measures for risks associated with individual hazards will vary enormously as far as time, cost and other resources are concerned. It is essential for realistic time limits to be set for the various items to be dealt with – in the same way that other management objectives are given deadlines.|
Once the risks associated with all of the hazards identified have been assessed and control measures have been introduced, the risk assessment exercise can be repeated to decide if the residual risk has been reduced to trivial or adequately controlled levels.
Continual assessment forms part of the monitoring and review phase of risk management.
Step 5: recording the results
Once the risk assessment process has been completed, the results should be recorded in a systematic manner. This means itemising the:
work sector, division or department involved
name of the person heading up the risk assessment
date on which the assessment was completed
work zone or location of the hazard involved
task, activity or work process involved
people who may be exposed to risks from the hazard
likelihood ranking of the risk (eg “Certain or imminent (10)”)
severity ranking of the risk (eg “Multiple deaths (10)”)
risk rating assigned (the numerical value – eg 100 – together with the conclusion reached about priority – eg “High”)
timescale for risk control (eg “Immediate – activity to cease until control is effective”).
A sample risk assessment record form is provided below.
|Risk assessment record|
|Work sector: Date prepared: Signed:|
|Work zone/ location||Task/Activity/ Work process||Hazard||People at risk||Likelihood||Severity||Risk rating/ priority||Timescale for control|
|Deadline for next assessment:|
|TipAny additional conclusions of the risk assessment which may be significant, together with any preliminary findings on improvements needed, should be detailed in the comments section of the form. This will assist in the risk control phase of the risk management process.|