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HEALTH & SAFETY


3 Calibrate if required If you are using a RAM to get a relative appreciation of risk [e.g. is risk of Turbine Tower collapse higher or lower than Nacelle fire?], then there is no need for calibration. However, if being used as a basis for decision making [e.g. is risk of Turbine Tower collapse tolerable or intolerable?] then the RAM should be calibrated. This can be achieved by aligning the RAM with the Health & Safety Executive’s [HSE] ‘Tolerability of Risk’ guidance discussed in the last issue and illustrated in Figure 4.


5 Use correctly and consistently Perhaps the most common mistake in using a RAM is not consistently categorising the likelihood and consequence ‘pair’ of a hazard. A good example of this is a fire in an office block. The ultimate consequences could be disastrous [multiple fatalities and total asset loss]. Small fires are fairly common, however, all small fires don’t lead to such severe consequences. The minimisation of combustible materials, fire protection systems, fire escapes, safe evacuation procedures and emergency response, will most likely be sufficient to avoid loss of life and total asset loss.


Select the most appropriate approach for your assessment. Never mix them up though, otherwise you will either exaggerate or underestimate the associated risk preventing you from managing them effectively. A good tip to avoid this is to assess the consequences of the hazard first, which allows you to assess the likelihood in that context.


Extremely unlikely


Major Societal Effects Catastrophic Extremely Serious Major Serious Minor


B B B


Figure 4: Alignment of RAM with HSE ‘Tolerability of Risk’ Guidance


A RAM calibrated in this way is unlikely to be symmetrical [see Figures 2&4]. This is due to society’s general aversion to low frequency, high consequence events.


4 Be prepared To use a RAM you need to understand how all potential hazards can be released, how they can develop and escalate, and the risk reduction measures in place to minimise their likelihood and consequences. Ensure it is used by competent people, preferably in a workshop environment where consensus can be reached.


Very unlikely Unlikely


Likelihood Quite


unlikely


Somewhat unlikely


Fairly probable Probable


U U U U U U 


U UUnacceptable B U


Tolerable U U U if ALARP


Broadly AcceptableB B


U U U


B B B B B 


It is therefore vital that when using a RAM you either assess:


A) the likelihood of the initiating event, making informed judgements on the most likely, credible, consequences [e.g. a fairly probable small fire leading to minor injury or health effects, see Point 1 on Figure 4], or


B) the consequences of the worst possible outcome, making informed judgements on the likelihood of this scenario [e.g. a very unlikely major fire escalating to cause multiple fatalities, see Point 2 on Figure 4].


6 Respect its limitations Where a RAM covers simple hazards, and is suitably calibrated, it is appropriate to use it to decide whether a risk is or is not worth taking. However, that said, for hazards that fall within the ‘Tolerable if ALARP’ region, more detailed assessment is likely to be required to determine whether the risk has been reduced ALARP [As Low As Reasonably Practicable]. More on this in a future issue.


A RAM is unlikely to be sophisticated enough to accurately assess more complex hazards. Here the RAM should be used as a screening tool for more detailed assessment. We will explore detailed risk analysis approaches such as the ‘Bow-Tie’ methodology and Quantitative Risk Assessment [QRA] in future issues.


As a final thought, always remember, risk analysis tools do not reduce risk. It is action that reduces risk. Always make sure you strike the right balance between analysis and action.


Whilst this article has focused on the use of a RAM to assess hazards in a Safety, Health & Environment [SHE] context, it is equally good at assessing other forms of risk such as Project Risk.


Gareth Ellor Risktec Solutions Ltd www.risktec.co.uk


www.windenergynetwork.co.uk


23


Broadly Acceptable


Tolerable if ALARP


Unacceptable


HSE ‘Tolerability Of Risk’ Guidance


Consequences


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