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LRTA, 18th February 2009HEALTH & SAFETY LABORATORY, BUXTON30th April 2009
SOCIETAL RISKLand-use planning around major hazard installations
Dr Paul DaviesLloyd’s Register
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SOCIETAL RISKLand-use planning around major hazard installations
Definition of risk
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• Risk is a product ofconsequence and likelihood
– easy to understand– a feeling of control
– impression is that we can measure it− if we can measure risk, we can manage it!
x
Risk = consequence x likelihood
SOCIETAL RISKLand-use planning around major hazard installations
Definition of risk
• Risk = consequence x likelihood
• Risk– a social construct that cannot be easily
reconciled by simple quantification
DANGERAHEAD
TIMESONLINE
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SOCIETAL RISKLand-use planning around major hazard installations
Definition of risk
• Simple quantification ignores the fact– a hard number is the same for everyone– but the consequences are not
• Concept of utility (Bernoulli, 1738)– risk is different for different people because the utility or value
ascribed to it relates to the relative gain or loss that might be experienced - and the value of this gain or loss is a personal (or group) judgement
• In simple terms, people view risk in a much wider context than simply the product of consequence and likelihood, and this view is often subjective because it is very much dependent upon your position and attitude to risk.
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SOCIETAL RISKLand-use planning around major hazard installations
Risk has a common theme
• Risk….
Future 1
Future 4
Future 5
Future 6
Future 7
Future n+1
Future 2Future 1
Future 4
Future 5
Future 6
Future 7
Future n+1
Future 2
uncertainty negative outcomes
OutrageSocietal Concern
=
likelihoodhow often?
consequencewhat is the outcome?
outrageis the likelihood, consequence or both tolerable to me or my group?
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SOCIETAL RISKLand-use planning around major hazard installations
Societal Risk
• Relationship between frequency and the number of people suffering from a specified level of harm [IChemE, 1985]
• Likelihood of a number of people being harmed in an incident [HSE Regulatory Impact Assessment]
• Occurrence of multiple fatalities at one point in time [HSE
Regulatory Impact Assessment]
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likelihoodconsequence outrage
Risk =
SOCIETAL RISKLand-use planning around major hazard installations
Accidents materialise societal concern
• Public outcryHow has this happened? Why were we not better protected?Whose to blame?
• Political outcryHave we failed to protect the public?Has HSE not done its job?
• More regulation - probably
• Fewer MHIs? Fewer jobs?
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SOCIETAL RISKLand-use planning around major hazard installations
To help decision-making - remember
• There are only a limited number of sites where societal risk calculations may result in advice different to that given now
– small proportion of sites give rise to a level of societal risk that makes such consideration appropriate
– only those using/storing toxic materials or flammable materials under refrigeration require consideration of societal risk beyond the existing CD
– only very large developments would have a significant impact on societal risk levels beyond the existing CD
– existing advice prevents many developments which would increase societal risk
– around many sites there are limited opportunities to develop e.g. the land around them is already built-up
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SOCIETAL RISKLand-use planning around major hazard installations
To help decision-making – two options
1. Modify the existing arrangements – implicit consideration of societal risk
2. Introduce an explicit societal risk measure
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SOCIETAL RISKLand-use planning around major hazard installations
Modify the existing arrangements
• Raised Criteria Sites (RCS)?– raise the existing criteria at the identified sites– determine a CD+ to cover large developments outside
existing CD (only this would require HSE consultation)
– Monitor MHIs (with QuickFN?) and remove/add sites to maintain a current RCS listing
• Does not limit ‘build-up’, but does ‘check’ societal risk• Maintains consistency with the existing LUP/HSC arrangements
(part of the existing PADHI system)
• Only requires HSE consultation for large developments within CD+• No blanket coverage of MHIs
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SOCIETAL RISKLand-use planning around major hazard installations
Explicit Societal Risk Measure
• FN Curve, EV / PLL, Societal Risk on a Map….?
• Advantages and disadvantages
• Are they easy to understand and communicate?• Do they introduce additional uncertainty?• Can they / Is there a need to distinguish between different
population groups? e.g. children and the elderly• Will they be consistent with the existing dangerous-dose
approach to land-use planning and hazardous substances consent?
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HEALTH & SAFETY LABORATORY, BUXTON30th April 2009
The Lloyd’s Register Group works to enhance safety and approve assets and systems at sea, on land and in the air –because life matters.
For more information, please contact:
Dr Paul DaviesGlobal Business ManagerRisk Management Services
Lloyd’s Register71 Fenchurch StreetLondon, EC3M 4BS
T +44 (0)1625 538 928E [email protected]
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