Failure mode effects analysis and methodology
Anayslise each component in he system in order - identify causes of component failure & effects on the system - best used at the design stage - chemical and nuclear plants where failure of a simple component could lead to a disaster
Methodology
1 - break system down into components
2 - identify failure methods & possible causes
3 - what are the effects
4 - what is the probability, severity and likelihood of an incident occuring
5 - what are means of detection
6 - rate = prfioritize ( severity x probability)
7 - controls - actions for reduction
8 - document in tabular format
Reasons to manage safety are
- moral
- legal
- economic
Explain the above as we’ll as what costs can not be insured against
Moral = obligation to staff / personal impacts on accidents and Ill health / personal values / pr implications of failure
Legal = compliance with legislation / enforcement notices and prosecution / avoid legal action / compensation
Economic = cost of failure / direct & indirect costs / nature of losses / financial benifits and good standards
Costs which can not be insured against = bad publicity / loss in morale and production / product & material damage / legal costs in defending civil claims / overtime & labour costs / fines / loss of trained staff
Hazard and Operability study (HAZOP)
- identifies the deviations from the intended -
- best completed at the design stage but can be used for modifications to a process
- has a team leader who must have an awareness of the scope of the study
- the process is broken down into key stages
- objective data - info supports study
- it involves brain storming
- uses guide words - applied methodology to each process parameter to form deviations from the normal operating standard
- process is documented and recorded - using a set format and must be kept in the project file
- ## HAZOP looks at the causes and consequences of each deviation
Fault Tree Analysis
- analysis the events of multiple causes - whether an event happens or not
- use of the symbols - multiply and gate / plus at and or gate
- probability of the top event being quantified
- helps identify critical stages for intervention
limitation - complex events need skill to work out the top probability
- only as good as the data used in calculations
event tree analysis and the methodology
- based on binary logic
- used to investigate the consequences of loss making events in order to find ways of mitigating rather then preventing loss
- used to estimate the likelihood of success or failure or to assess a particular outcome of an undesired event
- it starts with the initiating event and ends with the probability of the situation being controlled or not
limitations - lack of knowledge of component reliability and data as there are only 2 outcomes (success or failure)
- it does not take into account limited success
methodology
- identify the primary events of concern
- identify the controls which are assigned for dealing with the primary event
- start the event tree at the beginning with the initiating event then proceed through to the failures of the safety functions
- establish the resulting accident sequence
- identify the critical factors that need to be addressed
risk avoidance
- avoiding the hazardous activity altogether
- active steps to eliminate risk or discontinue the process
- a conscious decision
- by avoiding one risk you may create other risks
risk reduction
- reducing the risk to a acceptable level
- hierarchy of control
- actions taken to lesson the likelihood of a negative consequence
risk transfer
transferring the risk to another party (insurance provider or contractor)
risk retention
- retaining the cost of the risk within the company
- with or without knowledge
- risks which can not be transferred to insurance
- without knowledge can put the company in an unfavourable position
acceptable risk
risk which although is not negligable is persumed to not require any further attention
tolerable risk
- is a known risk which is run regularly and deliberately
- it is not negligible
- can not be ignored
- should be kept under review and reduced further if possible
selecting the most appropriate type of risk control
- cost vs benefit
- type and size of the organisation
- present state of technology
- public expectancy
- legal requirements
- economic state of the company
- insurance premium levels
- human factors
- competence of risk manager and confidence of the company
internal sources of information when completing a risk assessment
- accident and near miss investigations
- inspection reports
- audit reports
- maintaince logs
qualitative risk assessment
- informed subjective judgement
- needs good hazard identification
- looks at the likelihood of hazards occurring & severity of the consequences
- can be rated H/M/L
- completed by a risk assessor
quantitative risk assessment
- numerical
- based on frequency of the probability of events occurring & their consequences
- objective approach
- specific data comparison on a specific criteria
- attempts to calculate the probability of frequency with a specific event
external sources of information to consider when completing a risk assessment
- manufactures guidance - designers
- professional body guidance “reducing risks and protecting people”
- other companies who use the same equipment
- insurance companies
- ILO
- experts
- national government enforcement agencies (OSHA / HSE)
reasons for a difference in accident rates within similar companies
- different reporting culture
- different calculations of accident rate and what an accident is
- different HS culture - maintenance of equipment
- different equipment - age & type
- management issues - different levels of commitment - polices & procedures (measuring and disciplining non compliance)
- HR - selection - training - communication & consultation
- adequacy of risk assessment & control measures (SSOW, PPE &PPM)
- shift work - motivation - bonuses
- cultural issues - attitude, motivation , behaviour & peer pressure
- workplace layout
- product issue (piece work/shift work)
job safety analysis
- hazards associated which each component in a specific task are assessed
- it is established if the correct precautions are adequate to reduce the risk levels
- following this a SSOW is produced
Hierarchy of control
E = eliminate R = reduce I = isolate C = control P = PPE D = discipline
ERIC Prevents Death
factors to be considered to ensure a risk assessment is suitable and sufficient
- must address significant hazards that exist
- identify those who are exposed to the hazard
- correctly evaluate the risk generated
- adequacy of control measures
- recognise the need for further controls
- reference to relevant standards & legislation
- complexity of assessment must be appropriate for the complexity of the risk
- assessor must be competent
- must remain valid for a reasonable period of time
reasons for a deficiency in risk assessmeny
- lack of technical expertise
- insufficient reference to information sources
- insufficient training
- unfamiliarity with the hazardous area
- lack of commitment from management
- inadequate MOC
factors to be considered when completing a risk assessment
- activity & task performed
- equipment &material used (info and guidance provided by manufacturer)
- who and how many
- experience & status - are they vulnerable
- likelihood & severity
- adequacy of controls measures to be introduced, inc those required by law
- adequate environmental workplace standards eg. noise
SSOW
The method of carrying out a task in which hazards have been identified and eliminated or risks reduced to a acceptable level
issues to be addressed when implementing SSOW
- Consultation with the workforce
- verbal or written
- number of people involved
- who would be trained
- training arrangements
- management and supervisors understand their responsibility for implementing the system
- date and time of implementation
- procedures for monitoring & review
