HSEs Fatigue Index risk assessment tool

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HSEs Fatigue Index risk assessment tool

• Dr Deborah Lucas
• Head of Human Factors,
• Hazardous Installations Directorate
• UK Health Safety Executive
• AGGRI seminar October 2002

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Regulation 4 Hours of Work

• Every employer shall ensure, so far as is
  reasonably practicable, that no employee of his
  undertakes any safety critical work for such
  number of hours as would be liable to cause him
  fatigue which would endanger safety.

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What is fatigue?

• Perceived state of weariness caused by prolonged
  or excessive exertion
• Symptoms range from loss of alertness,
  drowsiness, loss of patience
• Errors include absentminded slips, memory lapses,
  losing the picture, etc.

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Safety consequences

• Three Mile Island, Chernobyl, Challenger, Exxon
  Valdese, Clapham Junction, Selby
• Significant number of road transport accidents
  due to fatigue
• Underestimation of risk - No blood test for
  fatigue

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Drunk with fatigue?

• Fatigue impairment - Blood-alcohol equivalence
• After 17 hours awake some aspects of performance
  equivalent to BAC of 0.05
• After 24 hours awake same as BAC of 0.10

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Causes of fatigue

• Fatigue is a function of
• nature of the task (workload, pacing)
• working environment (heat, noise, light)
• individual factors (eg tolerance to shiftwork)
• biological factors (eg circadian rhythms)
• shift system and working hours
• organisational culture

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HSEs Fatigue Index risk assessment tool

• Developed in support of Railway (Safety Critical
  Work) Regulations 1994
• Assesses daily and cumulative fatigue risks
  associated with rotating shift work
• How to do a fatigue risk assessment when work
  patterns change
• As an aid to education/information transfer
• Underpinned by existing research

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HSEs Fatigue Index

• 5 main factors which impact on fatigue
• shift start time
• shift duration
• length of time between duty spells
• breaks within duty spells
• number of consecutive shifts
• Based on a system of rating scales
• Developed by HF experts at DERA
• Validated by comparison with MOD data
• Freely available to all open to scrutiny

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HSEs Fatigue Index

• Research report Validation and development of a
  method for assessing the risks arising from
  mental fatigue CRR 254/1999 ISBN 0 7176 1728 9
  (also available on HSE website)

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Time of day and fatigue traffic incidents
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Time of day and episodes of cockpit napping
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Time on shift and accidents (after Folkard 1997)
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The biological imperative

• We are all human
• We need to sleep for about 8 hours
• Sleep loss leads to sleep debt
• Recovery from sleep loss needs time
• Quality of day sleep poorer than night
• Adaptation to rotating shift cycle never complete

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Human performance and sleep loss

• Performance effects include
• reaction time increases
• alertness reduces
• memory problems
• wider variations in performance
• Improved by sleep extension
• Need 2 nights recovery period

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Developments since 1999

• Operational use of tool
• Analysis of some accident data
• Profiling current rostering patterns
• Sharing information with companies
• AEA Rail incorporation in IRMA rostering software
• Use in rail, chemical and nuclear sectors
• Thoughts on interpretation of results
• HSE Excel spreadsheet

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Excel spreadsheet
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Example of graphical display
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Real TOC example
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When to use the Fatigue Index

• To compare old and new roster patterns. Are there
  any higher risks?
• To profile daily fatigue levels on a shift
  pattern. Are there any peak levels that need
  controls?

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Take care when

• Informal shift swopping exists
• Overtime is worked
• Shiftworkers have second jobs
• On call arrangements are in place
• Have policies in place for these conditions for
  safety critical work

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Fatigue Index wont help with

• Individual differences eg medical problems
• Family circumstances
• Permanent night shifts
• Split shift systems
• Offshore shift systems

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Interpretation of FI

• Comparisons of mean score and profiles is fine.
• Q.Is there an absolute benchmark figure? When
  is the FI too high?
• A. No absolute value is likely to be given but
  indicative approximate figures are emerging

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Accident data (N16)
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Effect of fatigue on rail incidents
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When to be concerned

• Current advice - mean daily score of FI 30 or
  greater would be a concern
• Or if there are a number of daily peaks of FI
  30 or higher
• But for shift patterns with lot of night working
  then FI daily peak scores are higher
• 6 of sample of 80 rosters across all industries
  had mean daily score of 30

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Review of Mean Daily Score on HSEs Fatigue Index
of 80 shiftwork patterns
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Also since HSEs publication

• Number of other shiftwork evaluation tools now
  available through consultancies and universities
• Basis for some of these not openly available and
  validation not clear
• May look at social aspects of shiftwork not just
  fatigue
• RS undertaking review of these methods

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Feedback to date

• Companies - very useful way of visualising where
  likely problems are
• Regulator - crystalises concerns and allows
  communication with dutyholder
• Staff - gives a shared picture of all aspects
  of shiftwork
• Consultants - using it or have own version
• Use of tool raising awareness, encouraging
  discussion

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Positive and negative experiences

• Moves by companies to flatten peaks by
  redistributing workloads
• Problem with use of benchmarks - strict use of
  25!
• Cases of over-extending use eg to night working
• Focus just on roster patterns to reduce peaks

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Fatigue management - the whole picture

• Time on duty limits
• Biocompatible shift scheduling
• Working environment design
• Risk assessment of critical tasks changes to
  work patterns
• Planning of work
• Shiftworker education
• Cultural changes

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Conclusions

• No ideal shift system but shift patterns for
  safety-critical staff need to be designed to
  avoid fatigue sfairp
• HSE FI tool useful way of seeing where problems
  lie
• Not the whole story many aspects of fatigue
  need to properly managed within SMS
• Clear link with staff numbers, with staff pay and
  therefore a sensitive issue