HEART technique for Quantitative Human
Human Error Assessment and Reduction Technique
(HEART) was developed by Williams in 1986.
Since that time it has been widely used
within the UK and continental Europe for
the purposes of assessing human reliability.
is an easily-used form of human reliability
assessment that has been used by a number
of organisations since its development.
This technique, which is derived from a
wide range of findings in the ergonomics
literature, has been designed to be simple
and easily understood. It assumes that basic
human reliability is dependent upon the
generic nature of the task to be performed.
and that under 'perfect' conditions this
level of reliability will tend to be achieved
consistently. HEART also assumes that any
predicted reliability of task performance
may be expected to change as a function
of the extent to which identified Error
Producing Conditions (EPC) might apply.
identifies nine generic task types and proposes
nominal human unreliability values and their
suggested bounding values, together with
thirty eight Error Producing Conditions.
Depending on the amount by which the EPCs
are judged to affect the predicted unreliability
a selection of error reduction strategies
are suggested to combat the most deleterious
effects of any identified EPC.
Experience with HEART
has used HEART in a number of nuclear
industry PSA studies. In the last two
years, Synergy has applied HEART in the
following installations to support PSAs:
submarine refit facilities at Devonport
for DML. This included the assessment
of both process control operations and
the physical tasks necessary when dismantling
and re-assembling reactor plant.
handling in connection with UK submarines
and storage of nuclear waste for NIREX
of refuelling operations at Heysham and
Hartlepool Nuclear Power Stations
of Reactor Cores at Rolls Royce, Derby
of human operations during various nuclear
emergencies at Heysham Nuclear Power Station.
HEART Theoretical Development
has been closely involved in developments
of the technique, particularly as follows:
integration of HEART with THERP (the other
most widely used HRA Technique in nuclear-related
account of dependency in HRA
assessment of cognitive tasks and predicting
measurement and prediction of human violations
HEART Source Data
staff have undertaken a number of the experiments
and practical studies which have been used
as source data for the HEART method. This
includes studies of inspection tasks, simulated
process plant fault diagnosis, and the study
of operators in nuclear plant simulators.
Synergy has also made influential contributions
to the study and application of task analysis
methods, particularly those methods which
are used in the study of complex process
operations. Task analysis is an important
ingredient in the application of HEART.