‘Human error’. ‘Unsafe conditions’. Class Exercise: Accidents & errors. Goals of safety engineering/management. Reduce errors Reduce proportion of errors that become accidents Reduce proportion of accidents that become injuries Reduce lost days/injury. Injury and severity rate.
‘Unsafe conditions’Class Exercise: Accidents & errors
= Injury cases/yr× 200,000 ÷ Actual hrs worked/yr
P The information must be Present.
R The warning must be Read.
U The reader must Understand the warning.
M The information must remain in Memory.
A The person must Act on the information.
E The warning must be Effective (the person
must be able to perform the desired
Most Fault Tree Analyses can be carried out using
only these four symbols.
Events and Gates are not component parts of the system being analyzed. They are
symbols representing the logic of the analysis.
Identify undesirable TOP event.
Link contributors to TOP by logic gates.
Identify first level contributors.
Link contributors to events by logic gates.
Identify 2nd level contributors.
Design FMEA Analysis
∆ = Critical characteristic which may effect safety, compliance with Gov. regulations, or require special controls.
SEV = Severity rating (1 to 10)
OCC = Occurrence frequency (1 to 10)
DET = Detection Rating (1 to 10)
RPN = Risk Priority Number (1 to 1000) = SEV * OCC * DET
RPN = SEV * OCC * DET