Fault Trees

unmask the mechanism behind defects

Several independent chain reactions simultaneously work in the very moment of the event.

The root cause of each reaction chain is a Basic Risk Factor

Fault Tree Example

Experts needed two days for identifying the causes of this expensive break down:

Faults and General Failure Types in a Fault Tree  (On a foil wheel the foil breaks with every start)

A Upset: Foil breaks with every start
B System doesn’t start properly
C EPROM with start routine didn’t function
D EPROM within spare aggregate is empty
E When overhauling aggregate electrician forgets to load EPROM and to test aggregate before putting it into the spare room
F General Failure Type: PD Procedures and Documentation: Testing is not a standard routine
G When repairing the wheel Electrician exchanges computer against spare not knowing that EPROM is empty
H Electrician doesn’t test computer after repair
I General Failure Type: CG Conflicting Goals: Following staff reduction electrician works under pressure
J Computer storage is empty
K Electric back-up is missing
L General Failure Type: PP Process and Plant: Back-up had not been planned as standard practice
M Main switch had been actuated for another repair. First it looked like human errors: Independently from each other two electricians had made a mistake. In reality several Management faults had prevented them from realizing their errors in time. 

The real causes thus lie in those caused by the Basic Risk Factor,  (Printed Bold).

Zero Defects Management will help you to find for all of your Loss Events the real causes.