TREES DIAGRAMS IN RISK ASSESSMENT
oleh : Rizki Rahmayanti (09111840000121)
Fault Tree Analysis (FTA)
EVENT TREE ANALYSIS (ETA)
DEFINITION
an important logic and probabilistic techniques. Commonly used in Probabilistic Risk Assessment (PRA) and reliability system assessment
a deductive method to identify type of ways that hazards can lead to accident
an approach that start by well defined accident, top event, or even works backwards to reach the various scenarios that can cause the accident
STEP TO DO ANALYSIS
Defining the scope of FTA
Defining the resolution of FTA
Defining the top event of FT
Defining the ground rules of FTA
Identifying the objective of FTA
Contructing the FT
Evaluating the FT, including interpretation and presents the result
REPRESENTATION SYMBOLS
FUNCTIONS
a proactive tool to prevent the top event
to monitor the performance
as a diagnostic tool for identifying and correcting causes of top event
to prioritize the contributors that leading the top event
To assist in designing a system
to understand the logic leading of the top event
To minimalize and optimize resources
ADVANTAGES AND DISADVANTAGES of FTA
ADVANTAGES
DISADVANTAGES
usually begins with the top event
properly used to determine the minimal cut sets
categorized as a complicated process
It requires considerable amount of time to complete
DEFINITION
begin with an initiating event and work towards the final resut
it provides information on how a failure can occur
serve informations about the occurence of probability
STEPS TO INVOLVE IN ETA
Identify the safety functions due to the initiating event
construct the ETA
Identify an initiating event of interest
describe the resulting accident event sequences
human error
process upset
system or equipment failure
Alarms that alert the operator when the initiating event occurs and operator actions
Barriers methods that are intended to limit the effects of initiating event
safety system that automatically respond to the initiating event
Enter the initiating event and safety function
Evaluuate the safety functions
ADVANTANGES AND DISADVATAGES of ETA
ADVANTAGES
DISADVANTAGES
Effectively performed on varying levels of design detail
Permits probability assessment
Structured and methodical approach
Partial successes and failures are not distinguishable
Requires an analyst with some training and practical experience
ETA only initiate event. thus, ETA need to evaluate the consequence of multiple initiating events
RECTANGLE
DOUBLE DIAMOND
DIAMOND
HOUSE
CIRCLE
BASIC FAILURE
BASIC FAULT
RESULTANT EVENT
REPRESENT AN EVENT
REPRESENT A BASIC EVENT