Quick Answer
The fault tree top-event probability calculator for redundant systems with common cause failure calculator computes top-event failure probability from the input values you provide.
Calculator
Result Interpretation
Fault Tree Top-Event Probability Calculator for Redundant Systems with Common Cause Failure Calculator computes Top-Event Failure Probability in dimensionless using the defined engineering formula and the input values provided. Top-Event Failure Probability is expressed in dimensionless. No universal acceptance threshold is defined by this calculator.
Worked Example
Verified calculation
Given:
- Basic Event Failure Probability = 0.01
- Number of Parallel Redundant Paths = 2
- Common Cause Factor = 0
Expected Result:
- Top-Event Failure Probability = 0.0199
Engineering Interpretation:
Under the given input conditions, the calculated result is: Top-Event Failure Probability = 0.0199 dimensionless.
The actual numerical result is computed by the Runtime engine using the persisted tool definition. The values shown here come from automatically validated test cases.
Formula / Method
top-event failure probability = 1 - pow(1 - basic event failure probability, number of parallel redundant paths) * (1 - common cause factor * (1 - pow(1 - basic event failure probability, number of parallel redundant paths)))Top-Event Failure Probability.
Variables
| Symbol | Label | Role | Description |
|---|---|---|---|
| basic_event_prob | Basic Event Failure Probability | INPUT | Basic Event Failure Probability |
| n_parallel_paths | Number of Parallel Redundant Paths | INPUT | Number of Parallel Redundant Paths |
| common_cause_factor | Common Cause Factor | INPUT | Common Cause Factor |
| result | Top-Event Failure Probability | OUTPUT | Top-Event Failure Probability |
Calculation Steps
- Enter the basic event failure probability in dimensionless.
- Enter the number of parallel redundant paths in dimensionless.
- Enter the common cause factor in dimensionless.
- Step 1: Compute top-event failure probability.
- Read the top-event failure probability (dimensionless) from the results.
Frequently Asked Questions
What does this calculator calculate?
The Fault Tree Top-Event Probability Calculator for Redundant Systems with Common Cause Failure Calculator estimates Top-Event Failure Probability based on the input parameters you provide
Why is basic event failure probability important in this calculation?
basic event failure probability is used directly in the calculation of top-event failure probability. Its effect on the result depends on the complete formula and the values of the other inputs.. When you enter basic event failure probability in dimensionless, the calculator uses it in the engineering formula to compute the output
How should I interpret the result top-event failure probability?
The calculator outputs top-event failure probability in dimensionless. The result is computed directly from the input values using the defined engineering formula
What units should I use for the inputs?
Enter each value in the units shown next to the input field: Basic Event Failure Probability (dimensionless), Number of Parallel Redundant Paths (dimensionless), Common Cause Factor (dimensionless). Make sure all inputs use the specified units for consistent results
What assumptions does this calculator use?
This calculator uses automatically validated engineering formulas. Results are approximate and should be validated against site-specific conditions, applicable codes, and professional engineering judgment
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