A simple way to assess system safety

A fault tree diagram is a top-down chart representing hierarchies of sub-system and component failures and how they could cause system failures. At the top sits a system event of interest, which is connected by a series of gates to component failures, with failure and repair data assigned to the system components. It’s a clear way to determine the cause of failure or test the reliability of your system.

Included in Isograph's Reliability Workbench™, FaultTree+ is a powerful systems reliability analysis tool with an easy-to-use interface for constructing fault tree diagrams. The software has earned a global reputation for its efficiency, accuracy and stability.

FaultTree+ performs detailed analysis to calculate reliability and availability parameters for the system and identify critical components. It also contains Event Tree and Markov Analysis modules and can also be used in conjunction with Prediction, FMECA and Reliability Block Diagram modules within Reliability Workbench™.



With FaultTree+ you'll be able to:

Accurately assess risk

FaultTree+ calculations involve quantitative system reliability and maintainability data to accurately predict potential failures. It gives you the insight you need to accurately and effectively manage risk. 

Improve reliability

When the critical components of a system are identified using FaultTree+, you can align your maintenance strategies to prevent failures and improve equipment reliability.

Maximize efficiency

FaultTree+ is equipped with features that allow you to easily and quickly build a fault tree diagram and automatically perform complex calculations.


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Batch Analysis

Compare results from multiple projects side-by-side using the batch analysis tool.

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Customized reporting

Output data to Microsoft Office, SQL Server and Oracle to present clear results to colleagues, management, customers and regulatory bodies.

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Enterprise system

Enable large-scale collaboration with easy version control and permissions; and access centralized libraries and parts data in a controlled environment.

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Intuitive user interface

Quick and easy to create fault tree, event tree and Markov diagrams. Gates, events and failure models can be added with just a few clicks.

Additional modules within FaultTree+

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Manage risk using forward logic to analyze the possible outcomes of a hazardous event 

Event tree diagrams provide a logical representation of the possible outcomes following an undesired or hazardous event. Event tree analysis provides an inductive approach to reliability and risk assessment and are constructed using forward logic.

The Event Tree analysis module is unique in its ability to handle large-scale problems and to fully handle success logic. The event tree model may be created independently of the fault tree model or may use fault tree analysis gate results as the source of event tree probabilities.

The Event Tree module handles both primary and secondary event trees, multiple branches and multiple consequence categories.



Intuitive User Interface

Quickly and easily create primary and secondary event trees with multiple branches and consequence categories.

Minimal Cut Sets

Full minimal cut set analysis. Success states are fully handled.

Wide-Range of Models

A range of event failure and repair models including fixed rates, dormant, sequential, standby, time at risk, binomial, Poisson and initiator failure models. 

Sensitivity Analysis

Allows the automatic variation of event failure and repair data between specified limits

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Model complex systems fast with Markov Analysis

Large systems with strong component interdependencies in isolated and critical parts of the system typically contribute to unplanned downtime due to overly optimistic predictions for system availability, reliability and safety.

The Markov Analysis module of Isograph’s Reliability Workbench™ allows you to model complex, dynamic, highly distributed, fault tolerant systems that would otherwise be very difficult or impossible to model which results in improved prediction accuracy.


The Markov Analysis module of Isograph’s Reliability Workbench™ is ideal for large systems with strong component interdependencies in isolated and critical parts of the system.


Fast calculation of probabilities

Calculate a wide range of probabilities and frequencies; and easily analyze the probability of an event resulting from a sequence of sub-events.


Clear modeling of transitions

Model multiple phases representing continuous or discrete transitions; and analyze processes with time-dependent transition rates using clear graphs and plots.


Split system lifetimes

Divide the analysis into phases using split system lifetimes representing (for example) preventative maintenance or standby.


Handle various dependencies

Typical dependencies that can be handled using Markov models include components in cold or warm standby, common maintenance personnel and common spare parts with a limited on-site stock.

Questions? We'll put you on the right path.

Talk to us about how we can help you improve system reliability. We're ready to help.

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