FMEA is a structured qualitative analysisboth applicable to products and services.

With a systematic, step-by-stepapproach, it identifies and evaluates the effects of all the component failure modes.

The purpose is toestimate the risk and to define prevention, detection or control measures that could be adopted in order to avoid, handle or limit the damage.

FTA is a deductive, top-down method whichaims to identify potential causes of thesystem failures using a booleanlogic approach: its result is a Fault Tree Diagram, that graphically represents the logical relationship between different components or sub-system failures which may cause a system failure.

In the Fault Injection tests (also known as Fault Insertion tests) component failures are simulated to confirm the existence of assumed diagnostics (see FMEDA and HAZAN) and to determine the exact behaviour in situations where that behaviour is not readily derivable from the design.

HAZAN is an evaluating procedure which considers the behaviour of critical SW functions under expected fault conditions, in order to determine if sufficient protection measures are in place to avoid or against the fault condition effects.

Through a review of the SW architecture and source code structure it is possible to identify, detect and handle the potential systematic problems, adoptingruntimesafety integrity measures that must be implemented.

The list of protection measures also contributes in creating a checklist for Fault Injection and Integration testing.

FMEDA is an inductive, bottom-up and quantitative analysis to estimate failure rates and metrics applicable to a hardware component, system or item, considering the design, the functionality and the failure modes.

For each failure mode, FMEDA determines the effects in relation to a safety goal or to a top-level safety requirement.

When a product used in a safety critical application have mechanical components, it is recommended to perform a Mechanical FMEDA, considering both the electrical and mechanical components to prove the robustness against systematic design faults.

For this specific purpose, exida developed a mechanical components database, integrated in the SILcal V9 tool.

DFA aims to identify the single events or single causes that could bypass or invalidate a required independence or freedom from interference between given elements and violate a safety requirement or a safety goal.

CCFA is an advanced technique evaluating the behaviour of redundant subsystemsin order to determine if sufficient logical and physical independence measures are adopted to avoid or limit the expected dependent failures and common cause initiators.

The goal is to identify all the possible safety measures to strengthen the independence and sets of ß-factors for redundant subsystems.

For analysis of Interference Freeness, see Safety Criticality Analysis (SCA)