Multiple analysis tools are available to perform hazard analyses for each program. Ranging from the relatively simple to the complex. In general, falling into two categories:
a) Event Driven – What could cause “EVENT”
b) Consequence Driven – What would be the outcome from “XYZ Behaviour”
Hazard Analysis Objectives
Identify hazards. To determine the hazards and hazardous events for all reasonably foreseeable circumstances including fault conditions and misuse
Identify causes. To analyse the event sequences leading to the hazardous events identified
Determine risks. To analyse the risks associated with the hazardous events.
When is a Hazard Analysis Performed?
Hazard analysis is an iterative process that continues for the life of a system.
The objective of progressive hazard analysis is to identify and mitigate hazards that can be introduced in the requirements, design, development, testing, installation, commissioning, operation and maintenance and disposal of a system.
Events that should trigger a hazard analysis include:
Requirements review
Design change review
Operating and support plan review
Fault Hazard Analysis
The (Functional) Fault Hazard Analysis is a deductive method either as a qualitative or quantitative analysis.
The fault hazard analysis requires a detailed investigation of the subsystems to determine component hazard modes, causes of these hazards, and
resultant effects to the subsystem and its operation.
The Fault Hazard Analysis of a subsystem is an engineering analysis that answers a series of questions:
What can fail?
How it can fail?
How frequently will it fail?
What are the effects of the failure?
How important, from a safety viewpoint, are the effects of the failure?
A Fault Hazard Analysis can be used for a number of purposes including
Aid in system design concept selection
Assist in operational planning
Provide inputs to management risk control Efforts
Operational constraints
Success and failure boundaries
Fault Hazard Analysis Limitations
A subsystem is likely to have failures that do not result in accidents. Tracking all of these in the System Safety Program (SSP) is a costly, inefficient process.
FHA concentrates typically on hardware / software failures, with inadequate, attention given to human factors.
One of the greatest pitfalls in fault hazard analysis (and in other techniques) is over precision in mathematical analysis. Too often, analysts try to obtain “exact” numbers from “inexact” data, and too much time may be spent on improving preciseness of the analysis rather than on eliminating the hazards.
SAS – Offers Multiple Courses covering Quality & Root Course Techniques – Please see www.sassofia.com or email office@sassofia.com
