safety SYSTEMS

Hazards Analysis & Risks Assessment

BySebastien A. DaleydenVincent M. Goussen

Hazards Analysis & Risks Assessment

• Importance of safety in design• Hazard analysis: What is it?• An useful engineer’s tool: Designsafe

Importance of safety in design

Unintentional injuries

• Cost of $399 billion a year only in the USA;• Fifth leading cause of death;• Due to interaction between machines and

their environment and the way people live and work

Engineers should more think about the safety of the users...

Importance of safety in design

The main reasons why we should more care about safety are:

Time Costs Competition International Influences Capturing knowledge Product liability

Hazard analysis: What is it?

Objectives:Tool for engineers and safety practitioners to

• identify possible hazards,• provide an evaluation of the risks, • prompt alternative design solutions to

mitigate or control the risks to an acceptable level.


Hazard: Potentially dangerous condition, which is triggered by an event, called the cause of the hazard.

Risk: hazard that is associated with a severity and a probability of occurrence.


Hazard analysis: Identify all possible hazards potentially created by a product, process or application.

Risk assessment: It is the next step after the collection of potential hazards. Risk in this context is the probability and severity of the hazard becoming reality.


When performed:Before the design begins.

Information used: Literature, Scenarios, Expert opinions, Personal experience.


D o cum e nt R esu lts

V e ri fy E ffec tiv e ne ss

R e d u ce R isks

D e riv e R isk R ating

A s se ss R isks

Id en t i fy Ha zards

E s ta b lish A na lys is P aram e te rs

General risk assessment protocol :



V e rify E ffec tiv e ne ss

R e d u ce R isks


A sse ss R isks

Id en ti fy H a zards

E s ta b lish A na lys is P aram ete rs

These parameters can be limits of the machine or design, limits on uses, limits on the scope of the analysis, or other limits.


D o cum e n t R esu lts


R e d u ce R isks

D e riv e R isk R a ting

A s se ss R isks

Id en ti fy H a z ards


The nature of this step lends itself to a team approach such as brainstorming.


D o cum e n t R es u lts

V e rify E ffec tiv e ne ss

R e d u ce R is ks


A ss e ss R is ks

Id en ti fy Ha za rds


Two risk factors are used:

• severity of injury

• probability of occurrence



V e rify E ffec t iv e ne ss

R e d u ce R isks


A sse ss R isks

Id en ti fy H a zards


Catastrophic Critical Marginal NegligibleFrequent High High Serious SeriousProbable High High Serious LowOccasional High Serious Low LowRemote Serious Low Low LowImprobable Serious Low Low Low

Severity CategoryProbability Level

Risk matrix:

If the risk is determined to not be acceptable, it is necessary to reduce that risk by implementing protective measures.




R e d u ce R isks


A s se ss R isks


E s ta b lish A na lys is P aram ete rs Remedy actions are taken to reduce risks following the hazard hierarchy:

• Eliminate hazards through the design Protect Warn the user Train the user(s) Personal protective equipment




R e d u ce R isks


A s se ss R isks



This assessment verifies that the remedy actions have reduced the risks to an acceptable level.




R e d u ce R isks


A s se ss R isks



The documentation can be added to a technical file for future use.


When to stop:

There is no zero risk, always some residual risk remains.

If the residual risk is acceptable, then the risk assessment process is completed.


Caution:Any hazard, which is not identified, will not be addressed by safety measures and will not be detecting during testing.

Hazard not identified during this analysis can create substantial risk to users of the design.


An efficient tool:A new computer tool, named

Designsafe, specially designed to speed the hazard analysis process has become available.

It uses a task-based method to ensure all hazards to users are identified.

An useful engineers’ tool: Designsafe

dse has developed a fast, easy-to-use tool for engineers and safety professionals to incorporate safety through design by:

identifying hazards prompting engineers to think about hazards which

they otherwise might overlook conducting a risk assessment for identified hazards reducing risks in a structured method preventing accidents and reducing liability


what it is... an engineering tool for improving product

designs and processes a systematic method for conducting a task-

based safety analysis a technique for eliminating and controlling

hazards


what it does... gives designers a quick and easy tool to evaluate safety

issues through design permits quick assessment of engineer's change orders

to safety issues assists design engineers in completing a safety analysis

for their products/processes helps companies identify potential hazards and

provides methods for elimination prioritizes design activities related to risk


what are the benefits... helps prompt remedy actions for existing hazards can be employed at all stages of the life cycle of a

design assists in obtaining the CE mark for assessing

European markets can be printed for documentation or a technical file helps assure all hazards are addressed to completion


what are the limits... It’s a guide, not an expert system; Poor inputs or incomplete data lead to poor results.

What could be the next steps ?

Fault Tree Analysis (FTA) • a powerful diagnostic tool for analyzing

complex systems,• begins with selecting the “top event”,• repeating this process at successive levels

using standardized symbols identifies primary and secondary faults.

What could be the next steps ?

Failure Modes and Effects Analysis identifies potential product modes which could

lead to accidents, breaks down designs into components or

subcomponents, then systematically evaluates the potential for and effects of individual failures,

results of the analysis are used to evaluate and implement preventive measures to eliminate or control hazards.

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