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METHOD TO IDENTIFY HAZARDS (Fault Tree Analysis (Symbol used (And:…
METHOD TO IDENTIFY HAZARDS
Job Safety Analysis (JSA)
Procedure which helps integrate accepted safety and health principles and practices into a particular task or job operation
to identify potential hazard and to recommend the safest way to do the job.
Four basic stages
breaking the job into a sequence of steps
identify the potential hazards
selecting the job to be analyzed
determine the preventive measures to overcome all the hazards: eliminate, contain, revise and reduce the hazard.
benefits of JSA
improve communication
create teaching aid
meet safety standard
prevent hazardous conditions
Fault Tree Analysis
A "deductive" analytical tool used to study a specific undesired event
The "deductive" approach begins with a defined undesired event and systematically considers all known events, faults, and occurences which could cause or contribute to the occurence of undesired event.
Symbol used
And
: represent a condition in which all the events shown below the gate (input gate) must be present for the event shown above the gate (output) to occur. This means the output will occur only if all the input event exist simultaneously.
Or
: represent a situation in which any of the events shown below the gate (input gate) will lead to the event shown above the gate (output). The event will occur if only one or any combination of the input event exists.
Rectangle
:The main building block for the analytical tree.It represent the negative event and located at the top of the tree and can be located throughout the tree to indicate other events capable of doing broken down further. This is the only symbol that will have a logic gate and input events below it.
Circle
: represent a base event in the tree. Can be found on the bottom tiers of the tree and require no further development or breakdown. There are no gates or event below these events.
Diamond
: Identifies an undeveloped terminal event maybe because of inadequate information or significance. A fault tree branch can end with a diamond.
Oval
: represent a special situation that can only happen if certain circumtances occur.
Triangle
: The triangle signifies a transfer of a fault tree branch to another location within the tree.When the triangle connects to the tree with an arrow, everything shown below the connection point transfers to another area of the tree.
Methods: define the top event, know the system, construct the tree, validate the tree, evaluate the tree, study trade offs, consider alternatives and recommend action.
Benefits
allow evaluation and improvement of the overall reliability of the system
evaluates the effectiveness of and need for redundancy
Limitation
time consuming and expensive
the overall of the process depends on the skill of the analyst involved.
Hazard and Operability Study (HAZOP)
A design review technique used for hazard identification and for the identification of design deficiencies which may give rise to operability problems
A structured and systematic examination of a planned or existing process or operation to identify and evaluate problems that may represent risks to personnel or equipment or prevent efficient operation
objective
identify deviations from design intent, deviation causes, consequences and safeguards
provide an action list with the dates and identify appropriate discipline to progress the action to close out harm
identify hazard and operaility issues associated with the design
advantages
systematic and comprehensive methodology
more simple and intuitive than other that commonly used risk management tools
helpful when confronting hazards that are dificult to quantify
disadvantages
no means to assess effectiveness of existing or proposed controls (safeguards)
may need to interface HAZOP with other risk management tools
No means to assess hazards involving interactions between different parts of a system or process