X

Download Event Trees Missouri University of Science and Technology PowerPoint Presentation


Login   OR  Register
X

Share page



  Preview

               
Home / Business & Management / Business & Management Presentations / Event Trees Missouri University of Science and Technology PowerPoint Presentation

Event Trees Missouri University of Science and Technology PowerPoint Presentation

worldwideweb By : worldwideweb

On : Jan 08, 2015

In : Business & Management

Embed :
525
views

0
downloads
Login / Signup - with account for


  • → Make favorite
  • → Flag as inappropriate
  • → Download Presentation
  • → Share Presentation
  • Slide 1 - Event Trees Quantitative Risk Analysis
  • Slide 2 - Event Trees - Overview Definitions Steps Occurrence frequency Mean Time between Shutdown Mean Time Between Runaway Example
  • Slide 3 - Accidents do happen! When an accident or process deviation (i.e. an “event”) occurs in a plant, various safety systems (both mechanical and human) come into play to prevent the accident from propagating. These safety systems either fail or succeed.
  • Slide 4 - Event Trees Event trees are used to follow the potential course of events as the event moves through the various safety systems. The probability of success or failure of each safety intervention is used to determine the overall probability of each final outcome.
  • Slide 5 - Event Trees An Event Tree is used to determine the frequency of occurrence of process shutdowns or runaway systems. Inductive approach Specify/Identify an initiating even and work forward. Identifies how a failure can occur and the probability of occurrence
  • Slide 6 - Steps to Construct an Event Tree Identify an initiating event of interest. Identify the safety functions designed to deal with the initiation followed by the impact of the safety system Construct the event tree Describe the resulting accident event sequences.
  • Slide 7 - Identify an initiating event May have been identified during a HAZOP as a potential event that could result in adverse consequences. Usually involves a major piece of operating equipment or processing step, i.e. a HAZOP “Study Node”.
  • Slide 8 - Identify safety functions From PID, process flow sheet, or procedures find what safety systems are in place and what their functions are. These can include things such as automatic controllers, alarms, sensors, operator intervention, etc. On you Event Tree write across the top of the page in the sequence of the safety interventions that logically occur. Give each safety intervention an alphabetic letter notation.
  • Slide 9 - Construct the Event Tree Horizontal lines are drawn between functions that apply Vertical lines are drawn at each safety function that applies Success – upward Failure – downward Indicate result of event Circle – acceptable result Cross-circle – unacceptable result
  • Slide 10 - Construct Event Tree (cont.) Compute frequency of failures B is the failure per demand or the unavailability of safety function B
  • Slide 11 - Occurrence Frequency Follow process through with each step to calculate the frequency of each consequence occurring. Typically three final results Continuous operation Shutdown (safely) Runaway or fail
  • Slide 12 - Mean time between Shutdown Mean Time Between Shutdown, MTBS is calculated from: MTBS=1/occurrences of shutdowns Mean Time Between Runaway, MTBR is calculated from: MTBR=1/ occurrences of runaways
  • Slide 13 - Example – Loss of coolant to reactor Four safety interventions High temperature alarm Operator noticing the high temperature during normal inspection Operator re-establishes the coolant flow Operator performs emergency shutdown of reactor
  • Slide 14 - Example – Loss of coolant Assume loss of coolant occurs once per year (occurrence frequency 1/yr) Alarm fails 1% of time placed in demand (failure rate of 0.01 failures/demand) Operator will notice high reactor temperature 3 out of 4 times (0.25 failures/demand) Operator will successfully restart coolant flow 3 out of 4 times (0.25 failures/demand) Operator successfully shuts down reactor 9 out of 10 times (0.10 failures/demand)
  • Slide 15 - Resulting Event Tree Analysis
  • Slide 16 - Example – Possible outcomes The lettering is used to identify each final outcome. For instance, ABDE Indicates that after Initiating event A occurs, that safety system B failed (high T alarm), that safety system D failed (the operator was unable to re-start the coolant) and safety system E failed (the operator was unable to successful shut down the reactor).
  • Slide 17 - Example – Determination of MTBS For Mean Time Between Shutdowns take the reciprocal of the sum of all sequences that resulted in a shutdown. (Example gives 1/.225 = 4.4yrs) For Mean Time Between Runaway do the same thing with all sequences that resulted in a runaway. (Example gives 1/0.250 = 40yrs)
  • Slide 18 - What is wrong with the logic of this example analysis?
  • Slide 19 - What is wrong? If the operator fails to notice the high temperature after the alarms fails, then he/she will never restart the cooling.
  • Slide 20 - In Class Example Construct an Event Tree and determine the MTBS and MTBR for a loss of coolant for the reactor shown in Figure 11-8. Assume loss of coolant occurs once every three years. Alarm fails 0.1% of time placed in demand Operator will notice high reactor temperature 3 out of 4 times Operator will successfully restart coolant flow 4 out of 5 times Operator successfully shuts down reactor 9 out of 10 times
  • Slide 21 - Solution – Construct Event Tree
  • Slide 22 - Solution Continued – Occurrence Frequency
  • Slide 23 - Solution Continued – Mean Time Between Events
Domino Free PowerPoint Template

Domino

Views : 603

Gym Free PowerPoint Template

Gym

Views : 574

Happy Birthday Free PowerPoint Template

Happy Birthday

Views : 640

Image Sharing Free PowerPoint Template

Image Sharing

Views : 484

Wedding Cake Free PowerPoint Template

Wedding Cake

Views : 845

Puzzle Free PowerPoint Template

Puzzle

Views : 329

Sperm Free PowerPoint Template

Sperm

Views : 876

Parents Free PowerPoint Template

Parents

Views : 442

Airplane Free PowerPoint Template

Airplane

Views : 438

Anniversary Free PowerPoint Template

Anniversary

Views : 614

ECG Heart Beat Free PowerPoint Template

ECG Heart Beat

Views : 1721

Firefighters Free PowerPoint Template

Firefighters

Views : 1323

Piano Free PowerPoint Template

Piano

Views : 628

Question Mark Free PowerPoint Template

Question Mark

Views : 526

Germ Free PowerPoint Template

Germ

Views : 833

Maple Leaf Free PowerPoint Template

Maple Leaf

Views : 507

Back to School Free PowerPoint Template

Back to School

Views : 542

Unity Free PowerPoint Template

Unity

Views : 568

Smoker Free PowerPoint Template

Smoker

Views : 522

Orthodontist Free PowerPoint Template

Orthodontist

Views : 500

Description : PowerPoint presentation on Event Trees Missouri University of Science and Technology, download now ppt of Event Trees Missouri University of Science and Technology

Tags : Event Trees Missouri University of Science and Technology

Shortcode : Get Shareable link