Failure Mode Effect & Criticality Analyses FMECA

FMECA System …….. Sub System …….. Failure Mode Ratio α Assembly …….. Item Function Failure Mode Cause Failure Mode Ratio α Failure Rate λ Failure Effect Severity Symptoms Criticality Risk Priority Number Immediate Level Next Level

4 5 8 6 3 7 13 10 2 11 12 1 9 1 Basket 5 Counter Weight 8 Switch & Distributor 12 Water out 2 Tank 6 Control Unit 9 Pump 13 Thermostat 3 Belt Drive 10 Hot Water in 7 Bearing 4 Motor 11 Cold Water in

System: Automatic Washing M/c Sub System : Water Assembly: Tank Item Function Failure Mode Cause Failure Mode Ratio α Failure Rate λ (10^4)Hours Failure Effect Severity S Symptoms Criticality α λ S Risk Priority Number Immediate Level Next Level TANK Contain Water Wrap Leak Burst Deformation Seal fail W.L. regulator fail 0.3 0.6 0.1 0.08 0.05 Catastrophic Impede shaft rotation 0.7 0.5 1.0 Wet Floor Severe Noise 0.017 0.03 0.005 0.052 Valves Control Water Flow Seize Seal Fail Spring failure No water flow Flood 0.21 0.91 Total Criticality 0.962

System: Automatic Washing M/c Sub System : Water Assembly: Basket Item Function Failure Mode Cause Failure Mode Ratio α Failure Rate λ (10^5)Hours Failure Effect Severity S Symptoms Criticality α λ S Risk Priority Number Immediate Level Next Level Basket Holds Clothes Wrap Crack Deformation Overload and Solids 0.5 0.4 Impede rotation Damage clothes 0.8 1.0 Noise 0.16 0.2 0.36 Bearing Support the shaft Seize Misalignment Corrosion Loss of lub. Oil Heavy loads 0.3 0.7 Not proper washing Shaft damage and leakage 0.147 0.49 0.637 Total Criticality 0.997

EVENT TREE ANAYSIS ETA

Accident Accident Accident Initiating Event Pivotal Events END STATES Escape of Poisonous Gas Gas Concentration is Dangerous Gas Detected Alarm Sounds All Personnel Evacuated P=1x10- 4 No Accident No P1=0.1 P=4.62x10- 4 No Accident Yes Probability of having NO Accidents = 5.62x10- 4 Yes P1=0.001 P1=0.6 P1=0.95 P=3.08x10-- 4 Accident No Yes P1=0.4 P1=0.9 P=4.05x10- 5 Accident No Yes P1=0.05 P1=0.9 P=9x10- 5 Accident No P1=0.1 Probability of having Accidents =4.38x10- 4

FAULT TREE ANAYSIS FTA

Given the following system of crude oil supply. The system is composed of three pumps sharing the load and a buffer tank Construct FAILURE TREE and evaluate the probability of failure. If the Mechanical failure probability of one of the pumps is 0.3 in a period of 6 moths. Electrical Failures have a constant failure rate of 0.2 failures/month. Failure rate of the buffer tank amounts to 0.3 failures/month. Evaluate the system Failure rate in failures/month. Pump A Pump B Buffer Tank Pump C

System Fails Buffer Tank fails Pump C fails Pump B fails Pump A fails 0.315625 OR AND 0.015625 Buffer Tank fails 0.3 Pump C fails Pump B fails Pump A fails 0.25 0.25 0.25 OR OR OR Elect Mech 0.2 0.05 0.2 0.05 0.2 0.05

A Computer System Failure Computer System Fails OR Mother Board Main Storage Peripherals Auxiliary Storage OR OR OR RAM HD Main Input Auxiliary Input Monitor Printer AND AND CD UBS Mouse Key Board Scanner CD Player

Method of Obtaining Cut Sets MOCUS Top Event 1 G1 2 OR 1 G2 G3 2 1 G5 3 4 9 2 1 G1 2 OR 1 G4 ,G5 G3 2 1 5 7 5 8 6 7 6 8 3 4 9 2 G2 G3 AND OR 1 G4 ,G5 3 G6 2 G4 G5 G6 3 OR OR OR 9 5 6 7 8 4

1 5 7 5 8 6 7 6 8 3 4 9 2 Given the Cut Sets in the previous example. Construct The Corresponding RBD 5 6 1 3 4 9 2 7 8