ETL 1110-2-560
30 Jun 01
Table D-3
Failure Rate Data of Mechanical Components
Failure Rate
1
6
Component
per 10 Operating Hours
Bearings (Summary)
2.9151
Ball (Summary)
1.6445
Roller (Summary)
2.8201
Sleeve (Summary)
2.3811
Couplings, Shaft (Summary)
1.0038
Flexible
1.4054
Rigid
2.6347
Shafts (Summary)
0.9298
Gear Box (Summary)
8.7082
Reducer, Worm
5.0000
Reducer, Spiral Bevel
5.0000
Gear Train (Summary)
3.4382
Gear, Spur
3.2232
Gear, Helical
2.6008
Gear, Worm
3.8258
Gear, Bevel
1.4722
Gear, Rack
1.7562
Brake, Assembly
2.1000
Brake, Electromechanical
10.6383
Hydraulic Cylinder
0.0080
Valves
Ball (Summary)
0.2286
Butterfly (Summary)
0.2900
Check (Summary)
0.0773
Gate (Summary)
0.0478
Globe (Summary)
0.1439
Hydraulic (Summary)
8.8292
Ball
2.3841
Bellows Diaphragm
14.8953
Check
5.3725
Control
57.7196
Relief
0.9201
25.0590
Seal (Summary)
5.4715
Packing
3.5308
O-ring
4.6511
Gaskets (Summary)
0.0195
Springs (Summary)
0.6134
Pump
Hydraulic (Summary)
46.9604
Centrifugal
10.4022
Fixed Displacement
1.4641
Positive Displacement
9.5620
Motor Driven
12.9870
Variable Delivery
54.0498
Centrifugal
51.1732
Piping (Summary)
0.4734
1
Failure rates are from Reliability Analysis Center (1995). The data including the summary data represent combined failure rate
data, which is a weighted merger of several failure rates.
D-8
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