Basic Information on Failure Rates
The following tables includes a number of mechanical items and representative failure
rate information. The tables also include qualifying factors.
The information included is of limited value and is not current and is in no way representive
a specific products. The failure rate of one company's product could be an order less
than another companies.
The only real value of this table is in providing realistic relative reliabilities of different
components. For most of the components in the table below more accurate reliability information is
provided in the suppliers literature.
Note: 106 hours = 114 years continuous operation....
Failure Rate Fo = Fr. C1 .C2 .C3
| Mechanical item |
Modifier |
Failure Rate = Fr |
| |
|
/ 106 hours |
| Ball Bearing |
Heavy Duty |
20 |
| Ball Bearing |
Light Duty |
10 |
| Roller bearing |
|
5 |
| Journal Bearing |
|
5 |
| Shafts |
Highly Stressed |
0.2 |
| Shaft |
Lightly Stressed |
0.02 |
| Pins |
|
15 |
| Pivots |
|
1 |
| Couplings |
|
5 |
| Belt Drives |
|
40 |
| Spur Gears |
|
10 |
| Helical Gears |
|
1 |
| Friction Clutches |
|
3 |
| Magnetic Clutches |
|
6 |
| Springs |
Highly Stressed |
1 |
| Springs |
Lightly Stressed |
0.2 |
| Hair Springs |
|
1 |
| Calibration Springs |
Creep |
2 |
| Calibration Springs |
Breaking |
0.2 |
| Vibrations Mounts |
|
9 |
| Mechanical Joints |
|
0,2 |
| Grub Screws |
|
0,5 |
| Nuts |
|
0,02 |
| Bolts |
|
0,02 |
| Rack and Pinion Assemblies |
|
2,0 |
| Knife Edge fulcrums |
|
10 |
| Bellows |
|
5 |
| Diaphragms |
Metal |
5 |
| Diaphragms |
Rubber |
8 |
| Gaskets |
|
0,5 |
| Rotating Seals |
|
7 |
| Sliding Seals |
|
3 |
| O Ring Seals |
|
0,2 |
| Filters |
Blockage |
1 |
| Filters |
Leakage |
1 |
| Fixed Orifices |
|
1 |
| Variable Orifices |
|
5 |
| Restriction |
|
5 |
| Pipes |
|
0,2 |
| Pipe Joints |
|
0,5 |
| Unions and Junctions |
|
0,4 |
| Hoses |
Heavily stressed |
40 |
| Hoses |
Lightly stressed |
4 |
| Ducts |
|
1 |
| Pressure Vessels |
General |
3 |
| Pressure Vessels |
High Standard |
0,3 |
| Relief Valves |
Leakage |
2 |
| Relief Valves |
Blockage |
0,5 |
| Hand Operated Valves |
|
15 |
| Ball Valves |
|
0,5 |
| Solenoid Valves |
|
30 |
| Control Valves |
|
30 |
| Pistons |
|
1 |
| Cylinders |
|
0,1 |
| Jacks |
|
0,5 |
| Pressure Gauges |
|
10 |
| Pressure Switches |
|
15 |
| Bourdan Tubes |
Creep |
0,2 |
| Bourdan Tubes |
Leakage |
0,05 |
| Nozzle/Flapper assembles |
Blockage |
6 |
| Nozzle/Flapper assembles |
Breaking |
0,2 |
| Environment Factor |
C1 |
| Ideal Static |
0,1 |
| Vibrations Free |
0,5 |
| Ground based |
1,0 |
| Ship |
2,0 |
| Road |
3,0 |
| Rail |
4,0 |
| Aircraft |
10,0 |
|
| Rating % of Normal |
C2 |
| 140 |
4 |
| 120 |
2 |
| 100 |
1 |
| 80 |
0,5 |
| 60 |
0,3 |
| 40 |
0,2 |
| 20 |
0,1 |
|
| Temperature (Degrees C) |
C3 |
| 0 |
1,0 |
| 20 |
1,0 |
| 40 |
1,3 |
| 60 |
2,0 |
| 80 |
4,0 |
| 100 |
10,0 |
| 120 |
30,0 |
|
|