Weibull Database |
Weibull databases require considerable use of engineering judgment
for meaningful application of the facts stored in database format. Do not apply the data blindly without understanding the specific
situation, as this database is solely intended for educational purposes.
Data, described in this database, are very general. The facts are broad as is usually found in engineering references. Typical values are given for a specific case which may not be applicable for each condition envisioned by the end user of the database as exceptions always exist. Therefore you are the sole responsible individual for use of this table--Barringer & Associates, Inc. assumes no liability for your use/misuse of these tables in any manner either obvious or implied.
Item |
Beta Values |
Eta Values |
||||
|
|
(Weibull Shape
Factor) |
(Weibull
Characteristic Life--hours) |
||||
|
Low |
Typical |
High |
Low |
Typical |
High |
|
|
Components |
|
|
|
My engineering judgment does
not support the range of a few values shown in published databases
|
||
|
0.7 |
1.3 |
3.5 |
14,000 |
40,000 |
250,000 |
|
|
Roller bearings |
0.7 |
1.3 |
3.5 |
9,000 |
50,000 |
125,000 |
|
Sleeve bearing |
0.7 |
1 |
3 |
10,000 |
50,000 |
143,000 |
|
Belts, drive |
0.5 |
1.2 |
2.8 |
9,000 |
30,000 |
91,000 |
|
Bellows, hydraulic |
0.5 |
1.3 |
3 |
14,000 |
50,000 |
100,000 |
|
Bolts |
0.5 |
3 |
10 |
125,000 |
300,000 |
100,000,000 |
|
Clutches, friction |
0.5 |
1.4 |
3 |
67,000 |
100,000 |
500,000 |
|
Clutches, magnetic |
0.8 |
1 |
1.6 |
100,000 |
150,000 |
333,000 |
|
Couplings |
0.8 |
2 |
6 |
25,000 |
75,000 |
333,000 |
|
Couplings, gear |
0.8 |
2.5 |
4 |
25,000 |
75,000 |
1,250,000 |
|
Cylinders, hydraulic |
1 |
2 |
3.8 |
9,000,000 |
900,000 |
200,000,000 |
|
Diaphragm, metal |
0.5 |
3 |
6 |
50,000 |
65,000 |
500,000 |
|
Diaphragm, rubber |
0.5 |
1.1 |
1.4 |
50,000 |
60,000 |
300,000 |
|
Gaskets, hydraulics |
0.5 |
1.1 |
1.4 |
700,000 |
75,000 |
3,300,000 |
|
Filter, oil |
0.5 |
1.1 |
1.4 |
20,000 |
25,000 |
125,000 |
|
Gears |
0.5 |
2 |
6 |
33,000 |
75,000 |
500,000 |
|
Impellers, pumps |
0.5 |
2.5 |
6 |
125,000 |
150,000 |
1,400,000 |
|
Joints, mechanical |
0.5 |
1.2 |
6 |
1,400,000 |
150,000 |
10,000,000 |
|
Knife edges, fulcrum |
0.5 |
1 |
6 |
1,700,000 |
2,000,000 |
16,700,000 |
|
Liner, recip. comp. cyl. |
0.5 |
1.8 |
3 |
20,000 |
50,000 |
300,000 |
|
Nuts |
0.5 |
1.1 |
1.4 |
14,000 |
50,000 |
500,000 |
|
"O"-rings, elastomeric |
0.5 |
1.1 |
1.4 |
5,000 |
20,000 |
33,000 |
|
Packings, recip. comp. rod |
0.5 |
1.1 |
1.4 |
5,000 |
20,000 |
33,000 |
|
Pins |
0.5 |
1.4 |
5 |
17,000 |
50,000 |
170,000 |
|
Pivots |
0.5 |
1.4 |
5 |
300,000 |
400,000 |
1,400,000 |
|
Pistons, engines |
0.5 |
1.4 |
3 |
20,000 |
75,000 |
170,000 |
|
Pumps, lubricators |
0.5 |
1.1 |
1.4 |
13,000 |
50,000 |
125,000 |
|
Seals, mechanical |
0.8 |
1.4 |
4 |
3,000 |
25,000 |
50,000 |
|
Shafts, cent. pumps |
0.8 |
1.2 |
3 |
50,000 |
50,000 |
300,000 |
|
Springs |
0.5 |
1.1 |
3 |
14,000 |
25,000 |
5,000,000 |
|
Vibration mounts |
0.5 |
1.1 |
2.2 |
17,000 |
50,000 |
200,000 |
|
Wear rings, cent. pumps |
0.5 |
1.1 |
4 |
10,000 |
50,000 |
90,000 |
|
Valves, recip comp. |
0.5 |
1.4 |
4 |
3,000 |
40,000 |
80,000 |
|
|
|
|
|
|
|
|
|
Machinery Equipment |
|
|
|
|
|
|
|
Circuit breakers |
0.5 |
1.5 |
3 |
67,000 |
100,000 |
1,400,000 |
|
Compressors, centrifugal |
0.5 |
1.9 |
3 |
20,000 |
60,000 |
120,000 |
|
Compressor blades |
0.5 |
2.5 |
3 |
400,000 |
800,000 |
1,500,000 |
|
Compressor vanes |
0.5 |
3 |
4 |
500,000 |
1,000,000 |
2,000,000 |
|
Diaphgram couplings |
0.5 |
2 |
4 |
125,000 |
300,000 |
600,000 |
|
Gas turb. comp. blades/vanes |
1.2 |
2.5 |
6.6 |
10,000 |
250,000 |
300,000 |
|
Gas turb. blades/vanes |
0.9 |
1.6 |
2.7 |
10,000 |
125,000 |
160,000 |
|
Motors, AC |
0.5 |
1.2 |
3 |
1,000 |
100,000 |
200,000 |
|
Motors, DC |
0.5 |
1.2 |
3 |
100 |
50,000 |
100,000 |
|
Pumps, centrifugal |
0.5 |
1.2 |
3 |
1,000 |
35,000 |
125,000 |
|
Steam turbines |
0.5 |
1.7 |
3 |
11,000 |
65,000 |
170,000 |
|
Steam turbine blades |
0.5 |
2.5 |
3 |
400,000 |
800,000 |
1,500,000 |
|
Steam turbine vanes |
0.5 |
3 |
3 |
500,000 |
900,000 |
1,800,000 |
|
Transformers |
0.5 |
1.1 |
3 |
14,000 |
200,000 |
14,200,000 |
|
|
|
|
|
|
|
|
|
Instrumentation |
|
|
|
|
|
|
|
Controllers, pneumatic |
0.5 |
1.1 |
2 |
1,000 |
25,000 |
1,000,000 |
|
Controllers, solid state |
0.5 |
0.7 |
1.1 |
20,000 |
100,000 |
200,000 |
|
Control valves |
0.5 |
1 |
2 |
14,000 |
100,000 |
333,000 |
|
Motorized valves |
0.5 |
1.1 |
3 |
17,000 |
25,000 |
1,000,000 |
|
Solenoid valves |
0.5 |
1.1 |
3 |
50,000 |
75,000 |
1,000,000 |
|
Transducers |
0.5 |
1 |
3 |
11,000 |
20,000 |
90,000 |
|
Transmitters |
0.5 |
1 |
2 |
100,000 |
150,000 |
1,100,000 |
|
Temperature indicators |
0.5 |
1 |
2 |
140,000 |
150,000 |
3,300,000 |
|
Pressure indicators |
0.5 |
1.2 |
3 |
110,000 |
125,000 |
3,300,000 |
|
Flow instrumentation |
0.5 |
1 |
3 |
100,000 |
125,000 |
10,000,000 |
|
Level instrumentation |
0.5 |
1 |
3 |
14,000 |
25,000 |
500,000 |
|
Electro-mechanical parts |
0.5 |
1 |
3 |
13,000 |
25,000 |
1,000,000 |
|
|
|
|
|
|
|
|
|
Static Equipment |
|
|
|
|
|
|
|
Boilers, condensers |
0.5 |
1.2 |
3 |
11,000 |
50,000 |
3,300,000 |
|
Pressure vessels |
0.5 |
1.5 |
6 |
1,250,000 |
2,000,000 |
33,000,000 |
|
Filters, strainers |
0.5 |
1 |
3 |
5,000,000 |
5,000,000 |
200,000,000 |
|
Check valves |
0.5 |
1 |
3 |
100,000 |
100,000 |
1,250,000 |
|
Relief valves |
0.5 |
1 |
3 |
100,000 |
100,000 |
1,000,000 |
|
|
|
|
|
|
|
|
|
Service Liquids |
|
|
|
|
|
|
|
Coolants |
0.5 |
1.1 |
2 |
11,000 |
15,000 |
33,000 |
|
Lubricants, screw compr. |
0.5 |
1.1 |
3 |
11,000 |
15,000 |
40,000 |
|
Lube oils, mineral |
0.5 |
1.1 |
3 |
3,000 |
10,000 |
25,000 |
|
Lube oils, synthetic |
0.5 |
1.1 |
3 |
33,000 |
50,000 |
250,000 |
|
Greases |
0.5 |
1.1 |
3 |
7,000 |
10,000 |
33,000 |
You'll recognize the form of the above table from Appendix A of the reference: Bloch,
Heinz P. and Fred K. Geitner, 1994, Practical Machinery Management for Process
Plants, Volume 2: Machinery Failure Analysis and Troubleshooting, 2nd Edition,
Gulf Publishing Company,
Bloch and Geitner's Appendix A is given in
failures per million hours. Information from Appendix A has been interpreted
and converted into ages-to-failure as shown under the low/high values by
Barringer & Associates, Inc. along with estimates of typical Weibull
values. Bloch and Geitner also give additional failure rates in their 1994
book: An Introduction To Machinery Reliability
Assesment, 2nd Edition, Table 4.3. This book
is also published by Gulf Publishing Company in
Bloch and Geitner also list Weibull shape factors in Table 7-2 of the above reference. You will find many of their values are different than listed above (remember you can always think of different applications and situations which result in different Weibull values for shape factors and characteristic life!!--be carefull when you use the data!!). The issue is not which Weibull value is right or wrong--the issue is to understand your conditions so you select the correct value for your operations based on your experience and your operating conditions. Frequently we find the same equipment in use in similar applications within large companies will display significantly different Weibull values because of the way it is installed, maintained, and operated--so don't be surprised by different Weibull values.
You can communicate with: Heinz P. Bloch, P.E. in 
hpbloch@mchsi.com
and Fred K. Geitner, P.Eng. in
fgeitner@compuserve.com.
Other information for this database was developed from details supplied
verbally by David P. Weber. Dave is a gas turbine reliability expert and author
of papers in fuzzy logic for solving reliability problems. He has an extensive
Weibull database information on gas turbines and other equipment. You can
contact Dave at Phone: 513-697-0852 or FAX: 513-697-0860 and e-mail. Also consider use
of Dave Weber's Weibul db
software. Weibull db uses data from the above database and
displays probability plots, hazard plots, and Monte Carlo variations of the
above information in an Excel spreadsheet--cost for the software is US$70 plus
shipping and handling.
This database is intended for educational purposes only. Barringer & Associates, Inc. clearly is not responsible (neither obvious liability or implied liability) for how you use this database. If you are not personally responsible for knowledgeable use of the details in this database, then don't use it.
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