Weibull Reliability Database For Failure Data For Various Components
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
Ball bearing
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, Houston,
TX. If you're interested
in machinery life, you'll find this book (and others written by Block and Geiter) worthy of adding to your library for good
maintenance practices and good solid advice on plant equipment.
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 Houston, TX.
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 West Des Moines, IA
by e-mail at  hpbloch@mchsi.com
and Fred K. Geitner, P.Eng. in
Brights
Grove, Ontario, CANADA by e-mail at 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.
Send us your comments . by e-mail about
this database.
 Return to Barringer & Associates, Inc. homepage
Last revised 11/19/2008
This database may be revised at any time to correct values or to
reinterpret operating conditions.
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