2. Reliability is:
A characteristic that describes how
good a device is.
Must be planned for, designed in both in
terms of the initial product and in
maintenance of that product.
3. Failure is:
The degradation of the performance of a
device (process) outside of a specified value
AND non-performance or inability to perform
its function for a given time period within
specified conditions.
Defect: imperfection
Deficiency: lack of conformance to specs
Fault: Cause of failure
Malfunction: unsatisfactory performance
4. Failure Measures
Real life failure: fact of life, define
normal operation, anticipate worst, try
to design out.
Failure rate typically = #failures/unit
time = failures/million hours for
devices.
5. Unreliability is:
A measure of the potential for failure of a
device (or process.)
Leads to high cost, wasted time,
inconvenience, poor reputation, unsafe
operation, …
- 9/9/99 more than 10,000 stepladders
recalled by Home Depot – steps too short,
improperly attached (RIDGID ladders,
Louisville Ladder Co, Louisville KY)
6. Quality is:
The ability to provide stated needs
NOW (and is implied during warranty
period.)
Warranty period: that period of time
that you guarantee to refund/replace/fix
your product.
7. Safety & Quality in Health
Care:
HHS Secretary Tommy G. Thompson today
(10/11/2001) announced the release of $50
million to fund 94 new research grants,
contracts and other projects to reduce
medical errors and improve patient safety.
This research initiative is part of HHS' broader
efforts to improve the quality of care in
America and better assure safety across
health care settings.
8. Reliability Implies:
MTBF of x years (for example, e-1 fail in
5 years), proportional to the probability
of service over a period of time, T.
= performs stated function, without
failure (even with misuse) in the stated
environment, for a specified period of
time.
9. Vanderbilt: Reliability & Risk
Engineering & Management
NSF IGERT awarded 2001
$2.7 M over 5 years
BME/ChE/CE/EECS/MT/Math/ME/Owen
2 year support toward PhD
Sankaran Mahadevan, CE
15. Maude Complaints - XXX Series
1999
2000
2001
2002
2003
2004
2005
2006
1999 2000 2001 2002 2003 2004 2005 2006
Date complaint recieved
Date
of
Manufacture
t
Is this a reliable ventilator?
17. Negligence
You owe a duty of care to another
The standards for that care have been
breached
As a result a compensable injury results
There are damages or injury to the
plaintiff
18. Strict Liability
The PRODUCT is defective or
dangerous.
Risk is too high (risk/benefit higher than
competition, etc.)
19. Breach of Warranty
Implied Merchantability (“King’s
Pacemakers”)
Implied Warranty for particular purpose
(pacemaker)
Breach of express warranty (written or
oral contract: cures 100%)
20. Defect
Actual defect (sharp edges, …)
Consumer expectations
Risk/benefit
State of the art
Defective warnings
Inadequate guarding…
21. Failure to warn!
You have a duty to warn. If you do not
warn that coffee is hot, you are likely to
get in trouble…
22. Examples
Coffee burn
“found with head trapped in side rails…”
Stepladder recall
Fluidized air therapy bed
X-ray/Cobalt therapy accident
Morphine infusion 3 hours not 24
LMA – cyanosis (see MAUDE)
23. Some final key phrases
Misuse
Negligent selection
Failure to inspect
Use with knowledge of defect
Alterations
Disclosure through MAUDE (FDA)
Disclosure through CPSC (non-FDA)
