ITT i-ALERT2 - Machine Selection Criteria

i-ALERT2 Application Guide 15 of 64
Risk is defined as Probability x Consequence. So by multiplying the assigned values from each table a criticality number can
be determined.
The value assigned for equipment will be based on the consequence of the failure of the equipment (called Severity)
multiplied by the probability that the failure will occur (called Probability). The asset matrix (list of all assets that have had
the business criticality determined) can then be sorted by priority. The equipment with the largest number as figured by
Severity x Priority is the most business critical equipment.
MACHINE SELECTION CRITERIA
Just as with every existing condition monitoring system, there are certain applications that best fit the technology
being leveraged. For instance, monitoring casing vibration on a large, slow moving shaft mounted in fluid film
bearings would yield very little quality information as to the health of the machinery. In order to maximize the
return on investment for any given CM system, it has to be applied to the correct machinery. The following tables
and comments help illustrate the best fits for the i-ALERT2 condition monitoring system.
Ranking
Hazard
Potential Safety, Health or Environmental issue. Failure
will occur without
warning.
Hazard
Potential Safety, Health or Environmental issue. Failure
will occur with
warning.
Very High
Very high disruption to facility function. All of Production is lost.
Significant delay in restoring function.
High
High disruption to facility function. Some portion of Production is
lost. Significant delay in restoring function.
Moderate to
High
Moderate disruption to facility function. Some portion of Production
is lost. Moderate delay in restoring function.
Moderate
Moderate disruption to facility function. 100% of Production may need
to be reworked or process delayed.
Low to
Moderate
Moderate disruption to facility function. Some portion of Production
may need to be reworked or process delayed.
Low
Minor disruption to facility function. Repair of failure may be longer
than trouble call but does not delay Production.
Very Low
Minor disruption to facility function. Repair of failure can be
accomplished during trouble call.
None
No reason to expect failure to have any effect on Safety, Health,
Environment or Production.
2
1
4
3
7
6
5
Consequence (Severity) Comment
10
9
8
Ranking
Very High Very High failure rate. Almost certain to cause problems.
High to Very
High
High to very high failure rate. Highly likely to cause problems.
High
High failure rate. Similar to past design that has, in the past, had high
failure rates that have caused problems.
Moderate to
High
Moderate to high failure rate. Similar to past design that has, in the
past, had high failure rates that have caused problems.
Moderate
Moderate failure rate. Similar to past design that has, in the past, had
moderate failure rates for given volume.
Occasional to
Moderate
Occasional to moderate failure rate. Similar to past design that has, in
the past, had moderate failure rates for given volume.
Occasional
Occasional failure rate. Similar to past design that has, in the past,
had similar failure rates for given volume.
Low
Low failure rate. Similar to past design that has, in the past, had low
failure rates for given volume.
Very Low
Very low failure rate. Similar to past design that has, in the past, had
very low failure rates for given volume.
Remote Remote probability of occurrence; unlikely for failure to occur.
Relative Probability of Occurrence
10
9
8
7
6
5
4
3
2
1
Table 2: Example of RCM Methodology based on consequence and probability of failure