Tissue360 - Fall/Winter 2016 - 36


must provide the adequate corrective task
time horizon. This P to F time horizon is formally documented during an RCM analysis
with the assets subject matter experts (typically the assets maintainer's operators and
engineers) utilizing their knowledge and
experience to document how long the progression to F will be. Math then determines
the Nett P-F curve, which is the remaining
time available to the maintenance planner
once a given P point is detected.
With the remaining time to functional
failure clearly understood and available for
comparison against the vendor's spare part
lead time, an informed stock vs. non-stock
decision can be made. For example, a fourto five-day vendor lead time on the spare
part required for a failure mode with a twoyear P-F interval leads to a clear non-stock
decision on the spare. Said another way, if
the vendor lead time exceeds the Nett P-F
inspection interval, then there is no need
to stock the part, providing you rigorously
perform the inspection.
36

Tissue360ยบ FALL/ WINTER 2016

NSM AND REDUCING
STOREROOM INVENTORY
It can be a challenge for the reliability professional to convince an organization that
through proactive CBM programs, the need
for stocking spare parts can be reduced.
In this second example, the challenge of
convincing an organization is even more
difficult when it comes to equipment for
which no proactive task can be developed
and therefore an NSM maintenance strategy
is adopted.
If the failure mode is random (upwards
of 80 percent of failure modes are) and the
P-F curve is of no practical use (such as in
the failure of an/many electronic device or
devices), then on what technical basis can a
non-stock spare decision be validated? The
answer they found in their RCM analyses
involved two additional data elements captured with the failure modes:
1. The consequence of the failure
2. The statistical probability of the
failure occurring.

An example of how this works is that,
out of an RCM analysis, the team will have
identified several failure modes with a
recommended action to review the spare
parts stocking policy. This action is routed
to the reliability engineer, who conducts a
review of the probability of failure based
on both the manufacturer's MTBF data
and the mill's internal MTBF data for the
asset to account for any operating context
differences between how the manufacturer
foresaw the asset being used and how it is
actually being used.
Once determined, the MTBF is compared
against the vendor lead time, cost of downtime, cost of the part, including expediting, and the number of locations that the
part will spare. Based on this information,
a probability cost model is calculated that
determines when (in number of years), for
a population of installed identical parts,
the cumulative probability of failure will
equal or exceeds 50 percent. It is this
number of years to reach the 50 percent
www.tappi.org


http://www.tappi.org

Table of Contents for the Digital Edition of Tissue360 - Fall/Winter 2016

Setpoint
Tissue Industry News
PrimeService for Modern Tissue Machines
Making the Most of Opportunity in Tissue?
Reducing MRO Inventory Using RCM Principles
Vacuum Blower Saves 40-50 Percent Tissue Dewatering Costs
Tissue360 - Fall/Winter 2016 - cover1
Tissue360 - Fall/Winter 2016 - cover2
Tissue360 - Fall/Winter 2016 - 3
Tissue360 - Fall/Winter 2016 - 4
Tissue360 - Fall/Winter 2016 - 5
Tissue360 - Fall/Winter 2016 - Setpoint
Tissue360 - Fall/Winter 2016 - 7
Tissue360 - Fall/Winter 2016 - 8
Tissue360 - Fall/Winter 2016 - Tissue Industry News
Tissue360 - Fall/Winter 2016 - 10
Tissue360 - Fall/Winter 2016 - 11
Tissue360 - Fall/Winter 2016 - 12
Tissue360 - Fall/Winter 2016 - 13
Tissue360 - Fall/Winter 2016 - 14
Tissue360 - Fall/Winter 2016 - 15
Tissue360 - Fall/Winter 2016 - 16
Tissue360 - Fall/Winter 2016 - 17
Tissue360 - Fall/Winter 2016 - 18
Tissue360 - Fall/Winter 2016 - 19
Tissue360 - Fall/Winter 2016 - 20
Tissue360 - Fall/Winter 2016 - 21
Tissue360 - Fall/Winter 2016 - 22
Tissue360 - Fall/Winter 2016 - 23
Tissue360 - Fall/Winter 2016 - PrimeService for Modern Tissue Machines
Tissue360 - Fall/Winter 2016 - 25
Tissue360 - Fall/Winter 2016 - 26
Tissue360 - Fall/Winter 2016 - 27
Tissue360 - Fall/Winter 2016 - 28
Tissue360 - Fall/Winter 2016 - Making the Most of Opportunity in Tissue?
Tissue360 - Fall/Winter 2016 - 30
Tissue360 - Fall/Winter 2016 - 31
Tissue360 - Fall/Winter 2016 - 32
Tissue360 - Fall/Winter 2016 - 33
Tissue360 - Fall/Winter 2016 - 34
Tissue360 - Fall/Winter 2016 - Reducing MRO Inventory Using RCM Principles
Tissue360 - Fall/Winter 2016 - 36
Tissue360 - Fall/Winter 2016 - 37
Tissue360 - Fall/Winter 2016 - 38
Tissue360 - Fall/Winter 2016 - 39
Tissue360 - Fall/Winter 2016 - 40
Tissue360 - Fall/Winter 2016 - Vacuum Blower Saves 40-50 Percent Tissue Dewatering Costs
Tissue360 - Fall/Winter 2016 - 42
Tissue360 - Fall/Winter 2016 - cover3
Tissue360 - Fall/Winter 2016 - cover4
http://www.nxtbook.com/naylor/PPIB/PPIB0118
http://www.nxtbook.com/naylor/PPIB/PPIB0217
http://www.nxtbook.com/naylor/PPIB/PPIB0117
http://www.nxtbook.com/naylor/PPIB/PPIB0216
http://www.nxtbook.com/naylor/PPIB/PPIB0116
http://www.nxtbook.com/naylor/PPIB/PPIB0215
http://www.nxtbook.com/naylor/PPIB/PPIB0115
http://www.nxtbook.com/naylor/PPIB/PPIB0214
http://www.nxtbook.com/naylor/PPIB/PPIB0114
http://www.nxtbook.com/naylor/PPIB/PPIB0213
http://www.nxtbook.com/naylor/PPIB/PPIB0113
http://www.nxtbook.com/nxtbooks/naylor/PPIB0212
http://www.nxtbook.com/nxtbooks/naylor/PPIB0112
http://www.nxtbookMEDIA.com