A deterioration model for establishing an optimal mix of time-based maintenance (TbM) and Condition-Based Maintenance (CbM) for the Enclosure System. Participants will: 1. Learn the two types of asset deterioration models 2. Explore the correlations when the two deterioration models are overlaid 3. Identify six different phases in the maintenance of an asset 4. Identify further model development needs

1. National Institute of Building Sciences Provider #G168
BEST4 Conference
Nibsbest4 • April 13-15, 2015
Credit(s) earned on completion of this course will be reported to AIA
CES for AIA members. Certificates of Completion for both AIA
members and non-AIA members are available upon request.
This course is registered with AIA CES for continuing professional
education. As such, it does not include content that may be deemed or
construed to be an approval or endorsement by the AIA of any
material of construction or any method or manner of handling, using,
distributing, or dealing in any material or product.
___________________________________________
Questions related to specific materials, methods, and services will be addressed at the
conclusion of this presentation.

2. A
Deteriora*on
Model
for
Establishing
an
Op*mal
Mix
of
Time-­‐Based
Maintenance
(TbM)
and
Condi*on-­‐Based
Maintenance
(CbM)
for
the
Enclosure
System
David
Albrice,
BSc.,
URP.,
ARP.,
PRA
RDH
Building
Engineering
Ltd.
MaKhew
Branch,
P.Eng.
RDH
Building
Engineering
Ltd.
David
C.
Young,
P.E.
RDH
Building
Sciences
Inc.

3. Par*cipants
will:
1. Learn
the
two
types
of
asset
deteriora*on
models
2. Explore
the
correla*ons
when
the
two
deteriora*on
models
are
overlaid
3. Iden*fy
six
different
phases
in
the
maintenance
of
an
asset
4. Iden*fy
further
model
development
needs
Learning
Objec*ves

4. Overview
• Background
• Why
do
we
need
a
model?
• Types
of
models
• The
mul*variate
model
• The
6
phases

5. Background
• Prepared
maintenance
manuals
since
1997
• Several
different
versions
tested
with
clients
over
a
15
year
period
• Started
with
data
in
Excel
then
moved
to
Access
and
finally
SQL
(web-­‐based)
• The
enclosure
system
does
not
lend
itself
to
*me-­‐
based
maintenance
(TbM)
in
the
same
way
as
electrical
and
mechanical
assets
• The
enclosure
system
requires
a
unique
balance
of
TbM
and
CbM

6. Why
do
we
need
a
model?
• To
an*cipate
the
service
lives
and
changing
behaviors
of
enclosure
assets,
such
as
roofs
and
windows
• To
understand
the
varying
needs
of
these
assets
as
they
gradually
age
and
deteriorate
• To
align
different
maintenance
strategies
at
certain
milestones
along
the
life
of
assets
• To
provide
building
owners
and
managers
with
maintenance
manuals
that
contain
an
op*mal
balance
of
Time-­‐based
and
Condi*on-­‐based
maintenance

7. TbM
vs
CbM
Maintenance
task
Interval
Det.
Model?
Diagnos5c
tools?
Prognosis
on
remaining
life?
Subjec5ve
Judgment
Scopes
100%
Costs
quan5fiable?
Time-­‐Based
“Wash”
windows
Fixed
–
2x
yearly
No
No
No
Some*mes
Yes
–
defined
Yes
–
predicted
Condi5on-­‐Based
Inspect
sealant
and
repair,
as
req’d
Certain
years,
but
afer
*me
lapse
(delayed)
Yes
Some*mes
Some*mes
Almost
always
Scope
*ed
to
findings
Unknown,
but
es*mated
by
a
model

8. Elements
of
the
Model
Degrada*on
Curves
Survivor
Curves

9. Type
1:
Degrada*on
Curves

10. Type
2:
Survivor
Curves

11. Curve
Overlay:
Mul*variate
Model

12. The
Six
Phases
of
the
Model
• Phase
1
–
“Too
early
to
tell”
• Phase
2
–
“The
emergence
of
poten*al
failures”
• Phase
3
–
“Gehng
past
the
global
minima”
• Phase
4
–
“Gehng
to
local
maxima”
• Phase
5
–
“Striving
for
global
maxima”
• Phase
6
–
“Finding
a
new
global
maxima”

13. Phase
1:
“Too
early
to
tell”

14. Phase
2:
“Emergence
of
‘P’
”

15. Phase
3:
“Gehng
past
G-­‐Minima”

16. Phase
4:
Gehng
to
L-­‐maxima

17. Phase
5:
Striving
for
G-­‐Maxima

18. Phase
6:
A
New
G-­‐Maxima?

19. Further
Developments
• Degrada*on
Curves
– Need
increased
data
from
domain
experts
• Survivor
Curves
– Data
needs
to
be
included
in
long
term
study
of
failures
in
different
condi*ons,
regions,
etc.
• Minimas
and
Maximas
– Encourage
private
sector
to
share
data
• Beyond
Economic
Repair
– Quan*fy
density
of
deficiencies
to
help
further
define
BER
• Total
Cost
of
Ownership

20. Conclusions
• TbM
doesn’t
fit
many
building
enclosure
assets
• Adding
CbM
helps
streamline
and
reduce
maintenance
over
the
long-­‐
term,
based
on
empirical
data
and
sta*s*cal
analysis
• Op*mizing
TbM
and
CbM
can
guard
again
under-­‐maintaining
and
over-­‐
maintaining

21. Q&A