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.

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.      

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  

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

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  

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  

 

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  

Elements  of  the  Model  

Degrada*on  Curves  

Survivor  Curves  

Type  1:  Degrada*on  Curves  

Type  2:  Survivor  Curves  

Curve  Overlay:  Mul*variate  Model  

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”  

Phase  1:  “Too  early  to  tell”  

Phase  2:  “Emergence  of  ‘P’  ”  

Phase  3:  “Gehng  past  G-­‐Minima”  

Phase  4:  Gehng  to  L-­‐maxima  

Phase  5:  Striving  for  G-­‐Maxima  

Phase  6:  A  New  G-­‐Maxima?  

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  

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    

Q&A