The CSA S478 guideline outlines the process and importance of durability in buildings, highlighting that durability is influenced by materials, environment, installation, maintenance, and replacement. The document discusses the creation of a durability plan, the necessity of defining roles among stakeholders, and methods to predict service life for various building components. It emphasizes that a structured approach is crucial to ensure components can perform their functions without unforeseen costs for maintenance or repair over time.

1. CSA S478 Guideline on
Durability in Buildings
David Kayll, FMA, P.Eng.
Principal, Building Science Specialist
MORRISON HERSHFIELD, Ottawa
May 8, 2014
The Durability Process

2. Take a deep breath…
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3. 1What Determines Durability?
 Durability is not a material property
 Durability is a function of a material
and its environment
 Durability is also a function of
installation, future maintenance
and replacements
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Durability

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Service Environment
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Durability
Location &
Exposure
Interior
Loads

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Required function(s) of:
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Durability
That depends on whether we are
manufacturing open web joists or
underwear.” Ted Kesik
Buildings:
Institutional, Industrial, Commercial, Residential…
Materials:
“What’s better – steel or cotton?

6. Durable requires the Team to perform their roles and
responsibilities from Conception to Occupancy.
Roles & Responsibilities
The Roles need to be clearly
defined for each of the following:
 Owner(s)
 Architect
 Durability Specialist
 Building Envelop Consultant
 Structural Consultant
 Other Consultants
 General Contractor
 Sub-Contractors
 Manufacturers

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A Durability Plan
Creating a Durability Plan

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The CSA S478 guideline provides:
 Set of recommendations to assist designers
 Framework for durability targets
 Generic advice
 Model documents
 Appendix with expanded discussions
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A Durability Plan

9. Tables, Design review, Field review
Sample MH Durability Plan

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A Durability Plan

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Service Life
Service Life:
 “The actual time during which the
building or any of its components
performs without unforeseen costs
or disruption for maintenance and
repair.” (CSA S478)
 Design Service Life (DSL) vs.
Predicted Service Life (PSL)
 Components will last for 10, 20, 30,
50, 100+ years?

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Predicted Service Life
Historical Materials – We know these ones…

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Predicted Service Life
Innovative Materials – Do we know these ones…???

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Agents of Destruction
Agent Type
Moisture Solid (ice, snow)
Liquid (rain, condensation)
Gas (water vapour, humidity)
Air Constituents O2, CO2
Air Contaminants Oxides, particulates, sea spray
Ground constituents Sulphates and other salts, acids (from
decomposition of organic matter)
Ground contaminants Chemicals from spills and leaks,
chlorides from road salt, induced
electrical currents
Biological agents Microorganisms, insects, other
animals, plants

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Agents of Destruction
Agent Type
Temperature Fluctuations
Solar radiation UV (ultraviolet radiation)
Incompatible
chemicals
Corrosion
Differential
movements
Between components (shrinkage
and swelling), within massive
materials (temperature gradient
response), creep/flow
Use or
exposure
Loading, abrasion, overloading

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How To Predict Service Life?
How do we predict the service life of a material or assembly?
 PSL of components within assembly
(shortest outside, longest inside)
 Use many methods in parallel
 Some components will be less
 Some components will be more

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How To Predict Service Life?
ISO 15686-1 Factor Method:
ESL = RSL x A x B x C x D x E x F x G
A. Quality of components as supplied to the project
B. Design level of a component (e.g. how protected it is from elements which may
degrade it)
C. Work execution level or skill level of the installers
D. Indoor environment (e.g. where the component will be utilized)
E. Outdoor environment (e.g. northern climate, coastal climate, southern climate)
F. In-use conditions (refers to specific use conditions of the building)
G. Maintenance level (what is the level of maintenance possible, and likely, for the
particular component for the span of its useful life?)

18. ?

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CSA S478 Method
 Engineering judgment
 Historical performance
 Chemical evaluation
 Modeling
 Performance testing
 Manufacturer’s estimates
Plus:
− Environmental conditions
− Installation
− Operating & Maintenance procedures
How To Predict Service Life?

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Owner’s expectation of Design Service Life
 Ownership type
 Building use (present and future)
 Future land development
 Adaptability
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A Durability Plan
How do you determine a building’s Design
Service Life?

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A Durability Plan
Category DSL Examples
Temporary Up to 10 years * Non-permanent construction buildings (sales offices, bunkhouses)
* Temporary exhibition buildings
Medium Life 25 to 49 years * Most industrial buildings
* Most parking structures
Long Life 50 to 99 years * Most residential, commercial and office buildings
* Health and education buildings
* Parking structures below buildings designed for long life category
Permanent 100 years
minimum
* Monumental buildings
* Heritage buildings
Design and construct with the intent that:
Predicted Service Life ≥ Design Service Life
Table 2 in CSA S478

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A Durability Plan
Category DSL Examples
Temporary Up to 10 years * Non-permanent construction buildings (sales offices, bunkhouses)
* Temporary exhibition buildings
Medium Life 25 to 49 years * Most industrial buildings
* Most parking structures
Long Life 50 to 99 years * Most residential, commercial and office buildings
* Health and education buildings
* Parking structures below buildings designed for long life category
Permanent 100 years
minimum
* Monumental buildings
* Heritage buildings
Design and construct with the intent that:
Predicted Service Life ≥ Design Service Life
Table 2 in CSA S478

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Component DSL in accordance with Table 3 in CSA S478:
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Service Life
Category Effects of failure Example
1 No exceptional problems Replacement of light fittings
2 Security compromised Broken door latch
3 Interruption of building use Repair requires discontinuation of service
4 Costly because repeated Window hardware replacement
5 Costly repair Extensive replacement/ scaffolding needed
6 Danger to health or ecological system Mold, dampness, asbestos
7 Risk of injury Loose handrail
8 Danger to life Collapse of structure
 Components in Categories 6, 7 and 8
– Design to last the life of the building
 Components in Categories 4 and 5
– Design to last at least half the life of the building

24. 1Where:
Component(s)/Assembly DSL < Building DSL
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A Durability Plan
What is “…readily replaced…”?
- Design and construct those component(s) and
assemblies so that they can be readily replaced.

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A Durability Plan
DSL1
DSL3
DSL5
DSL4
DSL2
DSL6
General Rule: Shorter PSL outboard of longer PSL

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A Durability Plan
Concept Design Review
 Review against the Owners
Project Requirements
 By someone not directly involved
in the main design functions.
 Could be separate specialist
 Document that Concept Design
Review was completed

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A Durability Plan

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A Durability Plan

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A Durability Plan
Design Review
 Sufficient Building Envelope reviews are
required to demonstrate compliance with
good practice.
 Reviews include managing:
− Air leakage
− Vapour diffusion
− Heat transfer
− Water penetration
 Method may include:
− Marked-up drawings
− Letter report(s)
− Meeting minutes

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A Durability Plan
Maintenance Requirements
Maintenance Requirements & expectations
developed during design:
 Appropriate material selection
(component by component)
 Frequency & Access of
Maintenance/Repair
(future costs); Initial Cost vs. LCC
 Risks associated with poor
maintenance
– Condos vs. Owner occupied
 Document Owner acceptance of
unusual decisions
Vs.

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A Durability Plan
Maintenance Requirements

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A Durability Plan
Commissioning the Building Envelope
BECx activities should be incorporated into
specifications. These may include:
 Testing requirements
(manufacturer or on-site)
 Shop drawing submittals
 Material submittals
 Material Compatibility Testing
 Mock-ups
 Manufacturer’s field reviews
 Sample removals/renewals

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A Durability Plan

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A Durability Plan
Quality Assurance makes sure you are
doing the right things, the right way.
Quality Control makes sure the results of
what you've done are what you expected.
Quality Management
Whose job is Quality?

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A Durability Plan
Key for all projects:
 Sub-contractor’s workmanship & quality control
 Potential transition issues
 The contractor’s Quality Assurance activities
 The Architect’s or BEP’s Quality Review
activities
 The expected quality of installation
(assists in finalizing the PSLs)
 The roles and responsibilities of all team
members
Mock-ups

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A Durability Plan
 To assess installation quality
control,
 Address “one-off” details
 Quality assurance activities are
documented.
 A final review is required to
confirm compliance with the
Project Documents.
 Frequency is dependent on
team make-up and
requirements
Periodic Site Review

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A Durability Plan

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A Durability Plan
 The Durability Plan must be endorsed by the
Owner (critical step)
 The Contractor must state that the building
was constructed in general conformance with
the Project documents.
Final Sign-off

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A Durability Plan
Appendices and Tables

40. QUESTIONS?

41. 1Durable (synonyms):
Long-lasting, hard-wearing, heavy-duty, tough,
resistant, strong, sturdy, stout, sound, substantial,
imperishable, indestructible, made to last, …
Durability (from CSA S478):
“The ability of a building or any of its components to
perform its required functions in its service
environment over a period of time without
unforeseen cost for maintenance or repair.”
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Durable vs. Durability

42. SO WHAT?
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43. Building Life vs.
Component Life
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Durability

44. Roles & Responsibilities

45. Roles & Responsibilities
Role Responsibility
Owner(s) Establish Building DSL
Architect Establish preliminary assembly DSL
Durability Specialist Consult on appropriate DSL + PSL
Bldg. Env. Consultant Consult on regional risks and agents
Structural Consultant Consult on regional loads
Other Consultants Roofing, leak detection, testing,…
General Contractor Establish QC plan
Sub-Contractors Consult on constructability / establish QA
Manufacturers Consult on PSL

46. 1
Common Issues:
 Design service lives for buildings and materials rarely
considered, especially at the start
 Applicable building industry knowledge is often there…
 … but how to use it not known.
 Roles and responsibilities not well understood
 Understanding of how to document the information not
known
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A Durability Plan

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Predicting Service Life
In the design phase, DSL goes from generic to specific:
Generic Assembly Specific Assembly
Example:
Composite Panel ABC Alum-Composite Panel (DSL 60+)
(DSL 45 years) 50 mm Z-girt (90 Gauge) (DSL 30)
50 mm rigid insulation type IV (DSL 60+)
ABC a/v/m barrier (DSL 40)
ABC sheathing w/ xxx screws (DSL 50)
etc…