Genge, kerr assessing the effects of climate change on buildings using the pievc process

14th Canadian Conference on Building Science and Technology - Toronto Canada

Assessing the Effects of Climate Change on Buildings using the Engineer’s Canada PIEVC Process

Gerald R. Genge, and Dale D. Kerr

Overview1. What is PIEVC and How does it work?2. Case Study Building3. Relevant Climate Parameters based on Aggregate of

Models4. Relevance to the Building Components5. Change in the Parameters Risk Assessment (related to

Buildings and Occupancy)6. Proposed Action Items


PIEVC• Public Infrastructure Engineering Vulnerability Committee

• Established in 2005 by Engineers Canada and Natural Resources Canada to oversee the planning and execution of the assessment of the vulnerability of Canadian public infrastructure to changing climatic conditions.

• The PIEVC established four areas to review:1. Storm water and wastewater collection and treatment systems;2. Roads and associated structures;3. Water resource systems; and4. Buildings


PIEVC Steps


PIEVC Process• A five step protocol to assure consistent and fair

assessment of the effects of climate change on infrastructure

• Involves a rigorous review of the climatic parameters that are expected to change along with an assessment of the impact those changes are expected to have on buildings.

• The period of time during which the infrastructure is expected to operate is 50 years.


Project Team• Consultant team members included:

• GRG and Heather Auld (Climatologist)

• Stakeholder team members were drawn from:• TCHC• City of Toronto Tower Renewal program staff, • Property management and maintenance personnel • City of Toronto Departmental representatives, • PIEVC Project Lead, • PIEVC Buildings Expert Group Lead, • Ontario Government Ministry representatives for Environment and

for Infrastructure.


Step : Project Definition

PIEVC Steps Building Selection

• Client selected this property as representative of the largest proportion of the portfolio being 40 to 50 years old.


The Building• 16-storey apartment building, • Constructed in 1964,• Typical of similar buildings of the vintage, • The study benefitted from recently completed

assessments on building condition and energy performance.


Step 2: Data Gathering

PIEVC Steps Data Gathering and Sufficiency of Data

• 179 building components were reduced to 30 by ranking in importance and considering probable effect of climate change on the component.

• Air conditioning was then added as a key component to be considered.


Exterior Wall Design

18 C

-18 C


Window Design



Component Inventory • Major components in the assessments include:

• Grounds and Site• Structure and Envelope• Roofing• Elevators• Electrical• Mechanical, and • Life Safety Systems


Component Importance RankingBuilding Component Importance (to Client)

Grounds and SiteDriveway, Parking, Walks, Drainage 5

Structure and Building EnvelopeBalcony and Railings 6Foundation Walls 7Doors and Windows 5Exterior Cladding 7

Roofing 5

ElevatorsEquipment 6


Component Importance RankingBuilding Component Importance (to Client)

ElectricalEquipment 6Lighting6

MechanicalMake-up Air and Convection Radiators 6Supply and Exhaust Ducting 5Heating Boilers 7Stormwater Removal 6Air Conditioning1

Life SafetyGenerator, Transfer Switch, Transformers 6


Window air-conditioners14th Canadian Conference on Building Science and Technology - Toronto Canada

Relevant Climate Events: Parameter Data

Temperature Historical

(usually 1971-2000)

2050s (Ensemble Projections)

Relative Change

(% less % more)

# days ≥ 30°C 15 40 +166%

# days ≥ 35°C 0.5 4 +700%

NBCC 2.5% July Dry Bulb Design Temperature 31°C 34°C

+9%

NBCC 1% January Dry Bulb Design Temperature -20°C -16°C

-20%

30-year period Extreme High Temperature 37°C 40°C

+8%

Annual Average Cooling Degree-days 356 640 +80%

Annual Average Heating Degree-days 3520 2900 -18%

Average Annual Freeze-Thaw Cycles 55 ~40 -27%

Average Annual Days < -20°C 1.4 0.3 -78%

Average Annual Heat Related Mortalities 120 280 +133%


Relevant Climate Events: Precipitation

Historical(usually 1971-

2000)

2050s (Ensemble

Projections)

Relative Change

(% less % more)

Average annual # wet days 113 ~ 125 +7%

Extreme annual precip (30-yr period) 1828 mm ~1940 mm 6%

Average Annual Precipitation 835 mm ~ 890mm 7%

Average annual Rainfall 710 mm ~> 800 mm +13%

NBCC 10 yr return period 15 min. rainfall 25 mm Likely increasing +

NBCC 50 yr return period 1 day rainfall 97 mm Increasing ~ 60% +60%

Average # days with > 25 mm rainfall 4.2 > 5 +2%

Maximum consecutive Dry days/year ~ 13 Likely increasing +

Driving Rain Wind Pressures (5-yr return period) 160 kPa Likely increasing

+

mNBCC design Ground Snow Loads Ss-0.9, Sr=0.4 kPaRain with snow and

intense storms - increase

+

Rain on snow events, snowmelt Increasing +


Relevant Climate Events: Extreme Wind

Historical(usually 1971-

2000)

2050s (Ensemble

Projections)

Relative Change

(% less % more)

NBCC 10 year return period wind pressures 0.34 kPa Likely increasing

+

NBCC 50 year return period wind pressures 0.44kPa Likely increasing

+

Average # hours/year > 70kph 24 (for 1994-2007) 26 (Pearson Area) +8%

Average # hours/year with Gusts > 80kph 5.9~7 mostly spring and

fall+2%

Average # hours/year with Gusts > 90kph 1.0 h ~1.9 h +90%

Tornado risks May increase +

Severe thunderstorm Average 1-2 d/yr Potential increases +


Step 3: Risk AssessmentR = P x S

R = Risk P = Probability of a Negative Event S = Severity of the Event

PIEVC Steps Risk Assessment


Probability / Importance Assessment for Climate Parameters

Probability Score (P)

Probability RankingMethod B

0 Not Applicable1 Recognize existence and include with other components3 Interested – Analyze if budget allows5 Analyze normally6 Relatively important – Analyse with more attention7 Important – Analyze with much more attention


Severity Criteria and RankingScore (S)

Severity of Consequences and EffectsMethod A Method B

0 No Effect Negligible - Not Applicable

1 Measurable Very Low - Some Measurable Change

2 Minor Low - Slight Loss of Serviceability3 Moderate Moderate Loss of Serviceability

4 Major Major Loss of Serviceability - Some Loss of Capacity

5 Serious Loss of Capacity - Some Loss of Function

6 Hazardous Major - Loss of Function7 Catastrophic Extreme - Loss of Asset


Risk Criteria from R = P x SRisk Range Threshold Response

< 12 Low Risk No Action necessary 12 - 36 Medium Risk Action may be required

Engineering analysis may be required

> 36 High Risk Action is Required


Results of Risk Analysis


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Driveways/Surface Parking 14 19 23 19 6 21 26 2 4 3 1 1 23 2 2 6 0 0 18

Sidewalks/Steps/Curbs/Patios 12 18 21 19 6 21 28 2 4 2 1 1 14 2 2 6 0 0 18

Drainage 18 28 33 16 5 14 14 4 9 2 1 5 2 2 2 1 0 0 0

Balcony Decks 2 4 12 11 15 12 14 12 9 2 1 1 2 2 2 6 0 0 12

Balcony Railings 2 2 2 4 3 2 2 2 9 23 1 9 2 2 2 1 0 0 0

Foundation Walls 12 21 11 4 3 14 2 2 4 2 1 1 2 2 2 1 0 0 0

Caulking 2 2 4 4 6 2 4 7 11 6 1 3 25 5 5 3 8 0 6

Doors 9 16 12 5 3 2 5 11 11 24 1 10 2 11 12 2 5 9 0

Exterior Cladding General 18 26 2 4 5 2 4 14 11 20 1 10 12 14 12 4 5 12 20

Windows 14 28 2 4 6 2 5 21 12 27 1 12 28 25 23 10 8 18 0

General Roof Repairs/Replace 2 25 2 9 18 2 21 7 12 5 1 11 23 16 25 2 7 12 0

Roof Flashings 2 2 2 4 4 2 5 16 12 15 1 9 2 2 2 2 0 0 0

Elevator Electrical Equipment 2 2 2 4 1 2 2 2 2 9 1 1 21 2 2 1 0 0 0

Elevator Sump 2 28 5 4 1 14 2 2 2 2 1 1 2 2 2 1 0 0 0

Exterior Lighting 2 2 2 7 4 2 11 7 12 2 1 11 2 2 2 1 0 0 0

Air Makeup System 2 2 2 4 1 2 12 2 11 6 2 1 18 19 5 1 6 18 0

Convection Radiators 2 2 2 2 1 2 2 2 2 2 1 1 5 11 7 1 2 0 0

Ducting - Exhaust 2 2 2 7 1 2 2 2 2 2 1 1 5 19 2 1 0 0 0

Ducting - Supply 2 2 2 4 1 2 2 2 2 6 1 1 7 19 2 1 0 5 0

Heating Boilers 2 9 2 2 1 2 2 2 2 2 1 1 2 5 5 1 0 14 0

Heating System - General 2 2 2 2 1 2 2 2 2 2 1 1 2 5 5 1 0 0 0

Heating System - Units 2 2 2 2 1 2 2 2 2 2 1 1 2 5 5 1 0 14 0

Storm Water Removal General 14 26 23 23 10 12 12 11 7 2 1 5 2 2 2 1 0 0 0

Heating Pumps 2 9 2 2 1 2 2 2 2 2 1 1 2 7 5 1 0 5 0

Heating Supply Lines 2 2 2 2 1 2 2 2 2 2 1 1 2 7 5 1 0 4 0

Air-Conditioning 2 2 2 2 1 2 2 2 2 11 3 2 42 32 5 7 0 0 0

Exhaust - General 2 2 2 2 1 2 4 2 2 11 3 1 16 19 5 7 3 7 0

Emergency Generator 2 2 4 2 1 2 32 2 2 26 11 11 19 2 2 1 0 0 0

Transfer Switch 2 2 4 2 1 2 16 2 2 17 6 5 2 2 2 1 0 0 0

Transformer 2 2 2 2 1 2 2 2 2 11 8 1 21 2 2 1 0 0 0

Roofing

Elevators

Climate Factor

Building Component

Grounds/Site

Structural

Building Envelope

Electrical

Mechanical

Life Safety

83.3% Low Risk

16.5% Moderate Risk

0.2% High Risk

Step 4: Engineering Analysis

• PIEVC Steps • Engineering Analysis

• No engineering analysis conducted as there are no empirical relationships established for climate loads on cladding, windows in the mNBCC.


Step 4: Recommendations

• PIEVC Steps • Recommendations

Building Action Items• Overcladding• Window Replacement• Air Conditioning

Management Action• Increased maintenance• Monitor health effects of

climate change• Staff training/ tenant education


Looking ahead • Over the next 40 years, the climatic changes expected in

southern Ontario include increased:• temperature;• frequency and intensity of heavy precipitation events and short

intense rainfalls (e.g. thunderstorms);• frequency and longevity of heat waves; • intensity of winter snowfalls due to more atmospheric moisture,

particularly in the lee of the Great Lakes and in freezing rain risks; and,

• Potential increases in extreme wind gusts.… and the resultant weathering processes including humidity, wetting, wind driven rain, carbonation, etc.;


Additional Research 1. Currently, buildings are designed using climatic

parameters calculated from historical climate data assumed to represent the conditions expected over the life of the building. As the climate changes, this assumption will no longer hold.

2. Building Envelope Design Standards should develop empirical relationships including load factors that accommodate climate prediction into the future life of the building.


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Questions and Discussion

Thank you for your attention and enjoy the rest of the conference….


Gerald R. Genge, B.A.Sc., P.Eng., C.Eng., BDS, BSSO, C.Arb., Q.Med.

Dale D. Kerr,M.Eng., P.Eng., BSSO, ACCI