-1000

-800

-600

-400

-200

0

200

400

600

800

A-C A-D A-C A-D A-C A-D A-C A-D A-C A-D

kg C

O2

eq

/ m

2 Athena

Tally 1(incl. biogenic carbon)

Tally 2(excl. biogenic carbon)

90185

52

-936

114

300 322214

557

296

-1200

-1000

-800

-600

-400

-200

0

200

400

600

800

kg C

O2

eq

/ m

2

lowest GWP

highest GWP

District Office

District Office

Carbon12

Carbon12

Glenwood CLT Parking Garage

Glenwood CLT Parking Garage

CLTHouse

CLTHouse

excluding biogenic carbon including biogenic carbon

CLT HouseLocation: Seattle, WAArchitect: atelierjones, llcStructural Engineer: Harriot Valentine EngineersGeneral Contractor: Cascade BuiltGross Area: 1,483 ft² (137.8 m²)Height: 27 ft (8.2 m)Use: Single family residentialReference Service Life for WBLCA: 75 years

Embodied Carbonbuilding size 137.8 m² (1,483 ft²)

global warming potential kg CO₂eq per m2

initial GWP 390 total GWP 557

GWP per material CLT, Glulam, and Wood 44%

Concrete 22%

Metals 3%

Thermal & Moisture Protection 22%

Openings and Glazing 8%

Finishes <1%

GWP per life stage A1-A3 379.5 kg/m2 68%

A4 10.19 kg/m2 2%

B2-B5 5.95 kg/m2 1%

C2-C4 161.1 kg/m2 29%

D -76.5 kg/m2

Embodied Carbonbuilding size 137.8 m² (1,483 ft²)

global warming potential kg CO₂eq per m2

initial GWP -157 total GWP 207

GWP per material CLT, Glulam, and Wood -13%

Concrete 44%

Metals 5%

Thermal & Moisture Protection 38%

Openings and Glazing 12%

Finishes 1%

GWP per life stage A1-A3 -167 kg/m2 -45%

A4 10.25 kg/m2 3%

B2-B5 5.71 kg/m2 2%

C2-C4 354.8 kg/m2 95%

D 2.944 kg/m2 <1%

523 km (325 mi) transport distance

CLTHouseSeattle, WA

Whole Building Life Cycle Assessment

Several whole building life cycle assessments (WBLCA) were carried out for the BC Passive House Factory using two different WBLCA softwares: Tally software (from KT Innovations), and the Athena Impact Estimator for Buildings (from Athena Sustainable Materials Institute). This poster details the results calculated using KT Innovation’s Tally® software, with a result including and excluding biogenic carbon.

Scope includes structure, foundation, roof, exterior and interior assemblies.

standing seam metal roof with CLT structure

wood frame windows and doors

CLT exterior walls

stairs

concrete slab foundation with insulation

Scope excludes:

mechanical, electrical & lighting, plumbing, connections, fasteners, and sitework

Structurlam FactoryPenticton, BC, Canada

Results per Division

CLTHouseWBLCA

6/25/2019

4

0%

50%

100%

113,718kg

Mass

53%

34%

66,170kg CO₂eq

Global WarmingPotential

22%

44%

22%

467.3kg SO₂eq

AcidificationPotential

61%

19%

60.32kg Neq

EutrophicationPotential

78%

12%

4,265kg O₃eq

Smog FormationPotential

21%

54%

14%

616,806MJ

Non-renewableEnergy

21%

32%

31%

11%

Legend

Divisions03 - Concrete05 - Metals06 - Wood/Plastics/Composites07 - Thermal and Moisture Protection08 - Openings and Glazing09 - Finishes

22%

3%

44%

22%

8%

Global Warming Potential

CLT and glulam

concrete

finishesopenings & glazing

thermal & moisture

metals

44%

22%

3%

<1%

22%

8%

end-of-life

end-of-life

transport transport

module D

maintenance & replacement maintenance &

replacement

material extraction and production

68% 95%

29%

2%

3%

<1%

1%

1%

Results per Division

CLTHouseWBLCA

6/25/2019

4

0%

50%

100%

113,718kg

Mass

53%

34%

32,812kg CO₂eq

Global WarmingPotential

44%

38%

12%

-13%

467.3kg SO₂eq

AcidificationPotential

61%

19%

60.32kg Neq

EutrophicationPotential

78%

12%

4,265kg O₃eq

Smog FormationPotential

21%

54%

14%

616,806MJ

Non-renewableEnergy

21%

32%

31%

11%

Legend

Net value (impacts + credits)

Divisions03 - Concrete05 - Metals06 - Wood/Plastics/Composites07 - Thermal and Moisture Protection08 - Openings and Glazing09 - Finishes

44%

5%

38%

12%

1%

Global Warming Potential

finishesopenings & glazing

thermal & moisture

concrete

metals

<1%

38%

12%

5%

44%

BC Passive House Factory

BC Passive House Factory

Transport distance assumptionsCLT: 523 kmConcrete: 24 kmSteel: 434 km

Including biogenic carbon results in the impacts being more heavily weighted towards end-of-life, when the biogenic carbon leaves the system.

Global warming potential (GWP) is a climate change indicator of the sum of greenhouse gas emissions over a period of time, typically expressed as kg CO2 eq. Including biogenic carbon results in a lower global warming potential.

Initial GWP is the net CO2 eq emissions associated with material extraction, material manufacturing, and transport to the construction site.

Total GWP is the net CO2 eq emissions associated with material extraction, material manufacturing, transport to the construction site, future deconstruction, and disposal of building materials.

When including biogenic carbon, wood and CLT reduce the GWP.

CLT and other wood materials are not shown because they contribute to a net reduction in the GWP when including biogenic carbon.

A1-A3 includes CO2eq emissions from extraction of raw materials and manufacturing of building products.

A4 is the CO2eq emissions from transport of materials from manufacturing to construction site.

B encompasses the CO2eq emissions from maintenance and replacement of materials during the building’s use. Module B1 is excluded.

C2 shows the CO2eq emissions from transportation to disposal site, C3 shows emissions from waste processing, and C4 shows emissions from final disposal. Tally averages multiple end-of-life scenarios for wood and CLT. In this WBLCA, it is assumed that 14.5% of wood and CLT is recycled, 22% is incinerated with energy recovery, and 63.5% is landfilled.

D indicates benefits beyond the system boundary. For wood, it shows potential credit for utilizing waste products for energy; it is expressed by the equivalent avoided emissions of US average grid electricity. The incinerated energy from wood products (or any landfill gas that is captured for energy) results in avoided production of energy from fossil fuels. Because avoided energy product cannot be directly attributed to the material use, it is expressed as a separate module “D,” which is considered beyond the system boundary.

raw material supply

A1 A3A2 A5 A4 B1-B5

B6-B7

C2-C5 D

Product Stage ConstructionTransport Use End-of-Life

Potential Benefits and

Loads

manufacturing & production

construction & installation

transport to site

use, maintenance,

repair, and replacement

operational energy & water

deconstruction, waste processing, &

disposal

recovery, reuse, & recycling

C1

this WBLCA excludes this WBLCA excludes

excludes

this WBLCA includes this WBLCA includesthis WBLCA includes

structure only structure onlystructure, enclosure, and interiors

highest and lowest values

of each WBLCA

structure, enclosure, and interiors

GWP GWP

per material per material

per life stage module per life stage module

GWP GWP

Tally, a software for WBLCA, can include or exclude biogenic carbon in an assessment. For mass timber buildings, this can have a large impact on the global warming potential. When biogenic carbon is included, the biogenic stored carbon in the wood materials is initially counted as a credit that reduces GWP. At the end-of-life, biogenic carbon leaves the system (expressed as emissions) through incineration, landfill, or recycling. Some biogenic carbon is assumed to be permanently sequestered in a landfill; that amount of carbon remains in the total GWP reduction.

image courtesy of atelierjones, llc

exterior photo of CLTHouse © Lara Swimmer Photography

Global Warming Potential: Case Studies in Tally and Athena

Whole Building Life Cycle Assessment of a cross-laminated timber houseincluding & excluding biogenic carbon

Research Team: Alison Kwok, Hannah Zalusky, Isabel Rivera, Lindsay Rasmussen, and Hannah McKayConducted under a research grant from the TallWood Design Institute, funded by the USDA Agricultural Research Service under award # USDA-ARS #58-0204-6-002