Seattle DPD - Wood: Concrete Of The 21st Century

Wood: concrete of the 21st centuryUsing a regional material to cut carbon emissions, build sustainably, and create a carbon neutral cityExecutive Summary:Seattle, a historic timber town, is grappling with the 21st century realities of curbing carbon emissions,promoting density, smart growth and fostering an architecture of place. Wood, Seattle’s oldest buildingmaterial, offers a solution to these issues. Contemporary research suggests that wood, a local resource,vastly outperforms other common building materials like concrete and steel in terms of both carbon emissionsand sequestration. This scientific research is occurring in step with the emergence of new engineered woodproducts and a greatly improved technical understanding of wood’s material properties. Coupling these newengineered wood products with sustainability imperatives, architects, engineers and researchers are solvingage-old problems of durability, stability and fire-safety; making wood a truly viable commercial alternative tocarbon intensive materials like concrete and steel. Many people even think that wood will be the concrete of the21st century.New wood products can re/connect Seattle building culture with local, low-embodied energy materials thatfoster the uniqueness of place and support local industries and green jobs. Considering the rich history oftimber in the Pacific Northwest, the City of Seattle is well suited to be the first city in the United States toembrace the use of these new wood building systems to sustainably address urban density needs and meet itspledge to be a carbon neutral city by 2050.

C o n t e nt sA Sustainable Regionalism3Reconnect with Seattle’s History4-5Forest Health and Jobs6-7Carbon Balance of Wood8Environmental Benefits of Wood9A Material for the 21st Century10-11Case Studies 12-18(Re)Connect Seattle 19Next Steps 20Bios 21Appendix:“Why Not Timber High Rises?”Photo by Emily Woods

A sUSTAINABLE r EGIONALISMS eat t l e an d th e No rthwest Nearly 22 million acres of the 43 millionacres in Washington State is forested,accounting for over half of the state’s totalland Lumber created the first boom in Seattleand Henry Yesler, with his steam-poweredsawmill, became the city’s first millionaire1905 Western Washington State. Photo by Darrius KinseyForests in Western Washington. Source: NASASeattle around the 1870s. Source: Washington State Digital Archives

rECONNECT WITH sEATTLE’SHISTORYS eat t l e’s Arch i te ctural Heritag e andL e g acy of Urban/Co mmercial T imberB u il di n gs Wood and masonry was readily availablein the Puget Sound region and other fireproof technologies were more expensiveand less familiar. Because of this Seattleturned to an approach called slow-burningconstruction (also called mill construction,semifireproof or fire-resistive) rather thantrue fire-proof construction The 1899 “A Treatise on Architecture andBuilding Construction” describes slowburning construction as:4-story timber building at 1024 E Pike Street Capitol Hill,Seattle, constructed in 1913 and still in use today. CourtesyBrendan McKeon3-story timber building at 613 E Pine Street inCapitol Hill, Seattle, constructed in 1917 and still inuse today. Courtesy Brendan McKeon“The individual members, suchas beams, columns, etc, are soproportioned that they retain strengthenough to do the work required of themeven after one-third of their bulk hasbeen charred or burned.”Slow Burning Timber Construction technology from A Treatise on Architecture and Building Construction, 1899

rECONNECT WITH sEATTLE’SHISTORYS eat t l e’s Hi s tori c Co mmercial T imberB u il di n gs : Timber construction is flexible andadaptable over time Timber construction is robust and capableof lasting hundreds of years if properlycared for Timber is beautiful and creates calminginterior spaces Timber is inherently fire-resistive and cansurvive fires without compromising thestructural integrity of the buildingValue Village, Capitol Hill, Seattleconstructed in 1916Elliott Bay Books, SeattleElliott Bay Books, Capitol Hill, Seattle constructed in 1918 as a Ford Service Center

Changing global forest coverF or e s t s H e a lth and jo b sC h a n g in g G lo ba l F ore st C o v e r :1990-2005Was hi n gton Stat e Forestry :Dryland degradation Forest stock is increasing every year on asustainable trendNet loss of forest Annual forest growth exceeds harvestCurrent forest cover Forest products are Washington’s secondlargest industry Increasing the use of wood in commercialbuilding projects supports local jobs andindustry With housing crisis sawmills and woodmanufacturers are sufferingNet gain of forestSource: MA 2005.U.S. Timber Growth and Removals, 1920 - 2006Billions of cubic feet/ yearDryland degradationNet Growth30Net loss of forest2520Current forest cover15Net gain of forest10Washington’s forestproducts industry isthe second largestmanufacturing sector inthe state at almost 15%of total ource: MA 2005.501920193319521976Source: Smith et al., USDA - Forest Service (2009).198619962006

F or e s t s a nd job sT he Mou n tai n P ine Beetle The Pine Beetle has devestated an areathe size of Wisconsin in British Columbia,Canada and has entered the AmericanWest British Columbia’s largest source of CO2emissions is currently from their deadstanding Pine Beetle killed wood While the trees are still standing this woodcan be harvested and used for buildingproducts, diverting CO2 emissions fromthe atmosphere and making use of anotherwise waste material Harvesting Pine Beetle killed trees alsoprevents devestating forest fires and therelease of huge amounts of CO2 into theatmosphereSource: Dr. Frank Lam University of British Columbia

C ar b o n ba l a nce of woodWo o d P rodu cts are Carbo n Neg ativ eCO2 data from CORRIM

e N V IRONMENTal Be ne f i ts ofwoodC a rb o n Em i s s i ons and BuildingM a t eri al s Wood is a carbon negative buildingmaterial which almost no other structuralmaterial can also claimEmbodied carbon in building components. Source: ArupNet Carbon Emissions in Producing a Ton of:MaterialNet Carbon Emissions(kg C/metric ton)Framing lumber33 (-457 with carbonstored in product)Medium density fiberboard(virgin fiber)60 (-382 with carbonstored in product)Brick88Glass154Recycled steel (100% fromscrap)220Concrete265Concrete block291Recycled aluminum (100%recycled content)309Steel (virgin)694Plastic2,502Aluminum (virgin)4,5321. Values are based on life cycle assessment and include gathering andprocessing of raw materials, primary and secondary transportation2. Source: USEPA (2006)3. A carbon content of 49% is assumed for wood

a mATERIAL FOR THE 2 1 STcENTURYM a ss i ve Wood Building MaterialsCross Laminated Timber (CLT). Source: MMKCLT. Source: KLH UKMassive Wood building materials like CrossLaminated TImber (CLT) are engineered woodproducts that have enhanced performancecharateristics: Much stronger and safer that traditionalstud construction Highly fire resistive Incredibly fast construction times Cost competitive with concrete and steel Clean and quiet construction process Ideal for tight urban sites Uses local NW materials and localindustries Sustainable material for carbon negativeconstructionCross Laminated Timber project at the University of British Columbia, Canada. Source: Structurlam

a mATERIAL FOR THE 2 1 STcENTURYM a ss i ve Wood a nd Fire Heavy timber forms a semi-protective layerof char during a fire event The char layer slows the speed andpenetration of the fire into the wood Massive wood floors and walls can burnfor extended periods of time without losingtheir structural integrity FPInnovations of Canada has recentlyfinished fire testing CLT floors and wallsshowing that a 7-layer CLT floor fullyloaded can be exposed to fire for nearly3 hours before failing. A 5-layer CLT wallwith one layer of gypsum board can beexposed to fire for over 2 hours beforefailing.Charring behavior. Source: UnknownCLT floor fire testing. Source: FPInnovationsCLT wall fire testing. Source: FPInnovations

cASE s TUDIESK a d e n Kl i n gb ei l ’s E3 : Berlin, Germany Germany’s first 7-story wood building This building is not allowed under currentSeattle Building Codes Massive wood construction consisting ofHeavy timber post and beams with infillsolid wood walls All wood floor and walls fire tested toreach a minimum 90 minute ratingSource: Kaden Klingbeil

C ase S t u d i e sV ä xj ö ’s Li m n ol og en, Sweden 8-story massive wood building; at thetime of completion, was the tallest timberbuilding in Sweden. The project consists of four eight-storybuildings containing 134 apartments This building is not allowed under currentSeattle Building CodesSource: Arkitekt Bolaget

C ase S t u d i e sS ch a n ku l a’s H8, Bad Aibling, Germany Germany’s first 8-story wood building Massive wood construction Each wood floor took only two days tocomplete, and the entire wood structurewas completed in only three weeks This building is not allowed under currentSeattle Building CodesSource: Schankula ArchitektenSource: Schankula Architekten

C ase S t u d i e sWau gh Th i s tl eton’s Stadthaus, London 9-story massive wood building All walls are Cross Laminated Timber Wood cut construction times by anestimated 23 weeks Cross Laminated Timber walls achieve upto a 120-minute fire rating This building is not allowed under currentSeattle Building CodesMassive wood construction. Source: TechnikerStadthaus under construction. Source: WaughThistleton/KLH UKThe Stadthaus. Source: TechnikerInterior of the Stadthaus. Source: Waugh Thistleton

C ase S t u d i e sS ch o ol s : Th e Ci t y Academy, Nowich 3-story CLT school designed by SheppardRobson with Ramboll Engineers and CLTprovided by KLH UK Internal steel frame with load bearing CLTexterior walls Contractor, Kier, praised speed andcleanliness of CLT system Kier estimated 4-6 months savings inconstruction time Illustrations of school: Source Sheppard RobsonDozens of schools built with CLT in the UKThe City Academy under construction

C ase S t u d i e sC ree Rh om b erg’s 20-Story T imberH ig hri s e: Th e Li feCy cle Tower (LCT) Demonstrates wood as a truly urbanoption Prefabrication allows for fast constructiontime and cost competitiveness Massive wood wall system and hybridmassive wood/concrete floors First LifeCycle Tower under constructionnow in Dornbirn, AustriaSource: CREE RhombergLCT One under construction. Source: CREE Rhomberg

C ase S t u d i e sVan c o u ver, Bri ti sh Co lumbia’s T imberH ig hri s e Feas i bi lity Study : Tall Wood Michael Green Architectshave designedImplied ArchitecturalImpact as Result of the Structureprototype for 12, 20 and30-storymassiveThe structuralconfigurations,in addition to determining theachievable building heights will impact both the design of thewood buildingsenvelope and floor plan of the building. For example, Option Demonstrates carbon resemblanceneutralto theconstructiontypical concrete benchmark in that it utilizes astructural core and perimeter columns that affords it a free-plan.for highly urban areas In options 3 and 4, where additional structure is required for the1 offers the greatest amount of flexibility in the design of itsinterior partitioning. This structural configuration bears closestTALLincrease in building height, constraints are placed on the designof either the interior partitions or envelope. As a result, theseconfigurations can be more advantageously applied to specificuses. For instance, where interior walls are utilized as structure,a residential application would be appropriate where thesestructural walls could double as unit demising walls.WOODOPTION 1 - Up to 12 StoreysOPTION 1 - Up to 12 StoreysOPTION 2 - Up to 20 StoreysOPTION 2 - Up to 20 StoreysOPTION 3 - Up to 20 StoreysOPTION 3 - Up to 20 StoreysOPTION 4 - Up to 30 StoreysOPTION 4 - Up to 30 StoreysSource: Michael Green Architects66 3.4THE CASE FOR Tall Wood BUILDINGS3.4 67