Rapidly Renewable Materials

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Rapidly Renewable MaterialsBy Preshani Maistry July 2007

When you hear the words rapidly renewable materials (RRMs), what kind of materialsdo you think of? Bamboo, cork, and straw all fall into this category. Additionally, natural andbio-fiber composites such as kenaf, hemp, flax, jute, henequen, and pineapple leaf fiber are all

emerging as sustainable alternatives in the green building industry.1

Indeed, bio-fibercomposites have potential to gain prominence as alternate materials especially as woodsubstitutes.2 Bamboo flooring and window screens are common green building products. Corkshavings are similarly used to manufacture flooring and fabric alternatives. Hemp and jute areprominent materials when contemplating eco-friendly insulation.3

These resources are considered sustainable because of their rapid regeneration--10years of less--and growth cycles. Due to the sustainability of these materials, rapidly renewableresources have gained significance within the LEED - Leadership in Energy and EnvironmentalDesign - rating system, has steadily become a standard trademark when discussing sustainabledesign and construction. Rapidly Renewable Resources are related to the LEED system, as theycontribute the achievement of certain LEED credits when implemented within a largersustainable design concept. These products are considered green as they are represent an

alternative to mainstream buildings materials that are composed from either finite rawmaterials or long-cycle renewable materials. For example, for LEED CI (Commercial Interiors)buildings, if 5% of the total value of all materials and products used in a building project, aremade from plants that are typically harvested within a 10-year or shorter cycle, the buildingqualifies for a LEED credit.4 Specifically, the building can achieve the MRc6, Materials andResources Credit 6 (Rapidly Renewable Materials).5 The 5% requirement is calculated by dividingthe total cost [$] of RRMs over the total cost [$] of all materials required to build the building.For LEED NC (New Construction) buildings, the LEED credit is available if the building isconstructed with rapidly renewable building materials and products for 2.5% of the total valueof all building materials and products used in the project. 6

Looking at Bamboo:

Since bamboo matures up to twenty times faster than some of the tree species used inhardwood flooring, bamboo is a more sustainable flooring alternative. To be specific, the oaktrees required for hardwood require 120 years to mature. Conversely, bamboo which is equallyas durable as hardwood, and which has a negligible impact on energy performance at its pointof use, requires 3-7 years for maturity. 7 In comparison to fast-growing pine forest, whichsupplies the fastest growing wood flooring, twice as much bamboo can be harvested from abamboo forest in one year than a pine forest.8 Moreover, bamboo does not have to be replantedafter each harvest, whereas conventional hardwood requires replanting. Bamboo stalks can betaken from existing plants that have already begun to grow the next round. Hence, bamboo isboth environmental and socially sustainable because labor normally allocated towardsreplanting can be allocated elsewhere.From chopsticks to scaffolding to even being housing frames, bamboo has definitely shown itsversatility in the many ways it can be used. In Vietnam entire houses are being built from

bamboo creating a log style look.

Depending on the quality of a harvest, bamboo is comparable to red oak in terms ofhardness and durability.9 The Janka Test is a standard testing method to establish the hardnessrating of all wood flooring types. In this test a .444 inch steel ball is embedded into wood halfof its diameter. Test results for natural bamboo flooring give a 1,380 and a 1,180 hardnessrating for carbonized bamboo flooring (treated with steam which results in darker shades ofbamboo). To put that in perspective, the same test gives red oak a 1,290 hardness rating andblack maple a 1,010. In terms of cost, good quality bamboo which starts at $3.50 per square


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foot uninstalled is significantly less expensive than conventional hardwood flooring. 10Consequently, bamboo can hold its own when competing in strength, durability and cost toconventional flooring but with a smaller environmental impact.

Bamboo flooring has also become a popular material on projects because of the LEEDrating system. If used on a project it can award you the Materials and Resources credit for

rapidly renewable resources. Recently, poor quality bamboo which contained high levels of ureaformaldehyde (UH) flooded the market and was a cause for concern. Fortunately, high qualitybamboo contains negligible levels of UH. Likewise the finish on bamboo can be a source ofemissions; however, these emissions can be reduced if the finish is completed at the factory. 11If a bamboo product does not contain UH, it becomes eligible for the LEED IndoorEnvironmental Quality credit as well.

Bamboo is best suited for areas with a consistent climate and does not adapt well toenvironments with extreme climate change such as the case with Albertas climate. Because ofthe severe changes in temperature and humidity that occur on a daily basis in Alberta bambooflooring has been known to shrink, causing the glued layers to separate and ultimately separatefrom the sub-floor as well. The type of bamboo purchased should be chosen with ones climatein mind. That being said, there is a new bamboo product coming to the market called Fusion

Bamboo that is supposed to better suited for the Alberta style climate. If you are looking intobamboo as a flooring choice be sure to ask about information on Fusion Bamboo.

Another issue that confronts the sustainability of bamboo is the amount oftransportation it takes to get bamboo to North America. The majority of bamboo used inhardwood flooring comes from Hunan Province in China which means it has to be shippedacross the ocean to North America and then onto trucks or trains to get distributed across thecountry. Aside from the large distribution and heavy embodied energy issues associated withbamboo, there have been other industry downfalls because of the bamboo boom as well.

In China the government runs the bamboo farms and in Vietnam they are privately run.This has made it difficult to put regulations in place on how toxic chemicals are to be handledand used. Due to the increasing popularity and demand for bamboo products forests have been

cut down in order for bamboo plantations to be put in their place. Logged forests have givenway to bamboo and drastically changed to bio diversity in those areas. Massive erosion hastaken place due to weeding and tilling on the bamboo plantations, which has been donemanually or with intensive chemical treatments, which add toxins to the environment. Also,during the manufacturing process up to 35% of the material goes to waste and is traditionallyburned.

Like all new products and technologies, bamboo is not without its downfalls. There arein fact manufacturers in Alberta that are ISO 9001:2000 and 14001-certified (InternationalStandardization Organization). This means those companies have checkpoints in place tomaintain a high level of quality control on their products. There are also companies that aredeveloping ways to bring down the amount of waste to 16%. New manufacturing methods arealso being used in which post industrial waste from other operations can be used to

manufacture flooring causing the waste percentage to go down across the board.

The bamboo industry continues to grow and adapt to help produce a more sustainableworld. Hopefully steps will be taken to regulate manufacturing processes and completelyeliminate chemical compounds such as UF from being used. Proper stewardship of bambooplantations needs to be in place to keep a healthy and viable ecosystem. When looking intobamboo flooring be sure to ask as many questions as you can to ensure the demand for trulygreen products.


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Cork as a RRM

A common misconception is that cork is going extinct but in fact it is quite the opposite.Similar to bamboo, cork is considered a rapidly renewable material because bark from the corktree can be harvested every 9 years, and like bamboo, it also has a negligible impact on energyperformance at its point of use.12 Unlike synthetic vinyl flooring, cork is a resilient building

alternative which has 50+ year lifespan compared to the 10-20 lifespan of synthetic flooring.Additionally, cork has a low flame spread, low off-gassing from natural oils, does not producechemicals during the manufacturing process (dioxin specifically) and is completelybiodegradable. Cork is also inherently anti-microbial and resistant to mildew; it adapts well toweight and recovers from large amounts of pressure hence it is well suited for kitchens andlaundry rooms. Ranging from $3-7 per square foot unfinished, cork is economically sustainableover vinyl flooring because of its durability. 13

Cork harvesting has been going on for over one thousand years and hasnt changed allthat much. Specially designed axes are used to cut, peel and strip the bark from the Cork Oaktree making the process done entirely by hand. Although machines have tried to be used tostrip the bark this age-old technique still proves to be the best way. Removing bark by hand isbetter for the health and preservation of the tree while maintaining thousands of jobs for

people. When cork is harvested not a single tree needs to be cut down. Only a percentage ofthe bark is removed from each tree, which allows them to maintain their protection whileregenerating.

Most of the time when looking into a product the question is, What are the ecologicalimpacts of harvesting/mining the raw materials? In this case the question is: What are theecological impacts if the raw material isnt harvested? It turns out that more than just peoplerely on the success of the cork industry. The entire habitat in the region where cork isharvested relies on the industry to keep going. If the demand for cork diminished people wouldhave to move on to look for a new source of income, which would in turn end the maintenanceof Portugals cork. This would eventually leave the Cork Oaks trees to die causing the region todry up. These forests are also used as grazing grounds for livestock which would also sendthem looking for greener pastures. Portugal is susceptible to forest fires and with the build up

of grass and dying trees the chances are made much greater. Ninety nine percent of the worldscork comes from the Mediterranean and within that seventy percent goes to the production ofwine corks. Due to the increased market share for alternative wine stoppers, these Cork Oakforests are now facing these risks.

Unlike bamboo, there is significantly more regulation for cork harvesting. Indeed,nations that harvest cork monitor the frequency at which the resource can be harvested in orderto minimize damage to the trees and eco-systems.14 The WWF (World Wildlife Fund) and the FSC(Forest Stewardship Council) have teamed up to ensure the sustainable maintenance of Spainand Portugals Cork Oak forests to preserve these unique forests and continue the survival ofthree endangered species who rely on the shelter and safety of these forests. The Iberian Lynx,Iberian imperial eagle, and Barbary deer are animals on the endangered species list that dependon the habitat the Cork Oak helps provide. By purchasing wine with real cork stoppers and

other cork products with FSC certification, it will help sustain the market share for real cork.15

From the three layers of the cork bark that is harvested, only the middle layer is used tomake cork products. The first use after harvest is to make wine stoppers and then the rest thatis left is ground up to make several different products including gaskets, bulletin boards, shoesoles, flooring tiles and large roles of cork sheeting which can be used a soundproofingbarriers, insulation layers and even sub floor. The left over layers of waste is burned in largefurnaces which heat the molds use to form ground cork compounds into other products.Another high point about cork is that it can be recycled back into the manufacturing process tominimize further waste. With products such as flooring tile that is available in several different


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shades, cork can also be heated at varying degrees to achieve the various range of color. Nodyes and stains are needed to alter the appearance of cork flooring products. Some productscan be found with natural water based dyes and pigments.

Similar to bamboo, the issue of product transportation arises with cork materials. Corkis manufactured in Europe, and the amount of energy required for shipping and fuel is

significant. Fortunately, the low amount of energy expended during its manufacturing processbalances the total amount of energy used in cork production, which still remains lower thanthat for any other resilient or laminate flooring. 16

Bio-Fiber Composites:

While flooring is certainly a potential market for the emergence of renewable materials,other areas of the green building industry benefit from rapidly renewable resources. Below, thecase study for hemp-flax insulation which is a ecological alternative to conventional insulation,is examined. Hemp is a superior material because the processing is clean and low on dust.Indeed, no waste products are produced from the production of hemp-flax insulation. 17 Unlikeconvential insulation, hemp is well tolerated by those who come into contact with it since itdoes not cause itching.18

Hemp fibre soaks up moisture and distributes it which results in optimal moistureregulation. As hemp fibre does not contain protein the material does not require chemicaltreatment against moths and beetles.19 According to a UK government research project, hemp-flax insulation has a direct impact on reducing greenhouse gas emissions. This is becausehemp and flax insulation is 5-10% more thermally efficient than conventional insulation. 20Additionally, hemp flax insulation is noted for its technical properties which meet the Europeantechnical admission requirements (ETA-02/0008) and DIN Standards.21

Bio-fiber products such as hemp insulation do not share the same issue of energyexpenditure during transportion in the same way as bamboo or cork. Since 1998, thecommercial production of hemp has steadily increased in Canada. As of 2006, there wereapproximately 48,000 hectres of land devoted to hemp production, with Alberta sharing 10% ofthat total.22 Subsequently, the potential for growth of bio-fiber composites exists within Canada.

Written By: Preshani Maistry


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Endnotes

1 A. K. Mohanty, M. Misra, and L. T. Drzal, Sustainable Bio-Composites from Renewable Resources:Opportunities and Challenges in the Green Materials World,Journal of Polymers and the Environment 10, no.1-2 (2002).

2

V.K. Mathur, Composite materials from local resources, Construction and Building Materials 20,no.7 (2006).

3 LEED and Green Building Products, Rapidly Renewable Materials, LEED andGreen Building Products Onlinehttp://leedpro.wordpress.com/tag/mr-6-rapidly-renewable-materials/ (accessed, August 6, 2007)

4 Armstrong, LEED Credits, Armstrong Onlinehttp://www.armstrong.com/sustainability/LEED-credits.html (accessed, August 6, 2007)

5 http://www.buildinggreen.com/auth/productsByLeed.cfm?LEEDCreditID=28

6 Armstrong, LEED Credits, Armstrong Onlinehttp://www.armstrong.com/sustainability/LEED-credits.html (accessed, August 6, 2007)

7 Build It Green, Build It Green Online

http://www.builditgreen.org/resource/index.cfm?fuseaction=factsheet_detail&rowid=48 Ibid9 Ibid10 Ibid11 Ibid

12 Build It Green, Build It Green Onlinehttp://www.builditgreen.org/resource/index.cfm?fuseaction=factsheet_detail&rowid=8

13 Ibid14 Ibid

15 World Wildlife Fund, World Wildlife Fund Onlinewww.wwf.ca (accessed, August 6, 2007)

16 Build It Green, Build It Green Onlinehttp://www.builditgreen.org/resource/index.cfm?fuseaction=factsheet_detail&rowid=8

17

Department for Environment Food and Rural Affairs, Improvement of Acoustic andFire Performance of Flax and Hemp Thermal Insulation, DEFRA Science and Research, 2004.http://www2.defra.gov.uk/research/project_data/More.asp?I=NF0605 (accessed, August 6, 2007)


19 Ibid

20 Department for Environment Food and Rural Affairs, Improvement of Acoustic andFire Performance of Flax and Hemp Thermal Insulation, DEFRA Science and Research, 2004.http://www2.defra.gov.uk/research/project_data/More.asp?I=NF0605 (accessed, August 6, 2007)


22 Agriculture and Food, Industrial Hemp Production Rebounding, Government ofAlberta, 2006.http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/econ9631 (accessed, August 6, 2007)


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Bibliography

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Mathur, V.K. Composite materials from local resources. Construction and Building Materials20, no.7(2006).

MohantyA. K., Misra M. and L. T. Drzal. Sustainable Bio-Composites from Renewable Resources:Opportunities and Challenges in the Green Materials World.

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