Page 249 - The Engineering Guide to LEED-New Construction Sustainable Construction for Engineers

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5.6 MR Credit 6: Rapidly Renewable Materials
The intent of MR credit 6 is to encourage the use of rapidly renewable materials, that is,
materials that are made from living products that have a short growth span. One point
is available for MRc6 in both versions 2.2 and 2009.

USGBC Rating System
LEED-NC 2.2 lists the Intent, Requirements, and Potential Technologies and Strategies
for this credit as follows (LEED 2009 is essentially the same):
Intent
Reduce the use and depletion of finite raw materials and long-cycle renewable materials by
replacing them with rapidly renewable materials.
Requirements
Use rapidly renewable building materials and products (made from plants that are typically
harvested within a ten-year cycle or shorter) for 2.5% of the total value of all building
materials and products used in the project, based on cost.
Potential Technologies and Strategies
Establish a project goal for rapidly renewable materials and identify products and suppliers
that can support achievement of this goal. Consider materials such as bamboo, wool, cotton
insulation, agrifiber, linoleum, wheatboard, strawboard and cork. During construction,
ensure that the specified renewable materials are installed.

Calculations and Considerations (LEED 2009 MRc6)
Rapidly renewable materials are considered to be sustainable since they tend to use less
land and have a faster economic cycle than materials with a growing span longer than 10
years. They are not limited to plant products, but may also be animal based. Some common
examples of products made wholly or partially from rapidly renewable materials are
sunflower seed board panels, bio-based paints, coir and jute geotextiles, soy-based
insulation and form-release agents, straw bales, linoleum, bamboo flooring, wheatboard,
cotton and wool products, and cork.
The determinations are based on the following definitions and equations.

MATL$ Total value of rapidly renewable materials (CSI 3 through 10 , 31.60, 32.10,
RRM
32.30, and 32.90) plus any similar portions of furniture or furnishings made
from rapidly renewable materials if furniture and furnishings are included
consistently in MR subcategories 3 through 7. Value determinations are
based on the weight percent of the rapidly renewable portion of each of
the individual item values.
MATL$ See definition under MRc3.
T
Then one point is earned for MRc6 if the following is true:

100(MATL$ )/MATL$ ≥ 2.5 (5.6.1)
RRM T
Most applicable construction items are not 100 percent made from rapidly renewable
materials, but rather are composites such as bamboo flooring or linoleum. Therefore,
the rapidly renewable value is only a portion of the value of the item, whether these
items are one piece (such as linoleum flooring) or an assembly (such as wheatboard
casework). The value determination is made on a mass percent basis. So for any item
the following can be defined: