Page 220 - The Engineering Guide to LEED-New Construction Sustainable Construction for Engineers

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waste management credit (MRc2), since existing concrete, masonry, or asphalt from
pavement on a site which is crushed and reused on-site or elsewhere should be included
in the weight or volume of the materials diverted from disposal. There may be exceptions
to this for special circumstances such as campus settings. Therefore, there might be a
need for narratives describing any such variations and how the project still meets the
intent of the credit. The importance of the LEED boundary to MRc2 is also noted in
Table 5.0.1.

Material and Resources Credit Calculation Summaries
There are so many different types and uses of materials that go into a building, and they
have vastly different values based on weight, cost, or application. Therefore, to determine
percentages of material usages, it is important to define which materials are included in
the calculations and what units the calculations are based on. The LEED-NC 2.2 and 2009
Reference Guides provide tables of MR credit metrics which help in organizing and
standardizing the calculations and credit criteria. The process for classification can be
summarized in four steps:
1. Segregation of materials into material uses
2. Segregation of the materials for the MR credits into applicable material types or
items
3. Determination of the units
4. Setting of the bases (denominator) for each calculation

The various calculations in the MR category are based on certain groups of materials.
This has not really changed from the 2.2 to the 2009 version. However, the categories of
materials as tracked on a project that are used in these calculations are segregated as
based on the Construction Specifications Institute’s MasterFormat Division Listing and
this listing has been revised in the interim. LEED 2.2 is based on the CSI 1995
MasterFormat and LEED 2009 is based on the CSI 2004 MasterFormat. The main
divisions in these two versions of the MasterFormat are summarized in Table 5.0.2.
Table 5.0.3 is an overview on how the materials are grouped and utilized for the LEED
2009 calculations based on the CSI 2004 MasterFormat.
Note that items used for mechanical, electrical, and plumbing (MEP) purposes are
not included in any of the calculations in the Materials and Resources category except
for construction waste management. The calculations for the items in subcategories 3
through 7 are based on value or cost. MEP items tend to be costly per unit weight
compared to many of the other bulk building materials. The intent of these subcategories,
to the greatest extent possible, is to be able to recycle or reuse or purchase local materials.
Therefore, it is assumed that having the high-dollar MEP items in these calculations
might bias the equations, without having the bulk materials included.
Note also that furniture and furnishings are optional, but only if fully included
consistently in subcategories 3 through 7. The choice is up to the project team. There are
many manufacturers of furnishings and furniture items which are providing product
options that can meet recycle content, certified wood, and regional material needs
among others. Figure 5.0.1a and b depicts many furniture options provided by some
manufacturers in the United States.