Page 232 - The Engineering Guide to LEED-New Construction Sustainable Construction for Engineers

206 Cha pte r F i v e

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
Extend the life cycle of existing building stock, conserve resources, retain cultural resources,
reduce waste and reduce environmental impacts of new buildings as they relate to materials
manufacturing and transport.
Requirements
Use existing interior non-structural elements (interior walls, doors, floor coverings and ceiling
systems) in at least 50% (by area) of the completed building (including additions). If the
project includes an addition to an existing building, this credit is not applicable if the square
footage of the addition is more than 2 times the square footage of the existing building.

Potential Technologies and Strategies
Consider reuse of existing buildings, including structure, envelope and interior non-structural
elements. Remove elements that pose contamination risk to building occupants and upgrade
components that would improve energy and water efficiency, such as mechanical systems and
plumbing fixtures. Quantify the extent of building reuse.

Calculations and Considerations (LEED 2009 MRc1.2)
This credit is not listed with the EB icon, presumably because it is not really applicable
for existing building reviews. Just as for MRc1.1, this credit is not applicable if there are
substantial additions to the building, totaling more than double the existing GFA. If
GFA is defined as being the gross floor area of the existing building portion of the
PEX
project which is to be retained and added on to, and GFA is the proposed total gross
P
floor area of the project including both the retained and the new areas, then MRc1.2
cannot be applied for if
GFA > 3 × GFA (5.1.1)
P PEX
This credit is intended to reuse as much as possible of the interior finished
(nonstructural) surfaces in the final structure. First, all interior nonstructural surfaces
in the proposed design (including the additions if applicable) shall be totaled. Since it is
usually based on the proposed design and the finished product, there is no need to
exclude hazardous materials, as these should not be included in any newly finished
or renovated building in the first place. These interior nonstructural surfaces include
all finished interior ceilings, flooring surfaces, doors, windows, casework, demountable
partitions (count both sides), walls (count both sides for interior walls for which the
finishes are remaining on both sides, but only one side for the interior sides of exterior
walls), and visible casework surfaces. It is easy to understand if one pictures the
finished interior surfaces that can be seen in all the rooms, but with the interior doors
and windows and sidelights counting only once. (LEED 2.2 did not include any exterior
doors and windows, even their interior side, but this has been modified in LEED 2009
as previously noted.) Let the total of all these areas be represented by INTFIN . Let
T
INTFIN be the total of all these finished interior surfaces that have been reused from
RE
the existing building, even those which may have been moved. Then one point is
earned for MRc1.2 if
INTFIN ≥ 0.5 × INTFIN (5.1.2)
RE T