Page 234 - The Engineering Guide to LEED-New Construction Sustainable Construction for Engineers

208 Cha pte r F i v e

Calculations and Considerations (LEED 2009 MRc2)
The intention of the two MRc2 points and the EP point for diversion of 50, 75, or 95
percent, respectively, of the construction and demolition (C&D) waste stream from
landfills is to find reuses for as many materials as possible from either demolition
activities or construction activities. Note that there are two different sources of these
waste materials. One source is from the existing manmade buildings or other structural
items on the site which are to be either reused or demolished, and one source is from the
construction process. If a project has no demolition on-site since the land was originally
not built upon, then the source is solely from the construction phase.
It is very important to establish a construction waste management plan that involves
the construction contractor to adequately verify that these goals have been met. Good
waste management plans will include proper designations of areas on-site for the
recycling activities, plans to train the workers in the recycling procedures, some feedback
or reporting system to oversee the activities, and proper labeling of all recycling facilities,
particularly in the languages of the workers. Care should be taken to avoid tight or not
readily accessible areas where either disposal or pickup will be difficult. Care should
also be taken to avoid problems with stormwater in and around the recycling facilities.
A significant amount of documentation is needed to verify the items throughout the
demolition and construction phases. These might include tipping fee receipts from the
recyclers or landfills and accounting of all the dumpster and waste removal procedures
on-site. For instance, dumpsters come in different sizes and may be removed when full
or partially full, depending on the pickup times. It is difficult to determine the volume
of a waste in a container if it is not documented as to its fullness at the time of pickup.
In some cases the weights will be given regardless from the tipping accounts, but some
debris items are valuable (such as metals) and recyclers may contract to haul them free
of charge, in which case the general contractor may not receive the necessary records
unless they are specifically requested in the contracts.
Good waste management plans will have the contracts and oversight in place
necessary to have dumpsters usually as full as possible when picked up, since this will
typically reduce overall hauling costs and environmental impacts of the transport phase.
Commonly used dumpsters in the United States range from a small size of 6 yards to a
large size of 30 yards or more. A yard in this case actually refers to a cubic yard. Dumpster
sizes are usually chosen based on the expected amount of different types of wastes
generated. Some wastes may also never be put into dumpsters, but instead either reused
on-site or loaded into dump trucks or other hauling vehicles and then transported off-
site. Typical examples of this are recycled asphalt or concrete pavements which are
usually first crushed and then piled on-site before they are reused.
The calculations are fairly simple if there is adequate control, recording, and
documentation resulting from the waste management plan. What is important is to make
sure that the items included in these calculations have been adequately documented.
The items used in the calculations for MRc2 are usually defined by the following
criteria:
• In all cases, hazardous materials, land-clearing debris, and soils removed from
the site are not included in the calculations.
• All the demolition wastes that go into the dumpsters and are hauled off-site are
included.
• All the construction wastes that go into the dumpsters and are hauled off-site
are included.