Environmental Engineering Reference
In-Depth Information
Although the practices or technologies employed in green building are con-
stantly evolving and may differ from region to region, fundamental principles
persist from which the method is derived: sitting and structure design efficiency,
energy efficiency, water efficiency, materials efficiency, IEQ enhancement,
operations and maintenance optimisation, and waste and toxics reduction. The
essence of green building is an optimisation of one or more of these principles.
Also, with the proper synergistic design, individual green building technolo-
gies may work together to produce a greater cumulative effect.
On the aesthetic side of green architecture or sustainable design is the
philosophy of designing a building that is in harmony with the natural
features and resources surrounding the site. There are several key steps in
designing sustainable buildings: specify 'green' building materials from
local sources, reduce loads, optimise systems and generate on-site renew-
able energy.
8.2.1 Life Cycle Assessment
A life cycle assessment (LCA) can help avoid a narrow outlook on environ-
mental, social and economic concerns by assessing a full range of impacts
associated with all cradle-to-grave stages of a process: from extraction of
raw materials through materials processing, manufacture, distribution, use,
repair and maintenance, and disposal or recycling [5,6]. Impacts taken into
account include (among others) embodied energy, global warming potential,
resource use, air pollution, water pollution and waste.
In terms of green building, the last few years have seen a shift away from
a
prescriptive
approach, which assumes that certain prescribed practices are
better for the environment, toward the scientific evaluation of actual perfor-
mance through LCA.
Although LCA is widely recognised as the best way to evaluate the envi-
ronmental impacts of buildings (ISO 14040 provides a recognised LCA
methodology), it is not yet a consistent requirement of green building rating
systems and codes, despite the fact that embodied energy and other life cycle
impacts are critical to the design of environmentally responsible buildings.
In North America, LCA is rewarded to some extent in the Green Globes
®
rating system, and it is part of the new American National Standard based
on Green Globes,
ANSI/GBI 01-2010: Green Building Protocol for Commercial
Buildings
. LCA is also included as a pilot credit in the Leadership in Energy
and Environmental Design (LEED) system, though a decision has not been
made as to whether it will be incorporated fully into the next major revision.
The state of California also included LCA as a voluntary measure in its 2010
draft
Green Building Standards Code
.
Although LCA is often perceived as overly complex and time consuming
for regular use by design professionals, research organisations such as BRE
in the UK and the Athena Sustainable Materials Institute in North America
are working to make it more accessible.
