The
following is excerpted from the Carbon Working Group's upcoming white paper:
The
embodied impacts associated with building materials (including structural
materials and other finishes and equipment) comprise a relatively small part of
the total environmental impact over the life cycle of a structure, with impacts
from heating and cooling typically far outweighing the materials impacts. In
North America, the relative life-cycle carbon emissions due to building
structural materials alone can range from 1 to 16 percent for a 50-year
building life, depending upon the building type, energy efficiency, and
location.
However, a
study of demolition records found that over 60% of the demolished concrete
buildings were less than 50 years old, and roughly 10% were less than 25 years
old. The numbers were even more striking for the steel-framed buildings: more
than 80% of these buildings were less than 50 years old when demolished, and
40% less than 25 years old. For these short-lived buildings, the embodied
impacts of the structural system could easily exceed 1/3 of the total
life-cycle building impacts for buildings that are highly energy efficient.
The
green building movement has primarily focused on improving operating
efficiencies to reduce carbon emissions, and building energy efficiency is
likely to improve. As a result, the relative embodied impacts of building
materials will likely grow. To decrease our risk of exposure to disastrous
climate-related events, we must not only reduce emissions from building
operations but also reduce embodied emissions in building materials including
structural materials.
The
success of this task depends in large part upon structural engineers who
understand the emissions associated with the materials they use and who can use
data, design, and material research to reduce the carbon emissions associated
with their projects.
So
structural engineers are faced with both a challenge and an opportunity.
Use this site to learn about structural design's contribution to climate
change, and become part of the movement for solutions.
