Green Building Consulting Services

1

Structural Steel Contributions


toward obtaining a
LEEDTM rating
S si
der the impact of each decision on
all system, and an outline of how the
selec- design effort. LEED was developed
by other
aspects of the project. This paper tion
of a steel building structure can
con- consensus of the membership of
the provid
es a brief overview of sustainable tribut
e to a LEED ratingmost USGBC, which
includes companies
building design and an outline of how
a significantly in the Materials
Re- from all segments of the building
indus- st
ructural system can contribute to
an sources and Innovation
Design trya membership that has grown
ex- enviro
nmental initiative.
Process categories,
explained in further ponentially since
1998.
The North American building
indus- detail herein.

LEED is the
most widely used green
try has a tremendous impact on our
en- Each structural system has
opportu- building rating system in the
U.S. As of
vironment, and a focused green
design nities and constraints when
evaluated as March 12, 2003, 44 LEED
certified build-
effort can bring benefits to all
stakehold- a part of an environmental
design effort. ings have been completed,
and more than
ers. Sustainable design and
construction Market demands for steel
production 500 projects are registered
with the p
ractices can bring environmental,
eco- spur a significant amount of
recycling, USGBC seeking LEED
certification. The
nomic and social benefits that
result inherently contributing to
sustainable certification process
requires the project
from careful consideration of
resource design efforts. According to
the Steel Re- team to pursue and
evaluate specific cred-
use and how the building will
affect the cycling Institute, 67 million
tons of steel its (see
www.aisc.org/sustainability), to
environment. Additional
benefits could were recycled in the U.S.
alone in 2001. document requirements
successfully met
be reduced operational costs, higher
fa- Worldwide, 400 million tons of
steel for each credit, and to submit
credit doc-
cility value, and increased worker
pro- were recycled - one and a half
times the umentation to the USGBC for
review. du
ctivity.

amount of all other recycled
materials Because the LEED rating system
relies
Today, sustainability, environmental
combined (including paper, glass,
alu- on the project team to generate
proof of d
esign, and green building are generally m
inum, and plastic). Approximately
40 compliance, LEED is considered a
self- inte
rchangeable terms, becoming in- million
tons (59 of total recycled steel) certif
ication system.
creasingly common to the language
of were derived from construction
and LEED credits are organized
within bui
lding design and construction. The demoli
tion waste, and the steel salvage six
core categories Sustainable Sites,
United Nations
Brundtland Commis- market accounts for
an additional 4 mil- Water Efficiency,
Energy and Atmos-
sion Report of 1987 defines
sustainable lion tons per year. Each ton
of recycled phere, Materials and
Resources, Indoor
development as development
that steel saves 2,500 pounds of iron
ore, Environmental Quality, and
Innovation
meets the needs of the present
without 1,400 pounds of coal, and 120
pounds of and Design Process.
Prerequisites within
compromising the ability of future
gen- limestone.1 In addition,
recycling re- several of these
categories must be met
erations to meet their own needs.
Such quires less energy, creates less
waste, for certification. Remaining
green meas-
a broad statement does not provide
a and releases less pollutants than
pro- ures form an à la carte system of
points, d
atum against which business practices, du
cing the same amount of steel from includ
ing both proven practices and
design solutions and
construction prac- virgin materials.
Recycling, however, is
tices can be measured. Architects,
engi- only one aspect of how structural
steel nee
rs, suppliers, fabricators, and can
contribute to green design efforts,
builders need to
understand how envi- and the steel frame
is only one compo-
ronmental design practices impact
the nent of the overall structural
system. d
esign and construction industry.
Fortunately, The
U.S. Green Building
Council (USGBC) has developed
the The LEED rating system is
designed L
EEDTM (Leadership in Energy and En- for
new and existing commercial, insti-
vironmental Design)
Green Building tutional, industrial, and
multi-story res-
Rating System. This tool provides
a idential buildings. Its purpose is to
set frame
work under which building de- an
industry standard for green build-
sign and construction
decisions can be ings, and in doing so,
help drive the




Ma
y 2003 (rev. 2/04) Modern Steel Construction
uccessful sustainable design made and
sustainable building projects marketplace
toward more sustainable results from a process
of in- can be evaluated. LEED has
rapidly be- development. It provides an
accessible tegrated decision making, come
a design tool embraced by design- and
understandable frameworka rec- beginning at
project incep- ers and owners interested
in bringing ognized reference for
project teams to tion. Throughout
every additional value to their
projects. This make decisions and
evaluate the overall

paper includes overview of
the LEED performance of a sustainable
building




ACKNOWLEDGEMENTS




OWP/P performed
the research for




this paper.Contributors
include

LEED RATING SYSTEM





Rand Ekman AIA




Michelle Halle Stern AIA,
P.E., a




consultant to OWP/P, was a
signifi-




cant contributor to this paper.
David Eckmann AIA, S.E., P.E. Tom Harrison
AIA, S.E., P.E.
2
emerging
technologies. A brief descrip-
LEED version 2.1 allows for a maxi- LEED
Version 2.1 is intended to simplify
tion of the categories
follows
mum of 69 possible points. Depending re
quired documentation by providing
Sustainable
Sites Thoughtful site upon the total
number of points project teams a series
of letter templates
selection is important to preserving
or achieved, a building can be
classified as to be printed on company
letterhead
restoring local ecology. Site selection
can Certified (26-32 points), Silver
(33-38 and signed by a team member
certifying
also influence credits that may not
seem points), Gold (39-51points) or
Platinum that the requirements have been
met. direc
tly related to the site. For example,
a (52 or more points). As with any
inte- The fill-in-the-blank documents
prompt si
te close to public transit or in an
already grated design tool, the earlier
LEED is team members for information and
com- devel
oped area helps reduce the amount conside
red in the design process, the pute
whether a particular credit has
of driving by the
buildings occupants. easier it will be
to achieve certification. been achieved.
The USGBC reserves the
Possible points in this category
are 14. Project teams may find
that pursuing right to audit credits on
any submission
Water Efficiency According to
the one credit may make it difficult or
im- to confirm backup information and
will World
watch Institute, buildings account possib
le to achieve another. It is not
pos- determine accepted and declined
cred- for
one-sixth of fresh water withdrawals. si
ble to achieve all 69 points.
its, or if additional
documentation is
Water is used in the manufacture
of Many project teams that
have uti- necessary.
building components and in
building lized the LEED system believe
there is
operation. LEED offers credits for
water little, if any, additional
construction cost
efficient fixtures and landscape
materials required to obtain the LEED
Certified
that do not require irrigation.
Possible level. However, as with any
effort that While the rating
system is set up to
points in this category are
5.
brings additional value, additional
costs evaluate an entire project in a
holistic
Energy and Atmosphere This
cate- may result, depending to some
degree manner (not simply material
selection),
gory encompasses a number of strate- on
the targeted certification level.
These as a building material, structural
steel gie
s to help reduce energy use and costs
could result from additional proj- can
make the largest contribution to
a protect
the ozone layer. Credits are ect team
fees (managing the LEED effort LEED
rating in this category. All materi-
given for using
renewable energy and and assembling the
documentation for als selected for a
project are evaluated
purchasing green power. A credit
for submission to the USGBC), as well as
in- based upon performance criteria,
either Fun
damental Building Systems Com- creased
construction costs.
by weight or cost, depending
on the mis
sioning and Measurement Verifi-
The certification process is
relatively credit. The structural system
can be a
cation helps to ensure a building simple.
Any member of the project team significa
nt portion of the cost or weight
operates as designed.
Possible points in can register a
project with the USGBC, of the building
materials and con-
this category are 17.

although discounts are available
for tributes to points for almost every
credit
Materials and Resources The
main USGBC members. Once a project is
reg- in this LEED category.
objective of this
category is to conserve istered, the
project team is given access
raw materials and resources,
such as fos- to the online LEED
Reference Guide and
sil fuels. Methods include increasing
re- credit rulings from past projects.
Be- cyclin
g and recycled content, diverting cause
no two projects are alike, situa-
material from landfills,
and reducing tions will arise that do
not explicitly
travel distances for material
transport. follow the listed
requirements. In such a
Structural steel can typically make
the situation, the project team should
first grea
test contribution within this cate- revie
w the Intent of each LEED credit,
as gory.
Possible points in this category
are described in the Reference Guide. If
the 13.


situation meets the
Intent of a particular
Indoor Environmental
Quality Be- credit, the project team
can pursue the
cause Americans spend 90 of
their credit. If the project team is
attempting
time indoors, the indoor environment to
obtain a credit, yet does not find
a has a
large impact on health and pro- precedent
for its situation, the online
ductivity. Issues related
to this include credit rulings (USGBCs
formal answer
occupant comfort, air quality,
thermal to a question submitted from a
previous c
omfort, and access to daylight.
Possible project team) can be consulted
to see if
points in this category are 15.
another project team
has posted a simi-
Innovation and Design
Process lar question. If the credit
rulings do not
The USGBC recognizes LEED is a
rela- address the situation, a credit
interpre-
tively new system and provides this
cat- tation can be submitted. Each
project is
egory to recognize the innovative entitl
ed to two free credit interpreta-
solutions of project
teams, which could tions.
range from
substantially exceeding the The
project team submits a certifica-
requirements of a given
credit or devel- tion package to the
USGBC for review
oping a completely new way to
increase after construction of the
project is com-
environmental responsiveness.
Possible plete. The certification
package must
points in this category are
5.
include documentation to prove require-



ments have been met for each
credit. M
odern Steel Construction May 2003 (rev. 2/04)
LEED MATERIALS AND RESOURCES Credit 1. Building
Reuse (2
possible points) Building reuse enables
development within existing buildings and
previ- ously developed areas, maintaining proximi
ty to existing infrastructure and preserving open
space. Materials that would have been utilized
for a new building are conserved, and the
environ- mental impacts from the transport
of those materials are also eliminated.
Usu- ally, the owners decision to reuse is based
upon a real estate evaluation, ren- ovation
costs, and square footage re- quirements.
In the LEED rating system, if 75 of the
building structure and shell (exclud- ing
windows) is preserved, the project earns one
point. Structure includes foundations, slabs,
and basement walls. If 100 of the building
structure and shell is preserved, along with 50
of the walls, floors, and ceilings, the
project earns two points. Because the
LEED templates con- sider the volume of
materials saved, reusing a steel frame for an
entire build- ing can be advantageous. When a
build-
3
ing is
reused, it often must serve a com- of
steel product. Lastly, the production mor
e common in project specifications
pletely new function,
requiring modifi- of steel structural
shapes is completed when LEED
certification for a project is
cations to the structure due
to changes through a method of
continuous casting, being
pursued. i
n loading conditions and relocated where
by materials transform directly
The equations for calculating recy-
floor openings. Steel
structures are more from liquid form to
near final shape. cled steel content
favor post-consumer
likely to be reused than other
structures (Prior to continuous
casting, steel was recycled content as
opposed to post-in-
because they can be easily and cost
ef- first made into square ingots and
then dustrial recycled content. Process
scraps fe
ctively modified and reinforced,
al- reheated to roll beams, a process
that re- that can easily be used as
feedstock are
lowing flexibility and adaptability
for quired more energy and
significantly not considered recycled
content. Calcu-
the buildings new use.
more
time.) Currently, the relatively
low lations for this credit can be
confusing
Credit 2. Construction Waste Recy-

cling (2 possible points)
Commercial construction
generates be-
tween two and two and one-half
pounds of solid waste
per square foot2 .
LEED defines construction waste
as both
demolition waste and waste as a
by-product of
construction. As landfill
space becomes more scarce, the
cost to du
mp wastes, tipping fees, etc. become
more expensive. To
avoid these higher
costs, diverting as much waste as
possi- bl
e proves beneficial. To achieve
this cred
it, waste can be diverted by recy-
cling or reusing.
Points are awarded for
diverting 50 (1 point) or 75 (2
points) Credit 4. Recycled Content
va
lue of the material 20
40
of waste as calculated by
weight or vol-
(2 possible points)
ume. As mentioned earlier, steel
is the The greatest advantage
of steel con-
most recycled material in the world,
en- struction is its contribution to
recycled
suring that virtually any steel on a
con- content. Steel production can
occur str
uction site can be recycled or reused.
through one of two processes. The
basic Cre
dit 3. Resource Reuse



post-consumer recycled content
and
(2 possible
points)


30
post-industrial recycled content
LEED awards points for
using 5 (1


would be equivalent to 395,000
worth poin
t) to 10 (2 points) salvaged or
re-


of material. A second point would
be furbish
ed materials (by cost), relative
to


achieved if the total value of
recycled
the total cost of materials for the
project.


content was 50 of the total value
of This
credit encourages the use of exist-


materials for
the project.
ing materials, as energy is required
to produc
e new materials regardless of


average and offers
two options for cal-
whether they are extracted from
recy-


culating recycled content. The first
op- cled
or virgin stock.



tion is for
post-consumer recycled
While it is possible to
return steel to


content to comprise at least 5 of
the a
fabricator at the end of a buildings


total value
of materials on the project.
useful life, it is much more
common to


The second is for all the
post-consumer
recycle steel. Innovations in the
produc-


recycled content plus ½ of the
post-in- t
ion process have resulted in a 35
de-


dustrial recycled content to equal 10
of cline
in steel material costs between


the value of all
materials on the project.
1983 and 1998. Therefore, even
with in-


As with the Version 2.0 method, if
these crea
sed costs in fabrication and con-


quantities are
doubled another point is
struction labor within the same
time


available.
frame, the net change in the cost of
in- stalle
d structural steel within the 15-


pany breakdown
as an example,
year period is 0.3 Furthermore,
the


100,000 worth of steel is calculated
as energy
required to produce new steel


follows. This
credit does not consider
has decreased 45 over the last
25


the 10 in-house crops and pit scrap
as years1,
largely due to improvements in


recycled content.
Therefore the total re-
yield. Before, 100 tons of raw
material


cycled content must be considered to
be produce
d 60 tons of steel product, and


over 80 rather
than over 90. The con-
now, the same 100 tons produces 90
tons


tribution of structural steel in this
exam-




May 2003
(rev. 2/04) Modern Steel Construction
cost for new steel does not favor the
sal- and were modified in Version 2.1 to
be- vage and reuse of structural steel
mem- come less complicated. Because
many bers in building projects.4
projects
that were previously registered In
cases where steel is reused, it
often continue to work with LEED 2.0,
we occurs on the job site where the laws
of have described the calculations for
both supply and demand dictate how
con- versions. struction and waste
haulers will dispose Under
LEED 2.0 (for one point) the of a particular
material. Although un- value of recycled
content materials had common, steel salvage can
occur when to comprise at least 25 of
the total structures are relocated. One example
of value of materials on the project,
with at complete reuse of a steel system
is least 20 post-consumer recycled
con- Beaver Stadium at Penn State
Univer- tent or 40 post-industrial
recycled con- sity. In this instance, the entire
building tent in aggregate using a
weighted was relocated from one end of the
cam- average per the following
equation pus to the other.


content


If a material exceeded
20 post-con-


sumer recycled content or 40
post-in-

dus
trial recycled content, it was


rewarded with a higher value.
For ex- oxygen furnace (BOF) process uses
25- 35 existing steel to make new steel. The
electric arc furnace (EAF) process uses almost
100 existing steel. In the U.S., the structural
steel industry has embraced the EAF process for
the pro- duction of steel for structural
shapes, along with the continuous casting method.
All three U.S producers of structural shapes
W1443 and larger use the EAF process. According
to the Steel Recycling Institute, the
post-consumer recycled content (steel that has
previ- ously been used in another
consumer productautomobile, refrigerator,
etc.) is 64, and post-industrial recycled
con- tent (steel that is waste/surplus of
an- other industrial production process)
is 30.5 LEED requires documentation
veri- fying which steel production process was
used for the steel on the project. AISCs
website contains letters from the largest U.S.
structural steel producers, certifying recycled
content from their fa- cilities. This letter can
be accessed at www.aisc.org/ sustainability. The
re- quirement for this type of letter to
be produced by a fabricator is becoming
ample, 100,000 worth of steel with
64 Version 2.1 eliminates the
weighted Using the Nucor-Yamato Steel
Com-

industrial
content value consumer
4
ple to
the overall project goal of 10
of scrap. Steel mills typically
acquire million cubic feet
(making it easier to
the materials value is

scrap from brokers, who obtain
materi- heat and cool) and
weighs over 950
of post- of post- Value
of Value of Recycled
consumer industria
l post-con- post-indus- value



lected based upon
metallurgical needs centage of
steel, such as a steel plate
75 5
75,000 5,000 77
,500


uses nine to
12 different types of fer- mate
rials in a building that can be
re-
For a project where the total value
of rous scrap, classified in various
grada- cycled in the future.
If the building is
materials is 1,000,000 (C) and steel
is tions including 1, 2, tin
plate dismantled in a later
project, the
the only recycled content material
(un- bundles, shredded, municipal,
cast LEED Construction and
Demolition
likely), compliance with LEED require- i
ron, plate, structural, and turnings.
Waste Credits could be achieved.
ments is
as follows
The David
Joseph Company, its pri- 4.
Deconstruction. Structural steel
can P
ost-consumer value as a Post-consumer plus
half
of total value of
post-industrial value as
(A/C)
of total value
(B/C)
7.5 which is more than
Because structural
steel is not a com- difficult to
achieve.
Werner
Sobek, a recognized German
posite material, the recycled
content is
simply the percentage of recycled
steel in
the new product. For composite mate-
rials like concrete,
the recycled content Structural
steel can also impact cred- is
designed so that the entire steel
of the assembly must
first be deter- its earned in this
category. Up to four structure
can be disassembled and
mined by dividing the weight of the
re- points can be awarded in this
category reused.9
cycled content by the
total weight of for strategies that go
above and beyond 5. Structure as
Plumbing. The Greater
material in the item, then
multiplying what is required in the 64
core credits, London Authority
building, de-
the resulting percentage by the
total either by a completely new idea or
by signed by architect Foster
and Part-
value of the item.

greatly exceeding the requirement
from ners, used HSS structure
members in
Credit 5. Local/Regional Materials

(2 possible
points) F
or the first part of this credit, LEED
re- quires
materials to be manufactured
within 500 miles of the
project site.
Manufacturing refers to the final
as- sembly
of components into the build-
ing product that is
furnished and
installed by the tradesmen.
AFebruary
2004 credit interpretation ruling
estab- lis
hed that, for structural steel, the
fab- ricat
ion shop is considered the location
where the final
manufacture of the
product occurred. Fabricators cut
steel memb
ers to their appropriate length,
punch or drill holes, weld
on connec-
tion plates, and add the necessary
cam- ber
to members. Fabricators may also
build the steel into
standard assem-
blies, such as trusses or frames.
Steel fabr
icators are available within 500
miles of any location in
the United
States and the use of local fabricators
fosters local
economies for the product,
which reinforces the intent of
the credit
.
The second point of this credit
is availab
le for raw materials extracted or
harvested within 500
miles of the proj-
ect site. For steel, this credit refers
to the
location where the metal served
its last
useful purpose before it became
Modern Steel Construction
May 2003 (rev. 2/04)


als from projects
and products tons less than
competing solutions.8
sumer (A) trial
(B) A(B/2) throughout the
country, which are se- 3.
Recyclability. Utilizing a high
per-

and cost. For
example, Nucor-Yamato shear
wall, maximizes the amount of


mary supplier, obtains 85 of its
mate- be welded or bolted. If
the structure

rial
from domestic sources. However,
is designed with bolted connections,


there is no way to track where
the raw thus allowing it to be
easily disas- 5 but less than
10 5 but less than
10

LEED
INNOVATION DESIGN
philosophy extensively. His resi-


PROCESS





dence at Römerstrasse 128 (Stuttgart)


an existing LEED credit. A
separate the atrium. Hot water
runs through

point
is available for having a LEED Ac-
the members, creating a giant
radia-

credited
Professional on the project. to
r. This is an example of true inte-


While the USGBC does list credit
inter- grated design and
economy of

pretation
rulings for specific requests
materials.10

submitt
ed by registered projects, they


have not yet published a list of
specific

ideas for
Innovation Design Process


that have been accepted on
certified In order to better
understand the im-

p
rojects. The following are suggestions pa
ct of structural material selection
on

that may qualify
for innovation points. LEED
certification, a survey was con-


1. Structure as finish. It is
possible to ducted of the LEED certified
buildings


expose a steel structure and avoid
in- to date. The survey identified the
mate-

stal
ling finish products such as ceil- rial
for the primary structural system


ing tiles or drywall. Any
time a for each project by speaking
directly

p
roduct is eliminated, the energy to with
the architect and/or structural
en-

extrac
t, produce, install, and dispose gineer
of record. A total of 44 projects


of that product is
saved.
were surveyedthe complete list
of

2.
Light-weight materials. Steel is
nat- LEED certified projects as of March
12,

urally
light in weight, making it ben- 2003. A
summary table of these survey


eficial for girders can also
be used results can be accessed at
www.aisc.org/


compositely with floor systems to
re- sustainability.


duce weight of the structural
system. Steel buildings
represent a large por-


Based upon past credit rulings,
in tion of this group, exceeding their
mar-

order
to achieve this credit, the proj- ket
share representation among building


ect team must clearly
describe a con- construction projects
throughout the


ventional building for a baseline
and U.S. Buildings in which steel
framing is


then demonstrate significant savings. th
e primary structural system comprise


The Utah Olympic Oval,
for exam- 50 of the LEED certified
buildings.


ple, uses an innovative cable suspen- Wh
en projects with more than one struc-


sion system to
support a very tural system are
considered (mixed sys-


shallow steel truss roof. This
design tems), structural steel is
included in 68


reduces the total arena volume by
2.6 of the LEEDcertified projects.
Structural

materials for a particular
piece of steel sembled, it is
more likely that mem-
came
from, making this second point
bers can be reused on other projects.




structural engineer, has utilized
this



COMPARISONS BETWEEN



STEEL
AND CONCRETE
5
steel
has successfully been employed
across a wide variety of
building type,
building size, and geographic
location i
n LEED-certified projects.
While those surveyed
indicated that
structural systems were selected
based upon
a variety of criteria, including
ini- tial
cost, serviceability, building
type, bay
size, and geographic location, they
also frequently cited
the advantages of
using structural steel when
seeking LE
ED certification, especially contribu-
tions to the
percentage of recycled mate-
rials used for a project.

Table 1 evaluates the contributions
major structural
building materials
(steel and concrete) could make to
a LEED
design effort. The table demon-
strates that material
selection also has
an impact in areas not directly related
to the
buildings structural system (note
Other Considerations
column).





opportunity for salvage
CONCLUSI
ON
Each structural system brings
bene- fit
s to different LEED credits. Aclear
en- vironm
ental advantage to either a steel
frame or a concrete
frame is not clear in
regard to the LEED certification
process. L
EED is a performance standard, not
a prescrip
tive standard. It does not favor
one structural system
over another.
As LEED certification becomes
more popu
lar among design professionals
and building owners,
further studies of
the relationship between primary
struc- tur
al material and LEED certification
will be possible. In the
meantime, struc-
tural steel remains a strong
option, w
hich can bring a variety of advantages
to environmental
design and a LEED
certification effort.
An integrated
design process that
thoughtfully considers the
implications
of the structural system on other
build- in
g systems, and its impact on the
envi- ron
mental design effort, will bring
value to
the project, the owner, the user and,
in a
broader sense, to the community.
RESOURC
ES
For further information please
see the
following resources



8. Utah Olympic Oval,
Modern Steel Con-



4. Webster, Mark D., The Use of
Salvaged struction July
2002.
www.aisc.org/sustainability

Structural Materials in New
Construction,
www.recycle-steel.org

International Green
Building Conference
www.usgbc.org

and
Expo, Austin, Texas, November 14,
www.greenterm.co
m
2002.



5. LEED Documentation of
Recycled Content