Lessening Environmental Impacts of Buildings
 Emerging trends to lessen environmental impacts and improve human
health are reshaping the design and construction industry. Sustainability,
energy efficiency, and indoor air quality issues affect all types of
construction and materials, whether for the commercial, institutional, or
residential sectors.
Assessment tools such as the Leadership in Energy
and Environmental Design (LEED)TM Green Building Rating System
attempt to reduce the overall impact of construction on the natural environment
while increasing benefits to human health and well being. LEED is a registered
trademark of the US Green Building Council. It is a credit-based system divided
among five environmental impact areas: Sustainable Sites; Water Efficiency;
Energy and Atmosphere; Materials and Resources; and Indoor Environmental
Quality. LEEDTM is a voluntary rating program intended to become the
currency of environmental value, yet it does not contain life cycle oriented
measures.
In 2002, the US National Institute of Standards &
Technology (NIST) commissioned an evaluation of the LEED rating system using
life-cycle assessment and concluded that 뱓he LEED rating system is not a
comprehensive methodology for assessment of environmental impacts and that LEED
needs to emphasize the integration of life-cycle oriented measures and
standards?/I>.
The LEED rating system aims to reduce the operating
energy in buildings and no consideration is yet given to embodied energy, which
is the amount of energy required to convert raw material into a finished
product. According to life-cycle assessment, when comparing three 50,000 square
foot office buildings constructed using wood, steel and concrete, respectively,
as the main structural materials, the wood building used the least energy. The
concrete option required 1.7 times the energy of wood. The steel option required
2.4 times the energy of wood.
If life-cycle assessment were to be taken
into account we would find that an insulated steel assembly requires far more
embodied energy than a wood assembly. An insulated steel assembly further
contributes to increased greenhouse gas emissions.
The LEED rating system
also contains credits intended to maximize water efficiency and to reduce the
burden on municipal water supply.
If the concept of water use reduction
was extended to promote the minimization of water pollution during the
manufacturing stage, the water toxicity index, based on life-cycle assessment,
when comparing the environmental effects of a 2,400 sq. ft. single family wood
house, sheet metal house, and concrete house is, for wood, 247% less than steel
metal and 114% less than concrete.
Water is a scarce resource in many
parts of the world and sustainability includes not only environmental impacts
but social impacts as well. Minimizing water pollution at the manufacturing
stage should be recognized in sustainable buildings.
Wood is the only
major building material that is renewable. It makes a principal contribution to
improving the overall environmental performance of any commercial,
institutional, or residential building by reducing energy use and environmental
impacts.
The LEED building rating system is a work in progress. It has
some good points but several aspects need to be addressed. The Canadian Wood
Council is a member of the US Green Building Council and together with the wood
industry we are working to ensure that wood and wood products are recognized as
environmentally responsible building
products.
|
Wood I-Joist Floors ?Part 2
 Construction and Design Considerations
While I-joists and
lumber each have their own advantages, account should be taken of differences in
installation practices.
Bearing Loads
Web stiffeners
and squash blocks [short lumber stubs] are often needed to help transfer
vertical loads through the I-joists. Manufacturers recommend that they be
1/16-in. longer than the I-joist depth to ensure the load is not applied
directly to the top of the joists. Lumber squash blocks are nailed to the
outside of the flanges at bearing points.
A web stiffener is lumber or
panel blocking nailed to the web of an I-joist to increase its strength
capacity, or to fill in the space between a hanger and the I-joist web. Web
stiffeners should be 1/8-in. shorter than the web height to prevent damaging the
joist during installation.
Along exterior walls, engineered lumber rim
joists also serve to transfer loads from upper stories and are sized slightly
deeper than the wood I-joists.
Lateral Stability
Some
I-joist manufacturers do not recommend use of conventional cross bridging partly
because they may not be applied effectively. They may have special alternate
recommendations. Altering the direction of the floor joists in different parts
of the floor plan can also provide additional lateral resistance for a floor
plate.
Hangers
Special hangers are needed for use with
wood I-joists. Web stiffeners may be needed so the joist ends do not twist in
the hangers, and to prevent splitting of the flanges. Conventional wood joist
hangers must not be used.
Holes
One advantage of the I
cross-section is that cutting holes through the web, according to manufacturers
recommendations, does not weaken the cross section significantly when their
location and size are chosen within permissible limits. This enables builders to
string pipes and ducts through the floor as needed.
A longer version of
this article is found in the Winter 2002 issue, Number 18 of Wood Design &
Building. For more information visit www.woodmags.com, click on the Wood Design & Building
logo, and then MagRack.
|
"Wood Design Awards" Book Series Receives Three Awards of
Excellence
 The Wood Design Awards 2002 Book, the first in a series of annual
Awards books, has received three awards of excellence for book design. Published
jointly by TUNS Press of Halifax, Nova Scotia and Janam Publications Inc. of
Gatineau, Quebec, it provides a complete and lasting record of the 15 winning
entries of the 2002 Wood Design Awards program.
The book received a
Citation Award from the Vancouver-based Alcuin Society for book design, placing
third in the Reference category. The U.S.-based ForeWord Magazine Book of the
Year Awards gave it a bronze award in the Architecture category. And lastly, it
received an award from Applied Arts Magazine, the premier visual arts magazine
in Canada, and will appear in that magazine뭩 January 2004 Design and Advertising
Annual.
밫he 2002 book is only the first in a series, so winning these
awards is a real vote of confidence as we produce future books,?says Awards book
editor and Awards program co-ordinator Don Griffith of Janam Publications
Inc.
The 2003 Awards Book maintains the standard and is now available.
For information, contact Don Griffith at 1-800-520-6281, ext. 304; or visit
the
The Wood Design Awards
2003.
| |
WoodWorks Software for Wood Design
WoodWorks USA Design Office 2004 will be released
within a few weeks. Current users should upgrade to ensure that they are
designing according to the latest wood engineering standard - the 2001 National
Design Specification (NDS) for Wood Construction. The software has been updated
to reflect changes made to the NDS, and new features have been added to all
three programs ?Sizer, Shearwalls, and Connections.
In particular, users
will appreciate the improvements made to the Shearwalls input/output. The
reports have been reorganized into distinct tables with borders and bolded
headings that are produced in Rich Text Format (RTF). New controls have also
been added to allow the user quick navigation from table to table throughout the
reports. The user can easily customize each report to reflect as much
information as he or she sees fit.
Other key features of the software
include the calculation of redundancy factor for seismic design; the calculation
of vertical earthquake load (Ev); and tear out check for connection
design.
A complete list of changes made to the Sizer, Shearwalls, and
Connections in the 2004 version of WoodWorks USA Design Office can be found at
WoodWorks US Design Office 2004
changes.
|
| |
 |
| |
 Did you know? The Canadian Wood Council features a span
calculator on their web site. It can be used to determine U.S. spans for
residential construction for major Canadian and U.S. lumber species, and is
fully in accord with the United States building codes and the Federal Housing
Administration (FHA) requirements. The calculator requires the user to input the
member type, species, size, grade, spacing, and loads, in order to determine the
maximum allowable span for floor joists, ceiling joists, rafters, and headers.
Click on 멝ore Info?to learn about the assumptions made for the application and
deflection limits of the calculated values. Currently, CWC is working to
increase the option for live load calculations for rafters to 100 PSF. If you
are working on a U.S. design, visit The US Span Calculator to calculate the maximum allowable
spans for your project! CWC is also currently developing a Canadian version of
the on-line span calculator. Look for more info in upcoming issues of the Wood
(IN)Site or visit the Canadian Wood
Council to order your English or French copy of The Span
Book.
| | 
| |
QuietZone?Framing
Sound is a vibration disturbance causing pressure
variations in the atmosphere. Sound waves are invisible, and form waves of sound
pressure much like those created when a stone is dropped into a pool of water.
Unfortunately, what is music to one is noise to another, and sound itself can
become noise pollution causing stress and negative health effects. Indoors,
these sound waves cause walls to vibrate, conduct, and radiate all types of
noise.
In addition to double wall or staggered stud construction, there뭩
a new option for those looking to improve the acoustical performance of their
wall framing. As an integral part of the Owens Corning QuietZone?Noise Control
System, QuietZone?Framing is designed to allow one side of the wall to float,
breaking the path of sound vibrations traveling through the wall. The sound
reaching the opposite side of the wall is greatly reduced, providing a quieter
more comfortable living space.
QuietZone?Framing (an Owens Corning
invention) is quality manufactured by Tembec and distributed by Jager Building
Systems. It is designed to replace conventional framing in noise control
applications. Each QuietZone?framing piece combines a section of
SELECTEMTM Laminated Veneer Lumber with TEMBEC SELECT Engineered
Lumber connected by several acoustically resilient metal clips. These built in
clips create a break in the sound vibration path allowing the drywall on the
inside of the room to float and isolate sound waves from the rest of the home or
structure.
QuietZone?Framing is installed and finished using the same
general principles as applied to conventional wood framing. The framing system
should be used in interior walls only and is available in 2x4 and 2x6 dimensions
pre-cut to standard lengths. A 2x4 QuietZone?Framing has load carrying
capabilities similar to No.2 SPF 2x3, and a 2x6 QuietZone?Framing system has
load carrying capabilities similar to No.2 SPF 2x4 lumber.
QuietZone?Framing is complemented by acoustic batting that absorbs sound
vibrations within the wall cavity; acoustic sealant that blocks the passage of
sound vibrations through gaps and openings; and an acoustic floor mat that
isolates sound at the point of impact. This complete QuietZone?Noise Control
System can deliver Sound Transmission Class (STC) ratings of STC 50 to STC 65
depending upon framing size.
For more information on product
installation and load carrying capabilities please contact Jager Building
Systems in Ontario and Atlantic Canada at 905-951-7477, in Western Canada at
403-259-0714, in Quebec at 450-430-1881, and all US inquiries at 301-233-1280,
or visit QuietZone?Framing.
| | 
| |
Visit the Canadian Wood Council IBS 2004
 The Canadian Wood
Council invites you to visit its staff at Booth # N933 ?North Hall, at the
National Association of Home Builders (NAHB) International Builders?Show IBS, the largest annual
home building industry trade show in the world. The 2004 Show, taking place
January 19-22 at the Las Vegas Convention Center in Las Vegas, NV is expected to
draw over 90,000 attendees from over 95 countries to see the latest in building
products and technologies.
CWC staff and representatives from its member
organizations will be on hand at the 900 sq. ft. booth to showcase new products
and learn what you, the design professionals, want and need from our wood
products. CWC will also be giving away US Span Books (while quantities last).
This handy pocket book provides a convenient reference for spans for common
species of Canadian and US dimension lumber, fully in accord with United States
building codes and Federal Housing Administration (FHA) requirements. Do you
have your own copy yet? If not, now뭩 your chance! And, don뭪 miss out on the
most talked about Builders Show of the year.
For more information on CWC뭩
participation in the 2004 IBS, please contact Rhonda Backmann, CWC뭩 Member
Communications Coordinator, at 1-800-463-5091, ext. 243 or via email rabackmann@cwc.ca.
| | 
| |
Construct Canada 2003
 Metro
Toronto Convention Centre
December 3-5, 2003
Toronto, ON, Canada
For
more information visit www.constructcanada.com
|
Houston Wood Solutions Fair
 Humble Civic Center
December 9, 2003
Houston, TX
For more
information visit www.woodsolutionsfair.com
|
NAHB International Builders?Show
Las
Vegas Convention Center
January 19-22, 2004
Las Vegas, NV
For more
information visit www.buildersshow.com
|
48th Annual CSI Show & Convention
McCormick Place
April
21-23, 2004
Chicago, IL
For more information visit www.thecsishow.com
|
The AIA Show (American Institute of Architects)
McCormick
Place
June 10-12, 2004
Chicago, IL
For more information visit www.aia.org
|
2004 Wood Solutions Fairs
Spring 2004 ?Vancouver (BC),
Seattle (WA) and Philadelphia (PA)
Fall 2004 ?Toronto (ON), Phoenix
(AZ) and Nashville (TN)
For more information visit www.woodsolutionsfair.com
| |
|
