Weatherization systems can benefit both builders and occupants:
Weatherization systems help seal the building envelope and improve energy efficiency
Kerry Shea,
Posted
12/01/2009
Attention
all developers, architects and contractors-remember to consider the
associated energy costs of your work when designing and building
commercial structures. Using weatherization products
collectively during construction can seal the building envelope in
a way that helps reduce air leakage and holds out bulk water, while
still allowing moisture trapped in walls to escape. This helps
prevent the accumulation of water which may lead to the formation
of mold and mildew, thus contributing to safer, more
energy-efficient structures.
There is also, potentially, a major economic advantage to the
building owner with sealing the building envelope with DuPont
Weatherization Systems. DuPont Tyvek weather barriers help to
contribute to an improved life cycle of a building, as well as
improved efficiency of the structure's highest energy use systems.
This all translates to lower operating and maintenance costs-a
powerful incentive for owners and potential buyers.
But what about green building and sustainable design? DuPont Tyvek
weather barriers in commercial building design can also help
contribute toward points for the U.S. Green Building Council's LEED
certification.
Increase Energy Efficiency
The energy consumed during building operations accounts for the
major share of energy consumption over the life of a building-
making energy efficiency one of the most critical components in
reducing the overall environmental impact of commercial spaces. By
reducing the unwanted escape of air from the building envelope,
products like the DuPont Weatherization System can positively
impact energy efficiency in three key ways:
Contribute to ventilation effectiveness: Air
leakage can have a significant impact on the effectiveness of HVAC
systems. By increasing the air tightness of the building envelope,
DuPont Weatherization System products can help increase energy
efficiency in one of the structure's highest energy demand
systems.
Protect
against exterior wall insulation's loss of R-value due to wind
washing: Properly installed DuPont Weatherization System
products create an air barrier system that reduces unwanted air
flow and helps maintain the installed R-value of insulation.
Protect against exterior wall insulation's loss of R-value
due to environmental wetting of the insulation: Wet
insulation dramatically reduces the effectiveness of the
insulation, regardless of its thickness. DuPont Weatherization
System products help protect structures against bulk water
intrusion and air transported moisture, two factors that not only
lead to wet insulation,but also ultimately lead to wood damage or
steel corrosion if water accumulates in the wall system.
Energy & Atmosphere (EA)
Using DuPont as an example, here is how Weatherization Systems
contribute to EA sustainable design in commercial structures
(LEED-NC Rating System):
EA Prerequisite 2:
Minimum Energy Performance
DuPont Weatherization Systems can contribute toward building
envelope sealing and help meet ASHRAE 90.1, 2007 requirements in
Section 5.4. Builders and architects can verify by specifying
DuPont Tyvek weather barriers and clearly identifying the air
barrier on the architectural drawing.
EA Credit 1:
Optimize Energy Performance (1-10
points)
Keeping drafts and wind out of wall cavities(dynamic air-flow) is a
requisite for maintaining the design thermal performance for
greater comfort and reduced energy consumption. When installed per
DuPont Installation Guidelines, DuPont Weatherization Systems can
help to achieve an airtight building envelope which contributes
towards reducing HVAC energy use.
Improve Indoor Air Quality
DuPont Weatherization System products can help improve indoor air
quality by reducing uncontrolled air leakage which helps the HVAC
system to maintain comfortable temperatures and their operational
designed air-flows. They also contribute by preventing bulk water
intrusion and accumulation in the wall systems, which can lead to
the formation of mold and mildew.
By installing DuPont Tyvek weather barriers at the start of
construction, building materials are protected from water
penetration and saturation when exposed to the elements, which can
lead to the formation of mold and mildew. DuPont Tyvek
CommercialWrap and DuPont Tyve Commercial Wrap D are specifically
designed to withstand the more rigorous construction site
conditions of commercial buildings. The are heavier and more
durable with higher air and water resistance than other building
wraps DuPont Tyvek CommercialWrap D is specially engineered to
provide additional drainage behind facades such as metal
panels.
Indoor
Environmental Quality (EQ)
Here is how it contributes to EQ sustainable design for commercial
structures (LEED-NC Rating System):
EQ Prerequisite 1:
Minimum IAQ Performance Requirements
When installed per DuPont Installation Guidelines, DuPont
Weatherization Systems can help achieve an airtight building
envelope to meet requirements of Sections 4 through 7 of ASHRAE
62.2, 2007: Build Tight, Ventilate Right. Builders and architects
can verify by specifying DuPont Tyvek weather barriers and clearly
identifying the air barrier on the architectural drawing.
EQ Credit 3.1:
Construction IAQ Management Plan (1
Point)
DuPont Tyvek Weather Barriers protect installed absorptive
materials (e.g. exterior sheathing,insulation, etc.) from moisture
damage during the construction phase, while allowing drying of
incidental moisture. Builders and architects can verify by
specifying DuPont Weatherization Systems and include
construction-related IAQ procedures in the pre-construction and
construction progress meeting agenda.
EQ Credit 4.1:
Low Emitting Materials (1 Point)
DuPont sealants used with DuPont Weatherization Systems meet SCAQMD
rule #1168 on VOC limits. Builders and architects can verify by
ensuring that VOC limits are clearly state in each section of the
specifications where adhesives and sealants are addressed.
Increase Durability of the Building Envelope
DuPont Weatherization System products, among others, can deliver a
unique balance of air and water holdout, combined with superior
vapor permeability, to help contribute to better moisture
management within the wall system. By helping to prevent bulk
moisture from entering wall systems and allowing moisture vapor to
escape, weatherization products help keep walls drier. Dry walls
can help extend the life of the structure by reducing the risk of
water damage or corrosion to structural materials.
Kerry Shea is the wall systems marketing manager
at DuPont, Wilmington, Del. For more information about DuPont,
visit www.construction.tyvek.com.
www.construction.tyvek.com