Let There Be Light
And then God said, "Let there be light," at which point man
replied, "How do we get light into these buildings without creating
leaks, thermal shorts and, above all, meet these confounding new
building codes?" Forgive the revisionist history, natural lighting
does save energy and can be achieved efficiently and economically
by incorporating "non-traditional" wall and roof lighting systems
into insulated metal wall and roof (IMP) panel assemblies.
Daylighting and Energy Savings
Sustainable design is transforming the way buildings are
constructed and operated to alleviate negative environmental
impact. Natural lighting systems, in conjunction with insulated
metal panels, allow design professionals to incorporate the latest
green technologies in building design. This can improve energy
efficiency and result in substantial savings on electric bills.
Daylighting reduces the amount of internal heat gains caused by
traditional electric lighting, as well as the amount of HVAC use
required to cool the added heat. Natural daylight also provides
occupant satisfaction and thermal comfort in which recent studies
have indicated increases productivity and health in workplaces.
These innovative green strategies can help new or existing
commercial buildings achieve LEED credits in several categories,
including Energy and Atmosphere, Indoor Environmental Quality and
Innovation in Design.
Furthermore, energy codes such as ASHRAE 90.1, the California
Energy Code Title 24 and the International Energy Conservation Code
(IECC) have begun to adopt standards to encourage the use of
daylighting practices in sustainable buildings. Integrating tubular
lighting systems and thermally efficient polycarbonate panels is an
important aspect in the design of net zero energy buildings.
Roofs and Skylights
Traditional approaches to skylights in metal roofs are either
nested matching corrugated reinforced plastic sheets, or domed
polycarbonate assemblies requiring curbs and steel reinforcement.
Corrugated skylights are inexpensive, but have always been
problematic due to safety issues, little to no thermal resistance
and limited product lifespan. Curbed skylights are not only costly,
but are notorious for leaking. Only double-domed skylights of this
variety provide some thermal resistance. Because IMP roof panels
are structurally superior to single-skin metal roof panels, they
are able to support Vista, Calif.- based Solatube International's
SolaMaster Series (or equal) tubular daylighting devices without
curbs or additional steel reinforcement.
Tubular skylight systems are cylindrical employing a "collar"
style gasketing that installs and seals easily and effectively.
They can be pattern located where needed to meet the specific
lighting (lumen) requirements, then installed either on the ground
or once the IMP roof panels are in place by cutting a rough opening
to the specified diameter. Available assemblies are designed for
open roofs or suspended ceilings, and light can be directed and
intensified through cleverly designed mechanical extensions.
Tubular skylights provide superior illuminating intensity, thermal
performance and light consistency compared with traditional
skylight assemblies described above.
For wall lites, again IMPs are a perfect complement for using
translucent polycarbonate honeycomb products like Lexan Thermoclick
provided by De Pere, Wis.-based AmeriLux International (or equal).
The honeycomb design provides excellent thermal performance,
structural strength and durability. Individual modules are
typically 120 inches high by 19.7 inches wide, and sit in gasketed,
lightweight, snap-together, extruded aluminum frames. They can be
installed individually or as a continuous strip, and can be cut to
fit on-site with a band saw, if necessary.
Set high on both eave walls, they allow for excellent natural
lighting in narrower width buildings. Used in combination with
tubular skylights in larger buildings, energy efficiency and
natural lighting is achieved without leaking or thermal shorts and
at a reasonable cost. Polycarbonate honeycomb wall lites are not
meant to replace windows and are not designed for mechanical
opening and closing.
William Lowery is president of Vacaville,
Calif.- based All Weather Insulated Panels for North America. To
learn more, visit www.awipanels.com.