Photovoltaic Systems

Archive for the ‘Materials’ Category

London and Dallas-based Accsys Technologies recently announced a new variant of the modified wood product Accoya, but this one is made with North American red alder.  The company puts wood through a proprietary acetylation process in whichwood molecules that want to bond with water are replaced with more stable acetyl groups.  This improves durability, hardness, water absorption, and dimensional stability.

Through now, Accsys has only used radiata pine but red alder option expands the company’s offerings through distributors in North America, Europe, Asia, and elsewhere.  Accoya Alder is sourced from PEFC- and FSC-certified forests and carries the badge of Cradle to Cradle Gold certification.

Accoya Alder can be used on exterior applications such as screens, outdoor furniture, windows, doors, etc.  It has a 50-year above ground and 25-year below-ground warranty against rot and decay.  The modified alder features an 80% improvement in dimensional stability and a 30% higher Janka hardness as compared to standard red alder, according to Accsys Technologies.

[+] More information about Accoya with North American Red Alder.

Credits: Accsys Technologies.

Related Articles on JetsonGreen.com:

1. Accoya Offers Durable Non-Toxic Wood
2. USGBC Pilots Wood Certification Options
3. Botanist Unveils New All Wood Bench

It seems like manufacturers are turning to third parties to validate environmental claims with increasing frequency lately.  For example, I just learned that DuPont expanded their Corian Terra line of solid surfaces and five colors have at least 20% pre-consumer recycled resin content, according to Scientific Certification Systems.  Several other colors have at least 13% and the rest have a minimum of 6% pre-consumer recycled resin content.  In addition, all colors are GREENGUARD certified; they’re non-porous and do not promote the growth of mold, mildew, or bacteria, according to DuPont.

[+] More about the Corian Terra collection by DuPont.

Credits: DuPont. 

Related Articles on JetsonGreen.com:

1. Smith & Fong Expands Line at Greenbuild
2. Elegant, Recycled, Solid Surface: Glass2
3. LEED Platinum Condos at Primera Terra

Wood is a desirable construction material for many reasons including its low embodied energy. But, until recently, it has not been possible to build tall wooden structures because of the relative weakness of conventional wood stud construction methods. This is starting to change as a new method of fabricating wood panels, called cross-laminated timber, or CLT, is making “massive wood” construction a possibility for mid-rise construction, as well as for other construction uses.

As a building material, cross-laminated timber (CLT) is a rather new development. The first work with CLT was done in Switzerland and Austria in the early to mid 1990s.

Because the panels are lighter than masonry and hollow-core concrete plank, and since the panels can be lifted with lighter equipment, construction can be faster and thereby less expensive. It also requires a smaller crew to install and connect the panels at the job site, which allows for rapid and efficient construction.

In one example, a 9-story building saved an estimated 22 weeks of construction time by using CLT instead of concrete. The panels are prefabricated in a shop, so the benefit of controlled conditions is present, as with structural-insulated panels (SIP) and other pre-fab materials.

CLT is used for both walls and floors. The panels are made as alternating boards are laid perpendicular to one another (the same thing is done with plywood) for greater strength. Since the CLT panels are predominantly solid wood, there is far less glue in them than an equivalent volume of plywood. CLT panels have been tested for VOC off gassing from the glues, and are far below regulatory limits in that regard.

Since they are prefabricated, CLT panels can be installed with tighter tolerances and provide more plumb and true construction. Solid wood is not a great insulator, but wood is better than CMU or steel, and the building can still be insulated on the exterior or interior.

Using a massive wood structure — from a carbon cycle perspective — not only produces far lower emissions during the manufacture of the material, but the wood also sequesters carbon for its lifespan.

Although one might think it would be a fire hazard, massive wood construction is actually fairly fire resistant. For decades, building codes have recognized this for buildings constructed with large solid-sawn post and beam construction. Wood will char on the surface, but it takes a very long time for it to burn through. CLT is the same.

At present, the only manufacturers of CLT panels are in Europe, but two plants in Canada and one in the United States are currently under construction. There are a number of examples of mid-rise apartment buildings constructed with CLT in Europe. The first North American non-residential CLT structure was a bell tower completed in 2010 in North Carolina.

[Ed. Note: In my backyard, the University of Utah's Integrated Technology in Architecture Center is working on an ICLT -- interlocking cross laminated timber -- system with no fasteners or adhesives. It's in development and testing with a 3-5 horizon for commercial availability. -- Preston]

Disclosure: Some information for this article and the sample of CLT wood for some illustrations were included in an Architect’s Toolkit box of promotional materials I received from the BC Forestry Innovation Investment/NaturallyWood.com.

[+] Read more about CLT and Cross Laminated Timber, the book [PDF].

Credit: Forestry Innovation Investment Ltd. and the author.

Related Articles on JetsonGreen.com:

1. Kirei Debuts New Reclaimed Wood Panel
2. Viridian Intros Reclaimed Wood Veneers
3. Accoya Offers Durable Non-Toxic Wood

Oregon-based Viridian Wood Products, maker of shipping pallet flooring, recently introduced a line of new architectural-grade veneer panels made with reclaimed North American wood.  The 4′x8′ panels include old-growth redwood previously used in wine tanks, Oregon black walnut reclaimed from urban salvage, and old-growth Douglas fir from warehouse deconstruction.

Viridian produces the panels in Portland with urea formaldehyde-free, FSC-certified MDF in a variety of thicknesses.

The new veneer panels can be used for casework, cabinetry, wall panels, and the like and may contribute toward LEED credits for materials reuse, recycled content, regional materials, and certified wood.  Viridian can provide a price quote.

[+] More info about Viridian veneer panels.

Credits: Viridian Wood Products.

Related Articles on JetsonGreen.com:

1. Kirei Debuts New Reclaimed Wood Panel
2. New FSC Floor Made with Old Pallets
3. FSC Reclaimed Teak by IndoTeak Design