Photovoltaic Systems

Scottsdale, Arizona is one of a growing number of American cities that have inserted LEED into their building code.  Scottsdale set the bar quite high with a LEED Gold requirement, but that wasn’t going to limit these architects.  When father-and-son architects Lawrence and Lance Enyart of LEA Architects were chosen in 2005 to design the 14,350 square-foot firehouse, they decided to shoot for LEED Platinum.  Lance Enyart said, “Gold was the mandate, but for us it wasn’t about points that we could achieve, it was about implementing strategies that were project appropriate.“  

You’ll be interested to know that LEA Architects met its LEED Platinum goal, and the building, according to Fire Chief, is the first LEED Platinum fire station in the world.  Some of its green features include the following:

• 5 kW photovoltaic array on the roof that provides 9% of total energy;
• Solar hot water that meets 95% of the domestic hot water demand; 
• Operable windows for added indoor environmental quality;
• Majority of occupiable space located along the perimeter of the building to take advantage of natural lighting;
• Arizona sandstone brick sourced only one hundred and fifty miles from the site;
• Interior block masonry only fifteen miles from the site   
• Interior block masonry used as thermal mass to capture cooling and heating loads;
• 100% of the irrigation sourced from shower and sink graywater; 
• Low flow fixtures, waterless urinals, and dual flush toilets throughout;
• Water harvesting pipes that double as shading devices as part of exterior trellis; and
• A design intended to use 40% less energy than a code-compliant firehouse.

When I spoke with architects Lawrence and Lance, they described the unique nature of designing a LEED Platinum firehouse.  Lawrence Enyart said, “a fire station is different than other building, it’s not an eight-hour-a-day office.  A fire station is used 24 hours a day, which is almost double what a normal building would use in energy.“ 

Block masonry is favored over drywall because firefighters carry metal equipment while running which would destroy a conventional gypsum wall assembly.  The block interior walls also lower heating and cooling loads by absorbing energy and radiating it out when the air handlers are off.  The air conditioning system has a “governor” on it because firefighters have to wear layers of hot, protective gear, even in the summer and can be tempted to turn the air conditioning to the highest possible setting.  Hot air is allowed to escape through a cooling tower, which also doubles as a climbing tower for firefighter training.

Lawrence Enyart has a long history of working in solar design.  The energy crunch of the 1970′s left a big impression on him.  He is one of the first degree holders out of Arizona State University in Solar Architecture and graduated the same day that his son, Lance, was born.  While Lance received his training from the University of Arizona, the two have been able to collaborate despite school rivalries. 

Photo credits: LEA Architects.

The photograph above may not be what you would expect.  The outdoor bench in this detail is not made from an unsustainably harvested tropical hardwood.  The wood itself is actually maple, a widely available species that can be farmed and harvested without ripping up acres of rainforest.  But maple and many other similar woods are too susceptible to decay and rot when used unprotected outdoors.  The usual alternative has been treatment with chemical pressure treatment.  Now, through a method called kebonization, a Norwegian company, Kebony ASA, treats soft woods in a non-toxic process that allows readily available woods to be used for outdoor uses.

The process of kebonization is similar to pressure treating wood (which
is another way to make soft woods usable for exterior use). But,
instead of soaking the wood in toxic chemicals like chromated copper
arsenate (CCA, which is now banned for most uses in the US and the EU) or alkaline copper quaternary compounds (ACQ, the most widely used replacement for CCA after the ban), it is instead soaked in furfuryl alcohol,
a waste byproduct from sugar cane. There are no special handling
requirements or precautions needed to deal with waste from this wood,
and it can be disposed of just like any other untreated wood.

During the kebonization process, the alcohol becomes a resin that reinforces the cells of the wood. The result is a wood with excellent outdoor exposure tolerance like teak or mahogany, but with a harder surface than many of the tropical woods that it replaces. The wood also naturally fades to a silvery-grey color much like those tropical woods, as well. Maple is used in place of teak, and southern yellow pine is used in place of ipe.

Kebony wood can also be used for building siding. In fact, it is so water and weather resistant that it is even been used for building roofs and for boat decking (see below). The process also makes the wood less prone to swelling due to moisture. There is no necessity to paint Kebony wood, and it can withstand decades of exposure to the weather before any maintenance is necessary. According to the company, a kebony wood roof can last for 30 years before any maintenance is required.

Kebony wood is probably not going to do much for you in terms of obtaining LEED credits.  The material is imported from Europe.  There is no indication on the company’s website of the material being FSC certified wood, either.  Still, it is a natural wood product.  More importantly, it is a wood product that is durable without having toxic additives.  And it is obtained without clearcutting tropical rainforests.

Even more pictures are available on the Kebony website.

Photo credits: Kebony ASA.

The new science and library building at Crossroads College Preparatory School, located in the city of St. Louis, is seeking LEED Platinum certification.  If obtained, it will be the first K-12 school in St. Louis to earn certification.  Head of School Billy Handmaker* was committed to achieving the highest level of certification possible, while still spending within the budget and ending up with a good looking building.  He said, “from the beginning, we said ‘we want Platinum, but won’t compromise.”

The renovated sections are great examples of building reuse.  The site was a skating rink during the 1904 World’s Fair and a grocery store after that.  Reusable elements, such as the original Terrazzo floor from the grocery store, were kept in place.  Some of the other green features include:

• Dimmable skylights that run low when there’s abundant natural light;
• 94% of construction waste was recycled;
• Light tubes with diffusers that provide natural light in hallways;
• “Borrow Lights” that cast natural light into the hallways;
• Adjustable thermostats that vary only 2 degrees up or down;
• CO2 sensors in each classroom;
• No-VOC paints and FSC certified woods;
• Solar hot water heaters on the roof to supply hot water to labs;
• Landscaping with indigenous Missouri plants;
• High performance windows and exterior shading;
• Low-flow faucets and urinals and a rain garden;
• Organic produce grown by AP earth science students that is served in school’s cafeteria; and
• Classroom white boards made of recycled glass on white painted walls.

Students were encouraged to contribute to the design process.  Hanna Norwood, now a freshman at the University of Chicago, was brought in as a design liaison her junior year of high school: “They showed us things like furniture and said ‘what is going to work for you?’”  And the students contributed feedback to influence the final design. 

As one might expect, integrating LEED into a school can bring unforeseen surprises.  Most notably, the new chemistry lab has a wall of tall, south-facing windows that shower natural light into the classroom.  As it goes, the emergency eye-wash station, which is standard in any chemistry lab, has a bright orange shower-head that birds see through the windows and mistake for a giant flower.  Billy Handmaker said they’re going to install bird feeders to help with the problem. 

Below is a photo of the chemistry lab under construction with the orange shower-head on the left.

*Full disclosure: Billy Handmaker was a teacher at this author’s high school before taking the position at Crossroads.

Photos Courtesy of Crossroads College Preparatory School.