Source: www.cnn.com
An eco-friendly building material might have saved
some of the 80 homes destroyed in a recent wildfire
in Southern California. But it can't be used there.
Rajesh Kanwar built his Alpine, California, house out
of AAC after his previous house burned down.
The masonry material, called autoclaved aerated concrete
or AAC, can withstand a 2,000-degree fire for four hours,
according to Underwriters Laboratories' test results.
"I just think the material's awesome. There's
nothing like it," said Doug Edwards, an architect
whose Edwards Design Group designs and builds green
homes in the Scottsdale, Arizona, area. "It's the
best building material in the world."
AAC is a mixture of sand, water, lime, portland cement
and aluminum powder that is formed into blocks and cured
in an autoclave, a sort of industrial pressure cooker.
It has been used in Europe, where it was invented, for
more than 70 years.
Besides being fire-resistant, AAC also deadens sound,
is energy efficient, is impervious to termites, is bulletproof
and waterproof, generates no waste in its creation,
and can be recycled, its fans say.
A sort of concrete bread, it's full of tiny air pockets,
making it one-fifth the weight of traditional concrete,
which means more can be transported with less use of
fuel. Workers can cut it and shape it with hand tools,
and its thermal qualities significantly lower energy
use, experts say.
Exton Quinn, an architect who fled her Santa Barbara,
California, home as wildfires approached in early May,
learned about the material at a green building seminar.
"It's a natural insulator, it's completely nontoxic,
it's just absolutely fabulous," she said. "And
with our homes going up here, we should be building
with this. ... The idea that we can't build with a fireproof
material, I think, is insane."
But in California, wildfires aren't the only concern.
Small earthquakes are part of daily life in many areas,
and stronger ones occur fairly frequently. And that's
the regulators' problem with AAC.
"Autoclaved aerated concrete cannot be used to
resist seismic forces because it has not been seismically
tested," said David Walls, executive director of
the California Building Standards Commission in Sacramento.
The restriction is based on guidelines from the National
Earthquake Hazards Reduction Program, he said.
The next International Building Code, slated to take
effect in 2011, will permit use of AAC in more places
that have minimal seismic activity, Walls said. But
even under those somewhat relaxed standards, most of
California would not qualify, he added.
Advocates for the product say California's qualms are
baseless -- and political.
"We've done all the testing, and the testing showed
the material works fine in any seismic area," said
Felipe Babbitt, a Mesa, Arizona, engineer who helped
develop code standards for AAC block. "It has not
been approved by California not because it can't perform,
but because they have not done a thorough review of
the testing data and are not convinced that it performs."
California's standards are no different from those
of other states, Walls insisted.
"We base ours off the national model code. For
the most part, for private buildings in California,
we do not add any extra stuff," he said. "So
it would be strictly based on what is the national standard."
That's not entirely true, Babbitt said.
California is the only state that adopted the 2006
International Building Code without the companion housing
code that includes acceptance of AAC in seismic areas,
he said. The two documents were meant to be applied
in tandem, he said.
"A lot of it's politics," Babbitt said. "Everybody's
protecting their own interests. You've got the wood
industry protecting theirs, you've got the steel protecting
theirs, and the AAC is just going up against all these
people."
The AAC industry hasn't been around long enough yet
to earn its place in the code, he said. Wood, on the
other hand, faces no challenge despite its obvious vulnerability
to wind, fire, flood, pests, mold and earthquakes, he
said.
"Each state has different code adoption laws and
processes," Walls responded by e-mail. "I
cannot explain what or why any other state makes their
choices. I can tell you that California has never adopted
a residential code."
Another architect isn't satisfied.
"What is baffling is this is a product that could
be enormously beneficial in California," said Michael
McDonough, a world-renowned New York architect who specializes
in sustainable industry. "The testing standards
they are rejecting are the testing standards that are
used in 49 other states, and they've been extant for
10 years.
"Therefore we believe it's reasonable to assume
there's some other agenda than the standards,"
he said. "This stuff has been tested within an
inch of its life."
Walls denies that politics played a role.
"I have been involved in the code adoption in
California for more that eight years and I am not aware
of any 'agenda' in California," he wrote in an
e-mail.
Mike Quaka, vice president-general manager of manufacturer
AERCON Florida in Haines City, Florida, defended his
company's product.
"From all of our independent testing, it meets
all the seismic zones, just as it does in Europe,"
he said. "I think there's a lot of external variables
floating out there when we talk about California and
AAC. ... We can build anywhere else without a hiccup."
Richard Klingner, an expert in earthquake-resistant
design at the University of Texas at Austin, conducted
what the industry considers the definitive tests of
AAC in 2000 and found it more than adequate to handle
seismic loading.
"In my opinion, testing done by me and others
has demonstrated that ductile shear walls of AAC can
safely be used anywhere in the U.S.," Klingner
said in an e-mail from Venezuela, where he was giving
a lecture on the seismic resistance of masonry. Ductile
shear walls are walls that flex slightly to resist lateral
force, the main cause of damage in earthquakes.
"I do not know why AAC has not had wider acceptance
in California," he wrote. "It may be a combination
of lack of familiarity, caution, and 'not invented here.'
That's too bad, because AAC offers many advantages."
A few houses made of AAC are scattered around California,
built before restrictions were put in place. One is
in Alpine, built by Rajesh Kanwar and Lori Ende after
their previous house burned down in the 2003 Cedar Fire,
which killed 13 people and destroyed more than 2,000
homes.
"When our home burned down, I looked into materials
that were less likely to burn down," said Kanwar,
who runs a small business.
"Before I went to the material, I did a substantial
amount of ground work to make sure I wasn't doing something
which was going to come back and bite me," he said.
"So when I looked into that, I didn't just look
into the fireproof aspect of it, I also looked into
the seismic aspect of it, because I was really concerned
about that.
"And from everything I learned ... it has done
very well under earthquake conditions."
AERCON's Quaka admits to being a little discouraged
by the long struggle for acceptance in California.
"You beat your head against a door so many times,
your head gets sore. And we're not there yet with California,
but our heads are pretty bloody." |