Construction Informer

If you haven’t heard of "pozzolans," then you are missing out on a concrete idea that can make projects greener.  Thousands of years ago the Greeks and Romans built structures that are still standing today by incorporating pozzolans into the mix. Literally into the mix.

The Romans used lime and a fine volcanic ash (pozzolana) to create cement that would harden underwater. These builders also figured out that by using stepped rings of concrete where each had a lower density than the one below they could then create large domes like the one at the Pantheon. That one is about 142 feet in diameter.

During the last century in the U.S. pozzolans were incorporated into the Hoover Dam, the Los Angeles aqueduct, the San Francisco-Oakland Bay Bridge and the Hungry Horse Dam in Montana, just to name a few. This cement also showed up in the tunnel between the UK and France, in France’s Puylaurent Dam and in the Commerzbank Tower in Frankfurt, Germany.

Today, everyone is getting on the pozzolans bandwagon but not everyone has natural ones like volcanic ash, pumice, tuff, diatomaceous earth, and opaline shale just lying around. So, people are now using the waste products that are generated when coal is burned while making electricity. It’s typically called fly ash.

They are also using rice husk, brick dust, calcined kaolin, condensed silica fume and waste from blast furnaces. These are all defined as fine-grained materials that react with lime resulting in cement. The result is that you can use less Portland cement. Depending upon the pozzolans that reduction can range from 15 to 60 percent. When you consider that the embodied energy of concrete is estimated to be 3 kWh per pound, and 90 percent of that is in the making of Portland cement, you can see how reducing the amount of Portland used can be a green thing.

There are also the added advantages of the concrete being lighter, more plastic and easier to work, and that it requires less water resulting in lower bleeding and lower heating.

Suppose you want to explore using pozzolans in the next or current project. Here’s a resource to get you started.

As the drumbeat of “green” continues at a frenetic pace, and businesses all over the globe contemplate ways to make money on green, I thought it might be worthwhile to look at simple ways construction companies can do green things without the appearance that they are just riding the wave to better profits. Simply promoting and using green products is only part of the process.

So, here are ways to be green for real if you are in construction. 

• Find ways to decrease the waste generated at your construction sites;
• Find alternative uses and recycling opportunities for the waste generated at your job sites;
• Adopt processes that reduce your reliance on gasoline and diesel fuel;
• Look for and adopt all the ways you can to eliminate printing things on paper;
• Stop traveling and commuting when web conferencing, conference calls, telecommuting and other forms of remote communication are really all that’s necessary;
• Set up policies, or install electrical and mechanical devices, that prevent energy from being used when it isn’t needed;
• Ask your employees, partners, clients and suppliers how they think you can operate in a more energy efficient fashion, and then take those suggestions to heart.

There is something more though to consider. Words and actions that aren’t heartfelt, (that don’t spring from a place inside you that makes them meaningful), can be seen by others as insincere. It seems it would be far better to say you don’t buy into all the green rhetoric and then just don’t participate, than it is to say you do but then only participate when it is profitable. If you really “feel” green then let it show. If you don’t then why not use other ways to improve your bottom line.

Looking back we can see the dawn of the awakening to green, and at that time it was just about energy. In the aftermath of the very first energy crises in 1973 the U.S., and the world, had its first wake-up call. There was a flurry of activity aimed at fixing the problem and they all focused on government and business efforts. Today, we see those earlier efforts by those entities changed very little the ways people create, acquire and use energy. Some may question when we will finally realize this is about individuals and the choices that individuals make. When individuals in business and government act from a heartfelt place of green then their actions will begin to have the most positive long term effects.

There are about 304 million people in the U.S. today, and a little more than 6.5 billion people in the world. A tree planted for every one of them this year might have an interestingly nice effect for all earthly inhabitants.

The rush to green is already carrying with it the seeds of its destruction – green claims that don’t stand up under close scrutiny. For those in the construction industry there is a lot at stake.

When we build things we usually do it with the intention that they last a long time. All of the components taken together in a building make up the whole but if one, or a few of them don’t stand up to their claims of environmental friendliness, health and safety then the entire building is compromised. How can you certify the healthiness of a component that was only created a few years ago when it is expected to perform for many years? Where do you get the long-term data to back up its claims?

There is also the concept that you have to take into account the life cycle of a material when evaluating its greenness. Generally referred to as a life cycle assessment (LCA), and more technically as a life cycle inventory assessment (LCIA), it is an attempt to place a value on the environmental impact of a material. Is a petrochemical-based product really green just because it reduces a building’s energy use? What about the energy used to produce it, the toxins given off, and what about the environmental costs of disposing of it when its life is done?

But even the techniques used, and especially assumptions that are made when doing an LCA can be called into question. As one expert in sustainability, Arnold Tukker wrote to the Society of Environmental Toxicology and Chemistry (SETAC), a nonprofit professional society, regarding the SETAC’s efforts relating to an assessment model for chlorine, PVC and hazardous waste management:

Personally, I believe it will never be possible to solve controversial discussions about products with an LCIA method that is based solely on mathematical relations between interventions and protection areas. There are simply too many uncertainties, there is too much ignorance, and they can only be overcome by all kinds of subjective, subtle, and basically value-laden choices.

Someone could argue that lumber is not a green choice for building because its harvest aborts an element of CO2 absorption, removes habitat for other life, increases soil erosion, requires the burning of oil products in its harvest and milling, and finally doesn’t offer the benefits to the soil of its decay when its useful life is over because it is most often discarded in a landfill, or burned (in which case it adds CO2 to the atmosphere).

In years to come we will be hearing more and more about building materials that were once called green but didn’t stand the test of time. As smart as we are, we still don’t have the crystal ball and we still can’t truly predict the long-term effects of our actions. The best we can do is make informed judgements and not only recognize we don’t have all the answers, but be willing to admit it as well.

Makers of materials and products might consider toning down their green claims before people start finding out they are really only a little bit green.

There is some legislation that has been signed into law that authorizes two billion dollars a year, over five years, in grants for communities to undertake energy efficiency and conservation efforts for things like:

• Public buildings;
• Transportation; and
• Use of renewable energy.

The funding however has not been released for these efforts so the National League of Cities brought four hundred signatures to Congress urging the release of the funds. Called the Energy Efficiency and Conservation Block Grant program it is said to stimulate efforts by communities to address factors affecting energy dependence and climate change. The proponents claim its funding will promote new jobs, reduce waste and support new technologies.

One of the purposes also allowed by the act is the development and implementation of building codes and inspection services that promote building energy efficiency.

In a previous post here I wrote of the struggle between Michigan builders and the state government over the state’s desire to mandate green building practices. Other states and other builder groups have also been engaged in this issue. The National Association of Homebuilders previously has come out against mandated green building practices saying:

NAHB discourages efforts to dictate and legislate what constitutes acceptable green building practices because the building science in this area is still evolving. We don’t want to see this dynamic process frozen in place.

It appears that this legislation on the one hand offers building opportunities but on the other it opens the door for federally funded efforts by states and municipalities to mandate green building practices. Just how states and municipalities interpret this remains to be seen but when viewed within the broader context of the Energy Independence and Security Act of 2007, in which it is contained, we could start seeing “green” entering the building codes to further extents.

The National Institute of Standards and Technology (NIST) just finished a study showing that residential fire sprinklers added to homes during initial construction makes economic sense. The agency placed the cost of a "wet pipe" sprinkler system at between $ .62 and $ .83 per square foot in three different types and sizes of homes. Interestingly a townhouse of 2,257 square feet had the highest cost of installation. The economists at NIST figured the net gain from sprinkler installation in 2005 dollars was between $704 and $6,048 over 30 years. The largest gain was for a ranch home of 1,171 square feet.

In other news…

It’s often given me a brain cramp trying to figure out why mobile homes, built in a controlled, factory environment, haven’t been more energy efficient. Sure, it’s supposed to be cheap housing but shouldn’t the cheapness of it be figured over the lifetime of the house? I would suspect that for many mobile homes if you added up the costs of just heating and cooling them you’d quickly surpass any savings derived from building them cheaply.

Now, Mississippi State University Professor Michael Berk has come up with a "Green Mobile." He has used "sound construction methods, as well as energy-saving concepts for lower utility costs." The units have photovoltaic options and the interior design makes better use of natural day-lighting and ventilation. But here’s the really neat thing. They are better built, will cost in the $50k range and are more affordable (lower monthly payments) than traditional single-wides.

A lot of people pop their heads in the sand when it comes to recognizing that affordable housing is the next building boom. When you consider a rapidly growing and aging population, and a growing immigrant population that wants out of apartments and it’s hard to miss the handwriting on the wall. In both cases though affordability is a key attribute. Affordability has to also be extended to the total cost of ownership of the shelter. So beyond energy efficiency another concept to incorporate would be the practice of building with materials that are maintenance-free.

It seems there may be some opportunities here for some creative thinkers and doers.