Building Lean and Green

by Gordy Slack

The expression "environmental footprint" does not begin to capture the full impact that a building and its occupants have over time. A building's cradle-to-grave influence on the environment is a shape-shifting and sprawling thing, with tentacles that extend far into the future and all around the world, says Arpad Horvath, Associate Professor in UC Berkeley's Department of Civil and Environmental Engineering and Director of the Consortium on Green Design and Manufacturing.

Professor Arpad Horvath leads efforts at UC Berkeley to develop practical tools that allow consumers and builders understand the impact of their choices.

To calculate that influence, Horvath and his colleague begin by looking at a building's direct impact on its site, its energy use, and its greenhouse emissions. But they also take into account aspects that most designers and builders do not sufficiently think about, he says. These issues include the source of the raw materials out of which the building is made, for instance, and the environmental cost of extracting and then transporting those materials-whether concrete, stone, carpeting, plumbing fixtures, or roofing. The researchers also study the impacts of remodeling and renovating the building over its decades of operation, and even the impact of demolishing the building and disposing of its parts once it is obsolete, many decades down the line.

As part of his efforts to put some teeth into the "sustainable" development movement, Horvath is developing practical tools that will help decision makers in the building business evaluate the real cost of the choices they make.

"Right now the emphasis is on greenhouse gasses and energy use," says Horvath. "Those things are important, but there are other things that do not get attention that may matter just as much." If the building is to be made of stone, for instance, and that stone is shipped from overseas where its extraction, albeit cheap in monetary terms, was environmentally costly, and if shipping that stone requires the burning of huge amounts of dirty diesel shipping fuel, those impacts might outweigh the perceived environmental benefit of making the building of stone in the first place. True, a building whose roof is covered with solar cells may use less fuel to power, but does the environmental cost of manufacturing the solar cells outweigh the energy savings over the building's lifetime? Maybe yes, and maybe no. Providing the tools to take a "scientific and data-driven approach" to determine what is the case for any given project is Horvath's aim.

To make such life-span calculations, he says, it is essential to know how long a building is likely to remain on the scene. "We tend to think of our new buildings as monuments," he says, "presuming, based on the old European model, that they will be around for centuries. But the buildings we are designing today are not likely to be around nearly that long. Most of them will be functionally obsolete in 50 years. We need to take that fact to heart when designing them in the first place."

Making versatile buildings that are not overbuilt and that have interior walls that are simple to reconfigure, for example, can reduce a structure's impact when it comes time for the inevitable remodeling and updating, says Horvath. The more adaptable a building is, the longer it may be productive and the less environmentally costly it will be to retool. Additionally, over-designing and over-constructing a building wastes materials. Twice: once in their acquisition, and once in their disposal when the building is torn down.

Perhaps the hardest part of Horvath's job, he notes, is figuring out what will matter to the environment decades from now. Fifty years ago, few people worried about global warming or greenhouse gas emissions. Architects in the early 20th century could not have imagined that heating fuel would cost what it does today or that the byproducts of our energy use patterns would catalyze climate change. Surely there are environmental impacts that are obscure to us today but in half a century will be plain as day, Horvath says.

"In our lab," Horvath says, "we are trying to put together tools that will allow people to figure out what the comprehensive life-long footprint of a building, or pavement, or transportation will be. Until they can do that, we cannot expect people to make the best long-term decisions."

The tools to make the right decisions are one thing. The will to do the right thing, even when it may be more costly in the short-term, poses another kind of challenge. Iris Tommelein, another professor in Berkeley's Department of Civil and Environmental Engineering, says this willingness to change is really a cultural issue, not a technological one. And the specific culture in question, that of the world of design, construction, and project management, is her area of expertise.

Professor Iris Tommelein works to help contractors and builders rethink the entire construction process.

Tommelein runs the Project Production Systems Lab (P2SL), which applies principles of "lean manufacturing" to one-of-a-kind projects. Lean manufacturing is an approach to production, developed over many decades by Toyota, that emphasizes value generation and the minimization of waste, both of materials and worker time.

"Reducing waste of all kinds shrinks a project's environmental footprint," says Tommelein, "even if the immediate incentive is really to save money and resources."

Many of the inefficiencies in building construction arise from the traditional relationships between owners, planners, designers, engineers, suppliers, regulatory agencies, and the dozens of different (sub)contractors on a job, according to Tommelein. Restructuring those relationships so that those in charge have strong incentives to get realistic project expectations, say, rather than just the lowest possible bids, is "very tricky business," she says.

"The whole system of blame assignment needs to be changed," says Tommelein. "We are trying to cultivate a culture that rewards realistic appraisals, cooperation, and truth telling."
One major factor is the current emphasis on individual projects at the expense of long-term relationships, Tommelein says. "We are trying to move from traditional transaction-oriented contracts toward relational contracting," she says. If a contractor's only aim is to win an individual contract, he may feel forced to underbid a project knowing full well that his overruns will be compensated when push comes to shove. But if forging a trusting, long-term relationship with the project owner is valued, then a realistic bid, even if it appears high, will eventually be rewarded.

Cooperation and coordination among sub-contractors minimizes the amount of reworking that needs to be done as well, says Tommelein. Rather than mapping a production schedule based on each sub-contractor trying to minimize his own exposure to liability, the lean approach stresses reality-based schedules that are reliable and keep the project flowing.

"We are very broad in our view of design and construction," says Tommelein. "We start with capital budgeting and making a business case for the owner early in the design process. We work with designers and engineers to design the facility and then with suppliers, manufacturers, fabricators, and contractors to build the facility. Throughout this process, we build in concern about lifecycle and sustainability issues."

By striving for what Toyota calls "mistake-proof design," an aspect of the Built-in Quality Initiative within P2SL, Tommelein notes that time and resources can be shaved off a job and safety performance improves. P2SL researchers design on-site operations, supervisory practices, and work with owners, designers, suppliers, fabricators, and regulatory agencies to systematically improve performance. A new building may have complex mechanical, electrical, and plumbing systems as well as wall partitions to be installed. If the parties responsible for this work coordinate their work through design and construction, the job overall can benefit significantly. "It is not uncommon," Tommelein says, "for contractors to save 20 or 30 percent of labor hours on a construction project by applying lean principles."

While Horvath aims to realistically appraise environmental impact and Tommelein strives to create an efficient process for project delivery, both researchers are trying to reduce waste by reevaluating the process from cradle to grave. "Iris (Tommelein) and I agree that without understanding the supply chain and all the steps that lead up to the making of a building, there is no understanding of the final building itself," says Horvath. "And unless you really understand a building and the processes of making it, there is no way to make it sustainable."