Post-Modern Engineering

For the past four decades, commercial buildings have been constructed with little or no sensitivity to their environment. And, to a certain extent, engineers have been the enablers of this phenomenon, because modern architecture's dysfunctions are facilitated by the lighting and HVAC systems that engineers design.

10/01/2002


For the past four decades, commercial buildings have been constructed with little or no sensitivity to their environment. And, to a certain extent, engineers have been the enablers of this phenomenon, because modern architecture's dysfunctions are facilitated by the lighting and HVAC systems that engineers design. It's high time for a new paradigm—post-modern engineering.The Portland Building helped set off the explosion of post-modern architecture. But the building would be better served if the philosophy was carried through on the M/E/P side

What is Post-Modernism?

Post-Modernism, according to the Sourcebook of Contemporary North American Architecture, defines itself in contrast to Modernism. Originally, the term comes from architecture, where modern architecture denotes the familiar glass, steel and concrete buildings with their straight, rectangular, geometric shapes. This led to a reaction in the 1960s by younger architects, who included different decorative elements inspired by earlier periods in their design. This eclectic mixture of styles was called "Post-Modern architecture."

One of the notable early Post-Modern architectural designs appeared here in the Northwest. In the early 1980s architect Michael Graves won a major design competition for a new City of Portland office building, which he designed in true "Post-Modern" style. The Portland Building (above, right) helped set off the explosion of Post-Modernism, which reintroduced color and historical motifs into steel-and-glass world of Modern architecture.

While a stylistic success, the building has been roundly reviled for its poor daylighting and atrocious working conditions inside, highlighted by jailhouse-sized windows. Additionally, the building lacks flexibility to handle an ever changing workforce. In fact, the city has spent at least $8.5 million over three years to remodel the building and move more employees into it—about one-third of what it cost to construct the building two decades ago.

That being said, the heart of the Post-Modern movement, which was really about setting a new stage in the history of ideas, is the most important notion from an M/E/P engineering perspective. Modern buildings have traditionally consumed enormous amounts of imported energy, typically in the form of electricity. Buildings were built—and are still being built—without reference to the location of the sun, wind direction and water resources, and to the use of local materials. Sites for new buildings are chosen and buildings laid out according to geometric "urban design," rather than more natural "ecological design" criteria.

Take a residential development in Tucson, Ariz., as a case study: The grid of the neighborhood has most streets running north-south so that all homes have a major set of windows facing the western sun, guaranteeing that the rooms will be uninhabitable most afternoons of the year—no matter how powerful the air conditioning. Again, none of these homes incorporates overhangs or shading for indoor rooms.

As a further example, take the case of a sixth-floor office for a corporate executive in Portland. The office features floor-to-ceiling glass on its southwest corner. This architectural expression requires four separate air-conditioning zones in the summer, as the building has no overhangs or slits to interrupt sunlight penetration.

As a result, such buildings display a monotonous sameness in every geographic region. In fact, if it weren't for their unique names, or unusual coatings or rooftops, one is hard-pressed to identify them. For their occupants, they offer an inhuman work environment, with extremely limited daylighting, natural ventilation and views to the outdoors.

Computational fluid dynamic (CFD) software has proved to be an invaluable green design tool, for modeling building airflow and temperatures.

But let's not just pick on architects. None of this would be possible if engineers refused to use their talents to allow architects to build these faceless facades. Instead, engineers facilitated this type of design by ensuring that these structures:

  • Maintain even temperatures 95% or more of the time (

  • Supply only code-mandated amounts of fresh air.

  • Provide an overabundance of lighting which generates more heat for the HVAC system to remove—100 footcandles, in fact, was at one point the recommended IESNA standard.

  • Provide water and power in unlimited amounts.

  • Carry wastes to some treatment plant, body of water or landfill.

That's the dirty laundry for everyone to see. The good news is that over the last 10 years, architects and engineers have begun to move away from this model and into sustainable or green design,

The greening of design

This new paradigm typically operates within the framework of an analytical evaluation system, the best known of which is the LEED system—Leadership in Energy and Environmental Design—a performance-oriented guideline promulgated by the Washington, D.C.-based U.S. Green Building Council ( www.leedbuilding.org ).

This system attempts to address the wasteful nature of modern buildings by focusing on siting issues, energy/water use, materials/resource use and indoor environmental quality. Several hundred buildings have been registered for LEED certification. So far, about 20 projects have received certification—representing about 6% of total commercial and institutional building in 2001.

Hundreds, if not thousands more are using LEED guidelines as a framework for evaluating siting, design, construction and monitoring.

Further, LEED also has different levels of certification ranging from silver to platinum. In fact, if the Portland Building were being commissioned today, it would probably be with the notion that it would strive for a gold rating, and the architectural award would likely go to one of almost a dozen local firms that have truly embraced a regionally conscious, sustainable vision of buildings that serves primarily the end users, not the architectural designers.

While that's all well and fine, it begs the question: Where do engineers fit into this new picture? In order to develop a truly sustainable society, engineers must relearn some old lessons, be open to learing new ones and ultimately, be prepared to change many of the modern engineering techniques they've used over the past 50 years.

Re-education

Of course, one of the best places to start is in school. Traditionally, an engineering student's curriculum focused on the physical sciences and engineering, with no courses in biology, ecology or any other life sciences. At Caltech in the 1960s, for example, students were required to take two years of physics and mathematics, one year of chemistry and two years of English and history. Sciences such as biology and geology were strictly options.

The curriculum of 40 years ago clearly is out of touch with 21stcentury reality, yet the world of engineering remains largely mired in an earlier era. One cannot get into much trouble by following ASHRAE's Handbook of Fundamentals and the building code. But a few brave engineers are risking the ire of client disapproval—and lawsuits if things don't work out—and are designing more environmentally sound buildings.

First lesson

Enough preaching, more lecture. What would post-modern engineering for the built environment look like? It would adopt some fundamental principles from physics, chemistry, biology and human factors psychology, and use them in site development, building design and building operations.

As a first effort, engineers would design buildings and their immediate environs to consider the following:

  • Sites would not be located in areas of natural sensitivity, such as habitats for rare or endangered plant and animal species, floodplains or near watercourses.

  • Buildings would be sited in accordance with passive solar design principles, which could mean a different layout of streets, buildings that are oriented with a long east-west axis, buildings with less extensive floor plates to allow for daylight penetration to the interior, and buildings with different window treatments on each fa%%CBOTTMDT%%ade.

  • Buildings would exist on available solar income, or ideally produce more power than they consumed.

  • Incident rainwater and stormwater would be managed on site, whenever possible, through a combination of detention, retention and infiltration, to reduce the rate and quantity of off-site flows.

  • Water use and sewage generation would be minimized through efficient fixtures; in more adventurous projects, all waste water would be reused on site.

  • Buildings would be designed with daylighting, using efficient controls to mix daylighting with electric lighting to provide adequate lighting levels, typically 30 fc for most office tasks. This measure alone would represent a 40% reduction in lighting energy use and heat generation from current 50-fc standards. (See "Taking the LEED with Advanced Lighting Controls, p. 39.)

  • Buildings would use 100% outside air most of the time and have operable windows. Such buildings would require more elaborate sensors and software, but would "breathe" much more naturally than buildings with mechanical HVAC equipment (see "Rising from the Depths," p. 42).

  • Energy efficiency would be optimized, with longer payback thresholds that would reflect the increased life expectancy of buildings; such thresholds as 20 years for public buildings would allow the inclusion of modest amounts of solar photovoltaic and thermal energy systems for most buildings.

  • Healthier indoor-air environments would be achieved with both structural systems such as underfloor air distribution, and with mechanical systems providing greater levels of air filtration (see "Undervalued," CSE 01/02 p. 28).

  • Engineering specifications would be more rigorously enforced, with full commissioning of buildings, to ensure that the finished product fully meets the design intent.

  • Outdoor lighting systems would employ lower illumination levels, thus preventing off-site migration of direct-beam illumination so as to not block out the night sky (see "Shielding Light from Trespass," CSE 07/99 p. 30).

  • Performance monitoring and verification systems would be designed into buildings so that the initial design performance could be maintained over a long period of time.

  • Lighter weight structures, wherever possible, would mean fewer materials are consumed in buildings; where concrete is used for durability or economy, engineers would ensure that as much regionally generated fly ash as possible is incorporated in the concrete mixture

  • "Structure as finish" would be incorporated in as many buildings as possible.

LEED takes the lead

The LEED performance standards incorporate all of these approaches, most of them representing best practices that most engineers are already familiar with or could learn. Some measures require new tools; for example, a heavy reliance on ventilation may require the use of computational fluid dynamics (CFD) modeling, just as energy efficiency measures require the use of the U.S. Department of Energy's DOE-2 and other models.

And there are already some good examples of buildings that were designed using post-modern engineering principles:

  • A studio for more than 100 architects, completed in 2001, on the Seattle waterfront was built with no mechanical cooling system—just fans for moving air. Admittedly, this is a cool, low-humidity climate.

  • A high school in the Portland, Ore., area incorporates "stack effect" chimneys for natural ventilation and extensive use of daylighting, with a new controller that allows precise mixing of natural and artificial light.

  • Dozens of office buildings on the West Coast use underfloor air distribution to conserve energy, allowing individual temperature control of spaces and improved air quality by concentrating pollutants above head height.

  • A building in Vancouver, British Columbia, has a double skin, so that all building windows can open for fresher air without severely increasing energy use for heating in the winter.

  • The Ford Motor Co.'s River Rouge plant in Dearborn, Mich., will incorporate a vegetated roof at a cost of $13 million, but will save $47 million that would have to be set aside to control pollution from the runoff of a conventional roof.

  • The Philip Merrill Environmental Center in Annapolis, Md., reduces water consumption by 90% over a conventional building, through conservation measures—including a composting toilet—and extensive use of recycled and treated rainwater for hand-washing sinks and landscape irrigation. Rainwater storage also doubles as fire protection.

The future of engineering

In what sense will postmodern engineering for the built environment change the way engineers practice? Here are a few examples:

  • Engineers will learn new systems that may require different thinking; for example, underfloor air distribution systems operate with far less pressure (0.1 in. wg pressure vs. 3.0 in. wg for forced air distribution) and at higher incoming air temperatures (33°F vs. 55°F).

  • Civil engineers will work much more closely with landscape architects and aquatic biologists when stormwater detention involves bioswales, green roofs and ponds.

  • Civil engineers will brush up on their microbiology to handle on-site wastewater treatment systems.

  • Structural engineers will become more familiar with the chemistry of various fly ashes.

  • Mechanical and electrical engineers will change from mere specifiers of equipment to "health, comfort and productivity specialists."

  • Engineers will become better communicators and psychologists, in order to sell the new methods to architects and building owners, and then to communicate these changes to those who actually manage and operate buildings. They will also have to use these skills to convince code officials to let them try new methods of building and site design.

Practicing engineers must not only learn these techniques, but also ensure that the engineers they hire have a practical grounding in these new techniques, or at least, a willingness to learn.

Ecological engineering

Principles of ecological design are widely available (for example, see van der Ryn and Cowan, Ecological Design, 1995; Wilson et al., Green Development: Integrating Ecology and Real Estate, 1998; and Hawkins, Lovins and Lovins, Natural Capitalism, 2000). These principles force us to go back to basic lessons: all energy should be from solar income; waste is food; water is a resource, not a problem; materials are finite; and human beings need an environment of light, air and connection to the outdoors.

Post-modern engineering will change the way engineering is practiced, but its introduction will require a thorough change in engineering education, training and practice, as well as client communications, legal structures and engineering handbooks. This is a race that will be run over the next 10 to 20 years, and those engineers and engineering firms that embrace this post-modern engineering for green design will be the ultimate winners.



Taking the LEED with Advanced Lighting Controls

Daylighting is a principal tenet of green building design. And even though it requires architectural choices in glazing materials, solar control and building geometry, the creation of an effective daylighting design falls squarely on the shoulders of the lighting designe

To take a recent example, daylighting is a central element in the architectural design and energy conservation program at the new 268,000-sq.-ft. Clackamas High School, which opened in April of this year in the Portland, Ore., metropolitan area. The building is expected to receive a Leadership in Energy and Environmental Design (LEED) certification from the U.S. Green Building Council by the end of this year.

Interface Engineering Inc., Milwaukie, Ore., provided lighting design, electrical engineering and building commissioning for the project. The task of designing lighting systems and commissioning the lighting controls that are essential to the daylighting program fell to Robert Dupuy, LC, IALD, and Scott Micucci, P.E., senior lighting designers at Interface.

Micucci was responsible for commissioning the system. The challenges included software issues, such as working closely with a factory representative to program the controls, and hardware issues, such as bad relays and proper placement of hundreds of photocells.

"One of the benefits of this particular control system," says Micucci, "is that incremental changes in system operation can be made on the spot, without an electrician, during building operations." The project employs photocells to tell the lighting controls to dim the electric lighting whenever natural light is sufficient to meet ambient lighting levels. Controls also include occupancy sensors to turn off lights in unoccupied classrooms, and software turns off most lights when school is not in session or the building is unoccupied.

According to Dupuy, effective daylighting design is an ongoing collaboration among architect, lighting designer, control manufacturer, energy engineer and electrical engineer. "The first steps," he says, "are to reduce ambient lighting levels, then to choose efficient fixtures—such as T5-HO units—and only then to start messing around with elaborate control schemes."

Micucci suggests that a major lesson learned from this project is that lighting designers should commission their own work: "It's the only way you can make sure that what you designed to happen is actually what's happening in the building."

Critical communication

Communication with the architectural team is also a critical component; otherwise, design intent will not be realized in the end. For example, a simple LED light that would tell teachers that the classroom lighting control system was working was "value engineered" out of the design. As a result, teachers may spend a lot of time toggling the control switches, further confusing the software.

"In retrospect," says Dupuy, "we probably should have made a bigger fuss over these small issues, because they'll ultimately have a lot to do with end-user satisfaction."

The team also found that daylighting design and controls are new enough that they had to spend a lot of effort explaining specifications to the contractors. Micucci comments, "With any new technology, to achieve the goal you have in mind, you have to collaborate with the contractor to avoid overlooking any pieces of the puzzle, no matter how small."



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