A Quality Northwest Brew

Connoisseurs of hand-crafted beers are well aware that the American Northwest has produced many fine brews in recent decades. So, when one hears about the Brewery Blocks in Portland, Ore., it's only logical to think beer. But this story isn't about brewing lagers and Pilseners. It's about an ambitious five-block, speculative mixed- use project in downtown Portland's Pearl District, which like m...

12/01/2004


Connoisseurs of hand-crafted beers are well aware that the American Northwest has produced many fine brews in recent decades. So, when one hears about the Brewery Blocks in Portland, Ore., it's only logical to think beer.

But this story isn't about brewing lagers and Pilseners. It's about an ambitious five-block, speculative mixed- use project in downtown Portland's Pearl District, which like many aging urban industrial neighborhoods across the United States, is being rejuvenated as a place where people can live, work and play.

At the heart of the five-block development sits the former site of the historic but defunct Blitz-Weinhard brewery, from which the development takes its name. But the $250 million project isn't just historic renovation. It blends the old with new construction, for a total of 1.7 million sq. ft. of new and remodeled retail and office space, condominiums and rental housing.

The Brewery Blocks' size and scope alone—with so many building scales, types and materials—make this a noteworthy design challenge worthy of a CSE ARC Award for M/E/P consultant Glumac's Portland office. But two other factors make this project a standout.

First, the five city blocks encompassed by the project incorporate a wide variety of energy-saving technologies and sustainable practices. All buildings in the project are registered with the U.S. Green Building Council for some level of LEED certification, a rarity for any speculative mixed-used development, let alone one of this scope.

But second, and just as significant, an important goal of the project was to increase the density of the area while maintaining the historic and cultural sense of place that has so much defined this neighborhood for almost a century. Architecturally, the major challenge was to integrate new, taller buildings with existing historic structures.

The project team had already decided early in the design process that all buildings on the site with historic value would be saved, renovated and integrated with any proposed new buildings. These buildings include not only the 1907 Weinhard Brewhouse and Cellar Building, but also the 1898 National Guard Armory and the fa%%CBOTTMDT%%ades of the 1929 A.B. Smith Chevrolet Building (at top left).

While integrating old and new can be a difficult job for architectural designers, it can pose some especially tough challenges for M/E/P systems designers. Solving these problems can lead to some satisfying innovations. As an example, Glumac engineers describe one solution that they are particularly proud of.

"Fitting modern conveniences into old buildings is always difficult," says Geoff Winslow, lead plumbing engineer on the project. "One of the great successes in adaptive reuse was repurposing the brew tanks in the old brewery building."

The old brewery building had four malt tanks. Two were removed to create more space in the building. Designers preserved two of the tanks to maintain the historic character of the building and hit upon the idea of refurbishing one of these into a water storage tank for fire protection, thereby optimizing space.

But while the Brewery Blocks redevelopment has had its share of chance opportunities such as this one, overall success depended less on luck and more on careful planning and a strong vision.

Taking the long view

The fact that the Brewery Blocks development is such a rare bird—a speculative project registered for LEED accreditation—says much about its developer, Portland-based Gerding/Edlen Development. "Gerding/Edlen wanted this from the get-go," says Bill Parry, P.E., lead electrical engineer with Glumac. "They were looking for green methods from the beginning."

Glumac engineers feel that the success of this project is clear proof that not all green building features need to be analyzed in terms of first cost, and that even large-scale speculative development can successfully incorporate green features and still remain competitive in the marketplace. "The project has been a great success with nearly full occupancy," says Parry. "The Block 3 condo tower is sold out and Block 5 is scheduled for May 2005 occupancy, both residential and ground-floor retail."

Not only can the developers realize a substantial payback in the long run, but residential, office and retail tenants will also find many advantages, some of them intangibles, such as improved indoor air quality and increased productivity. One thing that the developers understood from the start was that making sustainable design attractive to prospective tenants would call for education.

"The developers went to a considerable effort to create guidelines for the tenants and also to educate them with respect to the sustainable guidelines," says Parry. "Of course, they want to attract tenants and doing so requires that they not create too many obstacles. It's about educating tenants."

In fact, it would appear that taking the long-term, sustainable view was what offered many of the immediate engineering solutions. For example, a critical goal to the master plan was developing a site that emphasized the pedestrian. As a result, a contiguous three-block underground parking garage was designed to maximize parking efficiency and reduce the energy stream required to build separate garages under each building. While the parking garage primarily runs beneath the three adjacent Blocks 3, 4 and 5, "it does partly extend under Block 2 as well," explains Bob Schroeder, P.E., Glumac's lead mechanical engineer on the project. And this provides the ideal means for innovative utility routing, including the district chilled water loop from Block 1.

A high-efficiency central chilled-water plant sits atop Block 1 and serves the entire Brewery Block complex via chilled-water piping circulated through the parking garage. The system is a variable-flow system with tertiary pumps in each building. The present configuration has two centrifugal chillers, totaling 3,700 tons, with a future build-out capacity up to 10,000 tons of cooling. Glumac actually partnered with Portland Energy Solutions to do the central plant. The design eliminates point-of-use chiller plants in individual buildings and also includes a low-temperature chilled-air distribution system. This complementary strategy takes advantage of low chilled-water supply temperatures—typically 39°F—making it possible to produce colder than typical supply air distribution in the cooling systems, thereby reducing overall size of fan systems and ductwork.

The ability to downsize fan systems and ductwork was a double blessing, acknowledges Schroeder. When asked whether it was important for LEED points or as a general savings advantage, he notes that it meant a reduction in both energy use and in first cost.

Other aspects of the HVAC design point to how, in this project, less is more. The energy conservation features associated with retail spaces in all buildings include full economizer free cooling for the HVAC system utilizing 100% outdoor air when conditions exist, which is a large percentage of the time in the Pacific Northwest. This eliminates the need for mechanical cooling year-round that is typically associated with retail systems that introduce only minimum outside air.

As in most major sustainable projects these days, it's all about how to reduce the complexity and requirements of engineering HVAC systems through a combination of natural ventilation, advanced building controls and daylighting.

Au Natural

Natural ventilation strategies are employed in the office buildings as well. Manual-controlled operable windows are available for individual occupants, and microswitches were installed in the windows to shut off the air-conditioning system overhead when windows are opened. This has the added benefit of allowing design temperature set points to be relaxed and contributing significantly to energy savings.

However, the use of operable windows created problems elsewhere, problems that were solved early on through the remarkably integrated design process (see "All Disciplines In from the Start"). Operable windows made it difficult to provide smoke control systems for the high-rise buildings based on the typical pressure-sandwich approach. That approach would have been to pressurize the floor above and below the fire floor and exhaust the fire floor. Based on the use of operable windows, an analysis was done that allowed for a passive smoke-control system, thereby eliminating the need of smoke exhaust fans and downsizing generators.

As for the building automation, a number of direct digital control design strategies were implemented in the project to improve occupant comfort and reduce energy consumption, including the following:

  • Night flushing control sequences to pre-cool the building with cooler outdoor air at night to sub-cool the mass and delay the start-up of mechanical systems during the cooling season.

  • Demand limiting sequence to utilize temperature reset as part of the control sequences to provide the highest temperature possible and still satisfy the demands of the variable air volume boxes.

  • Increase temperature deadband in common spaces to relax temperature set points to potentially 68°F heating and 78°F cooling in response to buildings that are naturally ventilated.

  • Submetering, either in place or part of tenant improvement work, to submeter natural gas, electrical loads and chilled water usage in the building.

The core and shell design of the office buildings provided for daylight harvesting in office spaces. The design included the lighting control systems—installed during core and shell work—and direct/indirect fluorescent luminaires that would be installed during the tenant improvement portion of the work. The project developed a consolidated procurement package to obtain the best possible price for the tenants on the luminaires to encourage their installation during tenant improvements. Also, light shelves were incorpo-rated with select glazing to reduce glare.

Several tenant improvement projects have taken advantage of the daylighting features to install extremely low energy (less than 0.8 watts per sq. ft.) ambient lighting systems.

The complexity of this project—and of the engineered systems that went into it—speaks for itself. "Due to the unique needs of each block, there was a different design architect for each," says Bill Parry. "Also, each building was shooting for its own level of LEED certification." Nonetheless, designers attained a remarkable uniformity in achieving a high standard of design.



Does the sun ever shine in Portland?

There are plenty of cloudy days in a Northwest winter, but that hasn't put a damper on the use of solar power in Portland's Brewery Blocks. A combination of stand-alone and building-integrated photovoltaic systems, connected through a system of collectors and inverters to the electrical distribution system of one building, was installed to reduce the building's utility power loads. The roof-mounted, high-efficiency mono-crystalline array and the building-integrated thin-film array combine to maximize output while complementing the appearance of the building fa%%CBOTTMDT%%ade.

"Photovoltaic is concentrated on Building 4," says Bill Parry, P.E., Glumac's lead electrical engineer on the project, about the five-block redevelopment. "The PV system is rated at 21 kW and is expected to produce more than 20,500 kW over a year." But while solar so far has mainly been contributing to the energy use of Block 4, ongoing evaluation and monitoring is taking place to ensure the efficient functioning of the system and to compare actual performance to expected results. This effort is hoped to pave the way for future solar deployments.

Specifically, the Armory Building on Block 3 is still being developed, hopefully into a theater that will attain a LEED platinum rating from the U.S. Green Building Council. Winning LEED platinum would be a world's first for a historic renovation of a performing arts venue.

In order to attain this level, the Armory Building will most likely use sustainable features that were ruled out on other Brewery Block buildings because of cost, most notably wastewater systems and photovoltaics.

All Disciplines In from the Start

From conception, the Brewery Blocks redevelopment was un-dertaken using a collaborative design process. For the project as a whole, and for each individual building, all-day "design charette" meetings of all disciplines—and which included the developer—were conducted.

Participants researched possible design features and brought detail to the charettes, enough not only to brainstorm but also to begin the conceptual layout and coordination with other disciplines. With all disciplines participating from the start, every system and construction process in the project was thoroughly analyzed.

Items that were identified as "pushing the limits" were pursued in parallel with the conceptual design. Early on, the team began coordinating with city code officials to develop variances and interpretations for issues such as building separation, passive smoke control and street redevelopment. "There was a fair amount of coordination with the utilities in the streets," says Bill Parry, P.E., Glumac's lead electrical engineer on the Brewery Blocks project.

Despite the complexities of the project, the development team was able to identify and deliver myriad green building features of varying scale, cost and benefit. All of the individual sustainable features implemented, both large and small, were combined with thoughtful urban design to produce an unquestioned success. The result was impressive project-wide energy savings and an architecturally diverse, pedestrian-oriented environment—a healthy and ecologically sound mixed-used urban redevelopment.



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