In 2015, ULI hosted its annual Spring Meeting in Houston to great success. Following the devastation of Hurricane Harvey, we are republishing a selection of articles focusing on the city’s growth and resilience as it faces the future and recovery. We encourage you to give generously to the many organizations providing first response efforts such as the American Red Cross, Salvation Army, Jewish Federations of North America, Catholic Charities USA, Southern Baptist Disaster Relief and Global Giving.
It was not just Hurricane Katrina that convinced BP to build Helios Plaza, its new mission critical–type facility in Houston, with a strong resilience program. It was also the mundane reality that flood-prone Buffalo Bayou is only blocks away from its campus and that the electricity grid in Texas is painfully challenged. On a good day, the quality of electricity delivery is poor, and “hiccups” are not little when the power is used to run critical computers.
BP made a well-researched, value-engineered decision—taking into account employee safety and business operations—to pursue hard-core resilience with the entire six-floor, 350,000-square-foot (233,000 sq m) facility and parking structure.
Gensler and its team of design consultants—which includes mechanical, electrical, plumbing, civil engineering, structural engineering, curtain wall, and information technology groups—worked with BP to create a building that does some rather remarkable things that include generating its own power and harvesting millions of gallons of rain-water, groundwater, and air-conditioning condensation annually, with multiple backups in place. The high-performance Helios Plaza, which opened in 2010 and is Leadership in Energy and Environmental Design for New Construction (LEED-NC) Platinum certified, also staves off floodwaters with a ground floor lifted above grade, does its part to mitigate flooding downstream, and, ultimately, does not look or feel like a fallout shelter.
The following are the highlights of a multidiscipline approach to engineered resilience that was tailored to BP’s needs and specific to the Gulf region. The approach, by nature, is redundant and, by plan, is quiet about its very presence.
BP’s new facility had to have a workaround to the Texas electricity grid. It needed a primary source for electricity that was more reliable, controllable, and efficient than that available through established systems. This was accomplished through installation of an on-site central powerhouse.
It is a 4.6-megawatt cogeneration system that works with a natural gas–fed turbine. Not only does the system generate all the electricity the building needs (and more), but it also generates all the power needed for cooling. The super–efficient cogeneration system uses the waste heat produced by the turbine to drive the chillers for cooling.
Largely because of this combined heat and power system, which has proved highly reliable and is the building’s primary power source, the building was designed to operate at a level 34.1 percent more energy efficient than the ASHRAE 90.1 2004 standard. If the cogeneration system were to fail, or when it is down for maintenance, the building reverts to the grid. If the grid fails, the building can be plugged into portable diesel generators.
The challenge was to figure out a way to transform water—which is often seen as a threat, given Houston’s storm-prone -climate—into an asset. That was accomplished by first reducing the building’s total water needs and then harvesting and reusing nature’s abundance.
Within the building, the installation of efficient toilets and faucets was specified; outdoors, smarter landscape design and irrigation systems were used; and in the powerhouse, there are water-efficient cooling towers. Combined, these elements eliminated 26 percent of the building’s total water needs.
In addition, a 400,000-gallon (1,500 kl) cistern collects rainwater from the roof, groundwater, and air-conditioning condensation. This collected water be-comes the building’s nonpotable water supply, used for toilets, irrigation, outdoor water features, and, most important, as makeup water for the cooling towers. Cooling-tower water is the single biggest water use on the campus in Houston’s hot and humid Gulf climate.
BP’s nonpotable water harvesting system has the capacity to capture 7.8 million gallons (930 000 kl) of rain-water, groundwater, and air-conditioning condensation a year, which could offset another 40 percent of potable water demand and reduce total municipal demand by as much as 65 percent compared with that of a typical Houston office building. From a community perspective, that represents millions of gallons of water that BP avoided taking from the city’s water supply. It is also water saved from flowing into Buffalo Bayou, thus mitigating the potential for flooding downstream.
The city’s water supply is, of course, the backup to the harvesting system.
The high-performance glass facade was designed to reduce the thermal effect of the sun and to provide daylighting control for the interiors. Both strategies reduce the building’s power needs—a move that is both green and resilient, especially since BP produces its own power. The facades are designed to withstand hurricane-force winds. A “cool” roof completes the envelope’s thermal resilience and was similarly designed to withstand high winds.
Site Design and Community Connection
Resilience starts well before one gets to a building’s front door. The resilience strategy was enhanced by lifting the ground floor above grade so water from sudden rainstorms does not flow into the building.
Once again, beyond the building, water is the big issue, and the design turned water into an asset rather than a liability. The use of concrete and black asphalt as paving material was minimized and instead more porous block paving was used. During a storm, water runs to a water feature designed specifically to handle the additional flow, or it percolates into the ground. An indigenous prairie landscape was reinstated with plants that can weather a drought and can clean water as it flows through the campus to the northern water feature.
The site also provides a connection to the community through bike and pedestrian lanes, as well as public transportation. The new parking structure was sited at a high point so that it remains above floodwaters and gives employees a safe, dry path out to improved public streets that are not prone to flooding during normal rainfalls.
Read more about next-generation sustainability or engineered resilience, which adds adaptability and the protection of human life—through any disaster.