The Plaza at PPL Center

Project Profile

corporate office building on a long-vacant site in center city Allentown, Pennsylvania is a statement of the ongoing commitment of a locally-based international energy company and principal tenant, PPL Corporation, to the city’s downtown, and a physical expression of the commitment of PPL and Liberty Property Trust to sustainable design. The site, at the corner of North Ninth Street and Hamilton Street, was home to the former Hess Brothers Department Store, a mainstay shopping destination for the Allentown community until its closing in 1995.

Located just east of PPL’s historic 1928 office tower by Helmle, Corbett & Harrison Architects, the site is now the anchor of the city’s downtown business district and is the first major new downtown business development in 10 years.

The Plaza at PPL Center is a 252,193-square-foot office building on 1.7 acres with 3/4 acre south-facing landscaped plaza which creates a generous forecourt for the building while strengthening the historic tower’s position as the city’s prominent landmark and creating open space for the community and tenants. The Plaza at PPL Center includes approximately 215,000-square-feet of Class A office space for the principal tenant- PPL, including a state of the art 35,000-square-foot energy marketing and trading floor; approximately 32,000-square-feet of speculative Class A office space; and approximately 18,000-square-feet of Class A retail space to help support economic revitalization in downtown Allentown.

The plaza provides a welcome public gathering space in the heart of the downtown with a combination of flexible and permanent outdoor seating for outdoor dining, a bosque of shade trees, and a fountain focal point.

Within The Plaza at PPL Center, the main lobby and two secondary entrances converge on an 8-story, central atrium which brings natural light from the top of the building down through all eight floors while providing a centralized, common point of orientation. Extensive perimeter clear glazing provides abundant daylight, filtered through brise-soleil, directly to all building spaces while offering direct line-of-sight panoramic views of the region to all building occupants. The clear glass provides a “connection” between the building and the community—occupants can look out at the community and the community can look in. Two two-story, plant-filled, south-facing winter garden spaces, integrated into the office floors, overlook the plaza while providing opportunities for more casual interaction between building occupants.

The Plaza at PPL Center incorporates a broad spectrum of sustainable design features, including extensive daylighting and views to over 90% of all regularly occupied space; extremely efficient and innovative heating and cooling systems that outperform ASHRAE 90.1 by more than 30%; a vegetated roof and landscaped plaza that reduce urban heat-island effects and improve storm-water quality; high recycled and local material content; and superior indoor air quality.

Project Merits

1. Redevelopment of important long vacant downtown site utilizing principles of sustainable development and green design.
2. Spectacular building and site design providing generous open space front plaza for occupants and community.
3. Balanced urban design unifying original 1928 signature office tower with new high performance complimentary structure.
4. LEED™ Gold Award with less than 1% cost premium demonstrates that environmentally-wise buildings can be extremely cost-effective, good business decisions.
5. The building has been a significant catalyst for other economic development in downtown Allentown.

Revitalize existing communities and business districts:

The Plaza at PPL Center balances commercial development with good urban design. Occupying a previously developed center city site, the project fits a large mixed-use office building (252,193-square-feet) into a tight 1.7 acre urban site. The new building, the plaza, and two large existing office buildings across the street form a campus that is the corporate headquarters for PPL Corporation, an international energy company with 1500 employees who work in downtown Allentown. PPL chose to work with Liberty Property Trust and invest in the redevelopment of the city center where the new building could take advantage of existing urban infrastructure and the existing public transportation hub adjacent to the site. This site allowed the project to participate in a state program of focused urban economic development.

Encourage future development near existing infrastructure:

The City of Allentown had great interest in this project. By PPL moving forward with the new building it confirmed a commitment to the city that PPL would remain in the city and help provide much need revitalization to downtown business district. In addition, the development site was designated as a Keystone Opportunity Zone (KOZ). This designation offers tax incentives to companies who own the building and to businesses who operate in the building.

Since the building was announced in late 2001 and opened in May 2003, it has been a catalyst for econimic development in the business district of Allentown. Several restaurants and office buildings in the immediate area have opened or began construction, and others have been announced.

The project clearly demonstrates the value of a successful partnership between Liberty Property Trust as the building developer and PPL as the primary tenant, to create a viable and beautiful downtown renewal of a distressed long vacant core urban site; leading the way for the rebirth of downtown Allentown's commercial redevelopment.

Reduce traffic congestion and air and water pollution

Located in downtown Allentown, PA on a previously-used site, the building sits at a major public transportation node and forms a new public plaza at one end of the city’s main business district.

The building encourages bicycle and pedestrian commuting by offering covered bicycle storage for 5% of building occupants and locker rooms with showers. All lines of the regional bus system stop within a block of the building, and most stop at the building’s side entrance, allowing for easy access by public transportation.

• Water Use - Because the project is located atop a limestone ridge prone to subterranean erosion, on-site water infiltration and storage were limited to minimize the risk of local sinkhole formation. The project also focused on reducing potable water use throughout the project. Within the building, waterless urinals and sensor faucets reduce annual potable water use by more than 45% below code requirements. Outside, all landscaped vegetation has been selected to thrive with only rainwater for irrigation, and the plaza fountains retain rainwater to replenish evaporation losses. The vegetated roof and landscape together reduce site permeability by just over 15%, allowing for some on-site water retention. All stormwater from the site is filtered to remove debris, oil, and over 80% of suspended solids before it leaves the site. Additionally, the landscape plantings and hardscape surfaces have been selected for easy maintenance and care without products that contain potential stormwater contaminants like phosphorus.



• Energy Use - The Plaza at PPL Center is an extremely energy efficient building, designed to exceed the ASHRAE 90.1-1999 energy requirements by more than 30%. During the first year of operation, energy data show that the building (at 85% occupancy) used only 70% of the energy predicted, which is roughly equivalent to exceeding ASHRAE requirements overall by 50%. Energy efficiency begins with the building envelope, where brises-soleils and canopies shade the south façade of the building, and high-performance glazing, walls, and roofs reduce conductive gains and losses. Abundant natural light allows lighting controls to reduce lighting energy more than 30% during the day, while occupancy sensors further reduce lighting energy in support rooms without daylight. HVAC systems further contribute to energy efficiency: an enthalpy wheel recovers heat and humidity from exhaust air to precondition incoming ventilation air; CO2 sensors control the flow of outdoor air directly to spaces where it is needed; an ice storage system allows small chillers to run only at peak efficiency, and smart controls carefully regulate building system operation.

  Peak energy loads are reduced in this building by two means. The overall demand is reduced through architectural design measures, notably those like the external solar shading that reduce peak conditioning energy loads, and through advanced building controls, which reduce electrical demand through means like daylight dimming and occupant sensing to turn off lights and HVAC. Secondly, peak cooling demands are reduced significantly through the use of an ice storage system that allows the building cooling system to make ice at night which is used during the day for cooling. In addition to reducing the peak energy demand, this also shifts building cooling system use to night when systems operate more efficiently. This ice storage also allows the building cooling system to continue operation, in conjunction with an emergency power generator, when there is no grid-supplied power. The building is supplied with 100% Green-e certified power, which insures that at least 50% of the building’s electricity has been generated sustainably. Interior finish materials including paints, carpets, adhesives, sealants, and composite wood paneling were selected for low emission of VOCs, urea-formaldehydes, and other contaminants, and all building spaces were flushed with 100% outdoor air for at least two weeks before occupancy. High-traffic materials were selected for durability and environmentally friendly maintenance requirements, like the terrazzo flooring in the lobby and public areas, or for easy cleaning and the ability to be completely recycled, like the carpet tile system throughout the offices. Office operations emphasize recycling, and all floors have a recycling center located adjacent to the kitchen area.

Reduce land and resource consumption

The Plaza at PPL Center is an urban redevelopment project and, as such, provides benefits such as: utilizes land that is already developed; protects greenfields; preserves habitats and natural resources; utilizes existing infrastructure such as water, sewer, electrical, and public transportation; minimizes the amount of land used - "build tall instead of sprawl". It uses only 1.7 acres for 252,193 sq. ft. of rentable space, which is excellent utilizataion of the land. It is a excellent example of urban redevelopment creating an extraordinary work environment while enhancing the community and people's lives.

The Plaza at PPL Center was designed to minimize its environmental footprint. Over 20% of the building material (by cost) is composed of recycled materials such as structural steel and rebar, metal framing and panels, gypsum wallboard, carpet, and medium density fiberboard (MDF) wood. In addition, over 85% of the wood-based materials are from sustainably-managed forests that are certified in accordance with FSC guidelines. Approximately 25% of building materials (by cost) were manufactured within 500 miles of the building and 95% (by weight) of the construction, demolition, and land clearing debris was recycled. The Plaza at PPL Center deserves the ULI 2004 Awards for Excellence.