Pittsburgh's "breathing" building aims to be the world's greenest skyscraper

The PNC Financial Services Group hopes to exceed LEED Platinum requirements along with promoting a healthy indoor workplace with its latest development – the Tower at PNC Plaza. Located in downtown Pittsburgh on the corner of Fifth and Wood Streets, the building will be approximately 800,00 gross sq.ft (74,322 sq.mt) in size with a construction budget of approximately US$240 million. The "breathing" design created by architecture firm Gensler moves away from the traditional closed air-conditioned environment and has the lofty aim of becoming the greenest skyscraper in the world.

Site clearance and development began in the spring of 2012 and completion is scheduled for summer 2015. The Tower will stand with the PNC HQ at PNC Plaza, which also boasts one of the largest green walls in the U.S.

Employees in the 33 floor glass tower will be able to access daylight and fresh air, an experience which Gensler design director Hao Ko recognizes is much more of a European design feature then has been incorporated into current U.S. skyscrapers. Workspace in European buildings is often located near windows, allowing employees to work for more of the year with natural daylight. The PNC Tower design recognizes that the Pittsburgh climate can also provide increased levels of natural light onto the floorspace along with improved regulation of temperatures for much of the year without using traditional, energy-intensive HVAC systems. The Tower hopes to achieve this by using a double-skin facade consisting of two panes of glass separated by an enclosed cavity which will allow external air inside. The facade will feature operable doors and windows that admit fresh air into the building during optimal conditions, which is effectively when the building is "breathing." A solar chimney is another component of the structures passive system: it pulls air in through the open windows, rather than sucking air out as usually occurs in a high rise building, the air then travels across the floors, is heated and exhaled through the roof shaft.

As a sustainable development, The Tower hopes to minimize use of the surrounding Pittsburgh rivers, which are already at risk through overuse, storm-water and waste water systems. The building will use low flow fixtures and rainwater harvesting to irrigate the green roofs whilst treating grey and black water wherever possible. PNC is a proven sustainable developer with 118 LEED-rated buildings. The company opened its first green building in 2000 and state that it has reduced its energy budget by 25 percent since 2009. The design team is also considering fuel cells, solar panels, geothermal systems, and other alternative power sources to help reduce carbon emissions for The Tower.

The Tower development website confirms the focus on employee experience using research by Carnegie Mellon University, which indicates that fewer sick days are taken and employees are more engaged in buildings employing similar technologies to The PNC Tower then standard office environments. This suggests that companies are realizing that happy and productive employees are good for the bottom line, especially in the current economic climate. Over a period of 30 years the PNC website states that whilst initial building costs and operations/ maintenance account for just two and six percent of the total cost respectively, personnel costs account for 92 percent, which means efforts to improve productivity are very worthwhile.

Inside The Tower Gensler has used a smaller floor plate and connected two story levels to promote increased employee collaboration and stop the anonymity of elevator travel between floors. A typical U.S. skyscraper floor plate is four times larger then its European counterparts, therefore, by using a smaller plate, the aim is to bring light and ventilation further into the interior. Combined with the "breathing" facade, it is predicted the design will significantly reduce lighting and cooling consumption, which are two of the greatest energy demands in U.S. commercial buildings. Employees will sit within 30 feet of the double skin’s outdoor porches and will have the ability to adjust lighting and temperature. FSC certified Red Maple from Western Pennsylvania will be used for the interior curtain wall with sliding glass doors available almost to the top floor, these allow occupants to step out onto a three foot ledge between the facade layers, fear of heights permitting. To top the "Tower" experience off, there is also a five floor enclosed "skygarden" planned that's designed to feel like the outdoors.

All of this feel good factor for employee’s stems from the brief of Gary Saulson, PNC’s executive vice president and director of corporate real estate. The challenge for the designers is for staff to feel like they are sitting on a park bench, with a laptop, shoes kicked off, feeling the breeze. Saulson adds that The Tower will consume less than 50 percent of the energy a typical office building uses and will save PNC at least 30 percent on its energy costs. It all sounds idyllic and the results in 2015 should produce some interesting productivity statistics and sustainable building data for future constructions to use.

The community of Pittsburgh, which was once a steel industry city and now operates a center for financial services, healthcare, technology, and education, should benefit from the employment of around 2,500 construction workers over the next few years and the project aims to promote development and business growth in the downtown area. PNC is not including a full service cafeteria in the building but will instead encourage employees to venture out, thus providing a further boost to the local economy. This is a proven strategy from the opening of "Three PNC Plaza" a few years ago.

As developers strive to build the tallest and thankfully most sustainable skyscrapers, it is refreshing to see a design which adds more elements to responsible construction through its pursuit of employee comfort that is devised to sustain a productive environment and positive work experience. As the construction progresses we can hope that the climate control solutions and community endorsement can be realized and provide additional sustainable solutions to skyscraper design

Sources: PNC Financial Services Group, Gensler