The New York Times is not your average client, and neither is its new 51-story headquarters to be located on 8th Avenue between 40th and 41st Streets. What makes the Times stand out as a client is its research approach (it is a news organization after all) and its project management style, which it developed as a result of building two major printing facilities over the last 20 years. The new building's design is complex, and the process to create it has been even more so. While the project will be home to a whole host of technologically advanced building systems, it is the daylighting mock-up that has garnered particular attention.
In the parking lot of its College Point, Queens, printing facility, the Times has constructed a one-story, 4,500-square-foot, full-scale mock-up of the southwest corner of the planned building. Its purpose has evolved well beyond its original function as a furniture mock-up and constructability exercise; it is a comprehensive investigation of daylighting in combination with shading systems, not paired in this way before, or for a project of this scale. The findings are certain to influence how lighting and the integration of daylighting will be incorporated in future high-rise office buildings around the world.
To Shade Or Not To Shade?
From the outset, the building's design parti has been the expression and thorough incorporation of light and transparency. The building's 'skin' is a double-layer system comprised of a clear, low-iron-glass curtain wall with a screen of ceramic tubes in front supported by an aluminum armature. The challenge created by this system has been how to control daylight levels so that the work environment is not overly illuminated (brightness and glare), yet maintains a connection to the outside.
The Times was interested in daylighting and energy-efficiency issues related to the building's design early on, which automatically implicated the need for a control system. The organization understands efficient control systems (its printing plants produce over a million copies of the newspaper on a daily basis), so it asked interior architect Gensler Associates, and Susan Brady Lighting Design (SBLD), responsible for the interior lighting, to design an equally systematic interior. The Times also required that each department be able to adjust the lighting according to its needs.
Despite an abundance of natural light in the building, electric light is still necessary to compensate for the very bright contrast at the building's perimeter. The client's desire to implement a lighting control system translated into three possible options: an easy on/off system, a 0-10 volt programmable dimming system, or DALI. But before committing to one, the Times needed more information. To figure out which control system was a viable option, SBLD began a detailed investigation into light sensors. The firm discovered that there were no such systems of note in the United States, and while double curtain walls are prevalent in Europe, the combination of dimming and shading controls in one system is not.
In keeping with the organization's thorough research methodology, David Thurm, vice president of corporate real estate development, had also been looking into daylighting and come across a paper written by Stephen Selkowitz, head of the building technologies program at Lawrence Berkeley National Laboratory (LBNL). Still not sure how to implement a dimmable lighting system or even if it should use one in the new building, the Times decided to visit Lawrence Berkeley. Client, interior architect, lighting designer and engineer made the trek to LBNL in January 2003. During the course of that visit and the discussion that ensued, Glenn Hughes, director of construction for the Times, asked the question everyone seemed to be skirting around: What was the best way to manage the façade and could it be done with a shade system? 'The parody of the space is that it allows connectivity to the world and the beauty of natural light to come into the building, but it needs to be tempered in order for people to enjoy it,' says Hughes. With that question asked, the visit to LBNL confirmed that both a shading and a dimming system were the answer to the daylight conundrum. Then, serendipitously, a conversation between Thurm and Selkowitz resulted in the mock-up—already in development to review the final three furniture vendors and the lighting control systems— becoming an advanced daylighting study. For this, the team received support from NYSERDA (the New York State Energy Research Development Authority), the California Energy Commission and the Department of Energy.
Daylighting Mock-Up 101
Glenn Hughes is very clear about the purpose of this mock-up: 'We are not collecting data to compare vendors. We are collecting data to find energy savings, to learn about shade control and to figure out the best possible system.' Three vendors are involved in the mock-up: Lutron, MechoShade and Siemens. Further neutralizing the playing field, the data collection has occurred under the watchful eye of LBNL, a leader in the field of daylighting and building systems research for the last decade.
A separate set of construction documents, prepared by Gensler and coordinated with LBNL, indicates the location of all the sensors and measuring devices. 'The rigging of the measuring equipment was an entire exercise unto itself,' says Gensler senior associate Rocco Giannetti. Data is being collected over a six-month period—December 21, 2003, to June 21, 2004. The two shading systems being studied measure daylight in fundamentally different ways. MechoShade's system responds to exterior conditions like the solar path of the sun, while Lutron's system responds to the immediate conditions of the space. The issue is not which is a better method, but which is the best solution for the New York Times application.
The south side of the mock-up and half of the western façade is divided into seven zones and outfitted with MechoShade's equipment. Three radiometers are strategically placed on the rooftop to coordinate the building's location with the direct solar angle. A total of 10 photo sensors—two on the exterior façade and eight inside, including three on the south wall and one in the open-plan area—monitor the brightness level as it changes across the window wall. The shading system maintains a luminance ratio of 10:1, which is a comfortable level for distinguishing visual task surfaces from the background. The notable characteristics of the MechoShade system are that it is both proactive (the system is already set to acknowledge the solar path of the sun) and reactive (the system responds to changes in sky condition and reflecting surfaces).
The MechoShade system is paired with Siemens' Instabus protocol control system, so that the team can test a DALI interface and how the brightness override could be incorporated. To study the DALI system, light level sensors are installed at the work plane. The Siemens system is responding to the general amount of daylight in the space, and dimming the electric lights accordingly so that the overall luminance level never exceeds 50 footcandles.
Lutron's integrated motorized roller shade and dimming ballast system is installed on the north side of the mock-up and along the second half of the western façade. It has one exterior sensor and eight interior sensors distributed throughout the five zones of its testing area. Lutron is using a closed-loop shield photo sensor system, meaning that the shades are responding to the measurement of light from within the space. The sensors, which read the window luminance, are placed in the ceiling plane near the windows. The goal is to strike a balance between glare and energy savings. Both systems are set so that at night the shades are fully raised. There is also a manual override feature.
There is a combined total of 107 sensors between the manufacturers' and LBNL's testing equipment. Web cams monitor the lighting conditions around the clock, so LBNL can confirm the testing conditions for the actual data collected. From a computer hub in the mock-up, the data is transmitted to the Times printing plant across the parking lot via an optical dish on two secure systems, and that in turn is sent to LBNL, who in turn has secure communication with the manufacturers. LBNL is also conducting a human factor study where a statistically representative group of 60 people will work in the space and then fill out questionnaires.
LBNL's goal is to provide the New York Times with parameters—the best features culled from each system—for its performance specifications. Results should also clarify how the shade system performed and indicate whether the technology of the system is robust enough for continuous use. Data regarding glare has already been analyzed. The Times will issue a performance specification at the end of July, and LBNL will issue its final report in September 2004.
The Future Is Clear
The study is a milestone opportunity for all parties involved. The Times hopes its daylight investigation will stimulate the marketplace to offer this technology cost-effectively. For the manufacturers, it is a way to test and confirm their systems via an independent third party, who also happens to be a world-renowned laboratory. Ultimately, this daylight investigation gives building owners, architects, lighting designers and manufacturers an accurate reference point, so they know that a daylighting-shading-dimming combination is a viable option for future buildings, and not just for commercial office high-rise design. Elizabeth Donoff