Durst's Four Times Square: a lesson in high-rise environmental responsibility.

How environmentally responsible can a 48-story urban high-rise office building be? Is it inherently a waste of structural materials and vertical transportation energy or can it be justified by its consolidation of space and energy services, its mass transit access, its minimum perimeter surface area, its ease of inter-communication and material distribution, its self-contained amenities, and its minimum use of precious land?

Urban high-rise architecture is having an ever-increasing impact on our built and natural environment. When the economy is booming, so does the construction of these tall buildings, and there is more square-foot-age of office space contained within these structures than in any other form. They are a global reality, and any effort to improve their energy efficiency, resource conservation, and ecological impact is a major step toward preserving our fragile and endangered environment.

Four Times Square, in the heart of Manhattan at 42nd Street and broadway, demonstrates how effective careful planning; technical know-how; product research; some additional up-front but short-term investment; and common sense can be in assuring that large scale development is sensitive to the environment. While environmental policies and statutes have their place, responsible ecological design must ultimately evolve from the planning and nitty-gritty details of each and every project. No single element of a design can go unchallenged and no in-place system or material can be assumed to be properly installed or maintained correctly for the life of the project.

At Four Times Square, every cubic foot of space, every system, and every material and finish has been, and continues to be, analyzed to ensure that all potential and feasible sources of natural daylight and energy have been utilized; fossil fuel usage has been minimized; any sources of pollutants have been reduced to their practical limits; each selected manufacturing and construction process has the minimum practical impact on the environment; all products will have the least possible impact on the interior (and exterior) air quality; and all products will have the maximum possible degree of sustainability and recyclability. For example:

* Fresh air will be supplied to all interior spaces through a state-of-the-art filtration system at a rate 50 percent greater than the current code.

* CFC- and HCFC-free natural gas-fired absorption chillers will be used for heating and cooling in place of conventional fossil fuel-driven electric systems.

* Each floor will have tenant-controlled individual air handling units to ensure minimum use of the system. An oversized outside air shaft will allow periodic purging of interior air from each individual floor.

* The exterior curtain wall system will minimize heat loss and allow for a 30 percent humidity level to be maintained inside year round, helping to reduce discomfort from dry skin and preventing dust and other irritants from becoming airborne.

* Windows will be oversized for deep penetration of daylight.

* Panels on all four sides of the tower will generate solar energy.

* Fuel cell technology which generates electricity from natural gas is also being considered as a possible alternative energy source.

* Multiple trash chutes will facilitate automated recycling of daily waste.

* A dedicated exhaust shaft will direct exhaust from all smoke-, fume- and heat-producing spaces.

* Materials specified contain the maximum percentage of recycled content and low-to-no VOCs.

* The building will feature energy-efficient vertical transportation equipment.

* A waste management plan for demolition of existing buildings on the site salvaged and recycled as much material as possible.

* Construction scheduling and control procedures will ensure efficient on-time deliveries to minimize vehicular idling/waiting time and traffic congestion.

* No toxic or hazardous materials or construction techniques potentially harmful to construction workers' health and/or the environment are permitted.

* Dangerous or potentially damaging materials will be handled only by skilled construction workers and be properly secured at all times.

* Modular, pre-fabricated or pre-assembled systems will be used wherever feasible to minimize construction waste.

* Construction field staff and subcontractors will be educated, and their procedures carefully reviewed to ensure quality management and compliance with all project guidelines.

Once construction is completed in 1999, thorough testing of each and every control device, fan, motor, pump, valve, exterior wall component, etc., will verify that the performance criteria established by the design documents are met and maintained. Subsequent testing will be performed a minimum of every five years for the life of the building.

Because this project was conceived as an investment building with no particular user/tenant in mind, if was important to develop a methodology to ensure that the objective of environmentally responsible design be maintained throughout the project, not just in the base building core and shell. For this purpose, the project team developed a set of guidelines for the tenants. The rationale was that once the tenant was given the benefit of the research and taught in simple terms how the deployment of ecological design into their space could save energy costs and improve the health and productivity of its employees, they would naturally follow suit.

Efficient lighting and lighting control systems, the impact of daylight penetration on energy usage, the most effective floor-by-floor HVAC distribution, control and exhaust systems, and the use of non-toxic materials are among the factors addressed. To date, the building is currently more than 80 percent rented and tenants have so far responded favorably and enthusiastically to these guidelines.

Four Times Square is well on its way to realizing its objective of integrating high-rise design and construction with the principles and practices of "green" development. By stimulating demand for "green" products, setting the standard for new office space, and serving as a "laboratory for applied research," the Four Times Square endeavor is destined to shape the future development of large-scale projects within New York City and throughout the world.