Working With Light

A major Amsterdam bank building provides a decade of evidence that sustainable design is good for employees and for the bottom line

One of the articles in Designing A Sustainable Future (IC#35)
Originally published in Spring 1993 on page 12
Copyright (c)1993, 1996 by Context Institute


When the board of directors of one of Holland’s leading banks needed a new headquarters, they asked for a design that would honor the human spirit while creating a new, progressive image for the bank. The result is a structure that integrates art and natural materials, sunlight and energy conservation, low noise levels and unique water features. Karl Maret, a consultant with the Metanoia Group and formerly an associate of Ton Alberts and Max Van Huut, the architects who designed the new headquarters, provided this description.

The head office of what is now the Internationale Nederlanden Group (ING) Bank stands in southeast Amsterdam near the Bijlmer metro station. Completed in 1983, this "groundscraper" is a synthesis of energy efficiency, human-scale functionality, artistic inspiration, and organic architecture.

What strikes the observer at first sight are the sloping walls of the complex’s 10 towers. This design lends the building a sense of stability, while providing advantages in terms of natural lighting, solar heat collection, decreased wind resistance, and acoustical efficiency.

The 538,000-square-foot complex is broken up into 10 slanting towers arranged in a loose S-shape. A 1,400-foot-long internal "street" runs through the bottom connecting level.

Repetitive features in the towers helped keep the building’s cost down to $96.3 million in 1991 dollars, just 3 percent more than an equivalent standard office complex in Holland. Many of the energy-efficient features that added to the cost paid for themselves in less than a year.

A 1,400-square-foot sloping glass pentagon with an attached glass house crowns each tower. These structures contain the exhaust air heat-exchange systems and the computer-controlled blinds for the solar collectors. They also serve as skylights, converting each tower into a light well.

All employees sit within 23 feet of an operable window, allowing each some control over light and fresh air. Internal ceiling louvers, which bounce daylight deep into each room, allow employees to work in natural daylight 80 percent of the time, saving significant amounts of energy. Task lights, wall sconces, and overhead fixtures provide the rest of the lighting.

The passive solar building stores heat in its half-million cubic feet of precast concrete. Seven-inch-thick concrete walls, sheathed with four inches of insulation and faced with 2.8 million bricks, store solar heat and the heat generated inside the building by power equipment, lighting, elevators, and people. Seven of the 10 towers have a southern orientation, maximizing incident solar light and heat.

Air-to-air heat exchange systems capture 70 percent of the heat from the exhaust air to preheat the fresh air intake. Four 6,600-gallon hot water tanks store the heat generated in conjunction with on-site electricity generation. The hot water feeds hydronic radiators. A central computer system makes adjustments as necessary.

In place of air conditioning, the building is cooled by mechanical ventilation, fresh air, and a back-up absorption cooling system powered by waste heat from the cogeneration system. Cool air is admitted at night, put through a thermal energy transfer device, and circulated throughout the building during the heat of the day.

Instead of humidifiers, a specifically calculated number of plants provide the necessary moisture. The plants are watered by rainwater collected in outside ponds and oxygenated and conditioned through specially constructed flowforms.

The building’s annual energy consumption of 52,000 Btus per square foot is less than one quarter of the bank’s old headquarters and about a third of conventional modern office buildings. The bank saves $2.4 million annually as a result; it recovered its $700,000 investment in the energy system in the first four months of operation.

HUMAN-CENTERED DESIGN

The architects aimed for an organic theme and a human-centered design. To provide a sense of connectedness with the building, each employee works at a natural wooden desk, touches birch banisters while walking through a multitude of inviting, light-filled stairways, and enters each room by depressing a solid bronze door handle.

Workers move through an interior in which few walls are parallel or perpendicular. The halls within the towers are filled with light and life. They are also the lungs of the building, where an exchange of energy between inside and outside takes place. Even though there are 31 elevators, most prefer the stairways, where they’re likely to encounter their fellow workers.

A sense of aliveness and rejuvenation occurs when they walk alongside the trickling streams of collected rain water that flow through central handrails and banisters. The flowing water in these sculpted handrails also provides a soothing background noise that drowns out distractions.

Absenteeism at the bank has dropped dramatically and initial reports indicate that workers’ blood pressure is improving. Architects Ton Alberts and Max Van Huut estimate the bank may save $1.4 million annually from decreased absenteeism alone.

It was the synergy between the architects, builders, engineers, craftspeople, artists, and interior designers that created such a marvelous sense of collaboration, creativity, and love. All who participated in the building were deeply touched by this process; some of the craftspeople even said they felt like they had participated in the creation of a modern cathedral.

For those who may spend as much as half of their waking lives working in offices, the future may well lie in such "organic" buildings that are designed to stimulate interaction, creativity, and invention.

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