Green Buildings: Greening the Air

Wednesday, January 6, 2010

hearst “What do you put in the air?” the building superintendent at the Hearst Tower on 57th Street in New York City says he is frequently asked.

What the people who work there sense as something added is actually something taken away: the off-gassing of toxic chemicals from flooring materials, wall paints and furniture, the accumulated CO2 from a day’s breathing by the people who work there, the lack of adequate moisture in the air – everything that most people who work in office buildings have to live with every day.

Making a building energy-efficient is all the rage, but very little is heard about the crucial balance among the factors that make a building environmentally sound. A building can use little or no energy and make everyone who lives or works in it very sick, or at least chronically unhealthy. The California Air Resources Board recently released a study of new homes in the State. The report revealed that, “Nearly all homes had formaldehyde concentrations that exceeded guidelines for cancer and chronic irritation, while 59 percent exceeded guidelines for acute irritation.” Unlike older houses, most of which leak around windows, doors and electrical and other outlets, these homes were sealed without being correctly ventilated. The money saved on energy was probably spent on medical bills.

The Hearst building has received many awards for being not only energy-efficient but for providing optimum indoor air quality for its occupants. What the 47-story building does have, and what helped it to earn its LEED Gold certification, is a central, air-handling system that responds to local changes in CO2 content and temperature and humidity levels to keep the air feeling fresh and clean.  It helps that the interior designer used low-VOC materials for the walls, floors and furniture, so that there are virtually no toxic chemicals to remove from the air.   It also helps that the substances used to clean the building and its equipment have been selected for their low toxicity.

To make a building both energy efficient and healthy, its designers have to create a balance between the factors that heat, cool and light a building, and the elements that make it healthy and pleasant to live in. To do that they have to seal to the maximum, ventilate at least to the minimum required to keep the air fresh, and hold moisture within the median – not too wet, not too dry.

What the Hearst building and other homes and buildings constructed to LEED and Energy Star standards are providing is controlled ventilation, where the movement and quality of the air in the building is as important as the building’s energy-saving aspect. As the statistics provided by the California Air Resources Board show, most of the homes we’re constructing aren’t built to take indoor air quality – IAQ – into account. And considering the general dissatisfaction much of the workforce expresses with their work environments, we’re doing a bad job of commercial buildings as well.

yawn The discomfort created when buildings fail to provide control over these factors can be felt as the stuffiness or uncomfortable temperature of an office, or a home where everyone is prone to colds and fatigue. While all these symptoms can be attributed to other causes, indoor air quality can be a major factor. But only recently is data beginning to show that even though the toxic chemicals in our building environments are mostly present in very tiny amounts, there are so many of them that the combined dose is often dangerous and, as the hidden cause of illnesses like cancer, sometimes fatal. The growing awareness that so many of our public and private buildings are afflicted with a combination of toxic substances and poor ventilation is hopefully going to create a drive for remediation of existing buildings and better design for new construction.

A basic element of IAQ that is often hardest to control is condensed moisture. When condensed moisture is out of control, the result is mold, which can cause or worsen asthma and a host of allergic reactions, sometimes to a serious degree. Aside from leakage, the most common source of molds is moisture in ducts, which is difficult but essential to control. Since the air in the return ducts is usually humid, even up to 100 per cent, these ducts have to be checked and cleaned and their filters changed regularly. Even the faintest smell of mold should never be ignored. If you can smell it, you have a problem that can only worsen over time and is guaranteed to affect your health to a some degree.

The LEED and Energy Star standards are a critical response to the growing awareness that the use of building construction and cleaning materials that contain volatile organic compounds (VOC’s) is causing not only continuous discomfort but serious illness to families in their homes and to people in their workplaces. These are in turn based on national standards set by ASHRAE, the American Society of Heating, Refrigeration and Air Conditioning Engineers. These are serious, scientifically worked out standards that every architect and engineer involved in construction respects. They specify the minimum amount of air that must be changed per minute for different kinds of spaces, and also specify spaces, like utility closets, kitchens, bathrooms and rooms where smoking is permitted, that must be vented directly to the outside.  Generally, you have to rely on professionals to get it right, and as the California statistic shows, not many of them do. As buildings like the Hearst Tower show us what it means when the design meets or exceeds these standards, we’re hopefully going to move in that direction.

The IAQ and ventilation standards for IAQ for both LEED and Energy Star buildings – and pretty much for the rest of the country –  are set by ASHRAE, the American Society of Heating, Refrigeration and Air Conditioning Engineers. These are serious, scientifically worked out standards that every architect and engineer involved in construction respects. These standards specify the minimum amount of air that must be changed per minute for different kinds of spaces, and also specifies spaces, like utility closets, kitchens, bathrooms and rooms where smoking is permitted, that must be vented directly to the outside.  Generally, you have to rely on professionals to get it right, and as the California statistic shows, not many of them do. As buildings like the Hearst Tower show us what it means to get it right, we’re hopefully going to move in that direction.

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