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Using Natural Ventilation for Sustainable Construction

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Natural ventilation is a healthy and cost effective way to save energy and provide fresh air for building occupants. It is defined as using passive strategies to supply outdoor air to a building’s interior for ventilation and cooling without using mechanical systems. Natural ventilation has become a key component of green building today and is required in order to be certified by LEED and the Living Building Challenge (LBC).

How it works

During the preconstruction phase of a project, research is done to determine the best positioning of the building to allow adequate ventilation from prevailing winds. There are also design elements that have to be incorporated into a building to allow for the free air access. For example, upper clerestory windows will be installed in the Brock Environmental Center in order to provide free air access to the workspaces below. 

natural-ventilation

During preconstruction, the team will also determine the range of ambient weather variables (i.e. 65-75 degrees Fahrenheit) in which the HVAC system will be turned off and natural ventilation will be used. Humidity and wind speed are also taken into account in order to provide the most comfortable and energy efficient environment for building occupants.

The benefits of natural ventilation

The primary purpose of natural ventilation is to allow the outside ambient weather to provide low humidity, moderate temperature wind currents as an alternate cooling source for the building and provide air circulation throughout. By using this method, building owners are able to save on energy costs by turning off the HVAC system when the temperatures are right. Natural ventilation can replace all or part of a mechanical system—reducing construction, energy and operating costs for the owner.

Indoor climate is critical for human well being. Similar to natural daylighting, natural ventilation helps keep occupants comfortable and healthy and increase productivity and learning.

LEED and LBC requirements

Natural ventilation falls under the Equity and Health petals, two of the seven performance areas, of the Living Building Challenge. The Equity Petal focuses on supporting a just and equitable world. Therefore, a project must not “block access to, nor diminish the quality of fresh air, sunlight and natural waterways.” The Health Petal of LBC focuses on maximizing physical and psychological health and well being of its occupants, so it requires projects to promote good indoor air quality.

According to LEED, the intent of natural ventilation is to “provide mechanical or natural ventilation systems that result in improved occupant comfort over conventional designs, increasing occupants’ well-being and productivity while reducing energy consumption of ventilations systems.” Natural ventilated spaces must follow the terms defined by ASHRAE 62.1, paragraph 5.1.

As the demand for sustainable construction increases, more and more buildings will begin to use natural ventilation to save on energy costs, meet LEED and LBC requirements, and increase air quality and productivity for occupants.

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