By Ashley Katz
Building controls play an integral role in the green building process. Of course, you can't have a building, green or otherwise, without an architect or an owner - but control professionals are critical to many of the features that define what a green building is.
Launched in 2000 by the U.S. Green Building Council (USGBC), LEED is the nationally accepted standard for high-performance green buildings. It provides a proven framework and benchmarks for green design and construction, and the program encompasses rating systems for every building type and phase of a building life-cycle. LEED recognizes achievement by awarding credits in each of five different performance areas: building site, water efficiency, energy performance, materials and resource use, and indoor environmental quality.
The benefits of LEED certification are numerous; those most frequently cited include huge reductions in energy, water, and materials use, leading to reduced environmental impact and operating costs and increased asset value. Green buildings are also healthier and more comfortable for their occupants, yielding increased tenant satisfaction, higher productivity, and reduced absenteeism.
The LEED Rating System calls upon controls and building automation systems as a means to acquire points in the energy performance and indoor environmental quality categories.
Energy and Atmosphere
Buildings are a major consumer of energy; in fact, buildings in the United States account for 39 percent of total energy consumption. Energy conservation is a focus of the rating system, and green buildings can reduce energy consumption by 30 to 50 percent. One of the energy prerequisites in LEED is fundamental commissioning of building energy systems. The intent of this prerequisite is to verify that the building's energy-related systems are installed and calibrated and perform to the owner's requirements.
The prerequisite notes the importance of commissioning in building design, pointing out that commissioning reduces energy use, lowers operating costs, improves occupant productivity, and verifies that the building systems perform as they are designed. Suggested systems for commissioning include heating, ventilating, air-conditioning, and refrigeration (HVAC&R) systems, and lighting and daylighting controls.
Building owners are encouraged to seek out qualified individuals to lead the commissioning process. Qualified individuals are identified as those who possess a high level of experience in energy systems design, installation and operation, commissioning planning, and process management. Those with hands-on field experience with energy systems performance, interaction, start-up, balancing, testing, troubleshooting, operation, and maintenance procedures, along with knowledge of energy systems automation control, are highly important to the certification of a building.
Indoor Environmental Quality
Another key aspect of the LEED rating system is the quality of the indoor environment. LEED projects are encouraged to enhance indoor air quality in buildings, thus contributing to the comfort and well-being of occupants. LEED-certified buildings promote air quality by designating buildings as nonsmoking; increasing ventilation; eliminating, reducing, and managing the sources of indoor pollutants; and increasing the thermal comfort of the space for occupants.
Building controls can monitor and control the temperature, lighting, and ventilation systems that work within a building. A prerequisite within the indoor environmental quality category is to meet the minimum requirements of sections of ASHRAE 62.1-2004, Ventilation for Acceptable Indoor Air Quality.
Another credit within the indoor environmental quality category requires the monitoring of outdoor air ventilation. Projects are encouraged to have permanent monitoring systems that provide feedback on ventilation system performance to ensure optimal functionality. Monitoring equipment should be configured to generate an alarm when the conditions vary by 10 percent or more from the set point. Buildings professionals should consider installing carbon dioxide and airflow measurement equipment and feeding the information to the HVAC system and/or building automation system (BAS) to trigger corrective action.
As the popularity of green building continues to grow, control professionals with knowledge and experience using these building control technologies will be highly sought after by buildings professionals who wish to achieve LEED certification. To learn more about the LEED rating system and how you can become involved, visit www.usgbc.org.
Ashley Katz (firstname.lastname@example.org) is communications coordinator at the U.S. Green Building Council.