The BAS at the International Code Council’s (ICC) LEED® Silver headquarters controls all base building mechanical and lighting controls. (Photo courtesy of Adam Auel for the International Code Council.)
The ICC doesn’t own the building housing its new offices. However, between the site’s location and a considerable commitment by both the owner and the ICC, their unusually shaped building points toward good design and environmental responsibility. See how the HVAC and controls perform alongside the other sustainable elements of the project to deliver a LEED® Silver space.
The International Code Council (ICC) is a membership association dedicated to building safety and fire prevention. As many in the HVAC industry already know, the organization develops the codes used to construct residential and commercial buildings, including homes and schools.
The basic mission of ICC is to protect the health, safety, and welfare of people by creating better buildings and safer communities. The organization decided to take its mission statement one step further when it recently moved its world headquarters from Falls Church, VA to a LEED®-Silver certified building in the heart of Washington, DC.
ICC is now leasing space in the National Association of Realtors® (NAR) Class A, 12-story building, which was completed in October 2004. The $46-million green building is situated on a triangular piece of land on Capitol Hill, on top of a reclaimed brownfield contaminated site that for many decades supported a gasoline station. NAR occupies five floors, while tenants - including ICC - occupy the remaining 48,000 sq ft.
ICC employees moved into their sixth-floor accommodations in December 2006, after finishing the build-out to the necessary green specifications, and by all accounts, they’re very happy in their new, environmentally friendly space.
Green Not the Goal
When ICC personnel first started looking for office space in May 2006, obtaining a lease in a green building wasn’t the primary objective. However, once they found the NAR building, they knew it was the right place for their world headquarters.“We looked at other places, but once we saw this space, we knew this was going to be the headquarters of the organization. There was no question that this was the right choice for ICC,” said Sara Yerkes, senior vice president of government relations for the ICC. “We wanted to walk the walk and not just talk the talk, so we felt this space was perfect for us. The location is outstanding, and the fact that it is a green building fits perfectly with our mission and goals.”
ICC chose a construction company and put together a project team so that build-out could begin in August. Maximizing the 8,200-sq-ft space for the 16 ICC employees was the main objective, and it was decided that offices would work better than cubicles. The building is a triangular shape - similar to a ship - so offices were built all the way around the exterior windows, while the elevator shaft and the bathrooms are located on the inside of the building. A conference room was placed at one of the ends of the “ship,” so occupants can see both 1st Street and New Jersey Avenue from the unusual space.
As can be expected, there were many tenant requirements that ICC had to abide by when building out its space, including specific guidelines for water usage, lighting, and products emitting VOCs. The types of materials and resources used during the build-out were of special concern, because according to the guidelines for the LEED-rated building, materials used must contain a minimum of 5% post consumer recycled content or 10% post industrial recycled content based on overall material cost.
In addition, the guidelines stated that the build-outs must contain at least 20% of materials by cost that were manufactured within 500 miles of the site and at least 10% of materials by cost that were extracted, harvested, or recycled within 500 miles of the site. Following these green rules was sometimes difficult but not impossible, said Yerkes.
“We worked with our architect to select everything, and everything had to meet the LEED Silver requirements. Everything we chose - from the non-endangered wood used for the doors to the recycled fabrics and carpeting - had to be approved by the landlord,” she said. “We purchased all the furniture through local vendors and manufacturers, because that encourages the local economy. Our construction team met every week and they were terrific. We were all very much in sync with each other.”
The biggest challenge Yerkes faced had to do with the carpeting, because there are not that many manufacturers of recycled carpet. “I was told that it was a fairly new product and difficult to install,” she said. “I think as more companies provide green-friendly materials, this problem will go away.”
A VAV unit supplied with tempered outside air and limited resistance heat serves each floor of the ICC headquarters. (Photo courtesy of Adam Auel for the International Code Council.)
HVAC Requirements
The HVAC system that was installed in the NAR building was, for the most part, adequate for ICC’s needs. A VAV unit that is supplied with tempered outside air and limited resistance heat serves each floor of the building, said Laurie McMahon, senior vice president for Cassidy & Pinkard Colliers (C&P), which provides property management and leasing and project management services for the NAR.“The units are condenser water cooled and equipped with a waterside economizer. The coils allow the system to take advantage of the seasonal conditions, reducing mechanical cooling requirements and thus energy consumption,” she said. “A motorized control valve isolates each unit from the condenser water system, allowing partial building operation as off hours tenant needs arise.”
VFDs on the condenser water pumps, cooling tower fans, and floor-by-floor units allow demand specific operation and avoid the need to run the entire system to meet smaller loads. Each unit is supplied tempered outside air from a roof-mounted fan through an air monitor damper controlled by the BAS. The amount of outside air is varied based on the CO2 sensor readings taken throughout the building, and the outside air fan is also equipped with a VFD. Of course, the system utilizes non-CFC refrigerants.
Air is distributed throughout the building via floor-by-floor AHUs serving shut-off type VAV boxes. The building exhaust systems are independent and discharge at the roof where they are separated from the fresh air intakes to avoid recirculation.
The base building design provided that the maximum area served by a box would be approximately 375 sq ft. The limited zone size enables individual comfort and keeps the equipment size small to maintain an 8-ft 8-in. ceiling height with only a 10-ft, 8-in. floor-to-floor height. McMahon noted that the ceiling height posed its own set of challenges, and “close coordination was required with the plumbing, life safety, and mechanical subcontractors.” In addition, low-profile equipment helped achieve the ceiling height goal.
The BAS controls all base building mechanical and lighting controls, including garage ventilation that is triggered by CO sensors. All tenant spaces are built with occupancy sensors and fixture-based daylighting controls throughout.
Additional Conditioning Needed
The base building systems provide standard HVAC services to all but the retail tenants in the NAR building. Additional HVAC systems for conference facilities and computer rooms have been installed in the building by a number of tenants, including ICC. Design and operation of these systems are bound by the tenants’ leases, which state that the HVAC systems “should reflect the green building principles of high ventilation effectiveness.”Specifically, the lease states that the design of the ductwork and the placement of supply air diffusers in the tenant space should be provided with ADPI of no less than 80 cfm. Ceiling diffusers selected must meet this minimum standard on ADPI to achieve the high ventilation effectiveness desired. All flexible ductwork serving the tenant space must be properly installed to provide the design airflows with maximum length of 6 ft, and only non-CFC based refrigerants are allowed in all tenant specified HVAC systems.
In addition, the tenant is required to obtain verification of the performance of any new HVAC, lighting, or daylighting systems for the space. This usually involves the services of a third-party commissioning reviewer to document performance of the tenant’s systems meeting the desired green building goals.
Yerkes said that an additional A/C unit in the conference room was installed during the build-out for that space. “We needed more ventilation, so we had a supplemental unit put in to keep that room cooler. When you fill it up with 30 people, it gets warm fast.”
According to the guidelines, tenants must keep the temperature in the summer at 75°F during occupied hours and 85° during unoccupied hours. In the winter, the temperature must be kept at 70° during occupied hours and 60° during unoccupied hours.
“During the summer, it has to stay at 75°, which is the LEED requirement,” said Yerkes. “It’s difficult to do that in the hot summer, because there’s a lot of glass. There are shades in every window, though, and the landlord asked all tenants to keep the shades down during the hottest days.”
An additional A/C unit was installed in the conference room to provide more ventilation in the space, which seats up to people. In addition, during the hottest days, the tenants are asked to keep the shades down to keep the temperature at a LEED-approved 75°F. (Photo courtesy of Adam Auel for the International Code Council.)
Other Green Features
As a LEED Silver structure, the NAR building has many sustainable features. The reclaimed brownfield site was discussed earlier, and the building is also close to the Union Station metro and multiple metrobus lines, which reduces the need for automobile use by tenants and visitors.The owners of the building have also taken numerous steps to reduce water usage, including the installation of water efficient landscaping. The grounds have been designed with native plant species and perennial plants that are well suited to the climate to further reduce irrigation requirements.
The building utilizes a 10,000-gal underground storage tank to hold captured rainwater, eliminating the need to use potable water for landscape irrigation. The NAR building also has the distinction of being the first building in Washington to be granted permission to use waterless urinals: at the time, the use required a code variance.
As far as energy use is concerned, the building exceeds local performance standards by meeting a more stringent standard than required by local codes and ASHRAE Standard 90.1-1999. According to McMahon, the building owners wanted to achieve a 30% optimization of energy performance over the base case (with the baseline model including a 50% window-to-wall ratio and the design case utilizing an envelope approaching 100% glass). “This required numerous simulations to find a curtainwall that could perform. What was used is a 1-in. double-paned, reflective, low-emitting insulating glazing with argon filled space.”
Because of the abundance of natural daylight within the building, the need for electric lighting is greatly reduced. Each high-efficiency fluorescent light fixture in the tenant space is equipped with an automatic daylight sensor and electronic dimming controls. This allows the output of the fixture to be adjusted based on the amount of available daylight (which happens so subtly that the changes in fixture output are imperceptible), and reduces the amount of electricity required to provide lighting. It also reduced the need for air conditioning, because the fixtures generate less heat. Occupancy sensors are utilized in offices and other enclosed areas to further reduce electricity consumption.
While all these features in the NAR building are designed to reduce energy, lower emissions, and decrease the impact on the environment, the aesthetically pleasing workspace is what Yerkes raves about. “We’re so proud of the building and our space. It’s a pleasant work environment, and we’re very fortunate to be here. It creates the image we want for ICC that we didn’t have before. Where we are now carries a very distinct message: What this organization is, what we stand for, and that we are focused on providing leadership in the areas of public safety and building green.”ES
