A sense of civic pride and community permeates the newly built Samuel Hadley Public Services Building — a fitting atmosphere for the birthplace of American liberty.

The facility's name honors one of the nation's first patriots, a Lexington, Mass., native (and minuteman) who died at the Battle of Lexington fighting for independence from England. Even the town's public works director is a living nod to local history; as a seventh-generation descendant of Samuel Hadley, William Hadley is carrying on a family tradition of public service.

But don't expect this utilitarian building to look like a quaint historical monument. It was built for the future: to take the next step toward sustainable municipal design. Since its August 2009 opening, it's helped the public works department operate much more safely and less expensively than its centuries-spanning predecessor.

Hadley believes that by setting an example, the facility raises public awareness of the need to manage limited local and national natural resources.

Home to the departments of public works and public facilities, the 9.6-acre campus provides numerous examples of conservation techniques: a rain garden shows how to use rainwater and plants to create a verdant landscape; the front green, which long ago was the town's nursery, takes on the feel of a small arboretum, with educational signs explaining the benefits of planting native species; bio-basins, constructed wetlands, and porous pavement illustrate stormwater management concepts.

Perhaps most significantly for residents, offices wrap around the lobby on both floors — a purposeful and symbolic design element to make residents visibly aware that the building's inhabitants are easily accessible and there to serve them.

TIME FOR SOMETHING NEW

In 1929, Lexington bought an 1800s-era trolley barn from the Middlesex and Boston Railway and converted it into a public works building. Other than an addition in 1966, no major upgrades had been made to the facility since then.

“The building was unsafe, unhealthy, and inefficient,” says Janet Slemenda, principal for HKT Architects Inc.

A study by a structural engineer in 1990, for example, found that the vehicle storage area was structurally unsound. Though once useful for housing long trolley cars, the building was inadequate for today's vehicles; the wood-columned service bays were so narrow that everything had to be moved before a vehicle parked in the back of the garage could get out. Several garage doors were too short to provide sufficient access for larger vehicles.

QUALIFYING FOR SILVER STATUS

In 2004, Lexington's Board of Selectmen approved a policy requiring all new public buildings to be designed and built to meet LEED Silver guidelines.

Three years later, residents voted to fund construction of a new, $25.5 million building by approving a referendum (a debt exclusion override) authorizing the financing of the project outside the limits of a state statute that limits property tax increases. Last year, the tax impact on a $729,000 single-family home was $212, a figure that decreases each year over the bond's 20-year term.

With funding ensured, the town contracted HKT Architects to design the building, in part because the firm had two LEED-certified buildings and multiple public facilities under its belt.

HKT used LEED standards as a guide for incorporating the U.S. Green Building Council's (USGBC) six aspects of sustainability:

Sustainable sites. The top of the facility is a “cool roof” that minimizes the potential for creating an urban heat island.

A green roof over the central storage area keeps the space below warmer in winter and cooler in summer while filtering stormwater runoff from that portion of the roof.

The rest of the roof has a solar reflectance index (SRI) rating of 79. The standard black roof on the typical commercial facility is 0. This “high-reflectance” rate was achieved by specifying a “white roof” system that reflects rather than absorbs sunlight and heat as black roofs do.

The system consists of a steel deck overlaid with polyisocyanurate insulation and a modified bitumen membrane called Ruberoid EnergyCap SBS 30 FR, which is made by GAF Materials Corp. In addition to being white, the membrane meets LEED SRI requirements.

Although it looks flat, the roof tilts very slightly so rain can be collected and reused. Under LEED Sustainable Sites Credit 7.2, the roof is “low slope,” which means it has a slope of less than or equal to 2 inches of slope per 12 inches of rise (2:12).

Stormwater runoff from the white roof is estimated to be 29,052 cubic feet in a 100-year rain event. Therefore, underground infiltration chambers that capture up to 29,200 cubic feet were installed. Rain flows from the roof to the chambers and infiltrates into the ground over time.

Bio-retention and constructed wet-lands also control and treat runoff.

Water efficiency. To reduce potable water consumption, the facility is equipped with low-flow plumbing fixtures and dual-flush toilets.

Rain flowing from the vehicle staging area's roof is stored in 500-gallon tanks installed in 10 locations throughout the site. The 5,000 gallons of “harvested” water fill street sweepers and vac-trucks and supplement the wash bay.

Energy and atmosphere. At the front of the facility, where offices and conference rooms are located, the wall system has almost three times the insulation value of the state's energy code at the time of construction. The rest of the facility has almost two times the insulation value.

In administration areas, HKT specified 2½ inches of rigid insulation with an R-value of 12.5, along with The Dow Chemical Co.'s 1-inch Thermax insulating exterior sheathing with a 6.5 R-value. The same rigid insulation, minus the exterior sheathing, was installed in the minimally heated operations areas: central storage, maintenance, shops, vehicle storage, and wash bay. In those areas, noninsulated exterior sheathing was used instead.

Based on energy modeling performed during the design phase, public works should recoup its investment in higher-than-required insulation values within seven years, according to HKT Project Manager Michael Lawrence.

Lighting and air circulation in the operations areas presented two opportunities to sustainably economize. The areas are enclosed with polycarbonate clerestory, an inexpensive alternative to glass that reduces the need for artificial light during the day. Gravity vents cool the interior spaces while dissipating any carbon monoxide generated from fleet operations, enhancing employee safety.

The maintenance bay's doors face south to make the most of the sun's rays for heat and light during the winter. A canopy above the doors keeps the sun's rays out during the summer.

Large windows throughout all occupied spaces provide natural daylighting, reducing the need for artificial lighting. Employees in office areas and conference and meeting rooms can open and close them as needed, further reducing mechanical heating and cooling requirements.

Materials and resources. Eighty-five percent of the old building, as well as construction waste, was reused or recycled. For example, the old facility's asphalt pavement was ground up onsite and used as structural fill under the new building.

Seventy-five percent of all new building material was extracted, harvested, or manufactured within 500 miles of the project.



SAMUEL HADLEY PUBLIC SERVICES BUILDING

Project delivery method:
Design-bid-build

General contractor:
CTA Construction Inc., Boston

Design:
HKT Architects Inc., Somerville, Mass.

Design and construction:
$25.5 million

Overall size:
82,100 square feet

Administrative area:
16,900 square feet

Vehicle staging/prep:
41,100 square feet

Maintenance area and wash bay:
11,500 square feet

Central storage and shops:
9,200 square feet

Mezzanine-level storage:
3,400 square feet

Green roof:
11,300 square feet

Goal:
U.S. Green Building Council's
LEED Silver certification

Indoor environmental quality. Low-emitting adhesives, sealants, paints, coatings, carpets, and composite wood products were specified whenever possible to minimize the amount of harmful VOC (volatile organic compounds).

Innovation in design. The campus includes a connection to, and destination for, a local bike path.

The design team and construction contractor also worked with the town's composting facility to use the material in all planting areas. They used more than 800 cubic yards of screened loam and 1,150 cubic yards of screened compost.

“This process is a wonderful example of how a community can recycle what some considered waste just a few years ago into a high-quality product,” says Hadley.

MAXIMIZING SITE PLACEMENT

The facility is located within a residential neighborhood, so minimizing noise and light pollution is critical.

To reduce noise on the north and west sides of the facility, where most of the homes are located, highly used areas such as maintenance and exterior storage face south. The vehicle staging and prep area, which is the campus' largest component, extends on an east-west axis through the site, containing noise on the south side while allowing for vehicle circulation within the site. Operations activities for sand and salt sheds are performed mainly inside the building, reducing noise and light levels when snow hits.

Located on a bus route, the facility is easy to get to. It also connects to the Minuteman Bikeway (also known as America's Revolutionary Rail-Trail), and encourages employees to bike to work by providing storage and changing rooms.

The facility earned a 2010 Engineering Excellence Award from the American Council of Engineering Companies and is being reviewed for LEED Silver Certification.

If accepted, it will be one of only a handful of certified public works facilities in the country. Also on the short list are the Naperville Public Works Center and the Oak Park Public Works Facility, both in Illinois, and the Pierce County Public Works building in Spanaway, Wash.

Meanwhile, Hadley is fielding calls and tour requests from municipalities interested in the building's green design elements.

“We're changing the future of public works organizations and the facilities they operate out of,” he says.

—Hirschfeld is a freelance writer in Chicago and editorial intern for PUBLIC WORKS; Sicaras is managing editor of PUBLIC WORKS.

THE EVOLUTION OF A FLOOR PLAN

In January 2006, the Samuel Hadley Public Services Building design team began assessing the various elements of the new public services facility for Lexington, Mass.

The 9.6-acre campus is surrounded on two sides by homes, raising siting and vehicle circulation issues. Other considerations included:

  • Initial, lifecycle, and maintenance costs
  • Impact on operational productivity
  • Employee safety.
  • Looking at these factors helped the team — comprised of HKT Architects Inc., Weston & Sampson Engineers Inc., RW Sullivan Engineering, The Bioengineering Group Inc., Weidlinger Associates Inc., and Advanced Storage Technology Inc. — develop a holistic design with low initial cost and high return on investment.

    The process started with a programming phase to determine space requirements for the building. The design team interviewed future occupants — public works, school facilities, town management, and town engineering employees — to determine what would be needed in required spaces.

    The team then analyzed rooms and occupants' desired sizes against industry standards, and revised accordingly. Room data sheets were reviewed and revised by the occupants.

    Below is a step-by-step description of how the room data sheets evolved into final floor plans.

    Room data sheets

    These are basically performance specifications: size and function of the space (audio-visual equipment; furnishing requirements), building system requirements (types of walls, floors, ceilings; HVAC; electrical and lighting), and adjacencies (which rooms should be close to each other).


    Administration area bubble diagram Facility bubble diagram

    The next step is arranging these spaces most logically. In the first diagram, the public physically accesses several departments but sees almost all of them (indicated by the broken yellow circle) from the lobby. The second diagram places the first one within “administration/operations” to show its relationship to the entire facility. Once future occupants approved the diagrams, they became the backbone of the floor plans, which were flushed out with details from the room data sheets.



    Finalized floor plan

    Detailed information about both the administration and facility spaces: an obvious entrance/exit for the public, secure off-hour public access areas, and a separate employee entrance with easy access to main public works operational spaces.