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3.5 Building Elements

U.S. Courthouse at Foley Square, New York, NY
U.S. Courthouse at Foley Square,
New York, NY

This section establishes design guidelines for the various building elements, which are defined as the physical parts of building construction. These may be individual materials, assemblies of materials, equipment, or assemblies of materials and equipment.

It is the architect’s responsibility to specify construction materials and systems appropriate to the final design. For special requirements on fire protection see Chapter 7: Fire Protection Engineering.

Substructure
Ground Water Control. The drainage mat and soil filter should relieve hydrostatic pressure on substructure walls and allow water drainage to the level of the drain. Drainage system piping may be clay tile or rigid PVC. Pipes should not slope less than 1:200. Subsurface drainage should discharge into the storm drain, by gravity if possible. Cleanouts shall be provided at grade to facilitate washing out the system.

Waterproofing. Membrane waterproofing should follow the recommendations of the National Roofing Contractors Association (NRCA) as contained in The NRCA Waterproofing Manual.

Underslab Insulation. Provide insulation under concrete slabs on grade where a perma-frost condition exists, where slabs are heated, and where they support refrigerated structures.

Exterior Closure
Products constructed of carbon steel are not permitted in exterior construction, which includes exterior walls, soffits or roofs, except where protected by a galvanic zinc coating of at least 460 grams per m2 (1.5 ounces per square foot) of surface or other equivalent protection.

Exterior Wall Construction. Brick masonry design shall follow the recommendations of the Brick Institute of America (BIA) contained in the publications, Technical Notes on Brick Construction.

Concrete masonry design shall follow the recommendations of the National Concrete Masonry Association (NCMA) contained in the publication, TEK Notes.

Architectural precast concrete design shall follow the recommendations of the Precast Concrete Institute (PCI) contained in PCI publication, Architectural Precast Concrete, Second Edition.

Exterior limestone veneer design shall follow the guidelines of the Handbook on Indiana Limestone published by the Indiana Limestone Institute of America.

Marble veneer design shall follow the recommendations in Exterior Marble Used in Curtain or Panel Walls published by the Marble Institute of America.

Vapor retarder must be provided in a building envelope where heat loss calculations identify a dewpoint within the wall construction and in any building or part of any building that is mechanically humidified.

Exterior Cladding and Articulation. The use of different exterior materials, window designs, sun control devices and other design elements contribute to the design articulation of a building. Each of these components, their use and how they are combined on a building must be reviewed for opportunities provided for birds to roost (“bird roosts”) on the exterior of the building. “Bird roosts” can create both maintenance and visual problems, particularly in high-rise buildings.

Such opportunities for ‘bird roosts’ must be identified in the design phase and alternatives ways to address this be pursued. Consider the use of steeply sloped surfaces, limited use of horizontal surfaces at window sills, sun control devices or other design features or design approaches to address this issue. See the Sun Control Devices section of this chapter.

Sun Control Devices. Projecting exterior sun screens may be used in addition to interior sun control devices where they are beneficial for building operation and energy conservation. Exterior shutters, blinds and awnings should not be used.

Design elements such as steeply angled fins or large scale gratings, instead of horizontal fins and flat planes, should be considered for sun screen components to provide shading for a building.

Consideration shall be given to operable and fixed sun control devices for maintenance, repair and replacement. Window washing systems used for the facility must also be compatible with any sun screens or sun control devices.

Glazing, shading devices, and sources of illumination should be analyzed in detail to minimize heat gain and maximize direct natural light into all spaces to produce the best microclimate for tenants in building perimeter spaces.

Exterior Soffits. Design exterior soffits to resist displacement and rupture by wind uplift. Design soffits for access to void space where operating equipment is located or maintenance must be performed. Soffits can be considered totally exposed to weather and should therefore be designed to be moisture resistant. Provide expansion and contraction control joints at the edges and within the soffit. Spacing and configuration of control joints should be in accordance with the recommendations of the manufacturer of the soffit material.

Sam Gibbons U.S. Courthouse, Tampa, FL
Sam Gibbons U.S. Courthouse,
Tampa, FL

Operating equipment or distribution systems that may be affected by weather should not be located inside soffits. Where it is necessary to insulate the floors over soffits, the insulation should be attached to the underside of the floor construction so that the soffit void may be ventilated to prevent condensation.

Exterior Windows. Although fixed windows are customary in large, environmentally controlled GSA buildings, in certain circumstances operable windows may be appropriate. Sometimes operable windows can also be used as a means of smoke control. In addition, operable windows may be used where they provide for window washing operations. In such cases, the operable windows should be able to be washed from the interior side. Replacement of windows in historic structures should exactly match original frame and munton profiles. First consideration should be given to rehabilitating the existing windows.

Consideration of glare control plus heating and cooling loads must be factored into decisions on amount and placement of windows.

Aluminum windows shall meet the requirements of ANSI/AAMA Standard 101-85. Only Optional Performance Classes may be used. Metal windows other than aluminum shall meet the requirements of the National Association of Architectural Metal Manufacturers Standard SW-1 for the performance class required. Wood windows should meet the requirements of ANSI/NWMA Standard I.S. 2-87, Grade 60.

Aluminum frames must have thermal barriers where there are more than 1670 heating degree days °C (3,000 heating degree days °F). Window mullions, as much as possible, should be located on the floor planning grid to permit the abutment of interior partitions.

Glazing. The choice of single, double or triple glazed windows should be based on climate and energy conservation and security requirements. Use thermally broken frames when double and triple glazing units are specified. Highly reflective glass that produces mirror images should be used with care to avoid creating glare in surrounding streets and buildings.

Robert C. Byrd Courthouse, Charleston, WV
Robert C. Byrd Courthouse,
Charleston, WV

Condensation Resistance.Windows should have a condensation resistance factor (CRF) adequate to prevent condensation from forming on the interior surfaces of the windows. The CRF can be determined by testing in accordance with AAMA 1502.7, Voluntary Test Method for Condensation Resistance of Windows, Doors and Glazed Wall Sections. Where a CRF in excess of 60 is required, do not use windows unless some condensation can be tolerated or other methods are used to prevent or remove condensation.

Window cleaning. The design of the building must include provisions for cleaning the interior and exterior surfaces of all windows.Window washing systems used in the region must be considered and a preferred system and equipment identified during design. In large and/or highrise buildings, such glass surfaces as atrium walls and skylight, sloped glazing, pavilion structures, and windows at intermediate design surfaces must be addressed. See also the Building Specialties, Window Washing Equipment section of this chapter.

Exterior Doors. Entrance doors may be aluminum and/or glass of heavy duty construction. Glazed exterior doors and frames shall be steel and meet the requirements of SDI Grade III with a G-90 galvanic zinc coating. Vestibules are desired to control air infiltration. Sliding automatic doors are preferred over swinging type. Motion detectors and push plates are preferred over mats as actuating devices.

Overhead coiling doors are preferred for loading docks. At least one personnel door should be provided in addition to the overhead doors.

Oakland Federal Building, Oakland, CA
Oakland Federal Building, Oakland, CA

Roofing. Roofing design shall follow the recommendations of the National Roofing Contractors Association as contained in NRCA publication, NRCA Roofing and Waterproofing Manual. The design of metal flashing, trim, and roofing shall follow the recommendations of the Sheet Metal and Air Conditioning Contractors’ National Association (SMACNA) publication, Architectural Sheet Metal Manual.

Roof Drainage. Dead level roofs are not permitted. Roof drains or scuppers are the only low points permitted. Provide a minimum slope to drains of 1:50 on roofing surfaces.When providing roof slope, consider sloping the structural roof deck. Over the life of the building this may be less expensive than providing tappered insulation each time the roof is replaced. Roofs shall not be used to retain water.

Insulation. Roof insulation should be installed in a minimum of two layers to minimize thermal breaks in the roof system.

Access to Roof. An interior permanent stair should be provided to permit access to roof-mounted equipment. Permanent access to all roof levels should be provided to facilitate reoccurring inspection and maintenance.

Roof-Mounted Equipment. Roof-mounted equipment shall be kept to a minimum and must be housed in penthouses or screened by walls. Penthouses and screen walls should be integrated into the building design and constructed of materials used elsewhere in the building exterior. Some roof-mounted equipment, such as antennae, lightning rods, flagpoles, etc., do not have to be screened, but these elements must be integrated into the building design. Roof-mounted equipment should be elevated as recommended in the NRCA Roofing and Waterproofing Manual and set back from the roof edge to minimize visibility. Critical roof-mounted equipment should be installed in such a way to permit roof system replacement or maintenance without disruption of equipment performance.

Penetrations through the roof to support equipment are extremely vulnerable to leaks. Flashing details must be studied for appropriate continuation of the waterproof barrier. Pitch pocket details should not be used,

No building element may be supported by the roofing system except walkways. Provide walkways on the roof along routes to and around equipment for maintenance.

Skylights and Sloped Glazing. Skylights are defined as pre-fabricated assemblies shipped ready for installation, while sloped glazing is defined as field-assembled. Skylights design shall follow the guidelines of the AAMA Standard 1600. For the design of sloped glazing, two AAMA publications are available: Glass Design for Sloped Glazing and Structural Design Guidelines for Aluminum Framed Skylights.

Skylights and sloped glazing should use low emissivity glass. Placement should be calculated to prevent glare or overheating in the building interior. Condensation gutters and a path for the condensation away from the framing should be designed.

Consideration shall be given to cleaning of all sloped glazing and skylights, including access and equipment required for both exterior and interior faces. See also Building Elements, Cladding and Articulation and The Buildings Specialties,Window Washing Equipment sections of this chapter.

Thermographic Testing. In order to verify performance related to the design intent of the exterior building envelope, regarding thermal resistivity, thermographic testing shall be performed at various conditions on the finished construction and before occupancy. This testing will verify that the actual construction meets the requirements as specified.

Cornerstone
A cornerstone is required for all new buildings as a part of the exterior wall. The cornerstone should be a cut stone block having a smooth face of size adequate to present the following incised letters: UNITED STATES OF AMERICA, (PRESIDENT’S NAME), PRESIDENT, GENERAL SERVICES ADMINISTRATION, (ADMINISTRATOR’S NAME), ADMINISTRATOR, (YEAR OF PROJECT COMPLETION). The words, UNITED STATES OF AMERICA, should be in letters 50 mm (2 inches) high and other letters should be proportionally sized by rank.

All names should be of those individuals in office during project development prior to construction, if construction is completed during a subsequent President’s term of office.

Interior ConstructionPartitions. Partitions should be selected for use based on the type of space and the anticipated activity within that space. The following should be evaluated: the volume of people; their activities; the type, size, weight and function of equipment (mail carts, forklifts, etc.) that will be used in the space; and any free-standing, moveable or wallmounted equipment that will impose lateral loads (builtins, wall-mounted televisions, etc.).

Postal Square, AOC Workstation
Postal Square, AOC Workstation

Each potential wall system must be evaluated for structure, backing, finish and protection factors. GSA prefers partition systems that are simple to construct, made from readily available materials, economical and easily moved and reassembled by common laborers.

Metal stud systems must meet the requirements ASTM C754. The application and finishing of gypsum board should follow standard ASTM C840. Adequate tolerances should be designed where the top of a partition abuts the underside of the building structure; allow for deflection and long term creep.

Partitions used at the perimeter of a humidified space must include a vapor barrier. In computer rooms the need for air plenum dividers below the floors must be checked.

Interior Finishes. Refer to the section on Interior Finishes in this chapter.

Interior Doors. Interior doors in tenant spaces should be flush, solid-core wood doors. Steel door frames should meet the requirements of SDI Recommended Erection Instructions for Steel Frames. Provide matching-edge veneers for transparent-finished wood doors. Avoid the use of wood door frames except to match wood doors in specially designed areas.

Ceiling Suspension Systems. The design of suspension systems for acoustical ceilings must meet the requirements of ASTM C.635 for heavy-duty systems and ASTM C.636. When designing a suspended ceiling system with drop-in components, such as lighting fixtures, specifications may not be incorporated that can only be satisfied by hard metric versions of recessed lighting fixtures unless market research of cost and availability has been done as outlined in Chapter One; General Requirements, Metric Standards, Metric Policy Guidelines.

Access Flooring
Accessible floor systems are a high priority for incorporation in all GSA buildings, where it is practical. They have the potential of requiring the least impact on floor to floor heights for accommodating building systems. The flexibility allowed by accessible flooring recognizes the dynamic changes that occur in the use of the space and the continual upgrades that occur to building environmental and communication systems. Refer also to the Technology Infrastructure section of Chapter 3.

If no load requirements are stated in the building program, design access flooring for 1210 kg/m2 (250 PSF) uniform load and 910 kg (2,000 pound) point load. Generally, floor panels should be concrete filled metal or concrete. Both pedestal and stringer systems are acceptable; however, for heavy cart traffic, stringer systems are preferred. The system must be coordinated with the design of the underfloor junction box for electrical power and communications. Designs should be selected recognizing the potential for frequent removal and replacement of raised access floor tiles. Systems that require extensive bolting and unbolting are not desirable.

For tiles with hard-surface finishes, access floor tiles shall have a high pressure plastic laminate surface; this will reduce static and dust associated with these areas. In order to reduce static in computer areas, consider the use of conductive laminated plastic, bonded to the access panels with a conductive adhesive. The building flooring under the access flooring, typically concrete, should be sealed to prevent the accumulation of concrete dust in this area. Access floor tiles may be finished with carpet tile. Bolted connections between pedestal and floor are preferred in seismic zones.

Building Specialties
Window Washing Equipment. Generally, window washing and exterior maintenance are performed by maintenance contracting firms that provide their own powered platforms, scaffolding, or chair lifts to perform these functions. To accommodate the use of maintenance equipment, suitable engineered systems shall be designed and incorporated into the building design. The design will be for buildings three stories or 12,200 mm (40 feet) and higher, and shall conform to OSHA Standard 29 CFR 1910.66, Subpart F - Powered Platforms, Manlifts, and Vehicle-Mounted Work Platforms, ANSI Standard A120.1, Safety Requirements for Powered Platforms for Building Maintenance, and ANSI Standard A39.1, Safety Requirements for Window Cleaning.

Waste Removal Equipment.Waste is normally removed from GSA buildings by contract maintenance firms. The firm will usually collect the waste from receptacles in the occupied spaces into carts, which will be taken to larger containers at the waste pick-up station. The firm will usually provide the containers as part of its contract.

The minimum architectural requirements for waste removal are: access for waste handling equipment from the occupied areas of the building to the pick-up station; housing for the on-site containers; and maneuvering space for the collection vehicles. In calculating numbers of containers, assume separate containers for recyclable materials (paper, glass and metals).Waste handling stations must be completely screened by walls and doors or gates constructed of materials complementary to that of the building.

Certain buildings may require additional waste handling equipment such as incinerators or compactors. All incinerator designs must be approved by the Environmental Protection Agency. GSA will coordinate this review.

Flagpoles. See Chapter 2: Site Planning and Landscape Design, Landscape Design, Landscape Elements.

Telephone Enclosures. Enclosures for public telephones should be provided in the main lobby, near the cafeteria, near the auditorium and in other building areas serving the public. Accessible public phones must be provided; they must comply with the UFAS/ADA Accessibility Guidelines for number, location type and design.

Shelves shall be provided at phone locations, and shall be designed and constructed to accommodate the weight of persons sitting or leaning on them. Assume a 113 kg (250 pound) load per 300 mm (1 foot) of shelf length. In historic buildings where original telephone enclosures exist, reuse original enclosures to the extent possible and design alterations to be visually compatible with original finishes.

Drinking Fountains. At least one water fountain should be provided on every floor near toilet rooms and near auditoria. One drinking fountain per location, and 50 percent of all fountains in the facility, shall be accessible to disabled persons per ADAAG Guidelines. Retain original fountains in historic buildings, retrofitting hardware and remounting, when possible, to provide access for the disabled. Where modifying historic fountains is not practical (e.g., fountain mounted in stone or other ornamental wall), supplement with new fountains of similar materials and detailing to original fountains.

Window Coverings. All GSA buildings should be equipped with adjustable window coverings. Describe the controls for coverings on clerestory and atria windows, and how they will be serviced for cleaning, maintenance, repair and replacement. In some instances it may be possible to consider automated blinds that respond to sun angle and internal temperatures. This may be particularly beneficial in the southern and southwestern areas of the country.

Ronald Reagan Federal Courthouse, Santa Ana, CA
Ronald Reagan Federal Courthouse,
Santa Ana, CA
Sculpture, Charles Evans Whittaker Courthouse, Kansas City, MO
Sculpture, Charles Evans Whittaker Courthouse,
Kansas City, MO

Artwork, Signage, and Registry of Designers
Artwork. The process of commissioning art for federal buildings and courthouses is a collaboration between GSA, the architect of the building, art professionals and community advisors. The Art-in-Architecture Program strives for a holistic integration of art and architecture. Through collaboration – from the initial concept through construction – the artist, architect, landscape architect, engineer, lighting specialist, and practitioners of other disciplines can work as a team to create new expressions of the relationships between contemporary art and federal architecture. The focus on integrating art with the design of new federal buildings and courthouses is predicated upon substantial involvement and responsibility of the A/E team. Provisions for cleaning, maintenance and security of the artwork should be coordinated with the Facility Manager.

The Art-in-Architecture project shall begin concurrently with the selection of the A/E and be timed so that the artist(s) have sufficient time to collaborate with the A/E firm on design concepts and that the artist be prepared to discuss their art concept at the Concept Presentation.

Please consult the Art-in-Architecture Program Guidelines for additional information.

Fine Arts Program Mission. To manage the portfolio of fine arts assets under GSA’s stewardship to insure their accountability, accessibility, preservation and appropriate use to enhance and promote superior workplaces for federal agencies and the public they serve.

Scope of Collection Statement. The Fine Arts Collection includes commissioned public works of art that enhance the architecture of federal buildings; portable works of art commissioned under the federal patronage of the New Deal; works of art purchased with Art in Architecture (AiA) funds; and maquettes. The collection includes over 17,000 installed or associated paintings, sculpture, architectural or environmental works of art, and graphics dating from the 1850’s. The collection does not include:

  • decorative arts, such as furniture and light fixtures (unless commissioned through the AiA program)
  • architectural ornamentation or details, such as historic mosaic flooring, stenciled borders, ceiling medallions, coffered ceilings, cast eagles, and ornamental molding (unless commissioned through the AiA program)
  • commemorative works of art, such as busts and portraits
  • artwork purchased for office space, such as reproduction prints and posters

Please consult the Fine Arts Program Desk Guide for additional information.

Graphics and Signage. Graphics and signs must be clear and simple, and shall be standardized to ensure easy identification of the building entrance, parking, and all the tenant agencies and services located in the building. Signs combining pictures and printed messages are recommended since they are easier to understand for people who do not read English. Sign design shall comply with the UFAS/ADA Guidelines; Underwriters Laboratory (UL) - Illuminated Signs Standard; Occupational Safety and Health Administration (OSHA) Standards for safety signs; and Federal Standard 795 for signs indicating accessibility to the physically challenged. Signage in historic buildings should be compatible with original signage design, using historic finishes, colors, and typefaces as a guide for new signage design. Serif typeface is acceptable within ADA requirements where adequate contrast, scale, and other design factors ensure signage legibility.

Signage must be designed to be adjustable for tenant moves and changes. The specifications shall ensure that GSA will be provided with the equipment and supplies required to make future signage changes.

Registry of Builders and Designers. A plaque shall be placed inside the building with the names of the individuals on the GSA project design team; the consultant architects and engineers; the onsite construction managers; and the construction workers will be inscribed on the plaque. The GSA Project Manager will provide the specifications for the design and construction of the plaque.


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