The provisions of this chapter shall govern special building construction including membrane structures, temporary structures, pedestrian walkways and tunnels, automatic vehicular gates, awnings and canopies, marquees, signs, and towers and antennas.
Special construction encroaching
into the public right-of-way or public space shall conform
to the pertinent standards set forth in Chapter 32, and other
applicable requirements, including the D.C. Department of
Transportation (DDOT) regulations set forth in 24 DCMR,
and D.C. Official Code, Title 10, Subtitle III.
The provisions of Sections 3102.1 through 3102.8 shall apply to air-supported, air-inflated, membrane-covered cable and membrane-covered frame structures, collectively known as membrane structures, erected for a period of 180 days or longer. Those erected for a shorter period of time shall comply with the
Fire Code. Membrane structures covering water storage facilities, water clarifiers, water treatment plants, sewage treatment plants, greenhouses and similar facilities not used for human occupancy are required to meet only the requirements of Sections 3102.3.1 and 3102.7. Membrane structures erected on a building, balcony, deck or other structure for any period of time shall comply with this section.
Noncombustible membrane structures shall be classified as Type IIB construction. Noncombustible frame or cable-supported structures covered by an approved membrane in accordance with Section 3102.3.1 shall be classified as Type IIB construction. Heavy timber frame-supported structures covered by an approved membrane in accordance with Section 3102.3.1 shall be classified as Type IV construction. Other membrane structures shall be classified as Type V construction.
Exception:
Plastic less than 30 feet (9144 mm) above any floor used in greenhouses, where occupancy by the general public is not authorized, and for aquaculture pond covers is not required to meet the fire propagation performance criteria of NFPA 701.
Membranes and interior liners shall be either noncombustible as set forth in Section 703.5 or meet the fire propagation performance criteria of NFPA 701 and the manufacturer's test protocol.
Exception:
Plastic less than 20 mil (0.5 mm) in thickness used in greenhouses, where occupancy by the general public is not authorized, and for aquaculture pond covers is not required to meet the fire propagation performance criteria of NFPA 701.
The area of a membrane structure shall not exceed the limitations set forth in Table 503, except as provided in Section 506.
Membrane structures shall not exceed one story nor shall such structures exceed the height limitations in feet set forth in Table 503.
Exception:
Noncombustible membrane structures serving as roofs only.
Membrane structures shall be permitted to be utilized as specified in this section as a portion of buildings of other types of construction. Height and area limits shall be as specified for the type of construction and occupancy of the building.
A membrane meeting the fire propagation performance criteria of NFPA 701 shall be permitted to be used as the roof or as a skylight on buildings of Types IIB, III, IV and V construction, provided it is not less than 20 feet (6096 mm) above any floor, balcony or gallery.
The structure shall be designed and constructed to sustain dead loads; loads due to tension or inflation; live loads including wind, snow or flood and seismic loads and in accordance with Chapter 16.
Air-supported and air-inflated structures shall be provided with primary and auxiliary inflation systems to meet the minimum requirements of Sections 3102.8.1 through 3102.8.3.
This inflation system shall consist of one or more blowers and shall include provisions for automatic control to maintain the required inflation pressures. The system shall be so designed as to prevent overpressurization of the system.
In addition to the primary inflation system, in buildings larger than 1,500 square feet (140 m2) in area, an auxiliary inflation system shall be provided with sufficient capacity to maintain the inflation of the structure in case of primary system failure. The auxiliary inflation system shall operate automatically when there is a loss of internal pressure and when the primary blower system becomes inoperative.
Blower equipment shall meet all of the following requirements:
- Blowers shall be powered by continuous-rated motors at the maximum power required for any flow condition as required by the structural design.
- Blowers shall be provided with inlet screens, belt guards and other protective devices as required by the building official to provide protection from injury.
- Blowers shall be housed within a weather-protecting structure.
- Blowers shall be equipped with backdraft check dampers to minimize air loss when inoperative.
- Blower inlets shall be located to provide protection from air contamination. The location of inlets shall be approved.
Wherever an auxiliary inflation system is required, an approved standby power-generating system shall be provided. The system shall be equipped with a suitable means for automatically starting the generator set upon failure of the normal electrical service and for automatic transfer and operation of all of the required electrical functions at full power within 60 seconds of such service failure. Standby power shall be capable of operating independently for not less than 4 hours.
A system capable of supporting the membrane in the event of deflation shall be provided for in air-supported and air-inflated structures having an occupant load of 50 or more or where covering a swimming pool regardless of occupant load. The support system shall be capable of maintaining membrane structures used as a roof for Type I construction not less than 20 feet (6096 mm) above floor or seating areas. The support system shall be capable of maintaining other membranes not less than 7 feet (2134 mm) above the floor, seating area or surface of the water.
The provisions of Sections 3103.1 through 3103.4 shall apply to structures erected for a period of less than 180 days. Tents and other membrane structures erected for a period of less than 180 days shall comply with the
Fire Code. Those erected for a longer period of time shall comply with applicable sections of this code.
Temporary structures that cover an area greater than 100 square feet (9.29 m2), including connecting areas or spaces with a common means of egress or entrance, shall not be erected, operated or maintained for any purpose without obtaining a permit from the code official.
A permit application and construction documents shall be submitted for each installation of a temporary structure. The construction documents shall include a site plan indicating the location of the temporary structure and information delineating the means of egress and the occupant load.
Temporary structures shall be located in accordance with the requirements of Table 602 based on the fire-resistance rating of the exterior walls for the proposed type of construction.
Temporary structures shall conform to the means of egress requirements of Chapter 10 and shall have an exit access travel distance of 100 feet (30 480 mm) or less.
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This section shall apply to connections between buildings such as pedestrian walkways or tunnels, located at, above or below grade level, that are used as a means of travel by persons. The pedestrian walkway shall not contribute to the building area or the number of stories or height of connected buildings.
Connected buildings shall be considered to be separate structures.
Exceptions:
- Buildings on the same lot in accordance with Section 503.1.2 shall be considered a single structure.
- For purposes of calculating the number of Type B units required by Chapter 11, structurally connected buildings and buildings with multiple wings shall be considered one structure.
The pedestrian walkway shall be of noncombustible construction.
Exceptions:
- Combustible construction shall be permitted where connected buildings are of combustible construction.
- Fire-retardant-treated wood, in accordance with Section 603.1, Item 1.3, shall be permitted for the roof construction of the pedestrian walkway where connected buildings are a minimum of Type I or II construction.
Only materials and decorations approved by the building official shall be located in the pedestrian walkway.
Walkways shall be separated from the interior of the building by not less than 2-hour fire barriers constructed in accordance with Section 707 or horizontal assemblies constructed in accordance with Section 711, or both. This protection shall extend vertically from a point 10 feet (3048 mm) above the walkway roof surface or the connected building roof line, whichever is lower, down to a point 10 feet (3048 mm) below the walkway and horizontally 10 feet (3048 mm) from each side of the pedestrian walkway. Openings within the 10-foot (3048 mm) horizontal extension of the protected walls beyond the walkway shall be equipped with devices providing a 3/4-hour fire protection rating in accordance with Section 715.
Exception:
The walls separating the pedestrian walkway from a connected building and the openings within the 10-foot (3048 mm) horizontal extension of the protected walls beyond the walkway are not required to have a fire-resistance rating by this section where any of the following conditions exist:
The previous exception shall apply to pedestrian walkways having a maximum height above grade of three stories or 40 feet (12 192 mm), or five stories or 55 feet (16 764 mm) where sprinklered.- The distance between the connected buildings is more than 10 feet (3048 mm). The pedestrian walkway and connected buildings, except for open parking garages, are equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1. The wall is capable of resisting the passage of smoke or is constructed of a tempered, wired or laminated glass wall and doors subject to the following:
- The wall or glass separating the interior of the building from the pedestrian walkway shall be protected by an automatic sprinkler system in accordance with Section 903.3.1.1 and the sprinkler system shall completely wet the entire surface of interior sides of the wall or glass when actuated;
- The glass shall be in a gasketed frame and installed in such a manner that the framing system will deflect without breaking (loading) the glass before the sprinkler operates; and
- Obstructions shall not be installed between the sprinkler heads and the wall or glass.
- The distance between the connected buildings is more than 10 feet (3048 mm) and both sidewalls of the pedestrian walkway are not less than 50 percent open with the open area uniformly distributed to prevent the accumulation of smoke and toxic gases.
- Buildings are on the same lot in accordance with Section 503.1.2.
- Where exterior walls of connected buildings are required by Section 705 to have a fire-resistance rating greater than 2 hours, the walkway shall be equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.1.
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Access shall be provided at all times to a pedestrian walkway that serves as a required exit.
The unobstructed width of pedestrian walkways shall be not less than 36 inches (914 mm). The total width shall be not greater than 30 feet (9144 mm).
The length of exit access travel shall be 200 feet (60 960 mm) or less.
Exceptions:
- Exit access travel distance on a pedestrian walkway equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 shall be 250 feet (76 200 mm) or less.
- Exit access travel distance on a pedestrian walkway constructed with both sides not less than 50 percent open shall be 300 feet (91 440 mm) or less.
- Exit access travel distance on a pedestrian walkway constructed with both sides not less than 50 percent open, and equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1, shall be 400 feet (122 m) or less.
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Separation between the tunneled walkway and the building to which it is connected shall be not less than 2-hour fire-resistant construction and openings therein shall be protected in accordance with Table 716.5.
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Awnings or canopies shall comply with the requirements of Section 3105, other applicable sections of the Construction Codes, the Zoning Regulations and other applicable requirements. Awnings or canopies projecting over or into public space shall comply with Section 3202.12.
A permit shall be obtained from the code official for the erection, or replacement of any fixed awning or canopy, or any retractable awning.
Exceptions:
A permit shall not be required to erect or replace fixed or retractable awnings projecting 40 inches (1016 mm) or less that are located outside the jurisdiction of the U.S. Commission of Fine Arts or the Historic Preservation Review Board, and are not subject to Section 3202.12, where the awnings meet one or more of the following criteria:
- Awnings installed on detached one- and two-family dwellings and townhouses not more than three stories above grade in height with a separate means of egress; or
- Retractable awnings installed above the first story.
Awnings and canopies shall be designed and constructed to withstand wind or other lateral loads and live loads as required by Chapter 16 with due allowance for shape, open construction and similar features that relieve the pressures or loads. Structural members shall be protected to prevent deterioration. Awnings shall have frames of noncombustible material
with an approved
covering that meets the fire propagation performance criteria
of NFPA 701 or has a flame spread index not greater than 25
when tested in accordance with ASTM E84 or UL723.
The minimum clearance from the sidewalk or any other space used by the public to the lowest part of any fixed or permanent awning shall be 8 feet (2438 mm). Fixed or permanent awnings installed above the first story shall not project more than 5 feet (1524 mm) from the face of the building.
Exception:
Above doors on detached one- and two-family dwellings and townhouses not more than three stories above grade in height with a separate means of egress, the minimum clearance from the sidewalk or any other space used by the public to the lowest part of the awning shall be 80 inches (2032 mm).
The minimum clearance from the sidewalk or any other space used by the public to the lowest part of any retractable awning shall be 8 feet (2438 mm). Retractable awnings shall be securely fastened to the building and, in the fully extended position, no part of the awning shall be closer than 12 inches (305 mm) to the vertical plane of the curb line. Retractable awnings shall be equipped with a mechanism or device for raising and holding the awning in a retracted or closed position against the face of the building.
Exception:
Above doors on detached one- and two-family dwellings and townhouses not more than three stories above grade in height with a separate means of egress, the minimum clearance from the sidewalk or any other space used by the public to the lowest part of the awning shall be 80 inches (2032 mm).
Canopies shall be attached to the building
at the inner end and supported at the outer end by not more
than two stanchions with braces anchored in an approved
manner and shall not extend closer than 2 feet (610 mm) from
the curb line. The minimum clearance from the sidewalk or
any other space used by the public to the lowest part of any
canopy shall be 8 feet (2438 mm). The width of canopies
shall not exceed 8 feet (2438 mm).
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Reserved.
Where the roof or any part thereof is a skylight, the skylight shall comply with the requirements of Chapter 24. Every roof and skylight of a marquee shall be sloped to downspouts that shall conduct any drainage from the marquee in such a manner so as not to spill over the sidewalk.
Every marquee shall be so located as not to interfere with the operation of any exterior standpipe, and such that the marquee does not obstruct the clear passage of stairways or exit discharge from the building or the installation or maintenance of street lighting.
A marquee shall be supported entirely from the building and constructed of noncombustible materials. Marquees shall be designed as required in Chapter 16. Structural members shall be protected to prevent deterioration.
Signs shall be designed, constructed and maintained in accordance with
the requirements of Title 12 of
the DCMR, including, but not limited to, Appendix N of the
Building Code which is hereby expressly adopted and incorporated
by reference, and the Property Maintenance Code,
until such time as the District of Columbia adopts superseding
regulations pursuant to the Sign Legislation.
Towers shall be designed and constructed in accordance with the provisions of TIA-222. Towers shall be designed for seismic loads; exceptions related to seismic design listed in Section 2.7.3 of TIA-222 shall not apply. In Section 2.6.6.2 of TIA 222, the horizontal extent of Topographic Category 2, escarpments, shall be 16 times the height of the escarpment.
Exception:
Single free-standing poles used to support antennas not greater than 75 feet (22 860 mm), measured from the top of the pole to grade, shall not be required to be noncombustible.
Towers shall be located such that guy wires and other accessories shall not cross or encroach upon any street or other public space, or over above-ground electric utility lines, or encroach upon any privately owned property without the written consent of the owner of the encroached-upon property, space or above-ground electric utility lines. Towers shall be equipped with climbing and working facilities in compliance with TIA-222. Access to the tower sites shall be limited as required by applicable OSHA, FCC and EPA regulations.
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Swimming pool enclosures and safety devices shall comply with the requirements set forth in the Swimming Pool and Spa Code.
Automatic vehicular gates shall comply with the requirements of Sections 3110.2 through 3110.4 and other applicable sections of this code.
Vehicular gates intended for automation shall be designed, constructed and installed to comply with the requirements of ASTM F 2200.
Vehicular gate openers, where provided, shall be listed in accordance with UL 325.
Fences shall comply with the requirements of this section, other applicable sections of the Construction Codes and other municipal regulations. All barbed wire and similar fences shall comply with the requirements of Section 3112.4.
Exception:
Fences or portions of fences located on privately-owned land beyond a building restriction line shall comply with the requirements for fences in public space set forth in 24 DCMR § 103.
Fence walls shall conform to the
requirements for fences.
Screens or trellises shall
conform to the requirements for fences.
Application for permits to erect or increase the height of a fence, or change the grade adjacent to a fence, shall be accompanied by an official building plat upon which the proposed fence location is indicated. Review and approval by the Zoning Administrator shall be required before a permit shall be issued.
Exception:
Review or approval by the Zoning Administrator shall not be required where (a) an existing lawful fence is replaced; (b) the extent, location, and the height of the fence is unchanged; and (c) the adjacent grade is unchanged.
Only those portions of the length of
a fence, including footings, which are partly
on each side of a
party line shall be considered as party line fences. Permit
applications for party line fences shall be
signed by the owners
of the adjoining properties on which the fence is to be
located.
A party line fence shall be a
wood, woven wire, or iron fence of open pattern, unless
otherwise agreed upon by the adjoining owners.
Where owners propose to
erect a party line fence over 7 feet (2134 mm) in height in
Residence or Waterfront Districts, or over10 feet (3048
mm) in Mixed Use, Special Purpose, Commercial, or
Industrial Districts, a written agreement as to the height of
the party line fence shall be executed by the owners of the
properties on which the fence is to be located and such
agreement shall be filed with the code official before issuance
of a permit.
Fences abutting a street
shall not exceed 7 feet (2134 mm) in height in Residence
or Waterfront Districts, nor 10 feet (3048 mm) in height in
Mixed Use, Special Purpose, Commercial, or Industrial
Districts.
Within a historic district or
at a designated historic landmark, fences or walls
between the front facade of a structure and the front lot
line shall not exceed 3 feet 6 inches (1067 mm) in
height. Fences between the front facade of a structure
and the front lot line shall be at least 50 percent open.
(The ratio shall be computed in elevation by dividing
the fence elements themselves by the open space
between the fence elements.) The code official is authorized
to allow fences or walls covered by this section to
exceed 3 feet 6 inches (1067 mm) in height upon recommendation
of the Historic Preservation Office.
Fences abutting alleys
shall not exceed 7 feet (2134 mm) in height in Residence
or Waterfront Districts, nor 10 feet (3048 mm) in Mixed
Use, Special Purpose, Commercial, or Industrial Districts.
Exception: The code official is authorized to approve a
greater height where the alley is 15 feet (4572 mm)
wide or more.
Fences located 10 feet (3048 mm) or less from a party line shall not exceed 7 feet (2134 mm) in height in Residence or Waterfront Districts, nor 10 feet (3048 mm) in Special Purpose, Mixed Use, Commercial, or Industrial Districts. Fences shall not obstruct light or ventilation for any required window.
Exception:
Where the written consent of the adjoining owners is filed with the code official, the code official is authorized to approve a greater height, not to exceed 10 feet (3048 mm).
Fences more than
10 feet (3048 mm) from (a) a lot line, including a party
line; (b) an alley; or (c) if applicable, a building restriction
line shall not be subject to height limitations except as
necessary to avoid (i) encroachment on a required yard or
court, or (ii) obstruction of the light or ventilation for any
required window.
Gates shall not exceed the height of
the fence.
Fences, barriers or obstructions,
composed in whole, or in any part, of barbed wire (collectively
referred to as "barbed wire fences") are prohibited in
the District of Columbia, except as expressly permitted by
this section. The term barbed wire shall include (a) barbed,
razor or electrified wire; (b) sharp or jagged glass; (c) metal
such as, but not limited to, razor-spikes; or (d) similar materials.
Barbed wire fences on private property that meet the following
conditions are permitted:
- The barbed wire fence is not located in a Residence District or along the zoning boundary lines of any Residence District, except where the code official determines that the condition or the nature of the improvements located upon the premises pose a significant, demonstrable hazard to members of the public;
- The barbed wire fence is not located on the lot line, or building restriction line if one exists, and does not project beyond the lot line or building restriction line;
- The minimum height of the lowest strand of barbed wire is 6 feet (1829 mm) above adjacent ground; and
- The barbed wire fence complies with any other applicable requirements, including, but not limited to, Sections 802.17, 804.14 and 825.13 of the Zoning Regulations.
No barbed
wire fence shall be erected, constructed, or maintained,
along the lot line or building restriction line if one exists,
or in or upon any street, or other public space, including
but not limited to any sidewalk, public parking or building
restriction area, in the District of Columbia.