D.C. Mun. Regs. tit. 24, r. 24-315
Unenclosed sidewalk cafes shall comply with the provisions of this section and §§ 310, 311, 312, 313, and 314, chapter 2 of this title, the Act, and all other applicable District laws and regulations.
The awning, canopy, or umbrellas of an unenclosed sidewalk cafe shall be adequately secured, retractable, or removable. Framing shall be made or constructed of incombustible or fire-resistant materials. The material used to cover the framing shall be flame-retardant and shall be approved by the Fire Chief.
The height of the awning of an unenclosed sidewalk cafe shall not be lower than eight feet (8 ft.) from the floor of the sidewalk cafe.
The valance of the awning shall not exceed twelve feet (12 ft.) and shall not exceed a horizontal plane extending from the first floor ceiling of the adjoining building, whichever is less.
The height of a railing, fence, or planter (including vegetation) shall not be higher than thirty-six inches (36 in.).
Artificial turf, carpet, platforms, or any other surface cover shall be allowed on the floor area only when specifically approved by the Fire Chief and the Public Space Committee.
D.C. Mun. Regs. tit. 24, r. 24-315