D.C. Mun. Regs. tit. 19, r. 19-2209
The ring in an event shall be at least sixteen feet (16') square and at most twenty feet (20') square within the ropes. The ring's floor shall extend beyond the ropes at least twenty-four inches (24"). The ring shall be padded with felt, corrugated paper, matting, or other soft materials to a thickness of at least one and one-half inches (1 1/2"). This padding shall, extend at least one foot (1') beyond the ring's ropes with a top covering of canvas, duck, or similar material tightly stretched and laced into the ring's platform. Material that tends to gather in lumps or ridges may not be used.
The ring shall not be more than four feet (4') above the floor of the building or grounds of an outdoor arena and shall have steps for contestants. The ringposts shall not be more than four inches (4") in diameter, extending from the floor of the building or from the ground to the ringpost height of fifty-eight inches (58") above the ring's floor and shall be wrapped in soft material.
The ring shall have four (4) ropes. Each rope shall be at least one inch (1") in diameter. The lowest rope shall be thirteen inches (13") above the ring's floor; the second lowest rope shall be twenty-six inches (26") above the ring's floor; the third lowest rope shall be thirty-nine inches (39") above the ring's floor; and the highest rope shall be fifty-two inches (52") above the floor. They shall be held together in the center on each side of the ring with a string extending from the top to the bottom rope. The ropes shall be wrapped in soft material.
The promoter shall provide a first aid stretcher which shall be kept under the ring's platform at all contests and ensure the availability of an ambulance on site during the contest.
The promoter shall provide a timekeeper's gong, also referred to as the "bell", which is at least ten inches (10") in diameter and adjusted securely on a level with the ring platform.
D.C. Mun. Regs. tit. 19, r. 19-2209