D.C. Mun. Regs. tit. 23, § 1714
1714.1 In any proceeding before the Board, each party shall have the right to present in person, by counsel or by designated representative, the party's case or defense, including oral and documentary evidence, to submit rebuttal evidence, and to cross-examine opposing witnesses, unless the matter at issue has been dismissed by the Board.
1714.2 Any member of the Board may question any witness at any time during or after examination or cross-examination, subject to objection by a party.
1714.3 Any oral or documentary evidence may be received, but the Board shall exclude irrelevant, immaterial, or unduly repetitious evidence.
1714.4 The Board may impose a time limitation on oral arguments and witness testimony as it deems appropriate.
1714.5 The Board shall afford all parties the opportunity to present oral argument.
SOURCE: Final Rulemaking published at 51 DCR 4309 (April 30, 2004); as amended by Final Rulemaking published at 55 DCR 12991 (December 26, 2008).