39 C.F.R. § 955.22
Witnesses before the Board will be examined orally under oath or affirmation, unless the facts are stipulated, or the Board shall otherwise order. If the testimony of a witness is not given under oath or affirmation, the Board may warn the witness that his or her statements may be subject to the provisions of 18 U.S.C. 287 and 1001 , and any other provisions of law imposing penalties for knowingly making false representations in connection with claims against the United States or in any matter within the jurisdiction of any department or agency thereof. Upon the request of either party, or if the Board deems it advisable, the Board may exclude witnesses from the hearing room. The Board will not exclude a party who is an individual, the properly designated representative of a party which is an entity, a person whose presence is essential to the presentation of a party's case, or a person required by statute to be present.
39 C.F.R. §955.22