(a) Generally. Computation of any period of time prescribed or allowed by this part shall begin with the first business day following the day on which the act, event, development, or default initiating the period of time occurred. When the last day of the period computed is a Saturday, Sunday, national holiday, or other day on which the Department of Housing and Urban Development is closed, the period shall run until the end of the next following business day. When any prescribed or allowed period of time is 7 days or less, each of the Saturdays, Sundays, and national holidays shall be excluded from the computation of the prescribed or allowed period.

(b) Entry of orders. In computing any time period involving the date of the issuance of an order or decision by a hearing officer, the date of the issuance is the date the order or decision is served on the parties by the hearing officer or Docket Clerk.

(c) Service by mail. If a document is served by mail, 3 days shall be added to the time permitted for a response.

(d) Extensions of time periods. Except where mandated by statute, the hearing officer (or in the case of a review under §§ 26.26 and 26.27, the Secretary or designee) may upon motion enlarge the time within which any act required by these rules must be performed where necessary to avoid prejudicing the public interest or the rights of the parties.