50 CFR § 221.3 - How are time periods computed?
(a) General. Time periods are computed as follows:
(1) The day of the act or event from which the period begins to run is not included.
(2) The last day of the period is included.
(i) If that day is a Saturday, Sunday, or Federal holiday, the period is extended to the next business day.
(ii) The last day of the period ends at 5 p.m. at the place where the filing or other action is due.
(3) If the period is less than 7 days, any Saturday, Sunday, or Federal holiday that falls within the period is not included.
(b) Extensions of time.
(1) No extension of time can be granted to file a request for a hearing under § 221.21, a notice of intervention and response under § 221.22, an answer under § 221.25, or any document under subpart C of this part.
(2) An extension of time to file any other document under subpart B of this part may be granted only upon a showing of good cause.
(i) To request an extension of time, a party must file a motion under § 221.35 stating how much additional time is needed and the reasons for the request.
(ii) The party must file the motion before the applicable time period expires, unless the party demonstrates extraordinary circumstances that justify a delay in filing.
(iii) The ALJ may grant the extension only if:
(A) It would not unduly prejudice other parties; and
(B) It would not delay the decision under § 221.60.