45 CFR § 1149.45 - How is time computed?
(a) In computing any period of time under this part or in an order issued under it, the time begins with the day following the act, event, or default, and includes the last day of the period, unless it is a Saturday, Sunday, or legal holiday observed by the Federal government, in which event it includes the next business day.
(1) Time calculating example. If the ALJ denies your motion for an appeal on Wednesday, December 10th you have 15 days to file the notice of appeal. Since the 15th day falls on Christmas, a legal holiday observed by the Federal government, the deadline will be the next business day, Friday, December 26th.
(b) When the period of time allowed is less than seven days, intermediate Saturdays, Sundays, and legal holidays observed by the Federal government must be excluded from the computation.
(c) Where a document has been served or issued by placing it in the mail, an additional five days will be added to the time permitted for any response.