18 Del. Admin. Code § 1313-10.0
In computing any period of time prescribed or allowed by this Regulation, the day of the act or event after which the designated period of time begins to run shall not be included. The last day of the period so computed shall be included, unless it is a Saturday or Sunday, or other legal holiday, or other day on which the Department is closed, in which event the period shall run until the end of the next day on which the Department is open. When the period of time prescribed or allowed is less than 11 days, intermediate Saturdays, Sundays, and other legal holidays shall be excluded in the computation. As used in this section, "legal holidays" shall be those days provided by statute or appointed by the Governor or the Chief Justice of the State of Delaware.
18 Del. Admin. Code § 1313-10.0
20 DE Reg. 372 (11/1/2016) (Final)