(a) Rules. In the construction of this Chapter, the rules and definitions contained in this Section shall be observed and applied except when the context clearly indicates otherwise:
(1) Words used in the present tense shall include the future.
(2) Words used in the singular number shall include the plural number, and the plural the singular.
(3) The word "shall" is mandatory and not discretionary.
(4) The word "may" is permissive.
(5) The phrase "used for" shall include the phrases "arranged for," "designed for," "intended for," "maintained for," and "occupied for."
(b) Definitions. The definitions found in Section 15-4-3 shall be applicable in this Chapter.