Artificial barricade. An artificial mound or revetted wall of earth of a minimum thickness of three feet, or any other approved barricade that offers equivalent protection.
27 CFR § 555.11
When used in this part, terms are defined as follows in this section. Words in the plural form include the singular, and vice versa, and words indicating the masculine gender include the feminine. The terms includes and including do not exclude other things not named which are in the same general class or are otherwise within the scope of the term defined.