1. Scope 1.1 General Clauses 4 to 7 of this Standard cover performance and testing requirements for personal hearing protection devices. Clauses 8 to 12 cover the selection, care, and use of hearing protection devices as required for an effective hearing conservation program. 1.2 Types The following types of hearing protectors are covered in this Standard: earplugs, earmuffs, communication headsets, and helmets equipped with earmuffs. 1.3 Mandatory Language In this Standard "shall" indicates a mandatory requirement; "should" indicates a recommendation or that which is advised but not mandatory; and "may" indicates an advisory or optional statement. Notes accompanying clauses do not include mandatory or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material that is not properly a part of the Standard. Notes to figures and tables are considered part of the figure or table and may be written as mandatory requirements; legends to figures are also considered part of the requirements of the figure.