Full definition
A rigid protective helmet worn to shield the head from impact by falling objects, bumps against fixed objects, and electrical contact hazards. Per ANSI/ISEA Z89.1 (US) and NOM-115-STPS (Mexico): Type I (top impact protection only) and Type II (top and lateral impact protection — increasingly required). Electrical classes: Class E (electrical, rated for 20,000V — for electrical workers), Class G (general, rated for 2,200V — standard industrial), and Class C (conductive, no electrical protection — not for electrical work). Shell material: HDPE (most common, good impact, UV resistance), ABS (better heat resistance), and fiberglass/composite (highest heat resistance, electrical insulation). Suspension: 4-point or 6-point (better force distribution) ratchet adjustment. Accessories: face shields, earmuff attachments, chin straps, and hard hat lights. Replacement: per manufacturer guidelines, typically every 5 years for the shell (2 years in harsh UV/chemical environments) and 12 months for the suspension. Hard hats must be inspected before each use: check for cracks, dents, chalking (UV degradation), and loose/damaged suspension. Never drill holes, paint with solvents, or store in direct sunlight. Per OSHA 29 CFR 1926.100, ANSI Z89.1-2014, and NOM-115-STPS-2009.