Industrial hard hats protect the heads of workers from falls and from impacts by sharp or blunt objects. Typical users include construction and warehouse workers and repairmen.
A hard hat's shell is designed to resist penetration by sharp objects and its suspension system of straps connected to a headband distributes the force of a localized blow over a broader area. The typical suspension system holds the shell at least 1.25 inches away from the wearer's head.
Safety hats of some sort go far back in history; but the early industrial ones such as those worn by miners merely protected against abrasions and cuts and were typically simple leather caps. The first effective head protection was developed for military use, starting in ancient times. Pictures on classic Grecian ceramics and temple carvings on the Acropolis and other sacred sites illustrate warriors wearing elaborate plumed metal helmets designed to protect against sword blows. Medieval European knights often wore full metal headpieces that guarded against smashing, slashing, and stabbing. All these were worn over heavy leather and fabric liners that protected skulls from helmet abrasion and provided further protection against injury.
By World War I simple domed steel helmets were designed to protect trench warfare fighters from wounds to their exposed heads. This idea was brought home to civilian use where it inspired the first industrial hard hats such as those used in post-WWI shipyards and on the Golden Gate Bridge project where safety was made a priority and head protection were mandatory.
Various materials were utilized for industrial hard hats over the years, beginning with stiffened leather, then steel, then aluminum, then fiberglass. Suspension systems were introduced early on to replace or supplement fabric liners, which greatly improved protection against concussion and skull fracture while increasing wearer comfort. By the 1950s thermoplastics were introduced in the manufacturing process, allowing easier molding for optimum shape and comfort, plus light weight and protection from electrical shock.
Modern hard hat shells are typically made of polyethylene or polycarbonate resin although such other materials as fiberglass, resin-impregnated textiles, or aluminum may still be used. Because of its strength, light weight, ease of molding, and non-conductivity, high-density polyethylene (HDPE) is used in most head protection. Suspension systems for modern industrial hard hats consist of strips of nylon webbing and bands of HDPE, nylon, or vinyl. Along with the suspension system, most Type II hats also use a foam liner.
By the late 1990s a change in ANSI testing procedures led to development of head protection with ventilation holes for coolness without compromised safety. Decorations were added as an option to boost the morale of workers wearing head protection, who now could wear a favorite sports team's logo or a patriotic design if they chose.
Accessories for head protection have become more sophisticated. Common accessories include transparent face shields, sun visors, sound-muffling ear covers, rear-view mirrors, perspiration-absorbing cloth liners and even electronic accessories. Brow pad choices for increased wearer comfort include foam-backed vinyl, foam-backed cotton terry cloth, and sweat-absorbing specialty fibers.
Under 1997 American National Standards Institute (ANSI) standards, Type I hats provide specified levels of protection from impact and penetration to the top of the head; Type HI hats also provide specified levels of protection for impact and penetration to the side of the head. Three class designations indicate the degree to which a hard hat protects the wearer from electrical current. ANSI-compliant head protection must also meet flammability criteria.
In addition to meeting specifications, hard hats must be properly cared for to ensure continuing effectiveness; and even with proper care and no damaging impacts, all hard hats should be replaced after five years use.
In the 21st century, the industrial hard hat has come a very long way from the simple leather caps worn by medieval miners and the massive metal helmets worn by knights; and the pace of improvement has accelerated in recent years. One can only imagine what further changes the future may bring.
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