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A hard hat is a type of helmet predominantly used in workplace environments such as industrial or construction sites to protect the head from injury due to falling objects, impact with other objects, debris, rain, and electric shock. Suspension bands inside the helmet spread the helmet's weight and the force of any impact over the top of the head. A suspension also provides space of approximately 30 mm (1.2 inches) between the helmet's shell and the wearer's head, so that if an object strikes the shell, the impact is less likely to be transmitted directly to the skull. Some helmet shells have a mid-line reinforcement ridge to improve impact resistance. The rock climbing helmet fulfills a very similar role in a different context and has a very similar design.
A bump cap is a lightweight hard hat using a simplified suspension or padding and a chin strap. Bump caps are used where there is a possibility of scraping or bumping one's head on equipment or structure projections but are not sufficient to absorb large impacts, such as that from a tool dropped from several stories.
In the early years of the shipbuilding industry, workers covered their hats with pitch (tar), and set them in the sun to cure, a common practice for dock workers in constant danger of being hit on the head by objects dropped from ship decks.
Management professor Peter Drucker credited writer Franz Kafka with developing the first civilian hard hat while employed at the Worker's Accident Insurance Institute for the Kingdom of Bohemia (1912), but this information is not supported by any document from his employer.
In the United States, the E.D. Bullard Company was a mining equipment firm in California created by Edward Dickinson Bullard in 1898, a veteran of the industrial safety business for 20 years. The company sold protective hats made of leather. His son, E. W. Bullard, returned home from World War I with a steel helmet that provided him with ideas to improve industrial safety. In 1919 Bullard patented a "hard-boiled hat" made of steamed canvas, glue and black paint. That same year, the U.S. Navy commissioned Bullard to create a shipyard protective cap that began the widespread use of hard hats. Not long after, Bullard developed an internal suspension to provide a more effective hat. These early designs bore a resemblance to the military M1917 "Brodie" helmet that served as their inspiration.
On the Hoover Dam project in 1931, hard hat use was mandated by Six Companies, Inc. In 1933, construction began on the Golden Gate Bridge in San Francisco California. Construction workers were required to wear hard hats, by order of Joseph Strauss, project chief engineer. Strauss strove to create a safe workplace; hence, he installed safety nets and required hard hats to be worn while on the job site. Strauss also asked Bullard to create a hard hat to protect workers who performed sandblasting. Bullard produced a design that covered the worker's face, provided a window for vision and a supply of fresh air via a hose connected to an air compressor. In those times many workmen's safety helmets were made of steel.
Aluminum became a standard for hard hats around 1938, except for electrical applications. MSA introduced the new plastic Skullgard Helmet in 1930 for the metals industry to withstand radiant heat loads of up to 350 °F (177 °C). New plastic Bakelite was used to provide protection rigid enough to withstand hard sudden impacts within a high-heat environment but still be light enough for practical use. The machinery of the times required that helmet materials used be electrically non-conducting. Bakelite resin compounded with wire screen and linen, the Skullgard Helmet is still manufactured. MSA also produced a low-crown version for coal miners known as Comfo-Cap Headgear.
Fiberglass came into use in the 1940s.
Thermoplastics took over in the 1950s, as they are easy to mold and shape with heat and cost less to manufacture. In 1952, MSA offered the Shockgard Helmet to protect electrical linemen from electrical shock of up to 10,000 volts. In 1961, MSA released the Topgard Helmet, the first polycarbonate hard hat. 1962 brought the V-Gard Helmet, which today is the most widely used hardhat in the United States. Today, most hard hats are made from high-density polyethylene (HDPE) or advanced engineering resins, such as Ultem.
In 1997, ANSI allowed the development of a ventilated hard hat to keep wearers cooler. Accessories such as face shields, sun visors, earmuffs, and perspiration-absorbing lining cloths could also be used; today, attachments include radios, walkie-talkies, pagers, and cameras..
Because hard hats are intended to protect the wearer's head from impacts, hats are made from durable materials, originally from metal, then fiberglass, and most-commonly (from the 1950s onward) rigid plastic.
Some contemporary cap-style hard hats feature a rolled edge that acts as a rain gutter to channel rainwater to the front, allowing water to drain off the bill, instead of running down the wearer's neck. A cowboy hard hat is a hard hat resembling a wide brimmed cowboy hat, although some organizations disallow their use.
Organizations issuing hard hats often include their names and/or logos (or some other message) on the front of each hard hat.
Hard hats may also be fitted with:
- A visor:
- An extra-wide brim attachment for additional shade.
- Ear protectors.
- Mirrors for increased rear field-of-view.
- A small device that is used to mount a headlamp or flashlight to a hard hat. The mounting device frees hands to continue working rather than having to hold a flashlight.
- A chinstrap to keep the helmet from falling off if the wearer leans over.
- Thick insulating side pads to keep sides of the head warm. Examples are seen in Ice Road Truckers.
- Silicone bands stretched around the brim for color worker ID and Hi Viz night retro-reflectivity.
Colors and identification
Hard hat colors can signify different roles on construction sites. These color designations vary from company to company and work site to work site. Government agencies such as the United States Navy and DOT have their own hard hat color scheme that may apply to subcontractors. On very large projects involving a number of companies, employees of the same company may wear the same color hat.
Supervisors often are not familiar with all workers on a construction site. Often, stickers, labels and markers are used to mark hard hats so that important information can be shared. Paint or permanent markers can degrade the plastic in hard hats; instead, labels or masking tape are often applied to a hard hat with the worker's name written on it. Stickers with company logos are common.  Stickers that indicate a worker's training or qualifications are also common; many companies provide ready-made stickers to indicate that a worker has been trained in electrical safety, confined space safety, excavation trench safety, or operation of specialized equipment. Environmental monitors often make stickers to indicate that the worker has been educated on the risk of unexploded ordnance or the archaeological/biological sensitivity of a given area. Stickers may indicate who is authorized to be present on site. Unions may offer free stickers for hard hats and other objects. 
A hard hat also provides workers with a distinctive profile, readily identifiable even in peripheral vision, for safety around equipment or traffic. Peripheral vision registers shapes but not colors; the obvious shape of a hard hat is therefore easier for machine operators to recognize and avoid. Some companies also require reflective tape to be applied to hard hats to increase visibility of workers at night.
OSHA regulation 1910.135 states that the employer shall ensure that each affected employee wears a protective helmet when working in areas where there is a potential for injury to the head from falling objects.  Additionally, the employer shall ensure that a protective helmet designed to reduce electrical shock hazard is worn by each such affected employee when near exposed electrical conductors which could contact the head. 
The OSHA regulation does not specifically cover any criteria for the protective helmets, instead OSHA requires that protective helmets comply with ANSI/ISEA Z89.1-2014 – American National Standard for Industrial Head Protection. 
Each hard hat is specified by both Type and Class. Types include:
- ANSI Type I / CSA Type 1 hard hats meet stringent vertical impact and penetration requirements.
- ANSI Type II / CSA Type 2 hard hats meet both vertical and lateral impact and penetration requirements and have a foam inner liner made of expanded polystyrene (EPS). 
- Class E (Electrical) provides dielectric protection up to 20,000 volts.
- Class G (General) provides dielectric protection up to 2,200 volts.
- Class C (Conductive) provides no dielectric protection.
A hard hat is specified by both Type and Class; for example: Type I Class G.
ANSI standards for hard hats set combustibility or flammability criteria. ANSI Z89 standard was significantly revised in 1986, 1997 and 2003. The current American standard for hard hats is ISEA Z89.1-2009, by the International Safety Equipment Association that took over publication of the Z89 standard from ANSI. The ISO standard for industrial protective headgear is ISO 3873, first published in 1977. 
In the UK, the Personal Protective Equipment (PPE) Regulations 1992 specifies that hard hats are a component of PPE and, by law, all those working on construction sites or within hazardous environments are required to wear hard hats.
In Europe all hard hats must have a manufacturer set lifespan, this can be determined from the expiry date or a set period from the manufacture date, which is either stuck to the inside or embossed in the hard hat's material.
|Wikimedia Commons has media related to Hard hats.|
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- Drucker, Peter. Managing in the Next Society. See: Franz Kafka, Amtliche Schriften. Eds. K. Hermsdorf & B. Wagner (2004) (Engl. transl.: The Office Writings. Eds. S. Corngold, J. Greenberg & B. Wagner. Transl. E. Patton with R. Hein (2008)); cf. H.-G. Koch & K. Wagenbach (eds.), Kafkas Fabriken (2002).
- "Hard Hat Types & Class Standards | Cooper Safety Supply". www.coopersafety.com. Retrieved 2021-05-28.
- "Cowboy Hard Hat Inventor – Bret Atkins". Archived from the original on 2010-08-14. Retrieved 27 Sep 2010.
- "Hard Hat Color Code - What Do Hard Hat Colors Mean?". Hard Hat Expert. 2018-08-22. Retrieved 2021-05-28.
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