Hard hat
From Wikipedia, the free encyclopedia
A hard hat is a helmet predominantly used in workplace environments, such as construction sites, to protect the head from injury by falling objects, debris and bad weather. They are typically required personal protective equipment where heavy labor is being performed. They were originally made from metal, then fiberglass, but from the 1950s rigid plastic has been the most common material.
Its lower edge sometimes has a small gutter to catch rainwater and shed it off the front peak. Fiberglass hard hats, which are brown, shed water without big drops forming.
Hardhats may also be fitted with a visor (either a welding visor or a thinner version of a riotsquad helmet visor), ear protectors, mirrors for increased rear field-of-view or a helmet light mount.
Blue-collar workers who engage in heavy professions that require protective equipment are sometimes called hard hats.
On construction sites hard hat colors can signify different roles. For instance: white for supervisors, blue for technical advisor's, red for safety inspectors and yellow for workmen.
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[edit] History
Management professor Peter Drucker credits writer Franz Kafka with developing the first civilian hard hat when he was employed at the Worker's Accident Insurance Institute for the Kingdom of Bohemia (1912).[1]
In the USA, the E.D. Bullard Company was a mining-equipment firm in California created by Edward Bullard’s father who was in the industrial safety business for 20 years. His father sold protective hats but they were only made of leather. Edward Bullard, arrived home from World War I with a steel helmet which provided him with an idea. His metal headgear was the inspiration to improve industrial safety. In 1919 Bullard patented a "hard-boiled hat", created through steaming canvas with resin, gluing several layers together which provided that hard molded shape. Within the same year the US Navy commissioned Bullard to create a shipyard protective cap, which began the widespread use of hard hats. Not long after, Bullard developed an internal suspension which would provide a more effective hat.
In 1933 construction began on the Golden Gate Bridge in San Francisco California.[2] This was the first construction site in history which required all employees to wear hard hats, by command of the project chief engineer, Joseph Strauss. He wanted the workplace to be as safe as possible; hence, he placed safety nets and required hard hats while on the job site. Strauss also asked Bullard to create a hard hat to protect workers who do sandblasting. Bullard came up with a design covering the workers face with a vision window and a pump to bring fresh air into the mask. Around 1938 aluminum became a standard for head protection except in electrical applications. In the 1940s fiberglass came into use. A decade later thermoplastics took over because they were easy to mold and shape with applied heat. Today most hard hats are made from a material called High-Density Polyethylene (HDPE).
Brown fiberglass is still preferred by workers who buy their own equipment, for better balance, lighter weight, resistance to scrapes and stains, and the shedding of rain without big drops forming on the edge. These hats also stay on when tilting the head at an extreme angle to do the job.
A type two hard hat has a foam inner liner of Expanded Polystyrene (EPS).
In 1997 ANSI allowed the development of a ventilated hard hat to keep wearers cooler. To it could be added accessories like face shields, sun visors, ear muffs, and perspiration absorbing cloths which line the hats. Today attachments include radios, walkie-talkies, pagers, and cameras.
[edit] Background
A hard hat is worn to prevent electric shock and falling objects from damaging the worker. The suspension connects the head to the hat. It secures the hat, providing spacing between the shell and the head so that if an object strikes the head, a safety distance cushion of approximately 3cm lessens the blow.
A hard hat also gives a worker a distinctive profile, identifiable even in peripheral vision, for safety around equipment or traffic. Safety colors like orange or green do not appear in peripheral vision, but the hard hatted shape of a worker will be avoided.
In 1997, the American National Standards Institute revised its performance standards for hard hats. Conformity to these standards and regulation are not necessary but almost all manufactures comply. For example a type one hard hat provides impact protection from vertically falling objects which will land on the top of the head. A type two hard hat protects from vertical and horizontal threats. There are also standards for electrical use in hard hats, which protect the wearer from electrical current. ANSI also has compliance for hard hats and their combustibility or flammability criteria.
Even if a hard hat is properly inspected and cared for, it should be replaced after five years of use.
[edit] References
- Drucker, Peter. Managing in the Next Society.
- a b Hoppe, Leslie (2004) "From the Hard-Boiled Hat to Today's Skull Bucket: A History of Hard Hats", Bullard Inc., http://www.bullard.com/company/hardhathistory.shtml
- How products are made, "HARD HATS"
[edit] See also
sv:Bygghjälm
