The helmets used by the armed services during World War I inspired the inventor of the first hard hat to create the forerunner of the hard hat used today when a "hard-boiled hat" was patented by Edward Bullard back in 1919. The hard hat has become an essential piece of safety equipment for those working on construction projects and elsewhere where the danger of falling objects and loose electrical wires pose a hazard for the safety of a worker's head area.
Thousands of employees who work in construction zones have survived potentially fatal accidents because they were wearing hard hats. The hat is designed to distribute the force of anything that falls onto it as it protects the wearer's head and brain from injury. The hat is also designed to protect the wearer from absorbing any electrical current into the body should a live electrical wire fall atop that person.
The unique design of the hard hat is exactly what makes it such an effective safety device, because it consists of an extremely durable polyethylene shell that floats atop a plastic suspension system which fits inside the dome of the hat. Hats can also be constructed of other materials such as resin, aluminum and fiberglass, so long as the material is relatively lightweight, extremely strong, and easy to mold into a helmet shape.
The hard hat is manufactured by pouring plastic pellets into a helmet-shaped mold. Then the suspension system, also constructed of plastic, is molded on the assembly line to include a headband and a system of strips that almost resembles a cobweb pattern. This nylon suspension system is then attached inside the molded hard hat, and the hat is ready for testing.
Each batch of manufactured hard hats goes through a testing process to be sure that the hat will protect the wearer from at least 1000 pounds of force being dropped onto the hat. The hat is also tested for its resistance to being penetrated by sharp objects. An electrical conductivity test and test to guarantee resistance to flame is also performed before the hard hat can be ready for actual wear. Most hard hats today must be able to withstand up to 30,000 volts of electric current without the current burning through the hat and reaching the wearer's head.
Hard hat manufacturers are constantly testing new materials to make this piece of safety equipment even more fail-safe. Hard hats must be lightweight and comfortable enough to wear for long periods of time, in addition to being sturdy and crush-resistant. They must also be resistant to damage from chemicals spills, extreme heat and ultraviolet radiation.
Hard hats are manufactured to different grades of resistance to shock and electrical current. If your job requires the use of a hard hat, it's important that the model you are wearing is appropriate for the conditions under which you will be working.