Where access is not anticipated, a fixed guard can be permanently applied by a bonding agent, welding, or secured with one-way screws. If access is generally not required, a permanently fixed barrier is the preferred option.
The idea of a simple machine originated with the Greek philosopher Archimedes, who studied the machines, lever, pulley, and screw, and discovered the principle of mechanical advantage in the lever. Furthermore, the Greek Philosophers defined the classic five simple machines, which were used to roughly calculate the mechanical advantages.
In terms of time and ongoing administration by managers and employers to ensure the desired behaviour occurs, administrative controls can be the most expensive and least effective form of hazard control.
Note: The use of PPE and administrative controls are low or last order controls used to deal with any residual risk associated with the hazard. As such, these last order controls can be used in support of higher order controls that deal with a hazard at its source and should not be considered as the sole means of control. These types of risk controls require constant monitoring and reinforcement.