People performing tasks, such as maintenance, repair, installation, service and cleaning, are highly vulnerable, and have a higher risk of being killed or maimed through inadvertent operation of machinery and equipment they are working in, on or around.
Where frequent cleaning is required, the guard may be constructed of mesh that prevents intrusion of body parts, but allows for hosing. Food production workplaces, that use conveyors in areas where hygiene or food safety is an integral part of the operation, use fixed mesh guarding of conveyor end rollers.
Working at height. Providing people with a suitable work platform for the task being undertaken reduces the risk of injury from falling from machinery and equipment. Often safe access equipment, made available during installation of machinery and/or equipment, is removed after commissioning.
Heron of Alexandria in his study listed the five mechanisms as the lever, windlass, pulley, wedge, and screw, which were known to set a load in a motion. Flemish engineer Simon Stevin derived the mechanical advantages of the inclined plane that was merged with the simple machines. Leonardo da Vinci also contributed to the study of machines by discovering the classic rules of sliding friction.