The two buttons must be pushed at the same time and are located at a distance from each other that prevents simultaneous operation by one hand. The operation should be designed so that if either or both of the buttons are released, the hazardous action of the machinery and/or equipment cannot be reached, or if it can be reached, the mechanism returns to a safe state.
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.
Presence sensing systems. If physical guards cannot be used, then a presence sensing system can be used as a control to reduce risk. Presence sensing systems can be used where people enter areas shared by moving production equipment. Presence sensing systems are capable of providing a high degree of flexibility with regard to access.
A tool generally is any physical item that can be used to achieve a goal, especially if the item is not consumed in the process. Informally, it also describes a procedure or process with a specific purpose.