Hot Topics: Multiple Energy Sources/Multiple Items of Equipment

Multiple Energy Sources

Equipment or machines that are subject to the Lockout/Tagout standard may possess more than one type of hazardous energy. These may be in the form of mechanical, hydraulic, pneumatic, chemical, thermal, or other types of energy. Any such hazardous energy sources must be locked out/tagged out and all stored energy dissipated and/or restrained before an authorized employee engages in any servicing and maintenance activity.

Hazardous Energy from Interconnected or Nearby Machines or Equipment

When authorized employees implement an energy control procedure for a particular machine or equipment without regard for other machines or equipment in the area, they could still be subject to hazardous energy from interconnected or nearby machines or equipment.

Interconnected Machines or Equipment

If an authorized employee is exposed to the unexpected energization, start up, or release of stored energy from interconnected machines or equipment, the energy control procedures for all interconnected machines or pieces of equipment must be implemented.

Example: An authorized employee is changing a snapped belt on a motor. The authorized employee has deenergized and locked out the motor according to the energy control procedure for that piece of equipment. The motor is located directly over the interconnected conveyor, which is stopped but has not been deenergized or locked out. The conveyor has a different energy isolation point than the motor and may have an auxiliary power source or the capacity to release stored energy and startup unexpectedly. The authorized employee must stand on the conveyor in order to replace the belt. If the conveyor were unexpectedly started, the authorized employee could be severely injured. Since the conveyor is interconnected and exposes the authorized employee to the potential for injury from unexpected startup, the energy control procedures for the motor must ensure that servicing and maintenance employees are not exposed to hazards posed by the conveyor. The energy control procedures for the motor must require that energy control procedures for the conveyor be implemented, as well.

Nearby Machines or Equipment

If an authorized employee, in performing service and maintenance work on a machine or piece of equipment, is exposed to hazardous energy from nearby machines or equipment, the employer is required to provide the employee with protection from these hazardous energy sources.

Example: Using the belt replacement scenario above, the authorized employee could be subject to the hazardous energy associated with a nearby production process where a robot arm is operating. When the robot arm operates, it could strike the authorized employee replacing the belt. In this event, the employer must provide protection from the hazardous energy associated with the nearby robot arm by either:

• Complying with the machine safeguarding standards and effectively guarding the nearby robot arm to not only protect the operators of the equipment but to protect servicing and maintenance employees replacing the belt.
• Locking out or tagging out the nearby robot arm if:
  • the guarding is not adequate, or
  • the design or installation of the equipment would not permit such machine safeguarding, or
  • compliance with the Lockout/Tagout standard, 1910.147, provides the only feasible method.

In either instance, the employer must ensure that servicing and maintenance employees are not subject to hazardous energy from nearby machinery and equipment while carrying out servicing and maintenance activities on machines or equipment.