Step 2. De-Energize Equipment
To de-energize equipment, you must physically separate or isolate it from its energy sources with energy-isolating devices.
Energized/De-energized/Energized
Push Buttons and Switches
It's important to know that merely turning off equipment does not deenergize or separate it from its energy sources. Push-buttons, selector switches, safety interlocks, control circuit type devices, and programmable logic controllers (PLCs) used in many modern machine applications are NOT considered energy-isolation devices.
Energy Isolation Devices
On the other hand, energy isolating devices do physically prevent the transmission or release of energy. To physically separate or "isolate" the equipment from its energy sources after the equipment has been turned off, you must use energy-isolating devices.
Energy isolation devices may vary in design and configuration. The most common types are:
- Circuit Breakers
- Disconnects
- Plugs
- Valves
- Flanges
Worker Killed by Pressurized HVAC Piping
During a mall expansion project, a pipefitter was working on the installation of a new air-conditioning system at a commercial construction site. While the job was underway, work was performed on HVAC piping that still contained stored pressure. When the piping was opened, the released pressure created a struck-by hazard that fatally injured the worker.
Investigators found that the piping system had not been verified to be free of pressure before work began. They also found that employees had not been properly trained to recognize and avoid the hazards involved in removing end caps from pressurized HVAC piping systems.
The employer was later cited for two serious violations, with proposed penalties totaling $28,135. According to investigators, the employer failed to ensure the piping was fully depressurized before work started and failed to provide proper hazard training related to pressurized HVAC systems.
This fatal incident is a reminder that stored pressure can be just as dangerous as other forms of hazardous energy. Before work begins, employers should make sure piping systems are fully depressurized, use energy-control procedures to address stored pressure hazards, and train workers to recognize and avoid struck-by risks.
Check out this great reference from DE energize that covers how to de-energize various types of energy.
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3-3. What does an energy-isolating device do?
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