Energy Isolation - Strategies & Effective Practices to Manage and Mitigate Hazards

Effective Practices to Manage and Mitigate Hazards

Reduce risk by minimizing work on lines or equipment still connected to operating portion of the process unit

• Consider deferring work activities requiring line or equipment opening to a future turnaround or outage when inventories of hazardous materials are at a minimum or eliminated.
• Consider deferring work activities on energized electrical circuits to a future turnaround or outage when these circuits can be properly de-energized.
• For batch processes schedule maintenance and repair activities to avoid running cycles

Properly isolate chemical and thermal energy in lines or equipment to be worked on

• Use blinds or line breaking as a means of isolation, if possible.
• Use double block and bleed for isolation of lines or equipment handling hazardous or hot materials.
• Do not use control valves for isolation.
• Do not use check valves for isolation
• Verify that isolation valves are properly locked so they cannot be operated.

Properly isolated kinetic energy before starting work on the equipment

• Lock-out the energy source to the rotating equipment to be worked on.
• Verify the correct energy source is locked-out by trying to start de-energized equipment in the field.
• Verify that rotating equipment has coasted to a full stop before starting work activities.

Properly isolated electric energy when working on electrical circuits

• All electrical isolation activities should only be performed by electrically qualified personnel and with the proper PPE for electrical isolation.
• Disconnect and lock-out energy sources.
• Control circuit devices, such as push buttons, selector switches, and interlocks, should not be used as the sole means for deenergizing circuits or equipment. Interlocks for electric equipment should not be used as a substitute for lockout and tagging procedures.
• Stored electric energy which might endanger personnel should be released. Capacitors should be discharged and high capacitance elements should be short-circuited and grounded, if the stored electric energy might endanger personnel.
• Verify that the proper energy source is locked-out before starting work activities

Properly isolated hydraulically operated equipment

• De-energized and lock out hydraulic pumps.
• Verify that correct equipment is de-energized by testing in the field.
• De-pressure hydraulic systems to assure that potential stored energy is not release during work activity.

Review the worksite for potential stored energy releases due to gravity

• Support or tie off any piping or equipment that may move (fall or swing to the side) when it is disconnected.
• Use blocks or chains to assure that equipment such as top parts of casting molds or presses do not fall due to gravity during work activities.

Create a safe working environment

• Assure that personnel performing the work install their locks on the equipment (or on a lockbox, if used) and verify that equipment is properly de-energized.
• In every location that the installation of a lock is specified, there should be an installation of a tag
• Ensure that an equipment specific Lock-Out/Tag-Out procedure is available and used.
• Ensure an isolation log is developed, is adequate and is updated (consider marking the P&IDs as well). 
• Require proper PPE to protect personnel during initial line breaking.
• Personnel breaking lines must place themselves in a defensive position to avoid a spray of liquid or release when attempting the initial opening.
• Identify location of the nearest safety shower and eye wash to be used in case of an emergency.

Energy Isolation / Lock Out / Tag Out is often used in conjunction with other SWP activities such as Line Opening, Hot Work, and Confined Space Entry.  Please read those SWPs for details  related to those activities.  Energy Isolation actions related to these other SWPs might include the following.

• Line Opening:  Verify that de-pressurization of lines or equipment and absence of material has been accomplished by opening vents and drains or by other means deemed appropriate.
• Line Opening:  Assure that drains are not plugged giving a false indication that the line is empty.
• Energy Isolation of flammable gas lines
• Confined Space Entry:  Energy isolation of lines containing asphyxiants (e.g. – Nitrogen) or toxic gases.

Identify access issue or congestion in the area

• Assure adequate access to work site is available
• Identify any congestion issues and possible additional hazards (i.e. quarter-turn valves that could be bumped open on another line)
• Apply Lock-Out/Tag-Out/Try procedures to any additional hazards that are identified

Analyze hazards and identify means of control

• Ensure that where work is performed on elevated piping or equipment, the area below the work will be barricaded and splash pans provided as needed.
• Identify all potential sources of hazardous energy and develop proper Lock-Out/Tag-Out procedures to de-energize

Understand operational status

• If line or equipment is isolated with a single valve, consider the possibility of leakage.

Recognize changes in process or work conditions

• A permit for Energy Isolation / Lock Out / Tag Out activities should be re-issued at the beginning of each shift.
• New personnel that are added to a work crew should install their locks prior to performing any work.

Ensure resources to adequately assess safe work activities

• Pressure on authorizing personnel to get permits issued can compromise the safety process through the adoption of a “seems to be OK” process.
• Specify degree of operator presence and inspections required which should be consistent with the magnitude of the identified hazards.

Ensure that all workers are competent to execute their responsibilities

• Provide training to all personnel (including contractors) in Lock-Out/Tag-Out policies and procedures.
• Ensure contractors have required craft qualifications and lock-out/tag-out training.
• Closely supervise all contractors to ensure they are aware of all hazards and how to respond to emergencies.

Communication is essential between the control room, the Operating personnel and the people conducting the work

• Communication with the control room at all times is essential.
• If an emergency alarm is sounded, all work must cease immediately and the work area made safe.