Control of Hazardous Energy

Lockout/Tagout (LOTO) PROCEDURE

PURPOSE

Authorized workers conduct lockout/tagout (LOTO) in accordance with this procedure to prevent accidental startup of equipment or the unplanned release of energy. The primary purpose of this procedure is to protect workers from injury. A secondary purpose is to protect equipment from damage.

APPLICABILITY

This procedure applies to hazardous energy sources including, but not limited to, electrical, steam, hydraulic, mechanical, chemical, thermal, and pneumatic. Internal or stored energy sources such as charged capacitors, batteries, wound springs, fly wheels, raised loads and thermal sources are also covered under this procedure and must be properly relieved or restrained before activities begin.

AUTHORITATIVE REFERNCES

  • Occupational Safety and Health Administration (OSHA) Standard 29 CFR 1910.147 Control of Hazardous Energy
  • OSHA Standard 29 CFR 1910.269 Electric Power Generation, Transmission and Distribution
  • OSHA Standard 29 CFR 1910.333 Electrical, Selection and Use of Work Practices
  • National Fire Protection Association (NFPA) 70E Standard for Electrical Safety in the Workplace

DEFINITIONS

Administrative Lockout. Locks that are applied to equipment control circuits or energy isolating devices for the purpose of preventing operation by unauthorized workers. Padlocks used for administrative purposes should be accompanied by a control tag that states, “Caution, Operation of this Equipment by Authorized Personnel Only” or “Out of Service.” Administrative lockout shall not be used for isolation of an energy source.
Administrative Tagout. The placement of “Out of Service” or “Authorized Personnel Only” control tags to inform workers that operating restrictions have been placed on a piece of equipment. Administrative tagout can be applied without administrative lockout.
Affected Worker. An individual whose job requires him or her to operate or use a machine or equipment on which servicing or maintenance is being performed under LOTO, or whose job requires him or her in an area in which such servicing or maintenance is performed.
Authorized Worker. An individual who LOTO machines or equipment in order to perform servicing or maintenance on that machine or equipment. An individual who is current in LOTO training and who receives work assignments through his or her line manager requiring LOTO.
Control Circuit. A circuit that contains switching devices that control the activation and/or specific operations of a piece of equipment.
Energy Isolating Device. A mechanical device that prevents the transmission or release of energy. Examples include: circuit breaker, disconnect switch, flow control valve, slide gate, blind flange, block, or other similar device used to block or isolate energy. The term does not usually include push button or other control circuit-type devices.
External Energy Source. Energy source that is external to equipment such as electrical, hydraulic, pneumatic, gas, vacuum, high temperature, cryogenic temperature, or mechanical that could cause harm to workers or equipment.
Internal Energy Source. Energy source such as capacitor, accumulator, air surge tank, battery, hydraulic line pressure, or wound spring that is internal to equipment and could potentially be released and cause injury after external energy sources have been disconnected and secured.
Lockout. The placement of a locking device, such as a padlock, on an energy isolating device, thereby preventing the energy isolating device and the equipment being controlled from being operated until the lockout device is removed. Lockout must be accompanied by tagout.
Tagout. The placement of “Danger Do Not Operate” tags on an energy isolating device to inform workers that the energy isolating device and the equipment being controlled must not be operated. Tagout must accompany a lockout, and may be used alone if the energy isolating device cannot physically be locked out and when alternative isolating procedures are used, such as removal of a circuit breaker or fuse.
Zero-Energy State. A term that applies to equipment or systems status in which hazardous energy sources have been disconnected and secured and internal energy sources have been relieved or restrained in a safe manner.

RESPONSIBILITIES

Environmental Health and Safety (EHS) Office

  • Trains workers to be qualified to perform LOTO.
  • Provides guidance in developing LOTO Equipment Specific Procedures (ESP).
  • Provides guidance in performing regular field practicals.
  • Maintains the completed Field Practical forms.
  • Maintains the completed Non-Routine LOTO Removals forms.
  • Provides LOTO locks and tags to authorized workers.
  • Periodically reviews the procedure and updates it as required.

Supervisor (Supervisor/Line Manager/Principle Investigator)

  • Authorizes workers to perform LOTO, verifying that they are qualified and trained to perform the assigned work.
  • Performs regular field practicals for authorized workers reporting to them.
  • Reviews and approves LOTO ESPs.
  • Verifies that authorized workers have proper personal protective equipment (PPE) and tools, such as LO devices, electrically insulated/rated equipment, for the assigned work.
  • Performs verifications required for non-routine LOTO removal.

Authorized Worker

  • Maintains qualifications.
  • Verifies that LOTO is affectively applied prior to working on equipment that may potentially contain a hazardous energy source, including verification that the equipment is secured and in a zero-energy state.
  • Develop LOTO ESPs when required and obtain approval for supervisor/line manager/principle investigator.
  • Review/follow LOTO ESPs when required.

Affected Workers

  • Does not disturb equipment that is LOTO.

Contractor Host

  • Work with subcontractor to ensure both parties understand each other’s LOTO programs.
  • Ensure both Mines and subcontractor personnel are in agreement on the protection of both parties and the procedures to be used during projects requiring LOTO.

ASSESS WORK ACTVITIES

Perform a hazard assessment prior to performing an installation, service, maintenance or repair activities to determine whether LOTO is required. Determine whether:

  • You are “working” on a machine or piece of equipment that has hazardous energy either internal and/or external.
  • You have to remove or bypass a guardor other safety device that exposes you to hazardous energy in order to perform the work task. Remember some equipment is guarded by distance and if you enter the guarded distance then you are bypassing that guard.
  • You have to place any part of your body into a machine’s point of operation or associated danger zone.
  • You have to clear a jammed mechanism that could expose you to hazardous energy while performing the task or when the jam is removed.

If any of these criterion apply to your “work” then LOTO is required.

Diagnostics and troubleshooting activities are not considered “work” in regard to evaluating whether LOTO is required. Work is the installation, service, maintenance or repair activity. Where ever feasible diagnostic and troubleshooting activities should be performed in a de-energized/ LOTO state.

To determine whether energy sources are hazardous complete the following evaluation:

  • Does the energy source exceed threshold values identified in Table 1?
  • For energy sources that do not exceed threshold values, can you get hurt if there was exposure to or release of that energy when performing the work?

If you answer yes to either of these questions then the energy source would be considered hazardous.

Table 1

Energy Thresholds Requiring LOTO

Form of Energy / Threshold Requiring LOTO*
Electrical (AC – 60 Hz) / >50 V and >5 mA
Electrical (AC – 1 to 3KHz) / <50 V and >1,000 W
Electrical (DC) / >100 V and >40 mA
<100 V and >1000 W
Electrical (Capacitors) / >100 V and >1 J
>400V and > 0.25 J
<100V and >100 J
Electrical (Batteries) / >100 V
<100 V and >1000 W
Electrical (Sub-RF, 1Hz to 3 KHz) / >50 V and >5 mA
Electrical (RF, 3 KHz to 100 MHz) / A function of frequency (Reference IEEE C95.1 2005)
Thermal (Hot) / Liquid or gases ≥125° F (52°C)**, ***
Surfaces ≥140°F (60°C)**,***
Thermal (Cold) / Liquid and surfaces <27°F (-3°C)
Mechanical motion / No threshold established. All mechanical motion shall be controlled.
Potential / No threshold established. All sources shall be specifically evaluated
Pneumatic / >150 psi**
Hydraulic / >150 psi**
Ionizing radiation / No threshold established. All sources shall be specifically evaluated
Non-ionizing radiation / Class 3B or 4 lasers
No threshold established for other non-ionizing radiation sources. All non-laser sources shall be specifically evaluated
Chemical / No threshold established. All sources shall be specifically evaluated

* Sources that do not meet the specified criteria may still be required to be LOTO as part of your hazard assessment

** Double valve isolation or additional control measure should be required when temperatures are >200°F (93°C) or the operating pressure exceeds 500 psi

*** Work controls are in place when working in mechanical rooms and around steam systems.

The energy thresholds have been incorporated into a laminated information card that will be given to workers during training, refer to Appendix D.

SIMPLE LOTO

Equipment meeting the following criteria is classified as a simple LOTO and can be controlled through the use of standard application and removal procedures. A LOTO Equipment Specific Procedure (ESP) is not required for equipment meeting this criteria. Workers must be knowledgeable of the equipment, particularly as it relates to assessing the potential for stored or residual energy. Workers must verify this criteria applies each time before a simple LOTO may be performed.

Simple LOTO criteria:

  • The equipment has no potential for stored or residual hazardous energy, or re-accumulation of stored hazardous energy.
  • The equipment has a single hazardous energy source readily identified and isolated.
  • The isolation and locking out of the energy source will fully de-energize hazardous energy and deactivate the equipment.
  • The equipment is completely isolated from the hazardous energy source and locked out during installation, service, maintenance or repair activities.
  • A single lockout device will achieve a locked out condition.
  • Lockout is under the exclusive control of the authorized worker performing work.
  • Work does not create hazards for other workers.
  • There have not been any accidents involving the unexpected activation or re-energization of equipment during installation, service, maintenance or repair activities.

This LOTO evaluation criteria has been incorporated into a laminated information card that will be given to workers during training, refer to Appendix D.

LOTO EXCEPTION FOR CORD AND PLUG EQUIPMENT

Equipment that can be de-energized for service by unplugging it from its power source does not require LOTO if the following criteria apply:

  • The equipment must be cord and plug connected.
  • The equipment must utilize a single source of power.
  • The single energy source must be readily identifiable.
  • The equipment must not have potential for stored or residual energy.
  • The plug must remain under the exclusive control of the person performing work.

LOTO is required for equipment that does not fall under this exemption.

COMPLEX LOTO

Installation, service, maintenance or repair of equipment not meeting the criteria for a simple LOTO is considered a complex LOTO and requires a LOTO ESP to be developed. The LOTO ESP template can be found in Appendix A.

Workers who have identified their work activity meets the definition of a complex LOTO must:

  • Notify their supervisor that their work activity involves a complex LOTO.
  • Determine with the assistance of their supervisor whether a LOTO ESP has already been developed for that equipment/task.
  • Review the developed LOTO ESP prior to performing work to ensure there have been no changes to the equipment and the scope of the work is adequately addressed.
  • Developed a LOTO ESP if one is not available for the equipment/task. To develop the LOTO ESP walk down the job and equipment with a knowledgeable co-worker, and develop a LOTO ESP using the template in Appendix A. The developed LOTO ESP must be reviewed and approved by the job supervisor prior to performing work.
  • Perform the LOTO in accordance with the ESP.

The LOTO ESP template format is arranged in a manner that will step a worker through a complex LOTO application. The template is fairly self-explanatory, it is recommended that individuals work with EHS when initially working with the template. Clarifying information regarding the template is as follows:

  • The scope/purpose of the LOTO ESP must be sufficiently detailed that it defines the boundaries for the work that can be performed under that ESP. For example if work is to be performed on a specific branch of the steam line the scope should be clear enough to workers that the ESP can only be applied to that branch and not the entire steam system.
  • ESP # - This is an optional field. Assignment of an ESP # provide a unique trackable reference number that can be referred back to when reoccurring work is performed. The ESP number is user defined and managed. It is recommended that the number include the building designator, e.g. HH for Hill Hall; the organization/group performing the work, e.g. HVAC or PH for Physics; and an additional identifier specified by the user group.
  • For step 1, prepare and analyze energy sources identify all of the hazardous energy sources that may be encountered when performing the scope of work defined above. Check all of the hazardous energy sources identified, provide details on that energy source and identify whether there is stored energy associated with the identified hazardous energy source.
  • For step 5, isolate and control hazardous energy information that should be annotated includes:
  • Component and its location –Identify the location of the isolation device, this may be in a different location than the work being performed and provide specifics as to the device to be isolated. Examples include GRLA Electrical Room, Panel LEV1, circuit 7, 9, 11, or Steam Tunnel by Brown Hall, steam, HV10.
  • Alignment position – Note what position the isolation device should be placed in to achieve energy isolation. For example a breaker or disconnect switch you would note that it needs to be in the open/off position, or a hand valve needs to be in the closed position.
  • Verification Method – Identify what actions need to take place to ensure the isolation method was effective in controlling the hazards. For example for an electrical system you want to follow step 7.C and measure voltageat incoming power to fan motor, or verify there is no pressure in a line by observing pressure indicator PI20.
  • PPE required for verification – Identify what PPE is required to safely perform the zero energy verification. For example to verify zero energy on an electrical you may require dielectric gloves and arc flash PPE rated for 4 cal/cm2, or it may be as simple as requiring safety glasses to read pressure gauge.
  • For step 6, isolate and control hazardous energy, describe blocks –Identify if there are hazards that need to be controlled where a lock cannot be installed and installation of blocks, removal of linkages or lifting of leads are required to control the hazard. For example to prevent rotation of a fan blade you would install blocks to prevent rotation, or when working on a battery bank you would lift leads to reduce the voltage and power below a hazard threshold.
  • For step 7A, dissipate stored energy – Identify how stored energy will be dissipated before an individual can safely work on the equipment, information that should be annotated includes:
  • Stored energy location – This location could be the system you are working on such as steam lines or a sub-component of the system such as VFD.
  • Type of stored energy – List the form of stored energy identified in step 1.
  • Release procedure – Identify how the stored energy is to be dissipated. For example the release procedure may be to wait 5 minutes for the bleed down resistor on a capacitor to dissipate the energy; open vent line at HV3 to relieve pressure, or wait 2 hours to allow equipment to cool down.
  • Method of verification – Identify what actions need to be taken to verify the energy dissipation measures were effective. For example to verify a capacitor has been discharged follow step 7C and measure voltage at capacitor; or ensure temperatures are less than 140°F at temperature indicator TI6.

TAG OUT ONLY

A Tag Out Only is only allowed when a lock cannot be applied to the machine or equipment to isolate energy when it is being serviced, maintained or repaired. If a lock cannot be applied then additional measures must be taken to provide an equivalent level of safety such as:

  • Removing an isolating circuit element.
  • Blocking a control switch.
  • Opening an extra disconnecting device.
  • Removing a valve handle.

Tag Out Only situations must be treated as a complex LOTO. Refer to the requirements in the complex LOTO section above.

LOCKOUT LOCKS

Mines will use red master locks in LOTO applications. These locks will be individually keyed but not individually assigned with exception for those assigned to the electricians in the electrical shop. The electricians will use a set of common keyed locks and these locks will be assigned to individual electricians. The electricians will not be able to share their locks with other qualified workers. Other organizations may be allowed to have common keyed locks if a need has been demonstrated to EHS and they understand that these locks may not be shared with other qualified workers.

LOTO APPLICATION

All LOTO shall follow the following applications steps. Complex LOTO may have additional application steps identified within the ESP.

  • Prepare for shutdown. Before the equipment or machine is turned off, know the type and magnitude of the energy, the hazards of the energy to be controlled, and the method or means to control the energy. Ensure the necessary tools, materials, and PPE is available to LOTO the equipment andperform the work.
  • Notify Affected Workers. Before beginning work on equipment or systems, notify users and workers in the area who could be affected by the shutdown. If possible, schedule and coordinate work with other workers to minimize programmatic interruptions.
  • Shut down the equipment. Turn off or shut down the equipment using the procedures for that equipment. Complete an orderly shutdown to avoid additional or increased hazards to workers as a result of the equipment stoppage.
  • Physically disconnect and isolate energy sources. Physically disconnect and/or shut off the energy source with the appropriate energy isolation device and secure in the off/disconnect position. Energy isolation needs to be at the input power source, not the control circuit.
  • Lock out the energy isolating device.Each worker performing work must apply a red Master lock to the energy isolation device. Workers must not rely on another person’s LOTO for protection. When more than one individual is working on the same equipment, a group lock box or multi-lock hasp must be used and each worker must apply their lock.
  • Tag out the energy isolating device.Each worker performing work must install a “Danger Do Not Operate” control tag at the energy isolation device or group lock box. Mark the control tag with name and phone number of the person performing LOTO.
  • Perform zero energy verification. Prior to starting work on machines or equipment that has been LOTO, verify that isolation and de-energization of the equipment has been accomplished for each energy source. To perform a zero energy verification on an electrical circuit a volt meter must be used while wearing the appropriate PPE.

USE OF A GROUP LOCK BOX