ES&H Manual



6110 Appendix T1

Lock, Tag, Try (LTT) Procedure



1.0             Purpose


This appendix contains the guidelines for locking and tagging out of hazardous energy sources when maintenance or service work is to be performed. Lock, Tag, Try (LTT) references in this appendix apply to maintenance, service, and construction type work activities when performed by lab employees. Refer to ES&H Manual Chapter 6111 Administrative Control Using Locks and Tags for administrative configuration control applications.

Configuration management requirements for equipment specific LTT procedures include:

·         Document numbers

·         Owner identification

·         Revision number, if applicable

·         Date of efficacy

·         Expiration/review date

·         Approval record

·         Change record

·         Archival of previous versions


2.0             Responsibilities

NOTE:     Management authority may be delegated to a task qualified Jefferson Lab employee at the discretion of the responsible manager.

2.1              Anyone at Jefferson Lab

·         Recognize and respect LTT measures.

·         Do not remove any lock or tag except those meeting the criteria outlined within ES&H Manual Chapter 6110 Appendix T2 Special Lock and Tag Removal Procedure.


2.2              Qualified Tagger

·         Maintain appropriate LTT training (SAF 104 Lock, Tag, Try).

·         Obtain specific LTT training on equipment being serviced.

·         Perform LTT procedure process steps listed below.

2.3              Supervisor

·         Only assign Qualified Taggers, and provide equipment-specific LTT training, for equipment under your authority.

·         Maintain familiarity with Jefferson Lab's LTT programs and procedures. (If you supervise employee(s) who use LTT procedures.)

·         Perform inspections for compliance with lock and tag procedures as part of regular supervisory oversight.


2.4              Subcontracting Officer’s Technical Representative (SOTR)

·         Maintain LTT qualifications. (If they supervise subcontractors who perform LTT on site.)

·         Provide equipment-specific LTT procedures to subcontractors on an as needed basis.

·         Implement group LTT and act as Group LTT Coordinator in accordance with ES&H Manual Chapter 6110 Appendix T3 Group Lock, Tag and Try Procedure if Jefferson Lab employee(s) and subcontractor(s) are concurrently working on the same equipment/system.

·         If the subcontractor elects to use the Jefferson Lab program, ensure they perform the following:

o   Complete and maintain appropriate LTT training (SAF 104 Lock, Tag, Try) and equipment specific training;

o   Participate, if requested, in OSHA required annual JSA LTT review;

o   Undertake corrective actions, including retraining of staff and subsequent demonstration of proficiency, if JSA or subcontractor observations indicate unsafe or non-compliant performance.

·         If the subcontractor elects to use their own Lockout/Tagout program, review their program and approve if: 

o   The subcontractors’ program meets or exceeds the requirements of OSHA 29 CFR 1926 Construction Industry Regulations, when performing construction type work activities.

o   The subcontractors’ program meets or exceeds the requirements of OSHA 29 CFR 1910 General Industry Regulations, when doing service or maintenance on machines or equipment.

3.0             Process Steps


3.1              LTT Procedure

Only Qualified Taggers may perform the following process steps. 

Step 1:            Determine the Hazards

Perform or review the work’s Task Hazard Analysis.

·         Evaluate the type and magnitude of the potentially hazardous energy, and the means of controlling the energy.

·         Review specific equipment, written procedures, blueprints, system diagrams, valve lineups, and operating manuals.

·         Confer with people who know the equipment.

·         Be alert to multiple energy sources.

·         Do not proceed until knowledge of the hazard(s) is known.


Step 2:            Determine the Need for a Written Procedure

LTT applications require a written procedure unless all of the following elements exist:

·         The equipment has no potential for residual, stored, or the re-accumulation of stored, energy after shutdown.

·         The equipment has a single energy source, which can be readily identified and isolated.

·         The isolation and locking out of the energy source completely de-energizes and de-activates the equipment.

·         The equipment is isolated from its energy source and locked out during servicing and maintenance.

·         A single lock out device will achieve a locked out condition.

·         The lock out device is under exclusive control of the authorized employee performing the servicing or maintenance.

·         The servicing or maintenance procedure does not create hazards for other employees.

·         There is no record of incidents involving the unexpected activation or re-energization of the equipment during servicing or maintenance within Jefferson Lab.

NOTE:  An optional LTT form will satisfy the minimal information required to be included in a written LTT procedure. Equipment that is similar in its operation can be grouped under one LTT procedure.


Step 3:            Coordinate Work/Notify Others

·         Notify all affected individuals; inform them that the equipment will be placed out of service until work is completed. Coordinate work with system owners, building managers or safety wardens as deemed necessary.


NOTE: It may be more practical and safer to perform voltage verification before applying locks/tags to the isolation device. If this is the case, secure the equipment and proceed to Step 6. Once a de-energized state has been verified, come back to Step 4 and continue with the LTT process.


Step 4:            Isolate Energy Sources

·         Don appropriate personal protective equipment (PPE).

·         Secure the equipment:

o   Put all appropriate energy-isolating devices in a safe state (usually “off”) while following an orderly shutdown sequence.

·         Secure the energy source using a Jefferson Lab approved LTT lock. A multi-lock hasp is used if there is a possibility that other employees may also work on the equipment or system. 


NOTE: If the equipment is un-lockable see 4.2 Special Tag Out Situations Without Locks

·         Attach a “DANGER” tag. 

o   The tag must be:

§  Legible – Indicating the identity of the person who applied the device(s).

§  Attached by durable means to the shackle of the accompanied lock, or a non-reusable method capable of withstanding a 50-pound pull, minimally equivalent to a nylon cable tie.


Step 5:            Remove and Release Potential Energy:

·         Don appropriate PPE.

·         Put all control mechanisms into a safe state and lock controls where possible.

·         Bleed the system of energy.

·         Block raised dies, gears, or equipment that could descend or move when the energy is removed.

·         Lower suspended loads to the floor or secure them independently.

·         Release any stored spring tension.

·         Check the system for possible re-accumulation of stored energy. Continue this check until the possibility of re-accumulation no longer exists, or until the LTT is cleared.

·         Refer to Step 6 for the removal of stored/residual electrical energies.


NOTE: When using blocking devices (blind flanges, pancakes, blocking plates, …) to restrain stored or residual energy within piping systems during a LTT; the mechanical devices used must comply with the requirements of Jefferson Lab’s Pressure System policy and procedure.


Step 6:            Verify Lockout and Try (Attempt to Restart)

·         Don appropriate PPE.

·         Assume the equipment is energized, or charged, until it has been determined to be de-energized.

·         Witness the verification of a de-energized state.

o   All Qualified Taggers having applied a personal lock and/or tag are required to perform or witness the verification of the de-energized state (refer to ES&H Manual Chapter 6110 Appendix T3 Group Lock, Tag, Try (LTT) Procedure for any exceptions to this step).  

·         Verify the integrity of your lockout.

·         Try to restart the equipment. 

o   Have an authorized employee attempt to operate the equipment controls, or otherwise verify the equipment cannot be restarted. Return operating controls to the safe (usually “off”) position.


For electrical energies:

·         Test the metering equipment for proper operation immediately before verifying a de-energized state.

·         Verify incoming power has been de-energized. 

·         Test the metering equipment for proper operation immediately after verifying a de-energized state.

o   Refer to the VUU equivalency dated October 19, 2018, on the Electrical Safety Committee website under EAHJ actions, for an exception to this step.

·         Remove and release stored energy:

o   Use a grounding/shorting stick to dissipate any stored/residual energy. 

o   Ground the electrical components/circuits as required for the duration of the job or task. 

o   Verify that the stored/residual energy has been dissipated.

·         If deemed practical for use, then protective grounds shall be applied when working on de-energized electrical systems which normally operate above 600 VAC.


NOTE: In the event of a scenario where the energy source is not present during the lockout/tagout, additional safety measures are implemented to eliminate inadvertent energization. These additional steps are performed to ensure that the failure of any energy isolation device does not energize the equipment being worked on.


A written and approved Task Hazard Analysis is required under this no-energy lockout scenario, and the approval of the task includes a review from a second individual familiar with the equipment being lockout.


Step 7:            Perform the Work

·         Periodically re-check the integrity of the lock and/or tag, minimally:

o   When there is a possibility of energy build up.

o   When tasks last more than one shift.

NOTE: If the work being performed on the de-energized (LTT) equipment exists in an area with other energized equipment that is similar in size, shape, and construction, then an alerting method (for example safety signs, barricades, attendants, …) shall be employed to prevent one from entering the energized look-alike equipment.


Step 8:            Prepare to Re-Energize

·         Ensure the equipment has been properly re-assembled:

o   Electrical jumpers and grounds, tools, work aids, spare parts and other such devices have been collected and removed, and

o   Personnel have moved to safe positions.

·         Close all cabinets and panels completely.

·         Notify all affected individuals when work is complete and ready for energizing.

·         Ensure equipment/control switches are in a safe state (usually “off”) to guarantee:

o   Unexpected startup.

o   Inadvertent overload of circuit breakers and switches.

o   Safe start-up sequencing.


Step 9:            Remove Locks and Tags

·         Each Qualified Tagger removes their lock(s) and/or tag(s). Refer to ES&H Manual Chapter 6110 Appendix T2 Special Lock and Tag Removal Procedure, for any exceptions to this step.


NOTE: The removal of equipment, that has lock(s) and/or tag(s) attached to it, constitutes a removal of the lock(s) and/or tag(s); therefore all lock(s) and/or tag(s) shall be removed by their owners before work is performed on the equipment.

Step 10:        Energize

·         Be prepared to shutdown the equipment immediately if needed. Enlist the help of others as necessary.

·         Test equipment to verify proper operation.

·         If testing indicates the equipment must undergo LTT again, go back to Step 3.


4.0             Exceptions to the Use of a Lock and/or Tag


4.1              Cord & Plug - Electrical Equipment


LTT requirements do not apply to electrical equipment that is equipped with cords and receptacle plugs if removing the plug completely de-energizes the equipment and the plug is under exclusive control, of the worker, at all times. Unload the equipment prior to unplugging the cord-and-plug. If these conditions cannot be guaranteed, then LTT measures are required. 


NOTE:  There are lockable “boots” available to secure electrical plugs.

4.2              Special Tag Out Situations Without Locks


Jefferson Lab, in accordance with OSHA, permits the use of tags alone in certain limited situations. To be a candidate for a tag-only control, an energy source must meet all of the following criteria:

·         Equipment design precludes the installation of a lock on an energy isolation device(s).

·         At least one additional safety measure is employed that provides a level of safety equivalent to that obtained by use of a lock.

·         The LTT procedure to be used is documented.


5.0             Revision Summary


Revision 1.10 – 11/12/19 – Updated Purpose to add configuration management controls for equipment specific LTT procedures per CATS#NE-2019-05-02-01; updated SOTR responsibilities to clarify subcontractor’s use of Jefferson Lab’s program or their own program for Lockout/Tagout procedures; updated TPOC from T.Kujawa to T.Fitzgerald

Revision 1.9 – 10/24/18 – Updated verbiage for Process Step 6, electrical energies re: the revised VVU equivalency per TPOC

Revision 1.8 – 03/23/18 – Updated Process Step 6 regarding the use of equipment specific VVU per 10CFR851 requirement

Revision 1.7 – 04/24/17 – Minor edits to reflect recommendations from the annual LTT review

Revision 1.6 – 01/18/17 – Updated to include noteworthy practice on protective grounding and guidance for using blocking devices re: CATS MOA-2016-32-01 and MOA-2016-32-03

Revision 1.5 – 05/16/16 – Added note under Step 7 to clarify work performance in areas with both energized and de-energized equipment.

Revision 1.4 – 03/09/15 – Periodic Review; clarification of 2.0 Responsibilities; replaced ‘Work Control Document’ with ‘procedure’; deleted reference to ESH Manual Chapter 3310 OSP Program. 

Revision 1.3 – 08/02/13 – Added clarification to Process Step 9 for removal of equipment per T.Kujawa.

Revision 1.2 – 09/10/12 – Removed Special Lockout Situations without Tags in response to CATS item MOA-2012-19-01-01.

Revision 1.1 – 12/01/11 – Clarification of process steps and updates made to format. Qualifying periodic review, no substantive changes required.

Revision 1.0 – 04/04/09 – Update to reflect current laboratory operations.











ES&H Division

Tim Fitzgerald





This document is controlled as an on line file.  It may be printed but the print copy is not a controlled document.  It is the user’s responsibility

 to ensure that the document is the same revision as the current on line file.  This copy was printed on 11/15/2019.