6 December 2006
Including change 1, 7 December 2006
Development of Procedures. Establish safe clearance and lockout/tagout
procedures at each base or facility. Each service has documents controlling this
process; refer to Appendix A for a list of documents.
Lockout. A lockout is the placing of a valve, switch, or other line opening
device for a prime mover in the open or closed position, as appropriate, and ensuring by
some means (usually mechanically) that the position of the valve, switch, or line
opening device, including SCADA systems, can not be inadvertently changed.
Examples of mechanical means include removal of an isolating circuit element, blocking
of a controlling switch, opening of an extra disconnecting device, or the removal of a
valve handle. If a device is listed on the Safe Clearance and is capable of being locked
out, then lockout must be utilized. Use of only tagout and not lockout must be justified
on the Safe Clearance. This might occur when the device is not physically configured to
accept and cannot be adapted for a lockout device. In these cases, the Safe Clearance
must include provisions for other means to provide a level of safety equivalent to that
obtained by a lockout
Tagouts. Apply Danger (red) tags to prohibit changing the position of
devices by unauthorized persons. All energy-isolating devices must be provided with a
Danger tag, even those locked out. Use a Danger tagout for each Safe Clearance. Use
Caution (yellow) tags in connection with a Safe Clearance to provide precautions
necessary before operation of a switch or other device. Out-of-Order tags are not used
as part of a Safe Clearance. If used, green tags indicate placement of a ground on a
circuit or equipment. Tags and tag ties must be nonreleasable, with a minimum
strength of no less than 50 lb (23 kg).
Preparation of the Safe Clearance Form. The details and the person
preparing the Safe Clearance must include:
Details of blocking, switching, tags, and locks. A second worker who is at
least classified as an electrical journeyman must check this information.
This check must be done before beginning any switching. Enter details in
their proper sequence, reading down the form. Include any switch
operations (such as opening or shutting) necessary to transfer load or put
other equipment into operation.
Supplemental direction, if necessary, to be provided to the crew involved
in the work to ensure their understanding of boundaries of coverage of the
Issue (Approval) of the Safe Clearance Form (Switching Order). Only
designated persons must be authorized to issue (approve) Safe Clearances for work by
qualified personnel. These persons must be designated in writing in accordance with
local procedures. The designated person in issuing (approving) a Safe Clearance must
ensure that the following objectives have been met: