interlock training

7/30/2019 Interlock Training

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Policy and Practicefor

BypassingInterlocks

Click anywhere on the screen to continue


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Why Do You Need This Information?

You were selected by your supervisor as someone who wouldmost likely have cause to install an interlock-bypass.

Read the policy on the next few slides. It is followed byadditional material that will explain why the policy wasadopted, how the process flows, and offer some interlock-

bypass examples.


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page 1 page 2


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Why the Policy was Developed

On October 14, 2011, two YR magnets in the Northeast Spreader regioncaught fire and sustained heavy damage. Root cause was inadequate Work Control processes and practices . Two direct causes:

LCW valves for the dipoles were shut. A jumper (interlock-bypass) in the box supply prevented the thermal switches

from tripping the power supply .

What you are about to see is damage caused by the overheating of magnetcoils in the tunnel.

Keep in mind that this might have been avoided if the overheating protection

(interlock) on the RSEP9A power supply had not been bypassed or if more peoplehad known that it was bypassed.


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YR9S04


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YR7S03


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Damaged Coils


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YR7S03 Split


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Recommendation* byFire Investigation Team

Recommendation #4The use of interlock jumpers on equipment installed in theaccelerator should be avoided. In circumstances where they arerequired, they should be clearly marked to aid in identification.

All groups should have a systematic method of identifying theinstallation and removal of jumpers in addition to a method to

identify where all jumpers are installed.

* one of many


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These individuals were selected to develop a policy to addressrecommendation #4 and can answer any questions you mayhave concerning the new policy or its implementation:

Interlock Bypass Team

Jonathan Creel (Cryo)

Anthony DiPette (Mechanical)

Mike Drury (SRF)

Ron Lauz (Electrical)

Randy Michaud (Operability)

Tom Oren (Documentation)

Paul Vasilauskis (MCC Ops)


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Accelerator Bypassed- Interlock L ogABIL is electronic log that keeps track of bypassed interlocks in the accelerator

Follow the link ( http://opsweb.acc.jlab.org/abil/pro/ ) to familiarize yourself with ABIL. How to make or delete an entry in ABIL is straightforward and is not detailed here. You can Mouse Over

various fields to view what input information is required.

Some features of ABIL: ABIL is set up to notify individuals, via e-mail, when interlocks are bypassed, bypasses are removed, and

when their expected removal date is about to expire or has expired. ABIL notifies system owners whenexpirations dates have been exceeded.

Individuals can customize ABIL to view all bypasses or only ones they installed, group by system or showungrouped, sort on any column, move, resize, hide, unhide columns. Choices stay persistent between uses.

Individuals can sign up to receive e-mails when bypasses are installed/removed within a given system. To doso go to the Setup My Email tab and select the systems on which you want to be notified.
http://opsweb.acc.jlab.org/abil/pro/http://opsweb.acc.jlab.org/abil/pro/


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Interlock Bypassed Tag


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Tags located at each service building

door and near every tunnel phone


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Situational Examples

The following 9 example slides are meant togive you some idea of when and how to

apply this policy. They do not cover everysingle instance you may come across. Inmost cases you will be able to determine if a

tag and/or ABIL entry is required by simplyusing your best judgment.


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Example 1Crew Chief calls for support for a water flow fault on

Chopper 1 in the Injector. The fault is impeding thescheduled program. Technician determines that the flow is okay but the

electronic interlock circuit has failed. Technician and Crew Chief discuss the situation and

determine that its okay to bypass the interlock until the nextmaintenance day.

Technician makes an entry in ABIL, gets a tag number fromABIL, fills out and installs a tag at the flow meter .

Technician installs the bypass.


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Example 2Crew Chief calls for support for a magnet Box Power Supply that has

faulted off and is impeding the scheduled program. In order for the Technician to troubleshoot the power supply he

must bypass one of the door interlocks. Technician fills out a tag and installs it at a location that is obvious

to anyone that the supply has an interlock bypassed. Technician bypasses the interlock. Technician replaces a faulty circuit board, determines the supply is

operational, removes the bypass, removes the tag, and tells the

Crew Chief the supply is fixed.Note: work is being performed during immediate maintenance

and therefore, by policy, did not require an ABIL entry.


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Example 3Its a maintenance day and your ATLis to work on a

water flow meter that malfunctioned and requiredbypassing the interlock has been approved. Technician removes the bypass. Technician replaces the flow meter and verifies

operation. Technician removes the tag.

Technician deletes the ABIL entry.


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Example 4Crew Chief calls for support for an RF cavity that has faulted off and

is impeding the scheduled program. Technician determines that there is a water flow fault that will not

clear. Technician and Crew Chief discuss the situation and determine

that bypassing the RF Zone is the best course of action. However,

the technicians want to continue making repairs in a non-intrusiveway to operations.

Zone is bypassed. Technician makes an entry in ABIL, gets a tag number from ABIL,

fills out and installs a tag at a visible location.

Technician bypasses the water flow interlock and continuesworking on the zone.

Note : This started as immediate maintenance but changed when the zone wasbypassed. In that case an ABIL entry was not required for the water flow faultUNTIL the decision was made to bypass the zone with the interlock bypass inplace.


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Example 5While running beam to Hall C it became necessary to ask

permission to mask the Compton Ion Chamber FSDnode.

Operator/Crew Chief discuss this with the Hall C RunCoordinator and get permission to mask it. Operator makes an entry in ABIL. NO TAG

REQUIRED.

Operator masks the node.Note: An ABIL entry was required but a tag was notbecause the interlock-bypass was made via asoftware variable.


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Example 6Crew Chief calls for support for valves that will not open

because of a vacuum fault that will not clear; this isimpeding the scheduled program. Technician determines that there is not a leak and adjusting the set

point to a level below the allowable threshold will clear the problem.

Technician and Crew Chief discuss the situation, call for approval(if necessary), and if approved, make the adjustment.

No ABIL entry or tag are required.

Note: An ABIL entry would be required if the set point requiredadjustment above the allowable threshold.


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Example 7

Crew Chief calls for support for a valve that indicatesbeing closed and will not respond. Technician determines that the valve is actually open but the limit

switch on the valve is faulty giving a false indication. Technician and Crew Chief discuss the situation and determine its

okay to bypass the limit switch. Technician makes an entry in ABIL, gets a tag number from ABIL,

fills out and installs a tag at a visible location. Technician installs a jumper on the switch readback connector so

that the valve now indicates open.


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Example 8While running beam Crew Chief receives an accelerator

ODH alarm. Crew Chief contacts the Safety System Group (SSG).

SSG technician determines that the ODH head needs to be bypassed and gets permission from the Crew Chief to do so.

Technician makes an ABIL entry.

Technician disables the alarm in the PLC. No tag is required. Note: An ABIL entry was required but a tag was not

because the interlock-bypass was made via a PLC

set point.


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Example 9Technician is working on a piece of equipment in her shop. The job

requires that she bypass an interlock in order to calibrate it. Technician installs a tag at a visible location. No ABIL entry is

required.

Technician installs the bypass. Tag remains in place as long as the interlock is bypassed. Lets say

for this example that the bypass needs to remain in place becausethe bad part causing the problem is on order.

A few days later the equipment is needed to repair the accelerator to

restore the scheduled program. If the interlock bypass is still required AND it was determined that

the equipment could be run with the bypass in place, an ABILentry is required and the ABIL number placed on the existing tag.


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Summary

You took this training because you were identified as someonewho will likely be bypassing an interlock.

This policy is important. We cannot afford another fire caused

by an interlock being bypassed due to limited knowledge. You can direct any questions you may have to your supervisor

or one of the team members that developed this policy. Typically both a tag and ABIL entry are required, but in some

cases only one is. Tags are available both in the service buildings and in the

tunnel.


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If you have read and understand the policy, the reasonfor it, and the ten examples provided, click the box

below to update your record.

Confirmation

CONFIRM
https://misportal.jlab.org/mis/training/online_courses/completeClass.cfm?classId=77169https://misportal.jlab.org/mis/training/online_courses/completeClass.cfm?classId=77169https://misportal.jlab.org/mis/training/online_courses/completeClass.cfm?classId=77169https://misportal.jlab.org/mis/training/online_courses/completeClass.cfm?classId=77169

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