04.28.09Dan Stacey, Safety Program Consultant, Safety Health & Claims, Pacific Gas and Electric Company

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As discussed in my previous article, any utility in the United States will tell you its No. 1 priority is safety. Earlier, we explored the relationships between utilities and their external agencies in preparing for unified emergency response scenarios. Today I want to share some experience with the most important safety process for protecting employees while they perform their work: the clearance process -- isolating and properly clearing normally energized equipment.

Clearance processes are basically designed with two objectives/priorities in mind:

• Safe isolation of energy sources to protect employees.
• A process, for the operational group with overall jurisdiction, to manage scheduled and emergency work and outages with system conditions.

With the first point in mind, it's required that utilities utilize "lockout" and/or "tagout" processes, whereby equipment which is cleared is locked and/or tagged in the de-energized position, with breakers, switches and valves in their cleared positions and properly locked and/or tagged.

There can be many obstacles associated with clearing equipment. Transmission gas and electric clearances have clearance points stretched over miles of line, clearances which cross jurisdictional boundaries (both internal and external to the respective utility), clearances which take place between utilities and may have a common clearance point with a clearance tag attached for each utility, different criteria and locations for Reporting On and Off cleared equipment, remote Reporting On/Off, and so on. Within the bounds of this article, I will not attempt to list every potential scenario.

However, I'd like to share the "critical eight steps," in sequence, of the basic "tagout" clearance process as it applies to life in a power plant. Let's call this one the Bluegrass Generating Station.

Step 1: Author and Approve the Clearance

Updated operational maps, single line diagrams, schematics, P&IDs, etc., are used to choose the points which adequately clear the affected equipment. The clearance is authored by a subject matter expert and approved by a supervisor and the operational group with the final OK authority. The points shall be verified with a walkdown and any needed revisions are then submitted for change on the clearance and associated drawings. Critical Safety checks are inherent in this first step to ensure the right equipment is properly cleared prior to beginning work.

At Bluegrass Generating Station, the operations group (Ops) is the Clearance Supervisor (CS). They clear the equipment and make it available. They are the first to Report On a clearance and the last to Report Off. It's a requirement -- we must ensure our operators, who are responsible for the safe and efficient operation of our 1,000 megawatts of generation, are in complete control of their equipment. The maintenance and/or construction folks who want to Report On and do the work will be classified as secondary clearance holders. The clearance supervisors manage the Master Clearance Board and all secondary clearance holders Report On and Report Off to the CS.

Step 2: Place Master Clearance Point (MCP) Man On Line (MOL) Tag

This point is on the centrally located Master Clearance Board. This is the location where all station employees can see the equipment that's cleared and ensure their Master Clearance Point tag is posted and that they're Reported On, prior to beginning work. While the MCP MOL is in place, the equipment is not to be operated.

Step 3: Clear Field Points

The breakers, valves, switches, etc., required to isolate and clear the energy sources from the affected equipment are placed in their cleared position and tagged with the appropriate MOL/Caution tags. As the equipment is being walked down/cleared, points are being checked as adequate and any required changes are verified, approved and included in the clearance package. This is another critical safety check to ensure the right equipment is properly cleared.

Step 4: Report On the Clearance

Any person requesting the clearance has walked down the clearance points as defined in the clearance package and is Reporting On the cleared equipment. This is another critical safety check. They have ensured the equipment is safely cleared and they are ready to perform the work required. As long as they're Reported On the clearance, the tags placed on the clearance points will protect them from all energy sources. When they're Reported On, the tags are not to be breached and shall remain in place until the person Reported On has Reported Off.

Step 5: Perform Work/Testing

Work proceeds to completion and the equipment may be tested. Of course, we won't energize/test equipment while others are also Reported On the clearance, so they'll have to Report Off while testing is performed. Some tags will probably need to be changed for testing, and the Clearance Process in place will define the specific sequence required to accommodate changing of tags for testing of cleared equipment. At the conclusion of the test, any others who may need to report back on to complete their work may do so, or the equipment can be placed back in service, as applicable.

Step 6: Report Off the Clearance

Work has been completed by those Reported On, the equipment has been tested functional and can be made available for service. We must Report Off, prior to removing tags. If tags can be removed while employees are still working on equipment, then Step 4, above no longer provides any protection.

Step 7: Remove Field Tags and Return Clearance Points to Normal Operating Positions

The breakers, switches, valves, etc., used to isolate/clear the equipment are returned to their normal operating positions. Clearance tags are removed as the points are returned to normal.

Step 8: Remove Master Clearance Point MOL and Report Equipment Ready for Service

The MCP MOL is removed and the clearance is closed out. The equipment is now considered available for service. The designated clearance tags and clearance package can be retained, as required.

This eight-step process will absolutely ensure employee safety while working on normally energized equipment at Bluegrass Generating Station.

The basic design of a clearance process should be a fundamental part of the safety culture at any utility. It is, however, only a tool. And as such, if only partially utilized, or misused, the margin of error can have deadly results. With any safety process at your facility, I urge you take the time to refresh yourself on the content and spirit of the process. Stay engaged and look for opportunities to recognize deficiencies. Understand the process and communication chain for revision, when you spot a potential issue. Be safe, watch out for the safety of your brothers and sisters on the job and take action against unsafe situations.

Never lay your armor down when it comes to safety.

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Reader's Comments

Date	Comment
Jerry Watson 5.6.09	I have spent a few days in power plant myself, and it appears this outline has some weaknesses. I guess I am a little bit of a tagging or lockout cynic, but I have my reasons, a gentleman I started my utility career with as a laborer was burned to death early one April morning due to flaws in a LOTO system. Worthy of mention is that his apprentice and a contractor joined him at the pearly gates. There were a couple dozen of other injuries of various degrees. In my opinion procedural controls like LOTO are not the key factor in safety it is understanding risk management and the skills to do so that truly produces safe workers. Procedures do seem to often be the focus since they are concrete and controllable. I also theorize it is a carryover from military where it is a correction for the massive turn over rate of enlisted men. Procedures have a common weakness that by design they must protect the newest, dumbest, or laziest employee or contractor. It is much easier to protect experienced dedicated employees that follow procedures. Utilities mouth a good safety game but often give mixed signals by their actions. Many utilities still use Tag Outs rather than physical Locks and Chains to isolate energy sources. I have heard this practice defended my entire career. I know the real reason is because it is faster and easier than lock and chain. Tags still go missing even though it has become much rarer with tags made of superior materials secured by strong tie wraps. However, I have not seen a single case of the wind fraying a lock and chain in even windy locations. I have heard the argument that even with a lock many low voltage (480V) cubicles can be opened rendering the lock useless. Easy answer any door the opening of it bypasses a safety device should normally be locked itself (access control). Higher voltage cubicles normally are inherently safe by design since the risk of death by any accidental contact is so high. I have heard the argument with 4160 V breakers that even when racked out and locked out that it is possible that another breaker could be installed. My answer, if it takes two or even three locks so be it, it will only take a few moments longer to hang two compared to one. The worst part about Lock outs are the logistics of keeping up with and sorting the keys. However I feel it is well worth the additional effort. I really think it is hypocritical to say safety is the number one priority while refusing to expend the extra effort to use key and lock safety. There is nothing wrong with signing or logging onto some sort of a master tag, but putting your own master lock on steel box full the keys to locks protecting your life adds a level of safety that eliminates administrative errors like occur in tag out systems. The most careful of us in the courses of a career might miss a single entry or signature, but it is hard to miss 12 ounces of steel locked to a steel box. Or as I like to say “steel is real.” If nothing else the sudden need for a pair of bolt cutters will clue in even the densest among us. Back to the article, step one is ok as a starting point assuming that some sort of requesting process had already previously clearly laid out the work to be performed. Of course doing research on PID’s and such is a little scary to me. Instead clear LOTO guidelines should exist covering all but the most unusually of tasks and it should be performed by experienced employees. The whole LOTO thing really requires one to know and understand what one is doing. However, pulling “B” cooling water pump motor for a clean, dip and bake at a motor shop should require the same LOTO every time.
Jerry Watson 5.6.09	It appears to me that steps two and three are reversed. Hanging the Master before hanging every lock or tag is hung and verified seems needlessly risky. I am sure like all stations your contractors go through some sort of an orientation hopefully in a language they actually understand, but having a master hung on equipment not ready for work is misleading and therefore unsafe. In fact I have worked at six different stations for three different employers and at each one of them posting the master was the last step before allowing others to log or sign on and begin work. Step 4 is common but is still weak on complex lockouts for the following reasons: One, I am willing to bet that only contractor supervisors logs on for an entire crew. I doubt that 25 welders 50 helpers log on daily during a major boiler overhaul. They come in and go to work and hopefully at least their Supervisor is on the LOTO. It was this practice that took my coworkers life. He was on a loaner crew from another plant and his supervisor logged on multiple LOTO’s to allow his crew to work under his supervision. With out going into detail since I do not want to cause myself grief with my employer, but still wanting to help others avoid this mistake I will say this. A Generator can be isolated form the grid and all sources of electrical power and these isolators tagged and the associated turbine from all sources of steam and these isolators tagged and still contain a lethal charge of hydrogen and itself not cleared for work. Again expertise is required one must understand completely what one is doing, if not, checking fifty tags only serves to foster an illusion of safety where it in fact does not exist. I still find it ironic that many plants have higher standards for more knowledgeable internal involved employees compared to contractors who often have little knowledge outside the skill they possess. Step five is ok rather than blurb about testing, if you want to test you move to step six. After everyone has relinquished their clearance testing can be done safely. Relinquishing clearance doesn’t require removal of any tags or locks it merely allows it as a possibility. Step six is pretty apparent and common. It should go without saying the LOTO stays until the holders officially release it by what means is procedurally correct. As I said I like a steel lock on a box with the only keys to it in the workers pocket. Again steps seven and eight are reversed. It appears your plant is using the LOTO as an equipment status board, rather than, purely for a safety device to protect workers from hazardous energy. Before the first tag or lock is removed the master should be off the board affirming that this equipment is no longer available for work only then should the safety devices begin to be removed. Lastly this statement “This eight-step process will absolutely ensure employee safety while working on normally energized equipment at Bluegrass Generating Station.” is ridiculous there are very few absolutes in any industrial plant. Humans will make errors and blindly following procedures is such an error. Here is my statement “Intelligently following this procedure will lower risks to employees to an acceptable level, being ever mindful that no device is perfect and caution should be used in evaluating potential risks.”

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