Describe in detail the sequence of steps involved in a lockout/tagout procedure for a piece of electrical equipment located within a confined space, emphasizing the verification process.
Lockout/tagout (LOTO) procedures are critical for preventing accidental energization of equipment while working in a confined space. These procedures ensure that hazardous energy sources are isolated, controlled, and cannot be unexpectedly released, thus protecting workers from potential injuries. When dealing with electrical equipment within a confined space, the LOTO sequence involves several distinct steps.
The first step is preparation. Before any lockout or tagout procedure, a qualified person must identify all energy sources associated with the equipment, which in this case, are the electrical circuits. This requires an understanding of the equipment's electrical schematics or a thorough physical examination of the power source and the equipment itself. For example, if the confined space contains a pump with an electrical motor, then the energy source could be a disconnect switch located outside the confined space, as well as a control panel within it. Before beginning the lockout, the qualified individual will gather all necessary lockout/tagout devices, including locks, tags, and any other specific equipment needed for the task. For instance, if the disconnect switch requires a particular size of lock and tag, it's important to have these on hand.
The second step is notification. All affected employees must be notified before implementing lockout/tagout procedures. This notification may be verbal and written, and includes not only those workers entering the confined space, but also those working in the general vicinity who could be affected by shutting down the power. The team should understand what equipment is to be locked out, why, and for how long. For example, if there are other processes that rely on the equipment being shut down, those operators must be notified and prepared.
The third step is shutdown. The equipment needs to be shut down using normal shutdown procedures. For example, simply switching the equipment off at the control panel is the first step, and should be the normal way to stop the equipment. It must never be stopped by simply pulling a fuse, which could be unsafe. The equipment must be completely deactivated.
The fourth step is isolation. This is where the hazardous energy is physically isolated from the equipment. This is accomplished by turning off the power via the disconnect switch or breaker, and then installing the proper lock. All sources of electrical power must be locked out. For example, if the power supply to the pump motor goes through a disconnect switch, the switch must be turned off and locked in the off position using a unique lock. This lock is only controlled by the qualified worker who did the lock out, and the key to this lock must never be given to anyone else. Multiple workers will each attach their own personal lock when more than one worker is involved in the job. If there is a control panel inside the confined space that controls the same equipment, this also must be isolated and locked. Each disconnect must be locked with its unique lock.
The fifth step is the tagout. Once each energy-isolating device is locked, it must be tagged with a tag that clearly identifies who applied the lock, when it was applied, and why, along with contact information if there is a question or problem. This is especially important when multiple people are working on the same equipment. Each person working on the equipment, in this case inside a confined space, will lock out the energy and install their own tag on each device. This identifies who is protected by the lockout and allows contact to be made before the lockout is removed. For example, if the worker locking out the control panel is called away for an emergency, the tag will allow any other worker to contact them before the lock out is removed. Tags must be clearly visible and securely attached to the locks.
The sixth step, and one of the most important, is verification. This confirms that all energy sources are effectively locked out and cannot cause a release of energy that could injure workers. This verification typically involves attempting to operate the equipment. Before anyone enters the confined space, a worker will attempt to turn on the equipment. This may be by flipping a switch on the equipment, pressing a start button, or using a control panel located inside or outside the confined space. The purpose of this verification is to confirm that the lock is in fact effective in preventing the equipment from starting. If the equipment starts during this check, then the lock out has failed. If the equipment cannot be started, then the verification step has been successful. If the verification step fails, then the lockout procedure must be reviewed, and restarted with care.
Only after successful verification can entry into the confined space begin.
The final step occurs when the work is finished. The process of removing the locks is detailed and must be carefully followed. Each worker must remove only their lock. At no time is another worker allowed to remove anyone else's lock. If a worker is unavailable to remove their lock, a supervisor may take their place with management approval, but only after contacting and exhausting every effort to make contact with the unavailable worker. The equipment is then restarted according to the normal operating procedures.
By following this detailed lockout/tagout procedure and carefully verifying that all steps have been successfully completed, workers entering confined spaces are protected from the risks associated with uncontrolled electrical energy, enhancing workplace safety.