This part of the Annex is titled, “Human Performance Tools.” The tools mentioned reduce the likelihood of error when applied to error precursors. If you read the previous edition of this column, you may recall that Part 5 of this Annex is about error precursors.
Table Q.5 lists quite a few error precursors and arranges them into the four groups (task demands, work environment, individual capabilities, and human nature) discussed in Q5. That same table lists eight human performance tools:
- Pre-job briefing.
- Job site review.
- Post-job review.
- Procedure use and adherence.
- Self-check with verbalization.
- Three-way communication.
- Stop when unsure.
- Flagging and blocking.
Each of the human performance tools is detailed in Q.6.2 through Q.6.9. In the list of eight, the name of the tool gives you a pretty good idea of what the tool is about, but two of them are less obvious than the others.
Three-way communication might be better stated as three-step communication. Aaron tells Ron to open the motor disconnect for motor G2170. Aaron could assume Ron heard him and leave it at one step, but that's not safe. Ron could say, “Copy that,” to confirm he got the message, but did he get the correct message? Ron repeats the message, “Open the disconnect for motor G2170.” That's two steps. The third step is where Aaron validates the proper response with “That is correct” or “Affirmative.” If Ron wants to see if Aaron is alert, he might say, “Open the disconnect for motor G2190,” as the second step. If Aaron validates that, Ron will need to ask which motor is the correct one: “Would that be G2170 or G2190?”
What about flagging and blocking? A flag could be a marker, label, or device used when an error-likely situation exists, such as similar equipment (e.g., motor 2170 and motor 2190). Blocking is a method of physically preventing access to an area or to equipment controls. Flagging and blocking can be used together.