Color Sample Meaning Primary Use & Purpose Comments
Yellow   Good Yellow is to be used by Checkers and others on all types of drawings and other documents to indicate that the highlighted data is correct and does not need to be changed. Yellow is used for this purpose because it is the most transparent of the primary colors. Yellow should also be used by the piping supervisor for P&ID "yellow-off" of each line as piping isometrics are approved and released for issue.
Green   Notes Green is to be used by Checkers to indicate instructions to the person doing the corrections. Green is not used for DELETE because it is the universal color for GO or okay.
Red   Add Red is to be used by Checkers and others to indicate information or drawing data that is to be added. RED is used because it is the Universal color for STOP, DANGER and BE ALERT. It tends to get peoples attention.
Blue   Delete Blue is to be used by Checkers and others to indicate data or drawing information that is to be removed for one reason or another.  
Lead Pencil   Initial / Date A standard lead pencil is to be used by Checkers to record who did the checking and to make calculations. A standard lead pencil is to be used by reviewers of vendor drawings and interdisciplinary documents for mark-ups to record who made the changes or comments (i.e.: Initial & Date)

About the Author


{cb:James O. Pennock has more than forty-five years in the process plant design profession. He has been involved in both home office and job site assignments on refinery, chemical, petrochemical, power and other projects. His experience ranges from entry level designer to engineering manager. Much of this was with Fluor. He is also the author of the book "Piping Engineering Leadership for Process Plant Projects." He is now retired, living in Florida, USA and does only occasional consulting work.

Mr. Pennock can be contacted via E-Mail at This email address is being protected from spambots. You need JavaScript enabled to view it..}

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