There is much debate on the ideal frequency for pipe markers. One rule-of-thumb is that you should use a pipe marker every 30 feet for straight runs, one marker at each wall or floor penetration and another at each change in direction.

This arbitrary rule is often overridden by the practical concerns regarding "need-to-know". How much information do you want to convey and where do you want your workers to stand when they read it? As anyone who has tried to untangle three different sets of Christmas tree lights knows, there are no set rules on where to start and where you can best trace a particular strand. Similarly, there are always locations in your plant with frequent traffic or vantage points that provide a good panorama of the process piping. The determination of the frequency of pipe markers, then, is best made during a walk-down.