Given the sheer amount of pumps, adding seal water lines would complicate things a lot. One alternative would be to draw the lines coming the pump that pumps the seal water, and just symbolize them "phasing out" of the drawing, and then drawing the seal water in- and outlets into the pumps, with a tag labelling it as seal water, and the outlets just phasing out of the drawing just like before.

The different lines of seal water could be enumerated, since given that the lines aren't actually shown, a way of knowing what lines go where is needed.

For lubrication oil, this issue is even greater, as there's even more equiptment that uses it, and there's a few temperature measurement instruments that need to be shown. Again however, the issue of readability arises; showing all of these lines would surely litter the diagram?

So, my question is this: are these auxilliary systems required to be shown (by ISO standards), and if so, how does one do this without littering the drawing? Perhaps one needs two drawings?

  1. This one is drawn normally, though omitting seal water and lubricating oil lines.

  2. This one contains the seal water and oil lines (and the instruments on those lines), plus the equiptment they go to, and only this equiptment.

Perhaps one could, with certain softwares (or with transparent drawing sheets), superimpose them to get the full drawing, in all of its messy glory?

  • $\begingroup$ My experience is no, though I've never worked at a plant with piped lubrication. $\endgroup$
    – Tiger Guy
    Commented Jun 16, 2022 at 13:12
  • $\begingroup$ @TigerGuy Hmm I see. For hand-applied lubrication, it makes sense that it wouldn't be shown in a P&ID. However, surely the plant(s) you worked at had seal water in their pump? $\endgroup$
    – user110391
    Commented Jun 16, 2022 at 18:10
  • $\begingroup$ yes, but we had water everywhere (paper plant) and it was just field-fit, 1/4 inch tubing. Not on P&ID because it isn't process-related. $\endgroup$
    – Tiger Guy
    Commented Jun 16, 2022 at 18:15
  • $\begingroup$ @TigerGuy Aren't auxilliary systems, like seal water lines, process-related? Or was it somehow not process-related in the case of the paper plant? Not sure how this could be; without pumps, the process doesn't work. Without seal water, the pumps eventually break, (AND) product will be lost through leaking into, and subsequently, out of the pumps. $\endgroup$
    – user110391
    Commented Jun 17, 2022 at 0:07
  • $\begingroup$ no, it isn't part of the process, and you don't change prints changing from glands to mechanical seals. $\endgroup$
    – Tiger Guy
    Commented Jun 17, 2022 at 4:18


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