James:
You are right to expect various and different views on the subject of color coding plant piping. This subject is not new and has been discussed at length in other threads.
My advice and opinions on the subject have never changed after I ran, operated, and managed various plants during my first 10 years of engineering tenure. I dealt with various hazardous raw materials and end products, so I developed a different slant than most folks. My views and reasons are as follows:
1. The principal reason for color coding plant piping (this includes process and utility piping) is SAFETY. Leakage detection is also important – particularly when it falls under hazardous spills, fugitive emissions, and flammable/explosive fluids.
2. The safety ramifications become vitally important when you have outsiders working within what is ordinarily your closed, cloistered territory – like outside paramedics and firemen responding to your distress call when a local situation gets beyond your control. This is a particularly dangerous situation because the outside specialists that are trying to help you control a situation have no idea or concept of what is around them when they arrive in your “turf” (the Buncefield Terminal Incident - thread135-147885 is one such type of incident that could present such a situation to arise).
3. It is considered wise and prudent operational practice to always know exactly where all your hazardous lines are – as well as utilities. Knowing where your cooling water lines are can be a life saver during a local fire-fighting incident where the local fire hydrant turns up dry or not operable. I certainly would not allow the placement of inert Nitrogen lines near a process vessel together with instrument air and process air lines without making sure that each one of these lines is clearly and thoroughly color-coded and marked with signs indicating which is which. Too many times in the past humans have suffered asphyxiation during a vessel entry because maintenance personnel were not made aware of which line was process air and which was Nitrogen. Nitrogen may not be classified as “Hazardous”, but it certainly is deadly.
4. Even if you are dealing with totally benign and environmentally safe fluids, you still have to protect your pipe investment by painting. Paint essentially cost the same regardless of the color. Therefore, that only leaves the argument that you have to organize your paint inventory and probably add a couple of extra paint lockers.
5. Of particularly prime importance in color coding are lines that are not hazardous – such as potable water. If it’s my plant, I want proof positive that I can visually check and make damn sure that I know first-hand exactly where ALL my potable water lines are, where they are going, where they are coming from, and everything that is tied-in to them. I perceive that you propose to identify only those lines that transport hazardous fluids and I “paint” that as short-sightedness (please pardon my pun in trying to make my point).
I have other views, but the above are the obvious ones that come to mind immediately. I hope my experience can help you out.
