Adopting and maintaining proper color codes for treatment plant piping systems according to ANSI guidelines can help you avoid potential operational errors and workplace accidents by allowing your staff to identify the contents of all pipelines easily, quickly, and accurately. Though standard piping color codes have been developed for water and wastewater treatment plants, not all plants follow the same recommendations, causing a great deal of confusion. To clarify the procedural aspects relating to color coding standards for treatment plant piping systems, we’ll use this blog post to review the recommended identification color codes along with a summary of instructions.

treatment plant piping systems

Color Coding Standards for Treatment Plant Piping Systems

All new and modified treatment plant piping systems should be color coded according to the following scheme:

Water Lines

Olive Green                                        raw or recycled water

Light Green                                        non-potable water

Aqua                                                   settled or clarified water

Dark blue                                            finished or potable water

Waste Lines

Light Brown                                       backwash waste

Dark brown                                        sludge

Dark grey                                           sewer

Chemical Lines

White                                                 ammonia

Black                                                 carbon slurry

Orange                                              alum / primary coagulant

Yellow                                                chlorine

Yellow with Violet Band                   chlorine dioxide

Yellow with Orange Band                ozone

Yellow with Red Band                      sulfuric acid

Yellow with Green Band                   caustic

Light Green                                       lime slurry

Light Green with Yellow Band         sulfur dioxide

Light Green with Red Band             phosphate

Light Green with Orange Band       soda

Light Blue with Red Band                fluoride

Orange with Green Band                 coagulant aids

Violet                                                potassium permanganate

Other Lines

Red                                                     gas

Dark Green                                        compressed air

Light gray                                           other lines

General Instructions for Proper Color Coding of Treatment Plant Piping Systems 

To ensure a precise, easy, and rapid identification of the gases or fluids flowing through piping systems, the following guidelines should be considered:

  • For gases or liquids not listed above, it’s advisable to use a unique color scheme. When two similar colors are selected (e.g. light gray and medium gray), a six-inch band of a contrasting color should be applied to one of the pipes/systems (e.g. light gray with white band). Additionally, the name of the substance should be written on the pipeline.
  • When different coating systems are used, it’s important to choose a uniform color.
  • Appropriate stenciled marking should be used in conjunction with color coding standards. Specifically developed to indicate unit numbers, stenciled markings should contrast with the background color.  
  • Stenciled markings should include numbers along with flow abbreviations and arrows to indicate the flow direction where necessary (e.g. in areas where pipes pass through walls, at intersections, etc.).

Though modern treatment plant piping systems are made of different materials, metal remains one of the most common options. Metal pipes can be made of stainless steel, cast iron, copper, brass, or different alloys. The characteristics of individual metals or alloys, the type of fluid or gas flowing through the pipeline, and the environmental conditions must be carefully assessed prior to selecting protective coatings for specific piping systems. In addition, the treatment plant piping systems must comply with all applicable safety guidelines to ensure the safety of plant personnel.

For recommendations on the most appropriate protective coatings for treatment plant piping systems, feel free to contact our office in Jacksonville, Florida, at (904)-641-4800. At Performance Painting, our professional painters can take care of all your painting needs. 

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