Sunday, June 24, 2012

Colour Coding of Pipelines (Piping)

Identification and colour coding for the pipelines is essential to avoid potential hazards, accidents. Giving a colour code and maintaining the uniformity for colour coding in industrial piping will eliminate accidental chances, reduces operational errors. Moreover it enhances the safety aspects.

Different companies, local regulations have prepared the standards for colour coding of the pipelines

Examples: IS: 2379
BS: 1710
ANSI A 13.1

Colour coding or the colouring scheme is to know, identify which fluid is flowing inside the pipelines. This can be applicable to building piping, process piping, industrial piping, chemical or process plants. Complete piping systems including valves, fittings are to be painted accordingly.

Paints and paint shades selected should conform to the governing standard prior to provision. 

Colour Coding to Pipelines (Ground Colour and Colour Bands)

Giving a base or ground colour to pipelines based on fluid flowing, the line identification is done. Further colour bands are provided accordingly. The base/ground colour gives the basic nature of the flowing fluid (i.e. water, air, gases etc.).

Typically ground colours are provided on the full pipe section or minimum 300 mm length portion or by attaching the label.

Ground colour Fluid flow inside the pipe
Green Water
Sky Blue Air
Yellow Gases
Aluminum Steam

Over and above the base colour or ground colour to the pipeline, colour bands are provided to differentiate and identify the application of the basic fluid.

(1) Fluid: Water
Ground colour code: Green

Cooling water: Sea green (ground colour) and application is for cooling hence a further colour band of French blue is provided.

(2) Fluid: Air
Ground colour code: Sky blue

Plant air: Sky blue (ground colour) and application is for supplying the plant air hence a further colour band of silver grey is provided.

Colour Bands

As stated earlier, colour bands in single or double over the ground colour on the pipeline, and the ground colour on the entire or partial length of the pipeline is provided. These colour bands are provided at suitable locations such as:

  • At the beginning and termination points
  • For yard piping around 50 to 60 m distances
  • At change in flow direction points and flow diversion locations.
  • At locations where the pipe enters the building or exits from the building

Typical Practices Followed for the Provision of Ground Colour and Colour Bands on the Pipelines

(1) If colour bands are provided over the ground colour, then the ground colour should extend on both sides of the colour bands.

typical pipe color band

(2) When double colour bands exist on the pipeline, then a proportional width of 4:1 to the next colour band is provided.

(3) Minimum colour band width to be 25 mm.

(4) Generally below 80 NB piping width of the colour band is 25 mm.

(5) For piping 100 NB to 150 NB width of the colour band is 50 mm.

(6) Valves and piping accessories to be painted with the same colour as that of the pipe ground colour.

(7) For insulated pipes, non-ferrous pipes, S.S. pipe ground colour to be given for minimum 1.5 m length.

(8) For uninsulated piping above 100 Degree C, generally colour bands are not provided (only ground color Aluminum). If bands are to be provided then they should be of Teflon tape.

(9) Flow direction, arrows to be marked at suitable intervals along the line. Line carrying fluid, the fluid name should be written in the white box on the ground colour provided for the line.

Arrow sizes, dimensions differ w.r.t. company standards.


Below 200 NB line arrow dimensions are given below.

pipe lettering for fluid name

Lettering size for fluid name is also based on the pipe diameter


100 NB Pipe ---------------Legend Size is 30 mm
50 NB Pipe -----------------Legend Size is 25 mm
200 NB Pipe ---------------Legend Size is 50 mm

(10) Visibility of Marking: It should be such that the operator can see if it is at the normal height. If lines are above the operator's head (may be along the roof, or side wall or through the rack), then the lettering is to be done below or towards the bottom side of the pipe.

piping visibility marking

(11) Lighting provided in the plant should not affect the colour and shades in terms of visibility particularly at night.

(12) For closed circuit lines other than direction ‘F' for “Flow” and ‘R' for “Return” to be written for better understanding.

(13) Lines carrying hazardous materials have a panel of colour with dots, strips, crosses are marked based on the practices.

Hence, finally uniformity for color coding on pipelines will lead to better safety, less human errors. 

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1 comment :

  1. Good article. Very informative one. Thanks for sharing.



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