Chemical & Process Safety Management > Chapter-4 > Topic- Safety In plant operations and maintenance > Subtopic- Pipeline colour coding for identification of contents

 Que. Discuss in brief colour coding of pipeline & its importance in chemical industry ( Summer 2015)

In chemical industry and in other industries also, a number of chemicals are required to be transferred from one place to other. When there are fluids (liquids or gases), pipe lines are used. A number of such pipes are laid many times side by side, in a trench or on a bridge or overhead brackets. The identification of the contents of the pipe is very much essential for safe operations and particularly for maintenance of the pipe lines. More over to have uniformity some standard or code (a set of laws or rules) is necessary. This is achieved by IS 2379:1990.

Purpose & Importance of the colour coding for piping as per IS 2379- 

This code is applicable to pipes, fittings, valves and pipe coverings. Supports, brackets or other accessories are specifically excluded. 

1) It gives a color scheme for identification of the contents of pipelines carrying fluids in domestic and public buildings and such industrial installations where a specific color code does not exist.

2) This is not applicable to pipelines buried underground or for electrical services.  

3) The scheme consists of a color code or lettering or both.

4) The purpose is to identify the contents of the pipeline.

5) The ground color identifies the basic nature of the fluid carried and also distinguishes one fluid from another.     

Ground color:

It should be applied through out the entire length. It may be applied as a color coating of length, but not less than 300 mm (so that it is not mistaken as a color band) or As a color panel or On a label attached to the pipe or By the use of colored adhesive tapes of suitable material.

When it is not applied throughout the entire length it shall be applied near valves, junctions, service appliances, bulk heads walls etc. The ground color should be extended on both sides of the color band to avoid confusion.

Valves shall be painted with the same color as the main pipe line (some exceptions). 

Hazards – When it is desired to indicate that a pipeline carries a hazardous material a panel of color of suitable width minimum 100 mm shall be superimposed on the ground color at suitable intervals. 

Table no 1. Ground colors –

Sr.No	Fluid substance	Ground color
1	Water	Sea green
2	Steam	Aluminum (IS 2339)
3	Natural vegetable & mineral oils or combustible liquids	Light brown
4	Acids	Dark violet
5	Air	Sky blue
6	Gases	Canary yellow
7	Alkalies	Smoke gray
8	Other liquids or gases which do not need identification	Black
9	Hydrocarbons / organic compounds	Dark admiralty gray

Color bands – these should be superimposed on the ground color at different locations to distinguish 

1) One kind of condition from another kind of condition of the fluid or

2) One fluid from another but belonging to the same group e g carbon monoxide from

    coke oven gas, diesel from furnace oil.

These should be at the following locations – 

      1) At the battery limit points
      2) Intersection points and change of direction points in piping ways
      3) Other points such as midway of each piping way, near valves,junction joints of 
          service appliances,walls, on either sides of pipe culverts
      4) For long stretch yard piping at 50 meter’s interval and
      5) At start & terminating points.

 The minimum width of a color band shall be based on the size of the pipe line.

No	Nominal size	Width of color band
1	80 NB or less	25 mm
2	Over 100 NB up to 150 NB	50 mm
3	Over 200 NB up to 300 NB 75	75 mm
4	Over 350 NB	100 mm

• For insulated pipes nominal pipe size means the outside diameter of insulation.
• The color band shall be as per sequence and in the direction of flow
• The width of the first color band to subsequent band shall be 4:1.
• To indicate a hazard by lettering a panel of colors of suitable width shall be  superimposed.
• valves shall be painted with the same color as the main pipe line.
• Color code for Industrial services ( IS 2379:1990)
  

Table 2 – General services

No	Name	Ground color	First band	Second band
1	Cooling water	Sea green	French blue	-
2	Boiler feed water	Sea green	Gulf red	-
3	Condensate	Sea green	Light brown	-
4	Drinking water	Sea green	French blue	Signal red
5	Fire water	Fire red	Crimson red	-
6	Waste water	Sea green	Canary yellow	-
7	Comp air (< 15kg/cm2)	Sky blue	-	-
8	Comp air (>15kg/cm2)	Sky blue	Signal red	-
9	Vacuum	white	-	-
10	Light diesel fuel	Light brown	Brilliant green	-
11	High speed diesel	Light brown	-	-
12	Furnace oil	Light brown	French blue	-

 

 

 

Table 3 - Industrial gases

No	Name	Ground color	First band	Second band
1	Ammonia	Canary yellow	Dark violet	-
2	Butane	Canary yellow	Signal red	-
3	Chlorine	Canary yellow	Signal red	Light orange
4	Ethyl chloride	Canary yellow	Light gray	Signal red
5	Freon	Canary yellow	Light gray	Dark violet
6	Hydrogen	Canary yellow	Signal red	French blue
7	Methyl bromide	Canary yellow	French blue	Black-
8	Nitrogen	Canary yellow	Black	-
9	Oxygen	Canary yellow	White	-
10	Phosgene	Canary yellow	Black	White
11	Sulphur dioxide	Canary yellow	Dark violet	Golden green

 

Table 4 Hydrocarbons & naphtha

No	Name	Ground color	First band	Second band
1	Benzene	Dark admiralty gray	Canary yellow	-
2	Methanol	Dark admiralty gray	Deep blue	-
3	Naphtha	Dark admiralty gray	Light brown	Black
4	Sulphuric acid	Dark violet	Brilliant green	Light orange
5	HCl	Dark violet	Signal red	Light orange
6	Caustic soln.	Smoke gray	Light orange	-
7	Strong caustic	Smoke gray	French blue	White
8	Viscose	Black	Golden yellow	Brilliant green
9	Carbon disulphide	Black	Light orange	-
10	Mercury	Black	White	Brilliant green

 

 

Table 5 – medical gases

No	Name	Ground color	First band	Second band
1	Air	Sky blue	White	Black
2	Oxygen	Canary yellow	White	-
3	Vacuum	Sky blue	Black	-
4	Carbon dioxide	Canary yellow	Light grey	-
5	Nitrous oxide	Canary yellow	Black	-

• When further identification is required it may be done by the particular industry.
• Lettering is recommended for chemical industry for the products not covered in tables 2 to 5. the recommended size of lettering for pipes with outside diameters ranging from 20 to above 250 mm is ranging from 10 to 90 mm.
• The direction of flow may be by arrows or letters and they may be black or white and in contrast to ground color. Attention should be given to the visibility of the color markings.
• The electrical lighting should be such that proper visibility of colors is not affected in the night.

References : 

1) IS 2379

2) K.U.Mistry Book