ASME A13.1 is the American standard for the scheme for the identification of piping systems. Since the 2007 revision it assigns marking colours by the fluid hazard rather than the fluid type, using six designated colour combinations plus user-defined ones, and it sets the legend letter height and colour field length by the pipe outside diameter.

What are the ASME A13.1 pipe colours?

The six designated ASME A13.1 schemes are: flammable fluids, black legend on yellow; combustible fluids, white on brown; toxic and corrosive fluids, black on orange; fire-quenching fluids, white on red; compressed air, white on blue; and other water, white on green. Four further user-defined combinations using purple, white, grey and black are available for facility-specific services.

What colour should hydrogen piping be under ASME A13.1?

Hydrogen is a flammable gas, so under ASME A13.1 it takes the flammable scheme: a black legend on a yellow colour field, with a flow-direction arrow. The legend size follows the pipe outside diameter, and many facilities add the word FLAMMABLE and hazard details as a user-defined enhancement.

How big should a pipe label be?

ASME A13.1 sizes the marker by the pipe outside diameter including any covering. For 19 to 32 mm pipe the letters are 13 mm and the colour field 200 mm; for 64 to 150 mm the letters are 32 mm and the field 300 mm; for 200 to 250 mm the letters are 64 mm and the field 600 mm; and for pipe over 250 mm the letters are 89 mm and the field 800 mm.

Which direction should the flow arrow point?

The arrow points in the direction of normal flow and is shown at each legend location. Where flow can occur in both directions, arrows are shown pointing both ways. Arrows are placed at each end of the legend so the marker reads correctly from either approach.

What is the difference between ASME A13.1 and BS 1710?

ASME A13.1 is hazard-based: the background colour is set by the fluid hazard. BS 1710 is contents-based: it uses a basic identification colour for the pipe contents (for example green for water, silver-grey for steam, brown for oils, light blue for air) with additional code-indication colour bands. They are different systems and are not interchangeable, so a plant should adopt one standard consistently.

BS 1710 is the British Standard for the identification of pipelines and services. It applies a basic identification colour band for the pipe contents, with code-indication colour bands placed between two basic bands to give more detail, plus safety colours for hazards. It is widely used in the UK, the Middle East and Commonwealth countries.

IS 2379 is the Indian Standard code of practice for colour code for identification of pipelines. It defines ground colours for the main pipe contents with secondary colour bands to indicate the specific service, and is commonly specified on projects in India and South Asia.

PFI ES-22 is the Pipe Fabrication Institute Engineering Standard for the recommended practice for colour coding of piping materials. It is used in fabrication shops to mark pipe and fittings by material grade during fabrication so that materials are not mixed up, which is distinct from the operational hazard marking of ASME A13.1.

How often should pipe markers be placed?

Markers should be visible from the normal points of approach. Common practice places them adjacent to valves and flanges, at branches and changes of direction, on both sides of wall, floor and ceiling penetrations, at battery limits and equipment connections, and at intervals along straight runs, typically every 8 to 15 metres so at least one marker is always in view.

What is a line number?

A line number is the unique identifier of a piping line on a P&ID and isometric. It typically combines the nominal size, a service or fluid code, a sequential number and a piping material specification, for example 6-CWS-1001-CS1. Projects define the exact format, and this tool lets you compose and validate line numbers to a chosen convention.

Are the on-screen colours exact?

The on-screen colours are sRGB approximations of the standard marking colours and are intended for design and visualisation. For procurement of labels, paint or tape, match the colour to a physical reference such as a RAL or BS colour swatch specified by your project, because screen rendering and printer output vary.

Is this pipe colour code tool free and standards-compliant?

The tool is free and works offline in the browser. The ASME A13.1 colour scheme and sizing are implemented to the published standard. BS 1710, IS 2379 and PFI ES-22 data are representative engineering values to be verified against the actual standard, and all colours are on-screen approximations. Confirm the final marking against the governing standard edition and project specification before application.

PipeColorCode™

Identification Expert Suite · ASME A13.1 / BS 1710 / IS 2379 / PFI ES-22