ISO 20560-1:2020

INTERNATIONAL ISO
STANDARD 20560-1
First edition
2020-09
Safety information for the content of
piping systems and tanks —
Part 1:
Piping systems
Informations de sécurité relatives au contenu des systèmes de
tuyauteries et des reservoirs —
Partie 1: Systèmes de tuyauteries
Reference number
ISO 20560-1:2020(E)
©
ISO 2020

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ISO 20560-1:2020(E)

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© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
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ISO 20560-1:2020(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General requirements . 2
5 Elements of safety information systems for piping . 3
5.1 General . 3
5.2 Colour coding to identify the nature of the content in the piping . 3
5.3 Content name . 5
5.4 Flow direction indicators . 6
5.5 Warning signs and GHS pictograms . 7
6 Technical and operational information . 8
6.1 General . 8
6.2 Additional safety information . 8
6.3 Additional technical information . 8
6.4 Supplementary identification colours . 8
7 Layout requirements . 9
8 Installation of safety information systems for piping .10
9 Maintenance, inspection and revision .11
Annex A (informative) Standard colours and equivalent colour codes .12
Annex B (informative) Observation distance .13
Annex C (informative) Examples of safety information systems .17
Annex D (informative) Firefighting systems .23
Annex E (informative) Maritime piping systems .24
Bibliography .26
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ISO 20560-1:2020(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 145, Graphical symbols, Subcommittee SC
2, Safety identification, signs, shapes, symbols and colours.
A list of all parts in the ISO 20560 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
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ISO 20560-1:2020(E)

Introduction
Continuous growth in mobility of labour has resulted in a need to standardize safety information
and form a coherent system for non-verbal exchange of information that consists of distinct elements
to identify hazards related to the content of piping systems and tanks. Every element of the safety
information system defined in this document communicates specific information. When combined on
a pipe marking, these elements inform the viewer, in a unique and simplified way, of potential hazards
so accidents can be prevented and an appropriate response to emergency situations can be efficiently
accomplished.
The use of this document is expected to reduce risk by providing a means of improved training and
education to reduce possible confusion for people working with and near piping systems in both normal
and emergency situations.
The use of a standardized safety information system does not replace proper work methods,
instructions or accident prevention training and measures. Education is an essential part of any system
that provides safety information.
Many different countries’ national pipe marking standards were reviewed during the development of
this document. Important design concepts contained in these standards were incorporated into this
document.
NOTE Some countries’ statutory regulations could differ in some respect from the requirements given in
this document.
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INTERNATIONAL STANDARD ISO 20560-1:2020(E)
Safety information for the content of piping systems and
tanks —
Part 1:
Piping systems
IMPORTANT — The colours represented in the electronic file of this document can be neither
viewed on screen nor printed as true representations. For the purposes of colour matching see
Table 2 and Table 5, which provide colorimetric and photometric properties, and Annex A, which
provides references from colour order systems.
1 Scope
This document specifies safety information for overground piping systems related to the content of the
piping system and associated hazards for the purpose of accident prevention, reducing risks to health
and providing information for use in case of an emergency.
This document does not cover piping that is buried.
Safety signing of the hazards in an area is not part of this document.
This document can also be used for marine structures and ships.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 7010, Graphical symbols — Safety colours and safety signs — Registered safety signs
UNITED NATIONS, Globally harmonized system of classification and labelling of chemicals (GHS), eighth
revised edition, New York and Geneva, 2019, United Nations [viewed 18 May 2020]. Available from:
http:// www .unece .org/ fileadmin/ DAM/ trans/ danger/ publi/ ghs/ ghs _rev08/ ST -SG -AC10 -30 -Rev8e .pdf
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
additional safety information
information typically presented in the form of text, numbers or both to indicate details related to the
safety information system (3.8)
EXAMPLE Pressure or temperature.
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3.2
additional technical information
technical information that is additional to the safety information system (3.8) to indicate technical details
EXAMPLE Pipe identification codes or from–to information.
3.3
basic identification colour
colour used to indicate a group of similar media
3.4
content of the pipe
medium which is transported in the pipe
EXAMPLE Gasses, liquids or solids as powder or granulate.
3.5
flow direction indicator
arrow to indicate the flow direction of the content of the pipe
3.6
GHS hazard pictogram
graphical composition defined by the Globally harmonized system of classification and labelling of
chemicals (GHS) that can include a symbol plus other graphic elements, such as a border, background
pattern or colour, intended to convey specific information as given by the GHS
3.7
safety data sheet
SDS
standardized information template for a medium which identifies the medium and contains information
about its potential health, physical and chemical hazards, and emergency and firefighting procedures
3.8
safety information system
series of markings that consistently uses standardized elements to visually communicate information
necessary for the reliable recognition, identification and understanding of hazards
3.9
supplementary identification colour
colour used in combination with the basic identification colour (3.3) to indicate a specific purpose
3.10
warning sign
safety sign that indicates a specific source of potential harm
[SOURCE: ISO 3864-1:2011, 3.16]
4 General requirements
A safety information system for piping visually communicates information necessary for the reliable
recognition, identification and understanding of any hazard related to the type and character of the
content of a pipe. This safety information system shall be installed on site and near any place that might
require operation, maintenance or manipulation of a pipe’s contents.
This safety information system provides critical information that serves to assist in:
— the correct operation and use of the piping system;
— the safe maintenance of the piping system;
— conveying critical information to trained personnel in emergency situations.
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ISO 20560-1:2020(E)

The safety information system shall, in a comprehensive and uniform manner, accurately identify
the contents and hazards associated with the content of all piping and material transport systems in
conformity with the contents’ safety data sheets (SDSs). In some cases the safety information system
shall provide, in an integrated, coherent visual manner, specific hazard information related to the pipe
contents. Examples of this information include the exact nature of the substance, temperature, toxicity,
and the risk of asphyxiation if a release of the pipe contents occurs.
The safety information system shall consistently use multiple visual elements to accurately convey
its information, including colours and colour combinations as a coding system, text, safety signs, GHS
hazard pictograms and arrows. The information conveyed by the safety information system shall be
consistent with the organization’s risk assessment and its operation and safety plans.
All elements of a safety information system shall be distinguishable and contrasting from any
neighbouring information and shall be visible from the observation distance intended for safe operation,
intervention or manipulation. When the contents of pipes include hazardous substances (see GHS), the
safety information system shall include distinctive, unambiguous elements and the corresponding
warning signs, GHS hazard pictograms or both.
To avoid confusion, the same safety information system elements shall be consistently used and
installed throughout an organization’s piping system, whether it is a single unit, multiple units on the
same site or a multi-plant operation.
5 Elements of safety information systems for piping
5.1 General
The level of detail required to be displayed in a safety information system for piping will depend on
many factors, such as the type of plant, the complexity of the operation, the availability of check lists
and manuals and the competence and skills of operators. Organizations shall design safety information
systems for piping in accordance with their operational and risk communication needs as identified by
their risk assessment process.
A safety information system for piping shall consist of four key elements:
1) colour coding to identify the nature of the content in the piping;
2) content name;
3) flow direction indicators;
4) when applicable, warning signs, GHS pictograms or both.
5.2 Colour coding to identify the nature of the content in the piping
Safety information systems for piping shall incorporate colour coding that uses the basic identification
colours and the safety colour yellow for hazardous substances.
Where there is no need to further differentiate hazardous substances, the safety colour yellow shall be
used alone, without the addition of a basic identification colour. See Table 1.
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ISO 20560-1:2020(E)

Table 1 — Safety colour and basic identification colours
Content of a pipe Colour
Safety colour Hazardous substances Yellow
Basic Gases in either gaseous or Grey
identification liquefied condition
colour
Liquids and fixed materials Black
(powder, granulates)
Acids Orange
Alkalis (leaches) Violet
Firefighting medium Red
Water Green
Air Blue
The chromaticity coordinates of a basic identification colour shall fall within the relevant colour region
specified in Table 2. The luminance factor for each colour shall be as specified in Table 2. To measure
the chromaticity coordinates and luminance factor of pipe markings, the test method for ordinary
materials specified in ISO 3864-4:2011, 5.2.1 can be used. The testing shall be carried out on finished
markings or samples that are representative, with regard to the colour and surface texture, of the
material used in the finished marking.
Table 2 — Colour regions for safety colour and basic identification colours:
chromaticity coordinates and luminance factor for colours externally illuminated by CIE
standard illuminant D65
Corner points of colour region
Luminance factor
CIE standard illuminant D65
β
Colour
CIE 2° standard colorimetric observer
1 2 3 4 Minimum Maximum
Yellow x 0,467 0,514 5 0,470 0,432 0,45 0,60
y 0,516 0,472 5 0,440 0,478
Grey x 0,350 0,300 0,290 0,340 0,15 0,50
y 0,360 0,310 0,320 0,370
NOTE 1  Measurement geometry 45°/0° or 0°/45°.
NOTE 2  All colours except yellow and red are amended from ISO 14726. Yellow and red are safety sign colours from
ISO 3864-4.
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Table 2 (continued)
Corner points of colour region
Luminance factor
CIE standard illuminant D65
β
Colour
CIE 2° standard colorimetric observer
1 2 3 4 Minimum Maximum
Black x 0,385 0,300 0,260 0,345 0,03
y 0,355 0,270 0,310 0,395
Orange x 0,590 0,538 0,508 0.550 0,25 0,4
y 0,394 0,382 0,412 0,430
Violet x 0,320 0,319 0,329 0,340 0,1 0,2
y 0,218 0,272 0,295 0,230
Red x 0,705 0,592 0,574 0,663 0,07 0,2
y 0,295 0,291 0,351 0,337
Green x 0,250 0,330 0,330 0,287 0,25 0,35
y 0,580 0,580 0,458 0,439
Blue x 0,160 0,196 0,218 0,205 0,15 0,25
y 0,225 0,250 0,192 0,169
NOTE 1  Measurement geometry 45°/0° or 0°/45°.
NOTE 2  All colours except yellow and red are amended from ISO 14726. Yellow and red are safety sign colours from
ISO 3864-4.
NOTE Examples of identification colours are given in Annex A.
5.3 Content name
The pipe’s content name shall be displayed in text elements which can be either the content name or its
chemical formula, or by numbers in accordance with national standards.
Longer words may be abbreviated using standard approved abbreviations known by operators as found
in the organization’s operation safety manuals.
The content name shall be centred and placed within the basic identification colour or in the yellow
safety colour using the contrast colours as defined in Table 3. Alternatively, the content name shall be
the contrast colour black on a white background.
Table 3 — Contrast colours for content name to be displayed on the safety colour and
basic identification colours
Content of a pipe Basic Contrast
identification colour
colour
Safety colour Hazardous substances Yellow Black
Basic Gases in either gaseous or Grey Black
identification liquefied condition
colour
Liquids and fixed materials Black White
(powder, granulates)
Acids Orange Black
Alkalis (leaches) Violet White
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ISO 20560-1:2020(E)

Table 3 (continued)
Content of a pipe Basic Contrast
identification colour
colour
Firefighting medium Red White
Water Green White
Air Blue White
NOTE Further information on colour systems is given in Annex A.
To increase legibility, a sans serif font in the contrast colour as defined in Table 3 shall be used. To
increase readability, upper-case and lower-case letters shall be used. See Figure 1.
Figure 1 — Example of content name “Air” in the contrast colour white on the basic
identification colour blue
5.4 Flow direction indicators
The safety information system uses arrows to indicate the flow direction of the content of the
piping system.
The direction of flow shall be indicated with a single headed arrow (see Figure 2) or, where applicable
(e.g. ring main), with a double-headed arrow (see Figure 3). The shaft of the arrow may be shortened or
lengthened as needed to improve visibility by users at the intended observation distances.
The flow direction indicator shall be black on a white background or the contrast colour on the basic
identification colour or on the safety colour as defined in Table 3.
Key
x length of arrow point
y width of arrow point
Figure 2 — Direction of flow indicator (right)
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ISO 20560-1:2020(E)

Figure 3 — Direction of flow indicator to indicate a flow in either direction
5.5 Warning signs and GHS pictograms
Warning signs and graphical symbols are elements of the safety information system used to
symbolically communicate specific safety meanings. The SDSs, the organization’s risk assessment
or both shall identify the specific warning signs according to ISO 7010, GHS pictograms needed to
communicate hazards associated with the contents of pipes or both. The safety information system’s
warning signs and GHS pictograms shall be displayed on a white background or on the yellow safety
colour. See Figures 4 and 5 for examples.
Figure 4 — Examples of display of warning signs and GHS pictograms on a white background
Figure 5 — Examples of display of warning signs and GHS pictograms on the yellow safety
colour background
NOTE Ranking systems can be used to prioritize and reduce the number of GHS pictograms that need to be
displayed.
As a result of an organization’s risk assessment, safety information systems on piping may use safety
signs, supplementary text or both to communicate potential hazards not defined in SDSs. Such potential
hazards include:
— temperature extremes of the contents;
— biohazards;
— radiation;
— asphyxiation by oxygen displacement;
— electrical hazards;
— hazards related to pressurized content.
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ISO 20560-1:2020(E)

6 Technical and operational information
6.1 General
The safety information system for piping may include risk assessment-defined operational information
such as:
— additional safety information;
— additional technical information;
— supplementary identification colours.
6.2 Additional safety information
If additional safety information is required by the user, this information shall be placed on the coloured
background next to the content name in the same contrast colour as the content name as defined in
Table 2. Alternatively, the additional safety information shall be the contrast colour black on a white
background.
Examples include:
— high pressure;
— high or low temperature;
— speed;
— quantity of flow.
6.3 Additional technical information
If additional technical information is required by the user, this information shall be the contrast colour
black on a white background.
Examples include:
— pipe identification code according to the piping system;
— from–to information (e.g. “from V09 to P23”);
— line number consisting of outside dimension, product code, system number, line sequence;
— number and pipe classification code;
— short description of function or service.
NOTE As a result of risk assessment the height of additional information text could be smaller than the text
height of the content name (see Annex B).
6.4 Supplementary identification colours
If the content of the piping needs further specification, supplementary identification colours shall be
used. The supplementary identification colours shall be placed on both sides of the basic identification
colour area. On both sides, the width of the supplementary colour area shall be 10 % of the basic
identification colour area.
As a supplementary colour all basic identification colours as defined by Tables 1, 2, 4 and 5 can be used.
The supplementary colour shall be different than the relevant basic identification colour associated
with the content of the pipe. The safety colour yellow shall not be used as a supplementary colour.
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ISO 20560-1:2020(E)

Supplementary colours together with the basic identification colour are used for some special piping
systems, such as firefighting systems, water service, medical gas applications and maritime systems.
See Annexes C and D for additional information.
Only the combination of the two colours specifies the specific use. If supplementary colours are used,
they shall to be used according to Table 2. For the missing supplementary identification colours, see
Tables 4 and 5.
Table 4 — Supplementary identification colours
Colour
Supplementary White
identification colour
Maroon
Brown
Yellow (brighter than safety
colour yellow)
Table 5 — Colour regions for supplementary identification colours: chromaticity coordinates
and luminance factor for colours externally illuminated by CIE standard illuminant D65
Corner points of colour region
Luminance factor
CIE standard illuminant D65
β
Colour
CIE 2° standard colorimetric observer
1 2 3 4 Minimum Maximum
White x 0,350 0,295 0,285 0,340 0,75
y 0,360 0,305 0,315 0,370
Maroon x 0,455 0,480 0,480 0,460 0,05 0,1
y 0,359 0,364 0,330 0,330
Brown x 0,475 0,496 0,430 0,415 0,15 0,25
y 0,435 0,415 0,385 0,395
Yellow x 0,460 0,480 0,440 0,427 0,60 0,75
(supplementary)
y 0,509 0,494 0,458 0,472
NOTE  Measurement geometry 45°/0° or 0°/45°.
NOTE Further information on colour systems is given in Annex A.
7 Layout requirements
The following specifications should be considered to determine the correct size and ratio of various
elements of a pipe’s safety information system:
— The minimum width of the basic identification colour area or, when used alone, the safety colour
area on thin pipes should be 85 mm. See Figure B.1.
— If the pipe diameter exceeds 150 mm, the minimum width of the basic identification colour area or,
when used alone, the safety colour area should be 120 mm. See Figure B.2.
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— If the pipe diameter exceeds 500 mm, the minimum width of the basic identification colour area or,
when used alone, the safety colour area should be 200 mm. See Figure B.3.
2
— For pipes with a diameter up to 500 mm, the minimum colour surface area in mm for the basic
identification colour area or, when used alone, the safety colour area is 50 times the diameter (in
mm) of the pipe. For pipes with a diameter exceeding 500 mm a minimum colour surface area should
2
be 25 000 mm . See Figure B5 and B.6.
— When a basic identification colour is added on a hazardous substance (yellow) marking, the
minimum width of the safety colour yellow should be 50 % of the width of the basic identification
colour area.
— A maximum of two lines of text should be used for displaying the content name.
— The minimum text height for a safety information system should be 7 mm.
— The minimum arrow point height (y in Figure 2) for a safety information system should be 10 mm.
— The minimum height of warning signs, GHS pictograms or both for a safety information system
should be 20 mm.
— To maximize visibility, the safety information system on the pipe should have sufficient contrast
with the surface on which it is mounted.
— When a pipe will be seen from two sides, the safety information system should appear on both sides
of the pipe.
NOTE For information related to size and observation distances, see Annex B.
8 Installation of safety information systems for piping
Safety information systems for piping shall be permanently mounted on pipes at locations where it
needs to be observed, specifically considering:
— operational
...