ISO 3864-1: Safety Signs and Markings
ISO 3864-1 is the international standard that sets the design principles for safety signs and safety markings: the geometric shapes, safety colours and contrast colours that let a sign be understood before its symbol is read. It applies in workplaces and public areas, from factories and military bases to shelters and transport facilities.
The current edition is ISO 3864-1:2011. This article explains the five sign types, how safety markings work, how Part 1 fits with ISO 3864-2 and ISO 7010, and what it means for photoluminescent and tritium signs.
Why is ISO 3864-1 Important?
A safety sign has to work on someone who is in a hurry, under stress, in poor light or unable to read the local language. The standard makes the shape and colour carry the message first, so a red circle with a bar means a prohibition and a green square means a safe condition wherever the standard is applied.
Its stated purpose covers accident prevention, fire protection, health hazard information and emergency evacuation. It also sets the basic principles that other standards follow when they contain safety signs, which is why ISO 7010 builds on it.
- One visual language: personnel moving between sites, vessels or allied facilities read the same shapes and colours.
- Hazard communication without words: the meaning does not depend on the reader’s language.
- Consistent colour coding: fixed safety and contrast colours for prohibitions, mandatory actions, warnings, safe conditions and fire equipment.
- Visible materials: ISO 3864-4 sets the colour and photometric properties of the sign materials themselves.
- Compliance: workplace safety rules and tenders that cite ISO 7010 rely on the same design principles.
Types of Safety Signs Under ISO 3864-1
Table 1 of the standard gives each meaning one geometric shape and one safety colour, plus a contrast colour and a fixed colour for the graphical symbol. That produces five sign types, and every registered sign in ISO 7010 belongs to one of them.
| Meaning | Shape | Safety colour | Contrast / symbol | Example |
|---|---|---|---|---|
| Prohibition | Circle with diagonal bar | Red | White / black | No smoking |
| Mandatory action | Circle | Blue | White / white | Wear eye protection |
| Warning | Triangle with radiused corners | Yellow | Black / black | Electricity |
| Safe condition | Square | Green | White / white | Emergency exit |
| Fire equipment | Square | Red | White / white | Fire extinguisher |
Safe condition and fire equipment signs are square, not rectangular. Rectangles are reserved for supplementary signs, which add text or other information to a safety sign. They use a white background with black text, or the safety colour of the sign they support with a black or white contrast.
The standard also has layout rules for combination signs, which pair a safety sign with a supplementary sign, and for multiple signs, which carry more than one safety message on one carrier. Where mounting space is limited, as on a vehicle, shelter or vessel, a multiple sign can show several hazards at one entry point.
Safety Markings: Stripes for Hazards and Obstacles
Part 1 covers safety markings as well as signs. A safety marking applies a safety colour and its contrast colour directly to a surface, so it shows the full extent of a hazard that a sign can only point to, such as an obstacle, a low overhead beam or the edge of a platform. Clause 11 of the standard sets their layout.
In the European Union, Annex V of Directive 92/58/EEC asks for alternating yellow and black, or red and white, stripes for obstacles and dangerous locations, at an angle of about 45 degrees and of roughly equal width. Within the EU those rules apply to vehicle workshops and hangars like any other workplace.
The ISO 3864 Family and ISO 7010
A specification rarely cites Part 1 on its own. Part 1 sets the rules, and the other parts and ISO 7010 turn them into symbols, finished signs and sign materials.
ISO 3864-2:2016 applies the same principles to product safety labels on manufactured products, from consumer goods to industrial equipment. It governs the hazard label on a piece of equipment, while Part 1 governs the sign on the wall or door.
ISO 7010:2019 specifies the registered safety signs, with shape and colour to Part 1 and symbols to Part 3. It has been amended eleven times, most recently in 2026, and ISO lists it as expected to be replaced by ISO/DIS 7010, so check which amendment a contract cites.
In the European Union, Directive 92/58/EEC sets the minimum requirements for safety and health signs at work. The Commission’s non-binding guidelines of January 2022 explain how the directive relates to EN ISO 7010, the European adoption of ISO 7010.
Luminous Safety Signs: Photoluminescent and Tritium
Where mains power cannot be relied upon, in shelters, ships, aircraft and remote sites, luminous signs keep the shapes and colours of a safety sign readable in the dark. There are two technologies, and the ISO standards treat them differently.
Photoluminescent (phosphorescent) material charges from ambient light and glows as it fades. Table 1 of Part 1 accepts it as the white of a sign in daylight, ISO 3864-4 adds requirements and test methods for its use in unlit conditions, and ISO 16069:2017 covers it in safety way guidance systems.
Tritium signs are self-luminous: sealed gaseous tritium light sources glow continuously without charging or power. ISO 3864-4 expressly excludes luminous signs activated by a radioactive source, so their light output is assessed against other standards and listings, not against Part 4.
Our tritium exit signs list UL, NFPA Life Safety Code 101, BS 5499 Part 2, NEN 6088 and ANSI N540 on their product page. Our glow in the dark way guidance covers photoluminescent tape, signs and floor arrows.
The practical trade-off between the two light sources, charging against a continuous glow, is set out in tritium vs glow in the dark. Where a tender names ISO 3864-1 or ISO 7010 for luminous signs, send the legends, sizes and mounting conditions through our contact page, so design and certification can be confirmed before ordering.
Frequently Asked Questions
Yes. The second edition was published in April 2011 and, together with ISO 3864-4, cancelled and replaced ISO 3864-1:2002. ISO last reviewed and confirmed it in 2022 and shows no revision under development. Of the other parts, Part 3 has moved on to ISO 3864-3:2024, so a drawing that still cites the 2012 symbol rules is one edition behind.
ISO 3864 gives the design rules: Part 1 the shapes and colours, Part 3 the symbols. ISO 7010 is the set of registered safety signs built to those rules, with originals that can be scaled for reproduction. Where ISO 7010 registers a sign for the message, specifying that sign gives the same design on every site; Part 1 remains the reference for anything ISO 7010 does not cover, and for safety markings.
No. Its scope excludes signalling used to guide rail, road, river, maritime and air traffic. The colour of a tail lamp or marker lamp comes from the vehicle lighting standards, which DOT vs ECE vs SAE compares. It does apply to the safety signs and markings inside a vehicle workshop, a hangar or a field shelter.