ISO 3864-4:2011

Overview

ISO 3864-4:2011 - Graphical symbols - Safety colours and safety signs - Part 4: Colorimetric and photometric properties of safety sign materials - defines the colour and light‑related (photometric) requirements and test methods for materials used in safety signs for workplaces and public areas. It establishes how safety colours and contrast colours (as named in ISO 3864‑1) should be measured and verified for both normally lit (daytime) and unlit (phosphorescent) conditions.

Key technical topics and requirements

• Scope and applicability

  • Applies to safety signs addressing human safety in workplaces and public areas.
  • Excludes traffic signalling (rail, road, maritime, air) and sectors with differing regulations.
  • Does not specify properties for retroreflective materials or safety signs activated by radioactive sources.

• Colorimetric basis

  • Uses the CIE 2° standard colorimetric observer and CIE Standard illuminant D65 for measurements.
  • Defines colour regions in chromaticity coordinates (x,y) and specifies acceptable luminance factor or luminance ranges for each named safety and contrast colour.

• Photometric requirements

  • Provides test methods for externally illuminated, internally illuminated (maintained and non‑maintained), and phosphorescent materials.
  • For powered internally illuminated signs, the standard specifies luminance, luminance contrast between symbol and background, and permissible ratios of minimum to maximum luminance within a colour.
  • Phosphorescent materials have specific emission colour classification and test methods (see Annex B).

• Test methods and instrumentation

  • Includes procedures for measuring object colour under external illumination and for powered signs.
  • Refers to CIE and ISO measurement standards (e.g., CIE 15, CIE 69) and specifies required instrumentation performance (Annex C).

Practical applications and users

• Who uses ISO 3864‑4

  • Safety sign manufacturers and material suppliers (to specify compliant colours and batches).
  • Test laboratories and instrument manufacturers (to develop and validate measurement methods).
  • Health & safety managers, facilities engineers, and sign specifiers (to select compliant signs for workplaces and public spaces).
  • ISO Technical Committees creating industry‑specific sign guidance.

• Typical use cases

  • Specifying colour and luminance criteria for emergency exit signs, hazard signs, and informational signage.
  • Verifying phosphorescent escape-route markings for unlit emergency conditions.
  • Ensuring internally illuminated signs meet contrast and luminance performance for legibility.

Related standards

• ISO 3864‑1: Design principles for safety signs and markings
• ISO 3864‑2, ISO 3864‑3 (other parts of ISO 3864 series)
• ISO 17724 (vocabulary), CIE 15 (Colorimetry), CIE 69 (instrument characterization)

ISO 3864‑4 is essential for anyone specifying, producing or testing safety signage where accurate colour and photometric performance determine visibility and safety.