ISO 22578-2:2024

Overview

ISO 22578-2:2024 specifies a laboratory test method for measuring the photopic luminance of phosphorescent materials used in natural disaster safety way guidance systems (SWGS). The standard defines how to prepare specimens, excite phosphorescent components, measure emitted light over time, and report results so products can be classified and marked consistently for safety signage and escape-route guidance.

Key topics and technical requirements

• Specimens and conditioning
  • Test three specimens representative of the production batch.
  • Each specimen must have at least a 35 mm phosphorescent area.
  • Pre-condition in complete darkness for at least 48 hours.
• Ambient and environmental conditions
  • Test and conditioning ambient: 23 °C ± 2 °C and 50 % ± 10 % relative humidity.
  • Measurement chamber light level must be at least one order of magnitude lower than the lowest expected luminance.
• Excitation
  • Excite specimens for 60 minutes using a xenon-arc source (mean irradiance ~400 mW/cm²) or 3 000 lx from a D lamp.
  • Uniform irradiance/illuminance across five test patches is required (max/min ratio < 1.1).
• Instrumentation
  • Use calibrated, traceable instruments: irradiance meter (360–490 nm range), cosine photopic V(λ) corrected illuminance meter, and a photopic luminance meter (telephotometer or contact type).
  • Luminance instrument requirements include low spectral error, low UV response, high resolution (e.g., 0.01 mcd/m²), good linearity and SNR; calibration certificates are mandatory.
• Luminance measurements and timing
  • Measure luminance at least every 2 minutes after excitation removal and include values up to 720 minutes.
  • Required recorded points: 60 min, 120 min, 360 min, 720 min after excitation.
  • Report luminance values in mcd/m² and base performance on the mean of three specimens.
• Reporting and marking
  • Test report must reference ISO 22578-2:2024 and include specimen IDs, instrument details, excitation parameters, environmental conditions, full luminance results and any deviations.
  • Marking of materials shall include the standard reference, luminance values at the specified times, and classification per ISO 22578 thresholds (examples and format provided in the standard).

Applications and users

This standard is essential for:

• Manufacturers of phosphorescent paints, films and signage
• Test laboratories and conformity assessment bodies
• Building safety engineers, facility managers and emergency planners
• Regulators and certifiers specifying SWGS performance for natural-disaster escape routes

Practical uses: product development and quality control, safety sign certification, procurement specifications for emergency wayfinding, and compliance demonstration for building codes and safety programs.

Related standards

• ISO 22578:2022 (classification of phosphorescent materials)
• ISO 16069 (Graphical symbols - Safety way guidance systems)
• ISO/CIE 19476 (characterization of illuminance/luminance meters)