ISO/CIE FDIS 17166

Date: 2025-09-16
ISO/CIE/DIS FDIS 17166:2025(en)
CIE
Secretariat: CIE
Date: 2026-08-14
Erythema reference action spectrum and standard erythema dose
Spectre d’action erithémaled'action érythémale de référence et dose erithémaleérythémale normalisée
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ISO/CIE DISFDIS 17166:20252026(en)
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Contents
Foreword . v
Introduction . vii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Concept of erythemal irradiance and dose . 3
4.1 Erythemal irradiance . 3
4.2 Erythema spectral weighting function . 4
4.3 Standard erythema dose . 6
Bibliography . 7

Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Concept of erythemal irradiance and dose . 3
4.1 Erythemal irradiance . 3
4.2 Erythema spectral weighting function . 4
4.3 Standard erythema dose . 4
Bibliography . 5

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ISO/CIE DISFDIS 17166:20252026(en)
Foreword
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ISO #####-#:####(X/CIE FDIS 17166:2026(en)
This second edition of ISO/CIE 17166 cancels and replaces the first edition (ISO/CIE 17166:2019), of which it
constitutes a minor revision. has been technically revised.
The main changes are as follows:
— the Introduction has been rewritten;
— Formula (3)(3) has been added, and the relationship with Formula (4)(4) has been added;
— Figure 1Error! Reference source not found. has been added;
— history of the erythema action spectrum has been moved to a note;
— reference for classification of the skin types has been added;
— minor editorial changes.
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ISO/CIE DISFDIS 17166:20252026(en)
Introduction
Knowledge of the wavelength range is crucial in ultraviolet (UV) dose estimation, since elicitation of erythema
varies within four orders of magnitude between wavelengths of 250 nm and 400 nm. Thus, the radiant
exposure causing a just perceivable erythema at 250 nm will occur at about 1/10001 000 of the radiant
exposure at 400 nm.
In practice, being irradiated with e.g. an indoor lighting device emitting partly in the UV-A, an erythemal
response may be seen only in people suffering from pathological photosensitivity. The same radiant exposure
from the midday sun at e.g. latitudes near the Equator would result in marked erythema in most individuals
with untanned, light skin. Thus, expressing UV exposure as an erythemally weighted quantity is useful and
appropriate in fields such as photobiology and photomedicine.
The standardized measure for erythemogenic UV radiation is the "standard erythema dose (SED)". While the
term "minimal erythema dose (MED)" is sometimes used as a measure of erythemal radiation, it only
expresses the variable nature of individual sensitivity to UV radiation, and as such is not a standard measure.
The term "MED" is used in studies in which humans and animals are observed, i.e. when the individual
sensitivity is the endpoint of interest.

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DRAFT International Standard ISO/CIE DIS 17166:2025(en)

Erythema r
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