ISO 361:1975

Basic ionizing radiation symbol

Specifies shape, proportions, application, restrictions on the use of the symbol (possibly accompanied by additional symbols or words). Shall be used to signify the actual or potential presence of ionizing radiation (including gamma and X-rays. alpha and beta particles, high-speed electrons, neutrons, protons and other nuclear particles, but not sound waves and other types of electromagnetic waves). Does not specify the radiation levels at which it is to be used.

Symbole de base pour les rayonnements ionisants

General Information

• Status: Published
• Publication Date: 30-Sep-1975
• ICS: 01.080.20 - Graphical symbols for use on specific equipment
• ICS: 13.280 - Radiation protection
• Technical Committee: ISO/TC 85 - Nuclear energy, nuclear technologies, and radiological protection
• Drafting Committee: ISO/TC 85 - Nuclear energy, nuclear technologies, and radiological protection
• Current Stage: 9093 - International Standard confirmed
• Start Date: 16-Sep-2025
• Completion Date: 13-Dec-2025

Overview

ISO 361:1975 is an international standard established by the International Organization for Standardization (ISO) that specifies the basic ionizing radiation symbol. This symbol is essential for indicating the presence-whether actual or potential-of ionizing radiation. Ionizing radiation encompasses gamma rays, X-rays, alpha and beta particles, high-speed electrons, neutrons, protons, and other nuclear particles, distinguishing it from non-ionizing emissions such as sound waves or visible light.

This standard outlines the shape, proportions, and application of the ionizing radiation symbol, ensuring uniformity worldwide. While the standard defines the symbol's design and use, it does not set criteria for radiation levels at which the symbol must be displayed.

Key Topics

• Symbol Design and Proportions
  ISO 361 specifies the exact design and dimensions of the ionizing radiation symbol to maintain consistency. The symbol's shape must be preserved precisely to ensure easy recognition and understanding.

• Scope of Ionizing Radiation
  The symbol applies to all forms of ionizing radiations including:

  • Gamma rays
  • X-rays
  • Alpha particles
  • Beta particles
  • High-speed electrons
  • Neutrons
  • Protons
  • Other nuclear particles
    Importantly, the symbol is not to be used for non-ionizing radiation (e.g., sound, radio waves, visible light).

• Application and Visibility
  The symbol must be displayed prominently on equipment, materials, or locations where ionizing radiation is present, with a size suitable to be visible from a safe distance.
  Additional symbols or warnings may accompany the basic symbol to clarify hazards or radiation source types but must not obscure or dilute the symbol's clarity.

• Restrictions on Use
  The symbol is strictly reserved for signifying actual or potential ionizing radiation hazards. It should not be used for unrelated purposes, and any accompanying markings should conform to internationally recognized symbols to avoid confusion.

Applications

• Radiation Safety Signage
  Used on lab equipment, nuclear facilities, medical devices, and transport containers to alert personnel and the public about radiation hazards.

• Equipment Labeling
  Marking devices such as X-ray machines, nuclear reactors, and radiation sources for easy identification and compliance with safety protocols.

• Regulatory Compliance
  Ensures consistency with global safety requirements for controlling access and exposure to ionizing radiation.

• Public Awareness
  Enhances understanding and recognition of radiation dangers, contributing to occupational safety and public health.

Related Standards

• ISO 361 complements other radiation safety standards, including those that regulate radiation protection practices, monitoring, and radiological emergency procedures.
• It aligns with international symbol regulations issued by organizations such as the International Atomic Energy Agency (IAEA) and International Commission on Radiological Protection (ICRP).
• While ISO 361 defines the symbol's design and use, radiation threshold levels and measurement protocols are detailed in other standards focused on radiation safety and risk management.

Summary

ISO 361:1975 provides a clear, consistent framework for the basic ionizing radiation symbol, a critical component in worldwide radiation safety efforts. By standardizing the symbol’s design, application, and usage restrictions, this ISO standard ensures effective communication of ionizing radiation hazards across industries and borders-supporting safe practices in nuclear technology, healthcare, research, and industrial radiography.

Use of the ISO 361 symbol helps protect workers and the public, complying with international safety norms while facilitating clear hazard identification wherever ionizing radiation is present.

Standards Content (Sample)

INTERNATIONAL STANDARD
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION l MEXfiYHAPODHA(I OPI-AHM3AUMR no CTAHAAPTM3AUMM~ORGANISATION INTERNATIONALE DE NORMALISATION
Basic ionizing radiation symbol
Symbole de base pour les ra yonnemen ts ionisan ts
First edition - 1975-10-15
UDC 003.62 : 614.876.013
Ref. No. IS0 361-1975 (E)
Descriptors : nuclear energy, ionizing radiation, symbols.
Price based on 1 page
FOREWORD
IS0 (the International Organization for Standardization) is a worldwide federation
of national standards institutes (IS0 Member Bodies). The work of developing
International Standards is carried out through IS0 Technical Committees. Every
Member Body interested in a subject for which a Technical Committee has been set
up 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.
Draft International Standards adopted by the Technical Committees are circulated
to the Member Bodies for approval before their acceptance as International
Standards by the IS0 Council.
Prior to 1972, the results of the work of the Technical Committees were published
as IS0 Recommendations; these documents are now in the process of being
transformed into International Standards. As part of this process, Technical
Committee lSO/TC 85 has reviewed IS0 Recommendation R 361 and found it
technically suitable for transformation. International Standard IS0 361 therefore
replaces IS0 Recommendation R 361-1963 to which it is technically identical.
IS0 Recommendation R 361 was approved by the Member Bodies of the following
countries :
Austral i a Ireland Spain
Belgium Israel Sweden
Switzerland
Canada Japan
Chile Netherlands Turkey
Czechoslovakia New Zealand United Kingdom
Denmark Norway U.S.A.
Finland Poland U.S.S.R.
Germany Portugal Yugoslavia
Romania
Greece
South Africa, Rep. of
Hungary
following countries expressed disapproval of the
The Member Bodies of the
Recommendation on technical grounds :
Austria
France*
* Subsequently, this Member Body approved the Recommendation.
No Member Body disapproved the transformation of lSO/R 361 into an
International Standard.
G3 International Organization for Standardization, 19
...

NORME INTERNATIONALE
INTERNATIONAL ORGANlZA-/-j(-JN FOR STANDARDlZATlON .\lF-AJ)‘H 4P()JHAFI OPI-AHM34UMR I-IO CT4HX4PTC13AUMM .ORGANISATION INTERNATIONALE DE NORMALlSATlON
Symbole de base pour les rayonnements ionisants
Basic ionizing radiation symbol
Premiere bdition - 1975-10-15
CDU 003.62 : 614.876.013 Rbf. no : IS0 361-1975 (F)
Descripteurs : hergie nuclkaire, rayonnement ionisant, symbole.
Prix bad sur 1 page
AVANT-PROPOS
L’ISO (Organisation lnternationale de Normalisation) est une federation mondiale
d’organismes nationaux de normalisation (Corn ites Membres ISO). L’elaboration de
Normes lnternationales est confide aux Comites Techniques ISO. Chaque Comite
Membre interesse par une etude a le droit de faire partie du Comite Technique
correspondant. Les organisations internationales, gouvernementales et non
gouvernementales, en liaison avec I’ISO, participent egalement aux travaux.
Les Projets de Normes lnternationales adopt& par les Comites Techniques sont
soumis aux Comites Membres pour approbation, avant leur acceptation comme
Normes Internationales par le Conseil de I’ISO.
Avant 1972, les resultats des travaux des Comites Techniques etaient publies
comme Recommandations ISO; maintenant, ces documents sont en tours de
transformation en Normes Internationales. Compte tenu de cette procedure, le
Comite Technique ISOnC 85 a examine la Recommandation ISO/R 361 et est
d’avis qu’elle peut, du point de vue technique, etre transformee en Norme
lnternationale. La presente Norme I nternationale remplace done la
Recommandation ISO/R 361-1963 a laquelle elle est techniquement identique.
La Recommandation ISO/R 361 avait et@ approuvee par les Comites Membres des
pays suivants :
Afrique du Sud, Rep. d’ Hongrie Royaume-Uni
Allemagne I rlande Suede
Austral ie Israel Su isse
Belgique Japon Tchecoslovaquie
Canada Norvege Turquie
Chili Nouvelle-Zelande U.R.S.S.
Danemark Pays-Bas U.S.A.
Espagne Pologne Yougoslavie
Finlande Portugal
G r&e Roumanie
Les Corn it& Mem bres des pays suivants avaient desapprouve la
Recommandation
r des raisons techniques
Pou
Autriche
France*
* Ult6rieurement, ce Cornit Membre a approuk la Recommandation.
Aucun Comite Membre n’a desapprouve la transformation de la Recommandation
ISO/R 361 en Norme Internationale.
0 Organisation Dnternationale de Normalisation, 1975 l
Imprim en Suisse
NORME INTERNATIONALE
IS0 361-1975 (F)
Symbole de base pou
...

NORME INTERNATIONALE
INTERNATIONAL ORGANlZA-/-j(-JN FOR STANDARDlZATlON .\lF-AJ)‘H 4P()JHAFI OPI-AHM34UMR I-IO CT4HX4PTC13AUMM .ORGANISATION INTERNATIONALE DE NORMALlSATlON
Symbole de base pour les rayonnements ionisants
Basic ionizing radiation symbol
Premiere bdition - 1975-10-15
CDU 003.62 : 614.876.013 Rbf. no : IS0 361-1975 (F)
Descripteurs : hergie nuclkaire, rayonnement ionisant, symbole.
Prix bad sur 1 page
AVANT-PROPOS
L’ISO (Organisation lnternationale de Normalisation) est une federation mondiale
d’organismes nationaux de normalisation (Corn ites Membres ISO). L’elaboration de
Normes lnternationales est confide aux Comites Techniques ISO. Chaque Comite
Membre interesse par une etude a le droit de faire partie du Comite Technique
correspondant. Les organisations internationales, gouvernementales et non
gouvernementales, en liaison avec I’ISO, participent egalement aux travaux.
Les Projets de Normes lnternationales adopt& par les Comites Techniques sont
soumis aux Comites Membres pour approbation, avant leur acceptation comme
Normes Internationales par le Conseil de I’ISO.
Avant 1972, les resultats des travaux des Comites Techniques etaient publies
comme Recommandations ISO; maintenant, ces documents sont en tours de
transformation en Normes Internationales. Compte tenu de cette procedure, le
Comite Technique ISOnC 85 a examine la Recommandation ISO/R 361 et est
d’avis qu’elle peut, du point de vue technique, etre transformee en Norme
lnternationale. La presente Norme I nternationale remplace done la
Recommandation ISO/R 361-1963 a laquelle elle est techniquement identique.
La Recommandation ISO/R 361 avait et@ approuvee par les Comites Membres des
pays suivants :
Afrique du Sud, Rep. d’ Hongrie Royaume-Uni
Allemagne I rlande Suede
Austral ie Israel Su isse
Belgique Japon Tchecoslovaquie
Canada Norvege Turquie
Chili Nouvelle-Zelande U.R.S.S.
Danemark Pays-Bas U.S.A.
Espagne Pologne Yougoslavie
Finlande Portugal
G r&e Roumanie
Les Corn it& Mem bres des pays suivants avaient desapprouve la
Recommandation
r des raisons techniques
Pou
Autriche
France*
* Ult6rieurement, ce Cornit Membre a approuk la Recommandation.
Aucun Comite Membre n’a desapprouve la transformation de la Recommandation
ISO/R 361 en Norme Internationale.
0 Organisation Dnternationale de Normalisation, 1975 l
Imprim en Suisse
NORME INTERNATIONALE
IS0 361-1975 (F)
Symbole de base pou
...