Recommendation 1 of the 73rd CIPM (1984)

Concerning the sievert

The Comité International des Poids et Mesures,

considering the confusion which continues to exist on the subject of Resolution 5, approved by the 16th Conférence Générale des Poids et Mesures (1979),

decides to introduce the following explanation in the brochure “Le Système International d'Unités (SI)”:

The quantity dose equivalent H is the product of the absorbed dose D of ionizing radiation and the dimensionless factors Q (quality factor) and N (product of any other multiplying factors) stipulated by the International Commission on Radiological Protection:

H = Q · N · D.


Thus, for a given radiation, the numerical value of H in joules per kilogram may differ from that of D in joules per kilogram depending upon the values of Q and N. In order to avoid any risk of confusion between the absorbed dose D and the dose equivalent H, the special names for the respective units should be used, that is, the name gray should be used instead of joules per kilogram for the unit of absorbed dose D and the name sievert instead of joules per kilogram for the unit of dose equivalent H.

reference The reader should note that the official version of this Resolution is the French text


The CIPM, in 2002, decided to change the explanation of the quantity dose equivalent in the SI Brochure (Recommendation 2).

cipm LOGO

Navigation Menu