This European Standard specifies the apparatus and procedure for determining the heat of hydration of cements and other hydraulic binders at different test ages by isothermal conduction calorimetry. This test procedure is intended for measuring the heat of hydration of cement up to 7 days in order to obtain data homogeneous with EN 196-8. Nevertheless this test duration may be critical for some apparatus, even if they can work properly at shorter test ages. Contrary to EN 196-8 (solution method) this method gives the heat of hydration continuously over the time. Additionally, the heat flow versus time is given.