Temperature survey of the United States

P. L. Alger (General Electric Company, Schenectady, N. Y.): This question of limiting values of ambient temperature in which normal apparatus life may be expected under rated load operation has been discussed at length in recent International Electrotechnical Commission committee meetings. As a result, the IEC has proposed a dual value of ambient temperature of reference; a maximum or limiting value of 40 degrees centigrade being associated with a limiting value of 35 degrees centigrade averaged over any 24-hour period. The 35-degree-centigrade value was selected largely as a result of an investigation of limiting summer temperatures in Italy conducted by B. Cerretelli, who has kindly given me access to his data.