Document LpDR7BvK60L24vjvQEgXRNDQX

American Society of Heating and Ventilating Engineers Guide, 1928 standardization of design and method of tests for rating. Already this need has been partially met by a Radiator Test Code recently adopted by the Society. In the past the unit of measure recognized in figuring radiation was the square foot of heating surface. The use of this unit is rapidly being discarded however, for the reason that the heat-emission depends upon the design of the radiator as well as its surface area. The engineer is interested primarily in the amount of heat emitted by, rather jthan the amount of surface in, a radiator. As a result, radiators are being rated on the amount of heat given off either in B.t.u. per hour or in equiValent square feet based on 240 B.t.u. per hour. Heating effect or heating efficiency has recently become recognized as an important factor in heating by radiation. It has been shown by . Brabbee, Frost, and others, that two radiators of different design may warm a given space to a comfortable temperature by condensing different amounts of steam or by emitting different amounts of heat. This varia tion in heating efficiency depends upon whether the radiator warms the lower part of the room where the occupants are while pending more or less heat to the ceiling. Heating efficiency may depend upon a number of factors including the size, height, and shape of the radiator, the relative amount of heat it emits by radiation and convection, whether or not it is in an inclosure, and its location in, and the size and shape of, the room being heated. HEAT EMISSION OF RADIATORS ' Tables 1 to 7 give the heat emitted by cast iron radiators of the . 5 column,' wall, and window type, of various standard heights arid numbers of columns when using steam at 215 deg. fahr. iri a 70 deg. fahr. room. In the last three lines of each table the heat emitted in B.t.u. per inter mediate section, and the B.t.u. emitted per rated square foot of inteririediate and end sections are given. Table 8 gives conversion factors for determining the heat emission of' any radiator with steam or water at temperatures other than 215 deg. fahr. and with room temperatures other than 70 deg. fahr., when the emissiori for 215 deg. fahr. and 70 deg. fahr. are known. Tables 9 to 11 give the heat emitted by cast iron, column, wall,, and window radiators of various standard heights and numbers of sections for hot water heating with mean water temperature of 170 deg. fahr. and room temperature of 70 deg. fahr. The tables were computed from data given in a report1 of the Research Laboratory of the American Society of Heating and Ventilating Engineers, resulting from experiments by John R. Allen and F. B. Rowley. For reasons mentioned it is not possible at this time to give data on heat-emission for tubular or art radiation or for other types of direct and semi-indirect radiation on the market. Tables 12 and, 13 give the heat emission of various standard types of coi'l radiation for steam and hot water heating respectively. :1Direct Radiation Tables by F. Paul Anderson, F. C. Houghten. Louis Ebin, Journal, of the American Society of Heating and Ventilating Engineers, December, 1921. 58