Document k69RGEJ3N2DEVEp19QX2LEJ4J

American Society of.Heating and Ventilating Engineers Guide, 1932 Chapter 7^-GrAvity Convectors The stack height is usually taken 'as the vertical distance from; the bottom of the heating unit to the top of the enclosure. (See Figs. 5 and 6.) SELECTION OF WALL OR CABINET CONVECTORS The procedure for selecting wall or cabinet gravity convectors is. as follows: 1. Estimate the total heat loss from the room of space to be heated in accordance With' the procedure outlined in Chapter 2, making proper allowance for exposure, wind velocity, height of ceiling, etc. 2. Radiators With Enclosures. If heating units for which heat emission data are given only for use as exposed radiators, are to be used, estimate the percentage decrease in heat emission from a unit thus installed in accordance with Fig. 8, and add this percentage to the heat loss from the room as estimated in Paragraph 1. From the manufac turers' guaranteed performance data as given in the Catalog Data Section of The Type Arr. 1 Arr. 2 Arr. 3 Arr. 4 Arr. 5 ; Arr. 6 Installation Conditions When dimension A is as shown in Arr. 1 and dimen sion B is equal to 80 per cent of A................. ......... When dimension A is as shown and dimension B is equal to 80 per cent of A............................................. "' When .dimension B is equal to 80 per cent of A (as in Arr. 1), dimension C is equal to 150 per cent of A and dimension D is equal to A..................... When dimension E is equal to 50 per cent of A.......... When dimension E is equal to A.................................: When dimension is equal to 150 per cent of A..yr... When dimension E is equal to A............... When as shown.....,..;...--......... _______ ............ ..... Heat Emission Shall be Altered bt Per centage Indicated 10% increase 5% increase No change 10% reduction 20% reduction 35% reduction 30% reduction 5% reduction aFrom A.S.H.V.E. Code of Minimum Requirements for the Heating and Ventilation of Buildings (edi tion of 1929). Fig. 8. Types of Enclosures and Heat. Emission, of Enclosed Radiators, 108 Fig. 7. Sections Through Typical Heating Units of Extended Surface Type Guide or elsewhere, find the number of sections or size of each heating unit to supply the corrected heat loss. , .................. 3. Convectors (Concealed Radiation). If convection-type units with enclosures are to be used, decide upon the type and the number of units to be used. Then find from manufacturers' guaranteed performance tables for the particular type of unit apd en closure under consideration as given in the Catalog Data Section of The Guide, or elsewhere, the number of sections or the size of each heating unit required to supply the heat loss from the room. . No addition-because of enclosure need be made to the ratings as guaranteed by the manufacturer, .......... GRAVITY-INDIRECT HEATING SYSTEMS5 If the heating units are placed in the basement, properly encased, and this enclosure connected to the room by means of supply ducts* it is usually termed a gravity-indirect heating system. (See Fig. 9). The heating units for this type of heating are likewisejbf special design,- usually of the extended surface type, and give: off their heat by conduction to the air passing over them. *For further information on this subject see A.S.H.V.E. Code of Minimum Requirements for the Heating and Ventilation of .Buildings (edition of 1929) and Mechanical.Equipment,of Buildings, by Harding.gind Willard, Vol. I, second edition. 1929. '' 109