Document e11vRZoyaRdyKRdO5rr6Lng4m

American Society of Heating and Ventilating Engineers Guide, 1934 2. The lessened steam consumption may not materially change the radiator heating performance. 3. The enclosed radiator may inadequately heat the space. A comparison between a bare or exposed radiator (A) and the same radiator with a well-designed enclosure (B), with a poorly-designed enclosure (C), and with a cloth cover (D) will illustrate the relative heating effects. In Fig. 4 the curve (B) reveals that the enclosed radiator used less steam than the exposed radiator, but gave a satisfactory heating performance. A well-designed shield placed over a radiator gives about the same heating effect. Curve (C) shows the unsatisfactory effects produced by improperly designed enclosures. Curve (Z?) shows that the effect of a cloth cover extending downward 6 in. from the top of the radiator was to make the performance unsatisfactory and inadequate. Chapter 30--Radiators and Gravity Convectors Fig. 4. Difference in Steam Pressure on Water in Boiler and at End of Steam Main A practical interpretation of allowances to be made for radiator per formance with various styles and forms of enclosures is shown by the diagrams and values listed in Fig. 5. Practically all commercial enclosures and shields for use on direct radiators are equipped with water pans for the purpose of adding nioisture to the air in the room. Tests6 show that an average evaporative rate of about 0.235 lb per square foot of water surface per hour may be obtained from such pans, when the radiator is steam hot and the relative humidity in the room is between 25 and 40 per cent. This source of supply of moisture alone is not adequate to maintain a relative humidity above 25 per cent on a zero day. "University of Illinois Engineering Experiment Station Bulletin No. 230, p. 20. Ttpb 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 E is equal to 150 per cent of A____ 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 Fig. 5. Types of Enclosures and Heat Emission of Enclosed Radiators8 From A.S.H.V.E. Code of Minimum Requirements for the Heating and Ventilation of Buildings (edl tion of 1929). 413