Document 1gOeb4wpM93YYvXwyxDEE5zQ5

Heating Ventilating Air Conditioning Guide 1938 per hour for mechanically fired boilers when operating at design load. When operating at maximum, loads these values will run between 5000 and 6000 Btu per sq ft per hour.' Boilers operating under favorable conditions at the above heat transfer rates will give exit gas temperatures that are considered consistent with good practice. TESTING AND RATING CODES 1 The Society has adopted three solid fuel testing codes, a solid fuel rating code and an oil fuel testing code. A.S.H.V.E. Standard and Short Form Heat Balance Codes for Testing Low-Pressure Steam Heating Solid Fuel Boilers--Codes 1 and 2--(Revision of June 1929)*, are intended to provide a method for conducting and reporting tests to:deterimine heat efficiency and performance' characteristics. A.S.H.V.E. Performance Test Code for Steam Heating Solid Fuel Boilers--Code No. 3--(Edition of 1929)* is intended for use with A.S.H.V.E. Code for Rating Steam Heating Solid Fuel Hand-Fired Boilers4. The object of this test code is to specify the tests to be conducted and. to provide a method for conducting and reporting tests to determine the efficiencies arid performance of the boiler. The A.S.H.V.E. Standard Code for Testing Steam Heating Boilers Burning Oil. Fuel5 is intended, to provide a standard method for con ducting and reporting tests to'determine the heating efficiency and per formance characteristics when' oil fuel is used, with steam heating, boilers. Steel Heating Boilers Ratings ' The Steel Heating Boiler Institute has adopted a method for the ,rating of low pressure boilers based on theif physical characteristics arid expressed in square feet of steam or water radiation or in Btu per hour^as given in Table 2. The following requirements are included in this Code: 1. One square foot of steam, radiation is to be considered equal Yo the emission of 240 Btu per hour and'one square, foot of water radiation is to be considered equal to emission of 150 Btu per hour. 1 < - 2. The rating of a boiler expressed in square feet of steam radiation in which solid fuel hand fired is used is based on the amount equal to 14 times the heating surface of the boiler in square feet. . . . 3. The rating of a boiler expressed in square feet ofsteam radiation in which solid fuel mechanically fired, or in which oil or gas is burned, is based on the amount equal to 17 times the heating surface of the boiler in square feet. 4. Heating surface is to be expressed in square feet and include those surfaces in the boiler which are exposed to the products of combustion on one side and water on the other. In measuring surfaces, the outer, tube areas are to be considered^ When a boiler has the water leg height increased the heating surface noted in the published ratings are not to be increased. 5. A.grate area is to be considered as an area of the grate surface expressed in square feet and measured in the plane of the top surface of the grate; For double grate boilers the grate.surface is to be considered as the area of the upper grate plus one-quarter of the area of the lower grate. 6. The grate area of a boiler for rating as determined in No. 2 is to be not less than that determined by the following formulae: For boilers with ratings 1800 sq ft to 4000 sq ft of steam radiation:' Grate Area = ./Catalogue Rating (in square feet steam radiation) ---200 ". ^ Fordefinitions of designload and maximum load see pages'251 and 252. See A.S.H.V.E. Transactions, Vol. 35, 1929, p. 12. Also Chapter 45. See A.S.H.V.E. Transactions, VoL 36, 1930, p. 35. Also Chapter 45. See A.S.H.V.E. Transactions, >Vol.'37, 1931, p; 23; - Also Chapter-45. 248 Chapter 13.' Heating Boilers Table 2. Standard Steel Heating Boiler Ratings3 Hand Fibzd Capacity Rating Mechanicallt Fired Capacity Rating Steam Water Radiation Radiation Sq Ft Sq Ft Btu per Hr Heating Grate Steam Water Surface Area Radiation Radiation Sq Ft Sq Ft Sq Ft Sq Ft 1,800 2,2()0 2,600 3,000 3,500 4,000 4,500 5,000 6,000 7,000 8,500 10,000 12,500 15,000 17,500 20,000 25,000 30,000 35,000 2,880 3,520 4,160 4,800 ' 5,600 6,400 > 7,200 8,000 9,600 11,200 13,600 16,000 20,000 24,000 28,000 32,000 40,000 48,000. 56,000 432,000 129 7.9 528,000 158 8:9 624,000 186. 9.7 720,000 215 , 10.5 840,000 250 11.4 960,000 286 12.2 1,080,000 322 13.4 1,200,000 358 14.5 1,440,000 429 16.4 1,680,000 500 18.1 2,040,000 60S 20.5 2,400,000, 715 22.5 3,000,000 .. . 893 25.6 3,600,000. 1,072 28.4 ' 4,200,000 1,250 30.9 4,800,000 1,429 33.2 6,000,000 1,786 37.4 7,200,000 2,143 41.2 8,400,000 2,500 44.7 2,190 3,500 2,680 4,280 3,160 5,050 3,650 5,840 4,250 6,800 4,860 7,770 5,470 8,750 6,080 9,720 7,290 11,660 8,500 13,600 10,330 .16,520 12,150' 19,440 15,180. 24^280 18,220 29,150 21,250 34,000 24,290 38,860 30,360' 48,570 36,430 58,280 42,500 68,000 Btu per Hr 1 -525,600 : 643,200 758,400 876,000 1,020,000 1,166,400 1,312,800 1,459,200 1,749,600 2,040,000 2,479,200 2,916,000 3,643,200 4,372,800 5,100,000 5,829,600 7,286,400 8,743,200 10,200,000 Furnace Volume Bituminous Coal Cu Ft 15.7 19.2 22.6 26.1 30.4 34.8 39.1 43.5 52.1 60.8 73.8 86.8 108.5 130.2 151.8 173.5 216.9 260.3 303.6 . .Adopted by the Steel Heating Boiler Institute in cooperation with the Bureau ofStandards, United States Department of Commerce Simplified Practice Recommendation R 157-55. For boilers with ratings 4000 sq ft of steam radiation and larger: Grate Area = ,, /Catalogue Rating (in square feet steam radiation) -- 1500 col 16.8 7. The volume for furnaces in which solid fuel is burned is to be considered as the cubical content of the space between the bottom of the fuel bed and the first plane of entry into or between the tubes. Volume of furnaces in which pulverized liquid fuel or gaseous fuel is burned are to be considered as the cubical content of the space between the hearth and the first plane of entiy into or between the tubes. No minimum furnace volume is to be specified for mechanical fired boilers burning anthracite. 8. The furnace volume for a boiler, with a rating as determined in No. 3 in which oil, gas or bituminous coal stoker fired is burned is not to be less than one cubic foot for every 140 sq ft of steam rating. ; 9. The average height of furnace for the rating determined in No. 3 in which bitu minous coal, stoker fired is burned is not to be less than that determined graphically in Fig. 1 or mathematically by the following formula: where = + J-- yj 22.5 V A (3) H = average furnace height, inches as determined by the following formula; , Tf = 12F _ l2F A WL R = stoker fired boiler rating, square foot steam radiation:A = plan area of firebox, square feet measuredYYtfieJjottom of the fuel bed. F = furnace volume, cubic feet.