Document gaoEYqNRqQLwyj86jNqZ0X1X3

V American Society of Heating and Ventilating Engineers Guide, 1937 per hour for mechanically- fired boilers when operating at design loadI*' When operating at maximum load? 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 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 determine 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 and performance of the boiler. The A.S.H.V.E. Standard Code for Testing Steam Heating Boilers Burning Oil Fuel6 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 their physical characteristics and 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 to the emission of 240 Btu per hour and one square foot of water radiation is to be considered equal to emission of 150 Btu perhour. 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 of steam 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: * m >w drat* Atm = ../Catalogue Rating (in square feet steam radiation) -- 200 fij l( . 25.5 For definitions of design load and maximum load see pages 451 and 452. See A.S.H.V.E. Transactions. VoL 35. 1929. Also Chapter 44. `See A.S.H.V.E. Transactions, Vol. 36. 1930. Also Chapter 44. See A.S.H.V.E. Transactions; Vol. 37; 1931. Also Chapter'44. 448 Chapter 25--Boilers Table 2. Standard Steel Heating Boiler Ratings* Meciianicai.lt Fired Capacitt Rating Btu per Hr Furnace Volume CuFtOil, Gas or I Bituminous Coal 1,800 2,200 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 56.000 432.000 129 528.000 158 624.000 186 720.000 215 840.000 250 960.000 286 1,080,000 322 1,200,000 358 1.440.000 429 1.680.000 500 2.040.000 608 2.400.000 715 3,000,000 893 3.600.000 1,072 4.200.000 1,250 4.800.000 I 1,429 6,000,000 1,786 7.200.000 2,143 8.400.000 2,500 7.9 8.9 9.7 10.5 11.4 12.2 13.4 14.5 16.4 18.1 20.5 22.5 25.6 28.4 30.9 33.2 37.4 41.2 44.7 2,190 2,680 3,160 3,650 4.250 4,860 5,470 6,080 7.290 8.500 10,330 12,150 15,180 18,220 21.250 24.290 30,360 36,430 42.500 3,500 4.280 5,050 5,840 6,800 7,770 8,750 9,720 11,660 13,600 16,520 19,440 24.280 29,150 34.000 38,860 48,570 58.280 68.000 525,600 '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 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 For boilers with ratings 4000 sq ft of steam radiation and larger: ^Catalogue Rating (in squarefeet steam radiation) 1500 (2) Grate Area 16.8 T 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 whcih pulverized fuel liquid or gaseous fuel is burned are to be considered as the cubical content of the space between the hearth and the first plane of entry 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 eve9r.y T1h4e0 saqvefrtagoef hsteeiagmht roaftifnugrn. ace 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: H V*+v (3) where H = average furnace height, inches as determined by the foilowing formula; 12F 12F R A = = stoker fired boiler- rating, square foot steam plan area of firebox, square feet measured at radiation. the bottom of the fuel bed. R = furnace volume, cubic feet. 449