Document qYkNL0yML7odzQ7aEjzGG54q

American Society of Heating and Ventilating Engineers Guide, small installations it is advisable to keep the furnace temperature enough to avoid slagging the ash, with the consequent troubles of reiuo the slagged deposits from the hearth and walls; without the slaggin,, ash remains in a fluffy form and is easily removed. On the other h considerable ash may be carried out of the stack and create a nuisance- the district; the elimination of ash in the stack gases is one of the proble ^ associated with the application of pulverized fuel to heating b0;i2* Proposals have been made to use pulverized coal for household furnace delivering it into bins in its prepared state. Coal in pulverized iorrrp' transported to a limited extent in Europe. \1 STORAGE SPACE FOR COAL The storage space required for coal or coke is dependent upon frequency of fuel purchases during the heating season, as well as upon the rate at which the fuel is burned. In general, the size of the storage space can be determined on the basis of burning 3H tons of coal or coke per heating season per 100 sq ft of attached equivalent radiation, based on a heat emission of 240 Btu per square foot. Anthracite coal weighs approximately 52.5 lb. per cubic foot; bitu minous, 45 lb. per cubic foot; and coke, 28 lb. per cubic foot. DUSTLESS COAL The practice of treating the more friable coals to allay the dust, they create is increasing. The coal is sprayed with a solution .of calciumchloride or a mixture of calcium and magnesium chlorides. Both these salts are very hygroscopic and their moisture under normal atmosphericconditions keeps the surface of the coal damp, thus reducing the dust' during delivery and in the cellar, and obviating the necessity of sprinkling thexoal in the bin. The coal is sometimes treated at the mine but more usually by the-, local distributor just before delivery. The solution is sprayed under high pressure, using from 2 to 4 gal. or from 5 to 10 lb. of the salt per ton of coal, depending on its friability and size. HEATING COSTS WITH COAL In most cases, heating costs with coal are lower than the costs with gas, oil or electricity, even though the efficiency of combustion usually is less than that with gas and oil. At prices of today the cost of coal ranges from about 40 cents to $1.20 per 1,000,000 Btu, giving proper con sideration to efficiencies. For comparisons with the cost of other heat/ sources, see Chapters 16, 17 and 18. REFERENCES Steaming Tests of Coals and Related Investigations, by .Breckenridge, Kreisinger and Ray {Bulletin 23. U. S..Bureau of Mines). ' Five Hundred Tests of Various Coals in House-Heating Boilers, by Nicholla, Flagg and Augustine {Bulletin 276, U. S. Bureau of Mines). Coke as a Domestic Heating Fuel, by Nicbolls and Landry (Report of Investigations No. 2980, U. S. Bureau of Mines). Combustion in the Power Plant, by Marsh (D. Van Nostrand Co.) Relative Consumption of Various Solid Fuels in Residence Heating, by V. S. Day (A.S.'H.V.E. Trans actions. Vol. 34. 1928). - Analyses of Coals are issued by the U. S. Bureau of Mines; these and other of its publications can he obtained from the Superintendent of Documents, Government Printing Office, Washington, D. C. 254 Chapter 16 LIQUID fuels Domestic - Specifications for Liquid Fuels; Types of Oil Burners; Tempera ' BhiurreneCrso-nAtrtool;mPizraottieocnti;vAe irDefovriceCso; mInbtuesrtmionit;teIngtniatinodn;Htigehu-tLpovwi MA operation; Boilers for Domestic Systems; Storage Tanks; Instal lation- Service; Cost of Oil Heating; Commercial Oil Burners; ' Fuel Storage; Oil Pumps; Boiler Settings. kJL is used in domestic heating largely because it can be supplied auto| matically as required with practically no attention, and because re is no residue to be removed by hand. Cleanliness is also a factor, as ability to provide an ample supply of domestic water through the nmer with the same burner and boiler that heats the home. Different factors control the selection of oil for what commonly is [led commercial heating, involving such buildings as apartment houses, urches, office buildings, hotels, department stores, public buildings and lioois. The use of oil fuel for these buildings is governed largely by the onoinic factor rather than by the convenience, cleanliness or comfort merits. For large commercial installations, the design should permit ther liquid or solid fuel to be burned at will,.depending upon relative lit costs. This makes possible the production of heat at the lowest cost, id prevents excessive cost through control of the market on one or the ti.chQteourrafsu,lietoylsw.ainngdtocegertnaeinratyl aoccfelpotcaanlceoiol fsuunpifpolyrmraopilifdulyel are ceasing to be specifications, and fit growing tendency for coal dealers to sell oil fuel. Few heating plants re beyond a reasonable delivery distance from a reliable source of at Sat-three grades of oil, which simplifies the problem of selection of lurrier type. SPECIFICATIONS FOR LIQUID FUELS ...Uniform oil specifications were prepared in 1929 by the American Oil Burner Association, in cooperation with the American Petroleum Institute, the'.U. S. Bureau of Standards, the American Societyfor Testing Materials an^rither interested organizations. Oil fuels were classified into six groups, as indicated by Table 1. When these specifications were prepared, it was generally accepted that the first three grades were adapted to domestic .use; while the last three were suitable only for commercial and industrial .burners.. This differentiation has not proved stable, and today domestic . installations are using Nos. 4 and 5 of the so-called heavy-oil group. Several 1-------o^nt-lv been listed for automatic