Document DkXjRL5waaqK5v4vEN8eEdoN

Heating Ventilating Air Conditioning Guide 1938 Table 3. Commercial Standard Fuel Oil Specifications A. Detailed Requirements for Domestic Fuel Oils* Grade of Oil Approx. Btu per Gal.* Flash Point Min. Max. No. 1 Domestic Fuel Oil . A light distillate oil for use in burners requir ing a high grade fuel. 139.000 100 F 150 F or legal No. 2 Domestic Fuel Oil A medium distil late oil for use in burners re quiring a high grade fuel.' 141.000 125 F 190 F or lega: No. 3 Domestic Fuel Oil A distillate fuel oil for use in burners .where a low viscosity oil is required. 143.400 150 F 200 F or legal Water and Sediment, Maximum Carbon Residue Maximum 0.05% 0.02% 0.05% 0.05% 0.1% 0.15% Distillation Test Max. Min. 10% point 420 F Viscosity Maximum End point 600 F 10% point 440 F 90% point 620 F End point 600 F 90% point 620 F Saybolt Universal at 100 F 70 seconds Adapted from "Fad Oils," P. 2, V. S. Department o/ Commerce, Bureau ai Standards, Commercial Standard CS11BB-S35, Washiuingtopn, 1i93io5. 6Pour Point Maximum is 15 F. Lower or higher pour points may be specified whenever required by conditions of storage and use. However, these specifications shall not require a pour point less than 0 F under any conditions. Government specifications do not give Btu per gallon, but they are noted here for information only. B. Detailed Requirements for Industrial Fuel Oils'1 Grade of Oil Approx. Btu per Gal.* Flash Min. Point, Max. No. 4. Industrial Fuel Oil An oil known to the trade as a light fuel oil for use in burners where a low vis cosity industrial fuel oil is required. 144,500 150 F, See Note* No. 5 Industrial Fuel Oil Same as Federal Specifications Board specification for bunker .oil "B" for burners adapted to the use of indus trial fuel oil of medium viscosity. 146.00Q 150 F No. 6 Industrial Fuel Oil Same as Federal Specifications Board 150,000 specification for bunker oil "C for burners adapted to oil of high viscosity 150 F Water and Sediment, Maximum Ash Maximum 1.0% 0.1% 1.0% ' 0.15% . 2.0% Viscosity, Maximum Saybolt Universal at 100 F. 500 seconds Saybolt Furol - at 122 F 100 seconds Saybolt Furol at 122 F 300 seconds *Pour point may be specified whenever required by conditions of storage and use. However, these specifications shall not require a pour point less than 15 F under any conditions. Whenever required, as for example in burners with automatic ignition, a maximum flash point may be specified. However, these specifications shall not require a flash point less than 250 F under any con ditions. 174 Chapter 9. Fuels and Combustion substitution of one grade for another, the U. S. Bureau, of Standards in cooperation with the American Society for Testing Materials is figuring on a new set of specifications providing for definite limits for each grade. When these specifications are adopted, it is expected that the National Board of Fire Underwriters will retest all burners using oils of the maximum specifications for the grade so that if a burner is approved for a certain grade it will burn any oil meeting the specifications for that particular grade. Several burners adapted to industrial use have recently been listed for automatic operation with No. 5 oil. Usually oils No. 5 or 6 require preheating for proper operation, but where conditions are favorable, No. 5 can be used without the equipment that this entails. There are two reasons for the trend to lower grades of oil. While the lighter oils contain slightly more heat units per pound, the weight per gallon increases more rapidly than the decrease in heat units per pound, and oil is bought by the gallon. As a consequence, while a No. 1 oil may contain 139,000 Btu per gallon, oil No. 5 may test 146,000 Btu per gallon, or 6 per cent more. Usually there is a differential of 3 to 4 cents between the No. 1 and No. 5 oils, so that the economy of buying the heavier fuels is apparent; there remains the economic utilizationof the heat content of the heavier oils. ~ The cost of oil fuel is dependent also upon the amount that can be delivered at one time, and the method of delivery. Common practice has split the tank of the truck delivering oils for domestic use into compart ments of 150 to 500-gal capacity, and these unit dumps are made the basis of price. Where a truck can be connected to a storage-tank fill and quickly discharge its oil by pump, the price obviously can be less than where a smaller quantity must be drawn off in 5-gal cans and poured. For similar reasons an installation that can be supplied from a tank car on a siding provides for a lower unit fuel cost than one where the oil must be trucked, even in the large trucks holding 2,000 gal or more that are used for distributing the heavier oils. GAS CLASSIFICATION Gas is broadly classified as being either natural or manufactured. Natural gas is a mechanical mixture of several combustible and inert gases rather than a chemical compound. Manufactured gas as dis tributed is usually a combination of certain proportions of gases produced by two or more processes, and is often designated as city gas. When gas is burned a large amount of water vapor is produced as one of the products of combustion. This ordinarily escapes up the chimney, carrying away with it a certain amount of heat. However, when the heat value of gas is determined in an ordinary, calorimeter, this water vapor is condensed and the latent heat of vaporization that is given up during the condensation is reported as a portion of the heat value of the gas. The heat value so determined is termed the gross or higher heat value and this is what is ordinarily meant when the heat value of gas is specified. The heat that is reclaimed by the condensation of the water vapor amounts to about 10 per cent of the total heat value. It is impractical to utilize the entire higher heat value of the gas in any house-heating 175