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CONTINUED | 10 <br />Table 3: Above ground AMSE Tank vaporization rate, <br />LP-Gas Serviceman’s Handbook. <br />TEMPERATURE <br />TANK SIZE (Gallons) <br />150 250 500 1,000 <br />40°F 214,900 288,100 478,800 852,800 <br />30°F 187,900 251,800 418,600 745,600 <br />20°F 161,800 216,800 360,400 641,900 <br />10°F 148,000 198,400 329,700 587,200 <br />0°F 134,700 180,600 300,100 534,500 <br />-10°F 132,400 177,400 294,800 525,400 <br />-20°F 108,800 145,800 242,300 431,600 <br />-30°F 107,100 143,500 238,600 425,000 <br />* Tank frosting acts as an insulator, reducing the vaporization rate. <br />Figure 4: Typical LP vapor withdrawal system. <br />Base Rail <br />FULL FLOW <br />SHUT OFF <br />VALVE <br />The piping system connecting the outlet of the first stage regulator to the connection point on the second <br />stage regulator must be properly sized to provide the fuel voluume required by the unit at 100% load. <br />The piping system between the outlet of the second stage regulator and the generator connection point <br />must be sized to provvide the fuel volume required by the generator at 100% load while also staying <br />within the pressure range noted on the unit specificatotion sheet. <br />Allow a minimum of 10 feet between the primary regulator and generator <br />Flex HoseFUEL TANK <br />FULL FLOW <br />SHUT OFF VALVE <br />SECOND STAGE <br />REGULATOR <br />FIRST STAGE <br />REGULATOR WITH <br />RELIEF VALVE AND <br />PRESSURE TAP <br />Natural Gas Supply System Design Guide for Generac Industrial Spark Ignited Generators <br />under a range of environmental conditions and <br />various liquid levels in the tank. Liquid propane <br />absorbs ambient heat from the surrounding <br />environment to boil off liquid into a gas. Low liquid <br />levels in a tank coupled with cold ambient <br />temperatures can result in a condition where the tank <br />boil off rate is insufficient to meet the demands of the <br />generator. <br />The local propane supplier is often a good resource <br />to help with tank sizing. The Emerson-Fisher LP-Gas <br />Serviceman’s Handbook is another valuable resource <br />for sizing propane systems and includes tank <br />vaporization tables.8 In many cases, the tank volume <br />must be larger (sometimes much larger) than the gas <br />required to achieve a desired runtime. Where <br />practical, buried tanks can improve the vaporization <br />rate by protecting the tank from extremely low <br />ambient air temperatures. <br />8.3. Liquid propane system: This system delivers <br />propane in a liquid state (LPL) to the connection point <br />on the generator set. Liquid propane systems are <br />used where it is impractical to achieve the required <br />boil off rate from the available fuel tank volume. For <br />the engine to use the LPL fuel, the liquid must be <br />vaporized prior to being delivered to the fuel mixer <br />(carburetor). LPL will vaporize at a temperature of <br /> <br /> <br /> <br />(-44°F/-42.2°C). The generator set LPL fuel system <br />delivery pressure operates over the range of 58-180 <br />psi (400-1242 kPa), depending on the ambient <br />temperature and liquid level in the storage tank. <br />LPL enters the vaporizer and passes into a “flash” <br />chamber. The pressure drop in this chamber <br />vaporizes the liquid to a gas and is regulated to <br />negative 11"-14" w.c. (2.9-3.5 kPa). Heated engine <br />coolant from the jacket water heater is used to heat <br />the flash chamber of the vaporizer and to prevent the <br />vaporizer from icing. <br />Max. Intermittent Withdrawal Rate (BTU/HR) Without Tank <br />Frosting* If Lowest Outdoor Temperature (Average for <br />24-Hours) Reaches . . . <br />Docusign Envelope ID: 2F58BEE5-DDBE-42EB-8DFA-5E2508488B04