Copyright Goodheart-Willcox Co., Inc. May not be reproduced or posted to a publicly accessible website. Chapter 5 Measurement 87 The SI system also has various units of heat that may need to be converted. To convert from calories to kilojoules, the chart shows a multiplier of 0.004184. To convert from 12,000,000 calories to kilojoules, the calculation would be as shown. 12,000,000 cal × 0.004184 = 50,208 kJ Thus, 12,000,000 cal equals 50,208 kJ. To convert kilojoules to calories, the chart shows a multiplier of 239.00574. 50,208 kJ × 239.00574 = 12,000,000 cal Thus, 50,208 kJ equals 12,000,000 calories. Heat Measurement Conversion US Customary Multiply by: SI To get: To convert from: Btu 252.16 calories Btu 1,055.06 joules Btu 1.05506 kilojoules SI Multiply by: US Customary To get: To convert from: calories 0.0039685 Btu joules 0.0009486 Btu kilojoules 0.94782 Btu Goodheart-Willcox Publisher To convert from kilojoules to Btu, the conversion chart shows a multiplier of 0.94782. To convert 50,208 kJ to Btu, the calculation would be as shown. 50,208 kJ × 0.94782 = 47,588.146 Btu Thus, 50,208 kJ equals 47,588.146 Btu, which could be rounded off to 47,588 Btu. To convert Btu to kJ, the chart shows a multiplier of 1.05506. Thus, to convert 47,588 Btu to kilojoules, the calculation would be as shown. 47,588 Btu × 1.05506 = 50,208.19 kJ Thus, 47,588 Btu equals 50,208.19 kJ, which can be rounded off to 50,208 kJ. 5.9.6 Pressure Measurement Conversions Conversion Factors for Pressure Measurements of the US Customary System Multiply: by To obtain: pounds per square inch (psi) 2.036 inches of mercury (in. Hg) inches of mercury (in. Hg) 0.4912 pounds per square inch (psi) atmosphere (atm) 14.7 pounds per square inch (psi) atmosphere (atm) 29.92 inches of mercury (in. Hg) inches of mercury (in. Hg) 0.00342 atmosphere (atm) Goodheart-Willcox Publisher 5