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Once emission factors are determined , the equipment size (in horsepower) is assigned to each construction equipment type based on site-specific information or based on the most freq uently utilized equipment within the country in which the project is located as derived from NONROAD2008a. Emission factors and horsepower for each equipment type are then applied to the anticipated equipment work output ( i.e., horsepower-hours of expected equipment use). Lastly the usage factor and load factor are applied. Table A6-1 ( Example of Construction Equipment Data ) presents example construction equipment data such as horsepower, load factor, and usage factor. 

A usage factor accounts for the percentage of daily operation and a load factor accounting for the average throttle setting relative to full throttle rating is used and based on data within NONROAD model. For example, a usage factor of 0.75 equates to 7.5 hours of operation (based on a ten hour work day) and a load factor of 0.62 equates to 62 percent of full throttle rating during operation. 

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