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HP,e = Baseline burn hours <br />HPost = Performance Period burn hours <br />The energy usage of both the baseline and Performance Period lighting conditions are calculated utilizing <br />the same equations. The measured parameters collected during the pre -implementation period will be <br />used to compute the baseline fixture power use. The measured parameters collected during the post - <br />implementation period will be used to compute the Performance Period fixture power use. The equations <br />for a single fixture for both the baseline and Performance Period are shown below using the baseline <br />calculations as an example. <br />Equation 3 — Total Fixture Power Use <br />EPre EFixl,Pre <br />Where, <br />EFixt,Pre = Pre -implementation direct power usage of light fixture <br />Equation 4 — Fixture Lighting Power Use <br />EFix4Pre = PX 0 <br />Pre <br />Where, <br />P = Pre -implementation power draw of light fixture <br />Q = Quantity of associated light fixture <br />C. Key Parameter Measurement Strategy <br />This section outlines the measurements that will be conducted to determine the measured values in the <br />equations provided above in Paragraph B. For this lighting project, the key parameters that will be <br />measured are the power consumption of each fixture type and the burn hours for each occupancy type. <br />Measurement and documentation strategies for each project phase are outlined below. <br />Pre -Implementation Measurements and Documentation <br />Power measurements will be taken on a sample set of baseline fixture types to determine the average <br />power use for that fixture type. The minimum sample sizes and precision of results are different <br />depending on the number of fixtures included in the project. The most common fixtures will have a high <br />degree of certainty in the results, while the least common fixtures will have greater uncertainty in order to <br />ensure measurement costs are commensurate with performance risk. Three different classes of <br />measurement requirements are included: <br />1. Fixture types with less than 20 total fixtures will not be measured. The power shown in the table <br />below will be used in all calculations. <br />2. Fixture types with 20 — 100 total fixtures will have at least 4 measurements taken. Measurements <br />will continue to be taken until the 90% confidence interval for the true population mean spans no <br />more than 10% above and below the mean of the sample. <br />3. Fixture types with more than 100 total fixtures will have at least 10 measurements taken. <br />Measurements will continue to be taken until the 95% confidence interval for the true population <br />mean spans no more than 5% above and below the mean of the sample. <br />The mean of a sample set will be treated as the power consumption for that fixture type for all savings <br />calculations. The table below lists each fixture type to be measured, the estimated power of that fixture <br />type, the total quantity of that fixture type, and the minimum amount to be measured prior to removing the <br />fixtures to implement the retrofit. As stated above, more measurements may be needed if the sampled <br />fixtures have too much variance. <br />Energy Solutions Proprietary and Confidential <br />0028111 21 <br />