This guideline includes a. recommendations for methods and devices used to measure electrical usage@ fluid flow@ and temperature@ and b. procedures for acquiring the necessary data and calculating system efficiency. These procedures are for site-specific application. They do not discuss the comparison of collected data between different sites@ nor do they recommend that data obtained be applied in this manner. The procedures also do not discuss a. any plants except electrically driven chilled-water plants@ b. design and operation of central chilled-water plants@ except for recommending the instrumentation used to determine plant efficiency@ or c. selection@ application@ or operation of system components. PURPOSE This guideline defines recommended methods for measuring chilled-water plant thermal load and energy use and for calculating chilled-water plant efficiency.