This is the projection of the actual measured noise dose to what it would be if the measurement were to continue for a full 8 hours. This value is usually used to predict what the eventual outcome would be at the end of a standard working day when a representative period of time has been used to carry out the measurement. If the actual measurement lasted for 1 hour 30 minutes. And a measured noise dose was found to be 27% then the 8 hour projected value would be calculated as 27(8/1.5) = 144%.