What is required for baseline readings according to USACE 2012?

The requirement for baseline readings according to USACE 2012 specifies that 12 readings must be taken at 10-second intervals. This procedure is crucial as baseline readings help establish a reliable reference for evaluating the airtightness of a building during testing.

Taking multiple readings at consistent intervals allows for greater accuracy and helps to identify any fluctuations in the data, which can be important in assessing the integrity of the building envelope. The choice of 10-second intervals strikes a balance between sufficient data collection and avoiding unnecessary delay, ensuring that the readings reflect the building's performance effectively without introducing excessive testing time.

Other options involve either fewer readings or different intervals, which would not align with the established standard set by USACE 2012, making them less effective in providing a reliable baseline for analysis.