According to ASTM E1827 - 11, do both occupied and closed preparation methods apply?

The reasoning behind why both occupied and closed preparation methods apply according to ASTM E1827 - 11 is rooted in the standard's recognition of diverse building scenarios and conditions during testing. The standard allows for both methodologies to be utilized to ensure flexibility and practicality in different circumstances.

In an occupied preparation method, the building is tested while it is being used as intended, which allows for a realistic assessment of the building's performance during regular occupancy. This can provide valuable insights into real-world airtightness under typical living conditions.

Conversely, the closed preparation method involves testing the building when it is unoccupied or closed off, allowing for a controlled environment that may highlight different aspects of the building's airtightness. This method can also mitigate variables that occupants or normal operations might introduce.

The inclusion of both methods ensures that various scenarios can be considered, enabling a well-rounded evaluation of a building's airtightness performance.