Original sentence: In order to accurately estimate leakage areas, it is best to conduct the blower-door test over a wide range of building pressures (e.In order to compare the relative airtightness of buildings, it is useful to normalize the measurements for the size of the building.Leakage area estimates can also be normalized for the size of the enclosure being tested, For example, the LEED Green Building Rating System has set an airtightness standard for multifamily dwelling units of  of leakage area per  of enclosure area, in order to control tobacco smoke between units.One of the most common ways to normalize building airtightness is to calculate the number of times per hour that the total volume of the enclosure is changed, when the enclosure is subjected to a 50-pascal pressure difference
Edited sentence: Leakage area estimates can also be normalized for the size of the enclosure being tested, For example, the LEED Green Building Rating System has set an airtightness standard for multifamily dwelling units of  of leakage area per  of enclosure area, to control tobacco smoke between units.One of the most common ways to normalize building airtightness is to calculate the number of times per hour the total volume of the enclosure is changed, when the enclosure is subjected to a 50-pascal pressure difference.To accurately estimate leakage areas, it is best to conduct the blower-door test over a wide range of building pressures (e.To compare relative airtightness of buildings, it is useful to normalize measurements for the size of the building