According to ASTM E1827 - 11, what is the maximum percent difference allowed between high and low building pressures for pressure uniformity?

The maximum percent difference allowed between high and low building pressures for pressure uniformity, as specified in ASTM E1827 - 11, is 5%. This standard defines the methodology for conducting whole-building airtightness testing and establishes requirements for pressure uniformity. Maintaining a maximum difference of 5% ensures that the building is evaluated under consistent pressure conditions, which is critical for obtaining reliable airtightness measurements. This uniformity is vital for the accuracy of the test results, as significant variations in pressure could lead to misleading conclusions about a building's airtightness performance. Thus, adherence to this limit is essential in ensuring that the testing procedures are standardized and that the results are reflective of the actual conditions within the building.