What pressure points are recommended for fan calibration in ASTM E1258?

The recommended pressure points for fan calibration in ASTM E1258 are established to ensure accurate and reliable measurements of building airtightness. The pressure points chosen are 12.5 Pa, 25 Pa, 37.5 Pa, 50 Pa, 62.5 Pa, and 75 Pa because they provide a good range that effectively captures the performance of the fan across different operational states.

Using these specific increments allows for a systematic evaluation of the fan's characteristics and behavior at various pressure levels. The lower points (12.5 Pa, 25 Pa) ensure that the fan operates under conditions that are more reflective of typical air leakage scenarios in buildings, while the higher points (50 Pa, 62.5 Pa, and 75 Pa) assess the fan's capability to handle higher pressure differentials, which could occur in certain situations.

This range not only aligns with industry standards but also improves the likelihood of detecting potential issues with building performance, as it covers a wide spectrum of the pressure conditions that a building might experience. Overall, this comprehensive approach to fan calibration is essential for achieving accurate airtightness results.