he ventilation resistance for gas exchange on both sides of the mask should not be greater than 49Pa/cm³.
The ventilation resistance test takes the central part of the mask for testing. The gas flow rate for the test needs to be adjusted to (8±0.2) L/min, the diameter of the sample test area is 25mm, and the test area of the test sample is A. Use a differential pressure gauge or equivalent equipment to measure the pressure difference on both sides of the mask, and calculate the ventilation resistance according to the formula ΔP=M/A.
ΔP ——the pressure difference per square centimeter of the test sample, the unit is Pa per square centimeter (Pa/cm³);
M ——The pressure difference value of the test sample, the unit is Pa;
A ——The test area of the test sample, the unit is square centimeters.
