Face masks are often the first line of defense against the spread of infection or damaging particles. A properly designed face mask will stop dangerous materials, but allow normal air flow for breathing. The mask material must be woven tightly enough to trap unwanted particles, but the pressure drop through the mask should be low enough so that breathing effort is normal. Testing protective masks requires measuring pressure drops which equal to just a few millimeters of water.
The Validyne DP103 differential pressure transducer is available in full scale pressure ranges as low as 3.5 mm H2O. This pressure transducer was recently used to measure the pressure drop through prototype face masks that were on the order of 5 to 10 mm H2O. The pressure drop was to be recorded at different flow rates and this required a pc based data acquisition system for the output of the DP103.