Why:
To detect particle leakage and ensure proper fitment of a mask on the wearer.

Equipment:
TSI Portacount Pro+ 8038
TSI Particle Generator 8026

Test principle:
A respirator is fitted with a test probe and a tube is fitted to the probe. Another tube is open ended and both tubes are fed into the particle counter. Both the amount of particles in the ambient air and inside the respirator are measured by the particle counter. A fit factor is then calculated with those values. A high fit factor means the respirator fits well and no/little air and particles leak through the gaps between face and respirator or the filter material.