Humanlike Articulate Robotic Headform to Replace Human Volunteers in Respirator Fit Testing

Abstract

Abstract : In this era of competent materials and fabrication for air filtration the factor dictating the protection factor (ratio of concentration outside to inside the respirator) is unfiltered inward leakage. Respirator testing using humans is constrained by the requirement for advance approval of the protocol by a human use committee, by the diversity and caprices of the subjects used in testing, by factors such as fatigue and illness, and by health hazards of aerosol challenges. Hanson Robotics has designed and built a robotic headform with dimensions matching those of the medium headform identified from a NIOSH wearers panel. The polyurethane skull form and polydimethylsiloxane artificial skin covering (Frubber) also accurately reproduce skin thicknesses measured for a panel of male Caucasians aged 19 -22 and provide a good simulation of the gross surface texture of human skin and its elastic response to touch. An initial static test of fit of seven models of N95 respirators to a static prototype prepared from similar materials in the same dimensions showed a typical scatter of measured fit factors (FFs) after donning, and an average FF of slightly more than 200 in a second series of donnings in which a leak check was used to exclude samples for which FF was 100, showing that the headform does closely resemble a human head in the NIOSH medium size window. Statistical validation that this similarity constitutes functional equivalence is underway.