Abstract: A head form for testing a variety of respirators. The head form can prevent false leak failures by having a mask registration member upon which the mask under test is mounted, the mask registration member being self lubricating. In one embodiment, the registration member is an inflatable bladder. The bladder can be configured to limit lift away of the inflatable bladder from the recess, thereby mitigating leaks in the head form assembly. The bladder may be configured to limit roll away of portions of the bladder that register against the head form, thereby reducing or eliminating leaks between the inflatable bladder and the mask under test.

Abstract: An apparatus and method for estimating size segregated aerosol mass concentration in real time and using a single detector. A beam of electromagnetic radiation is passed through a particle stream made of a test or field aerosol. The single detector outputs an electrical signal proportional to the electromagnetic radiation scattered thereupon. The electrical signal may be conditioned to produce an integrated signal for measuring radiation scattered from all the particles in the interrogation volume, a pulse height from an individual particle within the volume, and/or a time-of-flight measurement from the individual particle. The integrated signal can be correlated to particle mass concentration. The pulse height signal and the time-of-flight signal may be converted to infer the size of the individual particle. Attendant size distributions for the particle sizes may also be obtained. Using known or assumed particle properties, the mass concentration may be estimated from the size distribution.