Recorded at AIHce EXP 2021
Hydrogen Fluoride Service Life Testing with Surrogates for PAPR Cartridges
A method of evaporation of hydrofluoric acid solutions is viable for generating a range of hydrogen fluoride concentrations. This is very important because using a gas cylinder is both cost prohibitive and challenging when running long tests. Use of smaller surrogate cartridges is an effective way to do service life testing quickly. By using surrogate cartridges, the team was able to reduce flow and the amount of HF generation by approximately 87%. Cartridge service life has been shown to follow a power regression curve for concentrations in the range 70 to 1200 ppm. These curves can be used to generate cartridge changeout schedules. Preliminary examination of the effect of humidity on HF service life for cartridges containing a nontreated sorbent showed a correspondence with a quadratic relationship. HF is extremely reactive, and all sorbents tested had some affinity to remove it. This demonstrates that impregnates or residual chemicals on the carbon surface are not necessary for HF removal and that it can interact with the carbon surface alone.
Presenter/Author: Erik Johnson, 3M St. Paul, MN
Co-Authors: K. Frankel, 3M, St. Paul, MN, USA S. Smith, (retired), Brockville, ON, Canada M. Peralta, Assay Technology, Livermore, CA, USA
Setup, Real-Time Detection, and the Challenges of High Concentration Formaldehyde Vapor for Respirator Cartridge Testing
Following the CBRN standard for formaldehyde respirator cartridge testing, a set-up is highlighted showcasing the vaporization of an in-house formaldehyde solution using two vaporizers in parallel to achieve the 500 ppm challenge concentration. Vapor challenge is increased to 823 ppm formaldehyde using both the in-house solution and a diluted formalin solution in order to obtain low relative humidity levels. Validation of generation is verified using a fourier transform instrument allowing for real time detection of both high and low formaldehyde vapor as well as multiple gasses at once.
Presenter/Author: Maria Peralta, PhD, Assay Technology Livermore, CA
Co-Authors: C. Manning, PhD, CIH, FAIHA. Assay Technology, Livermore, CA, USA.