Laboratory evaluation of airborne particulate control treatments for simulated aircraft crash recovery operations involving carbon fiber composite materials.

Objective: This study compared four treatment protocols to reduce airborne composite fiber particulates during simulated aircraft crash recovery operations.

Design: Four different treatments were applied to determine effectiveness in reducing airborne composite fiber particulates as compared to a "no treatment" protocol. Both "gold standard" gravimetric methods and real-time instruments were used to describe mass per volume concentration, particle size distribution, and surface area. The treatment protocols were applying water, wetted water, wax, or aqueous film-forming foam (AFFF) to both burnt and intact tickets of aircraft composite skin panels. The tickets were then cut using a small high-speed rotary tool to simulate crash recovery operations.

Setting: Aerosol test chamber.

Subjects, Participants: None.

Interventions: Airborne particulate control treatments.

Main Outcome Measures: Measures included concentration units of milligrams per cubic meter of air, particle size distribution as described by both count median diameter and mass median diameter and geometric standard deviation of particles in micrometers, and surface area concentration in units of square micrometers per cubic centimeter. Finally, a Monte Carlo simulation was run on the particle size distribution results. Comparison was made via one-way analysis of variance.

Results: A significant difference (p < 0.0001) in idealized particle size distribution was found between the water and wetted water treatments as compared to the other treatments for burnt tickets.

Conclusions: Emergency crash recovery operations should include a treatment of the debris with water or wetted water. The resulting increase in particle size will make respiratory protection more effective in protecting the response crews.