Risker med Kolfiberlaminat vid Brand (Dangers Relating to Fires in Carbon-Fibre Based Composite Material): Fid-Bau Portal

Risker med Kolfiberlaminat vid Brand (Dangers Relating to Fires in Carbon-Fibre Based Composite Material)

T. Hertzberg

Inhalable carbon fibers have been suspected to pose similar threats to human health, as do asbestos fibers. It is known that fibers having a diameter of less than 3 pm might be inhaled and transported deep into the human respiratory system. Some composite materials use carbon fibers as structural reinforcement. These fibers do not pose any risks as such as they are firmly connected to the laminate and surrounded by a polymer matrix. Also, these fibers typically have diameters >6 pm and thus, are not inhalable. However, if the material is subjected to a fire, the carbon fiber material might be oxidized and fractionated and thereby, inhalable fibers might be produced. Within this project, the capability of carbon fiber-based composite material to produce dangerous inhalable fibers from different fire scenarios has been investigated. Further, a literature survey on health risks relating to carbon fibers have been made. It was found during the project that the risk of fires generating inhalable carbon fibers is related to the surface temperature, the oxygen level and the airflow field close to the material surface. The temperatures necessary for oxidation of the carbon fiber is so high (>600C) that it is possible that only a flashover situation will be able to reduce the fiber diameter efficiently. Other possible dangerous scenarios are highly intense fires (e.g. a liquid fuel fire) where heat radiation is pronounced, or situations where structural damages is part of the fire scenario, exemplified e.g. by airplane crashes.