Summary of pinfa-NA – SAMPE online event on new challenges for materials fire safety in aircraft.
Tim Reilly, Clariant and Maggie Baumann, FRX Polymers, opened the webinar, welcoming over 150 participants, and underlining the fire-safety success of air and rail travel, where billions of passengers travel worldwide today with very high levels of safety.
Raj Manchanda, SAMPE (Society for the Advancement of Material and Process Engineering) underlined the high and accelerating rate of innovation in materials in transport applications, with non-halogen flame retardants playing a key role in enabling new materials. Tomorrow’s challenges include bringing high production rates from the automotive to train and aircraft industries.
Join the SAMPE Materials Innovation & Advanced Technology Leadership Forum, 26-27 January 2022.
Jeff Gardlin, US Federal Aviation Authority, outlined perspectives for fire standards for aviation and the challenge of enabling innovation whilst ensuring the ever increasing safety levels expected by the public. Research needs to address in parallel materials and technology innovation and appropriate safety standards. Standards need to be sufficiently precise to be demanding, but flexible to accommodate new materials. New challenges for fire safety will include 3D-printed materials, which may have different fire performance, and fire risks related to batteries.
John Harris, Boeing, presented results of extensive testing of resistance to UV-C light (222 nm), a potential solution for COVID virus disinfection of materials and surfaces. In a wide range of aircraft cabin materials, extended exposure to light intensity equivalent to repeated disinfection over twenty years showed little impact on mechanical properties or on flammability, but significant discoloration of some material (yellowing of white materials as widely used in aircraft cabins).
Further details and information are here https://www.boeing.com/confident-travel/?gclid
Thomas Fabian, UL, presented results of an internal UL testing programme comparing fire and electrical performance of two 3D filament printed materials to the same materials when injection moulded: non-halogenated flame retardant ABS, PEI (polyetherimide, an inherently fire resistant polymer). Results show lower fire and electrical performance (e.g. UL94, HWI, tracking index) in 3D-printed compared to injection moulded material. This may be related to higher surface roughness and air gaps (chimneys) in the materials structure. Results show considerable variation depending on printer settings, orientation, and even on the printer model for the same parameters. In addition to the Yellow card, UL has developed the UL Blue Card which addresses this by specifying in the test results both printer parameters and printer model.
Bhaskar Biswas, Safran Cabin, aircraft interior developer and provider with 80 years’ experience and global leader in several markets including cabin liners and galleys, summarised the types of testing protocol used to achieve fire security. FAA requirements pose stringent requirements for ignition, burning intensity, material integrity in fire and smoke density. These requirements drive materials selection and component design. For composites, three tests are key: vertical flammability, heat release (OSU) and smoke density. In general, these tests are performed for composites, using samples of application-specific configuration, at different levels of structural assemblies from materials to sub-component and components.
Matthew Blais, SwRI summarised results of room fire tests comparing UK furniture (non-halogen flame retarded) to French or US (non flame retardant), see pinfa Newsletter n°104. These full-scale tests show that UK furniture delays flashover from 2-4 minutes to 17-22 minutes, with also smoke obscuration similarly delayed. Lethal toxicity is reached in around 7 minutes with the non-FR furniture, whereas the FR-furniture showed little toxicity even after 20 minutes. Carcinogenic smoke components remained much lower with the FR-furniture, even after flashover. Recent room tests have confirmed these results in a well ventilated room, whereas the previous tests used a closed room. The FR materials generate lower smoke and make fires more survivable.
Thomas Chapin, UL, explained how and why batteries pose an increasing fire risk for air transport. Fatal accidents have already been caused by battery fires on aircraft, but the problems are accelerating fast, with increasing use of batteries, and bigger, more energy-dense batteries. Battery cargo is forbidden in passenger aircraft, but reverse logistics often mean that batteries are transported without indication on the packaging: returns, repairs, recycling. The US CSPC (Consumer Safety Protection Commission) has made 150 product recalls for batteries, concerning 21 million batteries, since 1990. Many of these recalled batteries are transported on aircraft, including batteries which are damaged or faulty. Advancements in flame retarded, lightweight, advanced materials for battery packaging and for transport containers are an important route for improving safety.