There are many types of commercially available fire extinguishing agents used for a wide range of applications. The specific extinguishing agent used for a given application depends on the fire threat and design criteria. For class-C cargo compartments on aircraft, a gaseous flooding agent is used. Halon 1301 is currently the sole extinguishing agent being used in class-C aircraft cargo compartments. It requires a replacement due to its harm to the environment.
The fire threat within cargo compartments is changing compared to the threat that existed when aircraft class-C cargo compartment requirements were first established. The quantity of lithium batteries being shipped in cargo compartments is increasing each year. Lithium batteries can spontaneously catch fire or undergo thermal runaway where they release a significant quantity of flammable gas composed of hydrogen, carbon monoxide and hydrocarbons.
The objective of this study was to evaluate the effectiveness of Halon 1301 and some of its potential replacements against several flammable gases including lithium battery thermal runaway gases.
Lithium batteries have been shipped aboard aircraft with existing United Nations (UN) classification numbers for many years. Although the UN classifies lithium batteries as dangerous goods, current UN numbers for lithium batteries do not indicate what level of hazard each individual shipment may pose. Lithium batteries can exhibit varied temperature rise and propagation characteristics when heated to thermal runaway. Therefore, This study was conducted to characterize the propagation of cylindrical cells and pouch cells at various states-of-charge (SoCs) to determine or verify key test factors that should be considered for development of a lithium battery propagation test.
Six cells were placed in line with each other (denoted cell # 1 through cell #6) in an insulated box, and thermal runaway was initiated in cell #1. Once thermal runaway initiated, power to the heater was cut off and propagation characteristics were recorded. Key findings included:
Knowing fire temperature and soot concentration in a fire is very important in fire safety research. The fire radiant energy, a function of fire temperature and soot concentration, contributes about 40% of energy loss to the walls of the Ohio State University (OSU) fire calorimeter during the burning of large area cabin materials. This report presents a method to measure the full field of flame temperature and soot volume fraction in fire using a digital camera. The report also outlines a new procedure to simultaneously calibrate and characterize the camera’s detector using a blackbody furnace. The developed methods are implemented to measure flame temperature and soot volume fraction in a liquid-fueled steady laminar diffusion flame, impacted by the phosphorus type flame-retardant material. The flame-retardant material is found to promote soot formation and suppress soot oxidation in the fire. The increased net soot concentration cools the flame, resulting in incomplete combustion.