The National Fire Protection Agency (NFPA) reported that in the year 2005, there were 1,602,000 fires reported in the United States that caused 3,675 civilian deaths, 17,925 civilian injuries, 87 firefighter deaths, and $10.7 billion in property damage. Amongst these fires 511,000 were structure fires, causing 3,105 civilian deaths, 15,325 civilian injuries, and $9.2 billion in property damage.
There is a critical need for structural materials that can withstand very high fire temperatures for a prolonged duration, allowing sufficient time for personnel evacuation over a period of up to one hour. Furthermore, in cold regions like that in Michigan, the materials used in structural components need to be especially corrosion resistant and durable, which makes the innovative material of carbon fiber reinforced polymers (CFRP) an inevitable choice. To meet all these requirements, the CFRP materials must be tested both for normal load cycles and for their performance during fires.
On the battlefields, the lives of many soldiers depend upon the performance of army tanks, and during field operations the tanks are frequently exposed to high risks from fire and explosions. Hence, materials that withstand high fire and explosion temperatures, yet are lighter in weight are highly essential to use in protecting the tanks. In order to meet the aforementioned requirements, the Army Research Lab (ARL) and the U.S. Army Tank-Automotive Research, Development and Engineering Center (TARDEC) are collaborating with Lawrence Technological University to set up a state-of-the-art laboratory named the Center for Innovative Materials Research (CIMR) for the research, development, and testing of CFRP materials for defense applications.
The CIMR houses a state-of-the-art, unique fire test facility. Lawrence Technological University is the only private university in the state of Michigan to have such a high-tech research facility set up with federal government funds. The fire test facility has enabled researchers to investigate the response of innovative armor, building and bridge materials being researched in the Department of Civil Engineering at Lawrence Technological University. Moreover, the facility will allow conducting tests on many kinds of vehicles and vehicle components, especially army tank structures which are subjected to blast and fire on the battle field. The facility includes a fire-testing furnace, loading actuator, test frame, and an extensive data acquisition system.
The fire-testing furnace is equipped to test structural components such as armor, columns, beams, floor systems etc. under extreme fire conditions to which they would likely be subjected in real life. Using natural gas flame jets from nine burners, the maximum temperature that the furnace can reach is 2,300 degrees F (1,260 degrees C). To gain a sense of civilian housing fire loading, the temperatures in a typical residential/household fire may range from 900 degrees F (482 degrees C) to 1,200 degrees F (649 degrees C). The interior dimensions of the furnace are 22'-3½" × 10'-6" × 8'-6" (6.8 m × 3.2 m × 2.6 m). The furnace is connected to an ejector stack of 45 ft (13.72 m) height to expel the combustion gases generated during the tests. Five viewing ports, three on the front and two on one side permit viewing the specimens being tested under fire. The furnace is controlled using electronic and mechanical process control devices, and it fully satisfies the latest safety standards prescribed by the NFPA, 2007.
During a typical residential fire, structural components attempt to support the service loads while subjected to the high temperatures. In the CIMR fire test chamber, the loading actuator and the test frame allow application of the service loads continuously on the test specimens while they are subjected to high fire temperatures. The maximum load (static, repeated, and impact) that can be applied using the actuator is of the order of 175 kip (778 kN). Thus, the arrangement serves well in simulating the real-life conditions during fire to which structural components are subjected.
The data acquisition system consists of different components each pertaining to elements of the fire ignition system and load application system. The temperature sensors are connected to a data acquisition system for temperatures, while the load-cells, strain gages etc. of the load application system are connected to another data acquisition system for loading and response measurements. Additionally, a sequenced signal is sent from one data acquisition system to the other, to correlate the data between the two systems. The closed loop hydraulic actuator system consists of a 160 gallons per minute (606 liters/minute) pump interfaced with a large cooling system and 2" (51 mm) hardlines to carry the fluid to the loading actuator.