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Applied Chemistry and Physics
Published in Robert A. Burke, Applied Chemistry and Physics, 2020
Some plastics may exhibit unusual burning characteristics compared to building materials made from natural polymers such as wood. Plastics as a group generally have higher ignition temperatures than wood and other cellulose-building products. Plastics have been reported to have very high flame spread characteristics, as high as 2 ft/s, or 10 times that of wood on the surface. Vinyl, when tested in a solid form in the laboratory, has been shown to burn slowly. However, when in the form of a thin coating on wall coverings, it spreads rapidly contributing to flame spread. Nylon has a tendency to self-extinguish when a flame is removed. When nylon is in the form of carpet fiber under certain conditions, it burns with great enthusiasm. Polyurethane foam that has not been treated with a flame retardant is very flammable. It is used as an insulating material in construction and burns with a very smoky flame. Because of its burning characteristics, it has contributed to rapid flame spread in several fatal fires. Burning of plastics may produce large quantities of thick, black smoke. When chemicals are added to retard burning, they may actually expand the amount of smoke that is produced. Because of their ability to melt and run, plastics can spread fires in ways that could mislead fire investigators. When skylights and light fixture diffusers are ignited by high ceiling temperatures, they may soften and sag. They can fall into combustible materials below and start fires in several isolated locations. This could lead an investigator to suspect an incendiary fire when in fact it was not.
Certification and Characterization of Photovoltaic Packaging
Published in Michelle Poliskie, Solar Module Packaging, 2016
Ignition, combustion, and flame propagation are the three principal processes used to define flammability. Ignition is the mechanism of fire creation between a fuel and oxidizer. As it is confined to this discussion, ignition is caused by an external heat source (i.e., a flame). Combustion is the chemical degradation of the material into gaseous products and char. Flame spread is a complex phenomenon related to a number of environmental variables, such as fuel concentration, wind speed, temperature, and mechanical slope. It generally describes the flame propagation along a surface.
Common Sense Emergency Response
Published in Robert A. Burke, Common Sense Emergency Response, 2020
Plastics have been reported to have very high flame spread characteristics, as high as two feet per second, or 10 times that of wood on the surface. Vinyl, when tested in a solid form in the laboratory, has been shown to burn slowly. However, when in the form of a thin coating on wall coverings, it spreads rapidly contributing to flame spread.
Design and production of sustainable lightweight concrete precast sandwich panels for non-load bearing partition walls
Published in Cogent Engineering, 2021
Fayez Moutassem, Kadhim Alamara
Precast sandwich panels were constructed using an identified optimum core mixture following the procedure outlined above. Consequently, testing was carried out to determine the technical properties of the precast sandwich panel system. These properties include density, compressive strength, flexural strength, fire rating and thermal insulation value. These technical properties were determined for both 100 mm and 150 mm thick sandwich panels. Additionally, installation time was monitored for each stage. The density of hardened EPS concrete was conducted in accordance with ASTM C567 (2019) at 28 days. For the compressive strength, EPS concrete cube specimens, with attached fiber cement boards, were cut out of the sandwich panel, cured in a water tank, and tested at 28 days. The flexural strength at 28 days was determined by subjecting the sandwich panel to an increasing uniform load until fracture. The service load deflection was determined by subjecting the panel to a uniform service load of 250 kg for 24 hours. The fire test for the EPS concrete wall system was conducted following ASTM E119 (2020) to determine the fire resistance of a complete assembly. This test evaluates the duration (fire rating) for which the building system contain fire, retain their structural integrity, or exhibit both properties during a predetermined test exposure. The fire test for the EPS concrete product was conducted following ASTM E84 (2020) to determine both flame spread and smoke development indices. The flame spread index is a numerical reference that measures how fast and far a flame spreads during a certain time duration. The smoke development index measures the concentration of smoke a materials emits as it burns for a certain time duration. Thermal insulation property was determined by calculating the U-value for the sandwich panel system. The U-value was calculated by considering the thermal conductivity values (K-values) for each material in the identified mixture. Accordingly, the thermal resistance values (R-values) for the volume fractions of wall components i.e. EPS, fiber cement boards and concrete, were calculated. The U-value for the system is then determined by finding the reciprocal of the summation of the R-values.