Fire exposure properties

It has been demonstrated that steel strength decreases rapidly with temperature increases above 260 °C (500 °F). At 538 °C (1000 °F), its strength both in tension and compression is approximately half, at 649 °C (1200 °F) its strength decreases to less than one quarter. Bare steel exposed to hydrocarbon fires may absorb heat at rates from 10,000 to 30,000 Btu/hr/sq. ft., depending on the configuration of the exposure. Due to the high heat conduction properties of steel, it is readily possible for normally loaded steel members or vessels to lose their strength to the point of failure within ten minutes or less of a hydrocarbon fire exposure. 

Exposure effects, toxicity, burns, bruises, biological effects Flammability, reactivity, explosiveness, corrosivity and fire-promoting properties of chemicals... 

CHEMICAL PROPERTIES normally stable, even under fire exposure conditions hazardous polymerization will not occur does not react with water when oxidation and peroxidation occurs in mineral oils it continues almost at a logarithmic rate no incompatibilities and reactivities reported FP (193°C, 380°F (open cup), 135°C, 275°F (closed cup)) LFL/UFL (unknown) AT (260-371°C, 500-700°F). 

The proposed modeling scheme for material mechanical properties can easily be incorporated into structural theory to predict mechanical responses on the structural level using finite element and finite difference methods. On the basis of the mechanical property models for FRP composites proposed herein, further investigations conducted on the mechanical responses of fuU scale cellular GFRP beam and column elements subjected to mechanical loads and reaHstic fire exposure are reviewed in Ghapter 7. 

It should be noted that the post-fire stiffness was estimated with only the inputs of the initial material properties (the values at room temperature), the thermal and mechanical boundary conditions, and the fire exposure time. This imphes... 

The recently developed models to predict time and temperature-dependent material properties and post-fire properties showed good agreement with the experimental results. On the basis of the proposed models, the post-fire stiffness of FRP composite materials can be predicted before fire exposure. As a result, the post-fire behavior can be predesigned based on the functionality and importance of the stmcture. 

As mentioned above, the thermal stability of polymers is closely tied to the manifestation of fire-protection properties. Many factors causing the stability of the materials to the exposure of high temperatures are characteristic for the fire-resistant polymers too. 

A major use of Kevlar is in rigid and soft body armour protective applications. Kevlar fabric is bullet and fragment resistant, lightweight, flexible and comfortable, has excellent thermal properties, is resistant to cuts and chemicals and is flame resistant and self-extinguishing. The uses include bulletproof vests, chainsaw leg protection and military uses for helmets and armoured vehicles, cargo containers, armour shields and cockpit doors. Kevlar and Nomex fabrics are used in the construction of flame-resistant protective clothing used in petroleum and petrochemical operations, by utility workers, NASA astronauts, racing drivers and their crews, the military and any industry where there is a chance of flash fire exposure or electric arc flash or blast. 

---