Fire damage can range from isolated damage to total structural destruction. Isolated damage areas will require evaluation for repair and replacement solutions. Unique materials such as steel, concrete, and wood respond differently to heat events and must be evaluated individually. Wood will burn and char. Wood degrades when exposed to elevated temperature, temperatures greater than 150 degrees F, for prolonged periods of time. Wood exposed to temperatures, less than 212 degrees F, for a short duration of time, generally maintain their strength and mechanical properties . Wood metal plate connected trusses require additional considerations because of how heat effects the metal and how the metal transmits heat into the wood. In addition, there may also possible chemical damage from corrosive effects of the fire. Other elements, such as fasteners and support brackets, can also be vulnerable to long-term acid attack from fire residue. Structural steel and other metals are extremely vulnerable to the heat produced by fire. Steel can begin losing strength at 400 degrees F, and it can lose 50% strength at 1050 degrees F. Most structure fires can average at least 1900 degrees F. Structural reinforced concrete is also susceptible to the heat produced in structure fires. When temperatures are below 200 degrees F, the concrete experiences little to no reduction in strength. Concrete that is exposed to heat between 200 and 300 degrees will experience expansion of the aggregate and shrinking of the cement matrix. This will result in micro cracking, which introduces oxygen and water. Air and water infiltration will result in a reduction in serviceability and structure life. Temperatures above 750 degrees F produce deterioration of the aggregate and a decomposition of the cement matrix, resulting in a deterioration of structural strength.