Study on combustion characteristics of overloaded wire insulation at the early stage of fire in weak buoyancy environment

It is studied experimentally that effects of pressure and oxygen volume fraction on smoke emission and temperature variation of overloaded wire insulation at the early stage of fire under weakly buoyant environments. Results indicate that the process of smoke emission consisted of two stages in typical weakly buoyant environment(10^-2g), which are insulation unbroken stage and insulation broken stage. With the increase of oxygen volume fraction, total reaction time decreases almost linearly, but the growth of peak temperature accelerates. Under low pressure environment(below 10kPa), the value of pressure is the main factor to affect the smoke emission process of overloaded wire insulation. With the reduce of ambient pressure, the insulation broke faster and its temperature rise higher, but the amount of smoke emitted lessen accordingly.