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Spontaneous combustion can occur, when -

Spontaneous combustion can occur, when - Correct Answer oil soaked rags are left clumped together or left without soaking in water

Explanation:

Spontaneous ignition

  • A chemical reaction in which there is a slow generation of heat from oxidation of fuel and under certain conditions, heat generation is accelerated until the ignition temperature of the fuel is reached is called Spontaneous ignition.
  • Rags and towels soaked with oils, including cooking oils, hot laundry left in piles, large compost, mulch, manure, and leaf piles, and moist baled hay can spontaneously combust in the right conditions. 
  • The chemical reactions generating heat spontaneously imply the risk of ignition and burning as “internal ignition sources”.

Flash Point: 

  • The flashpoint of a volatile material is the lowest temperature at which vapors of the material will ignite when given an ignition source.

Fire Point: 

  • The fire point of a fuel is the lowest temperature at which the vapor of the fuel will continue to burn for at least 5 seconds after ignition by an open flame. The main difference between fire and flashpoint is that at the flashpoint a substance will ignite briefly, but vapor might not be produced at a rate to sustain the fire. 
  • For every fuel, the flashpoint temperature appears before the fire point temperature.
  • Flashpoint and fire points are related to high-temperature characteristics of the fuel and tell the behavior of fuel at high temperatures.

Cloud Point: 

  • Cloud point is the temperature at which oil becomes cloudy or hazy when oil is cooled at a specified rate.

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