What do you mean by flammability or explosive limit?
Flammability limits or explosive range: The entire range of concentrations of a mixture of flammable vapor or gas in air (expressed as volume percent) over which a flash will occur or a flame will travel if the mixture is ignited.
What do flammability limits refer to?
Flammable limits apply generally to vapors and are defined as the concentration range in which a flammable substance can produce a fire or explosion when an ignition source (such as a spark or open flame) is present. The concentration is generally expressed as percent fuel by volume.
What is explosion limit in chemical kinetics?
combustion. …or three pressures, called the explosion limits, may correspond to one temperature. The mechanism of the reaction determines the explosion limits: the reaction can proceed only when the steps in the sequence of reactions occur faster than the terminal steps.
What is the meaning upper explosive limit?
The highest concentration of a gas or vapor (percentage by volume in air) above which a flame will not spread in the presence of an ignition source (arc, flame, or heat). Concentrations higher than UEL are “too rich” to burn. Also called upper flammable limit (UFL).
What is the difference between flammability and explosion limits?
Flammability limits also depend on the type of atmosphere (for example, limits are much wider in oxygen than in air), the pressure, and the temperature of atmosphere. Explosion limits usually refer to the range of pressure and temperature for which an explosive reaction at a fixed composition mixture is possible.
What is meant by first explosion limit?
A criterion for the isothermal first explosion limit☆ Explosions are termed here overdamped, damped, and underdamped corresponding to essentially no reaction, some reaction, and complete reaction, respectively. A damping factor is introduced and verified computationally in its predictive meaning.
What is LEL & UEL?
Lower explosive limit (LEL): the lowest concentration of gas or vapour which will burn or explode if ignited. Upper explosive limit (UEL): the highest concentration of gas or vapour which will burn or explode if ignited. From the LEL to the UEL, the mixture is explosive. Below the LEL, the mixture is too lean to burn.
What is LEL gas level?
The Lower Explosive Limit (LEL) is the lowest concentration of a gas or vapour that will burn in air. As well as the LEL, below which the gas/air mixture is too lean to burn, there is also an Upper Explosive Limit (UEL), above which the mixture is too rich.
What do you mean by upper explosive limits?
Upper explosive limits (UEL) are the maximum concentrations of a gas or vapor in the atmosphere that is able to generate a flash or a fire in the presence of an ignition source.
What kind of limits are needed for an explosion?
Exposure limits are only required for materials that may end up in air to cause an explosion. Such materials may include gas, vapor and dusts (i.e, metal powder). Engineering control measures need to be taken to reduce the concentration of such materials in air to avoid potential explosion.
How is LEL related to lower explosive limit?
In g as detection systems the amount of gas present is specified as a percentage (%) of LEL. Zero percent Lower Explosive Limit (0% LEL) denotes a combustible gas-free atmosphere. One hundred percent lower explosive limit (100% LEL) denotes an atmosphere in which gas is at its lower flammable limit.
What is the maximum concentration of a gas that can burn in air?
Whereas, the maximum concentration of a gas or vapor that will allow it to burn in air is the Upper Explosive Limit (UEL). Every combustible gas or vapor has a specific range of fuel to oxygen mixture during which it will ignite.