Introduction
Why fire occurs ? Why Explosion took places? What is the such phenomenon are there before fire and explosion ? can we prevent fire and explosion before took places ?
Above are general question arises in everybody’s mind after an incident or accident as fire and explosion occurs . no doubt , we can stop or prevent all accident related to fire and explosion. because there are something happen before accident happens. Some chemical phenomenon or reactions are exist. It means every accident have a its own reason or cause. when we are talking about Fire and explosion, the same are follow the natural process of fire. As research , There are three element required to fire occurs. The main three elements are :- Fuel , Heat and oxygen. Whenever these three elements mix in proper ratio as per kinetics, fire occurs. In today’s era , Most of product are manufactured with chemical. These chemical are hazardous and dangerous beacuse of its nature and ingredients. Most of explaosion and fire occurs in chemical, petrochemical, oil and gas industries. because this industrial units handling so many chemcials as soild, liquid and gas form chemical. it is very crucial to prevent these accidents.
in fire triangle , The Most important factor is fuel . Fuel is a leading element of fire and it could be in Gas , liquid or soild form. As per fire prevention princiapal , if we elimiante or remove or redcue the fual , fire can not be sustained for last. this is a known as starvation principal of fire extinction. Most dangerous form of fuel is gaseous form. Most of hazardous and dangerous cheicmal which are more susctible or sensitive to fire are in gaseuos form.
LEL and UEL are both known as explosive limit.
What does it means to LEL ?
LEL means Lower Explosive limit . each chemicals have its own LEL. As we know , fire or explosion are took place when three element of fire are present in a stoichiometric ratio. LEL show the presence of fual Level in fire prone mixture. LEL means the Lowest concentration of gas as fuel in a fire prone gas mixture voulume by volume. In other word we can say that it is lowest quantity of fuel below this, fire can not sustain for last. it is represent in % LEL. for Example , Ethylene Oxide , a gaseous chemcial have a LEL is 2.6 % by Volume. it means if a fire prone mixture have a Ethylene oxide concentration of total volume is 2.6 % and other element are also present in stoichiometric ratio , it could catch fire and explode. Below this limit , the mixture could be so lean because of short of fuel , it could not catch fire.
What does it means to UEL ?
UEL means , Upper explosive Limit , it means the maximum fuel concentration above which if fuel present in mixture , it could not cathc fire. becaue above this limit, the mixture could be so rich with fuel , it could not catch fire. because other element are not in as per stoichiometric ratio.
What does it means the Explosive range ?
The differecne between LEL and UEL is known as Explosive range. Suppose that “A” named chemcial have a LEL is 3.5 % v/v and UEL is 45% v/v , so the 3.5 to 45 is a explosive range of that chemical. it means , this chemcial mixture could catch fire if mixture conatin the “A” chemcial in its mixture with quantity of 3.5 to 45 % v/v voulune of mixture.