BLEVE

BLEVE

Meaning

Boiling Liquid Expanding Vapor Explosion (BLEVE) is an explosion that occurs when a contained liquid is heated to a temperature at which its vapor pressure exceeds the strength of the container, causing the container to rupture and the liquid to vaporize explosively.

Characteristic of a BLEVE

The main characteristic of a BLEVE is the sudden and explosive expansion of a large volume of vapor from a pressurized liquid. This expansion creates a shock wave that can cause significant damage to surrounding structures and infrastructure. The vapor cloud that is created by the BLEVE can also be ignited, resulting in a fireball.

Causes of a BLEVE

BLEVEs are typically caused by a fire that engulfs a vessel containing a pressurized liquid. The fire heats the liquid, causing its vapor pressure to increase. If the vapor pressure exceeds the strength of the container, the container will rupture and a BLEVE will occur.

Consequences of a BLEVE

BLEVEs can have devastating consequences. The shock wave from a BLEVE can cause structural damage to buildings, bridges, and other structures. The fireball that is created by a BLEVE can also cause severe burns and injuries to people who are in the vicinity of the explosion.

How to Prevent a BLEVE

There are a number of steps that can be taken to prevent a BLEVE from occurring. These steps include:

• Properly storing and handling flammable liquids. Flammable liquids should be stored in approved containers and in a cool, well-ventilated area.
• Using pressure relief valves on vessels containing flammable liquids. Pressure relief valves allow excess pressure to escape from a vessel, preventing it from rupturing.
• Installing fire suppression systems in areas where flammable liquids are stored or used. Fire suppression systems can help to extinguish a fire before it can cause a BLEVE.

How to Respond to a BLEVE

If you are in the vicinity of a BLEVE, it is important to take the following steps:

• Evacuate the area immediately. Move to a safe location that is at least 1,000 feet away from the explosion.
• Call 911. Report the explosion to the fire department and provide them with as much information as possible.
• Stay away from the area until the fire department has declared it safe.

FLASHOVER

This occurs in a fire when there is a sudden increase in the rate of combustion. This is due to the sudden combustion of all the surfaces or materials that up to that moment had not been involved in the fire. It is as if the fire had suddenly gained strength and was consuming everything in its path.

FREE-RADICAL CHAIN REACTION

A sequence of reactions in which a product or intermediate reacts with a reactant to produce another product or intermediate and a free radical, which then reacts with another reactant to continue the chain.

R= X / Y or also it can be R = X+- Y

Where X is the global value of the score of the generating or aggravating factors.

Y is the global value of the reducing and protective factors.

R is the resulting value of the risk of fire, obtained after carrying out the corresponding operations.

MESERI

The purpose of the Meseri method is to mathematically evaluate, with homogeneous criteria, the risk of fire in industrial buildings and large buildings.

R = P / M

B = The exposure to the risk of fire

P = is defined as the product of all the hazard factors

M = divided by the product of all the protection factors

INTRINSIC

The present technical note has two objectives:

1st. To disseminate the system for evaluating the intrinsic risk of fire of industries and warehouses contained in the Standard.

2nd. To complement, qualify or clarify some aspects of it for its application.

The weighted fire load Qp of an industry or storage contained in the Standard will be calculated considering all the combustible materials that are part of the construction, as well as those that are foreseen as normally usable in the manufacturing processes and all the combustible materials that can be stored.

Qp = The calculation of the weighted fire load

Pi: weight in kg of each of the different combustible materials.

Hi: calorific value of each of the different materials in Mcal/kg.

Ci: dimensionless coefficient that reflects the dangerousness of the products according to the following values:

A: constructed area of the premises, considered in m2

Ra: dimensionless coefficient that weights the risk of inherent activation of the industrial activity, in the following way:

GUSTAV PURT

Any measure of protection against fires has as its objective to reduce the danger of fires in a given object, and for this purpose two formulas are found:

Calculation of the risk of the building GR

The total or partial destruction of the building is considered depending on the intensity of the fire, the duration of the fire, the resistance of the construction, among others.

GR = (Qm.C + Qi).B.L / W.Ri

Qm = coefficient of calorific load

C = coefficient of combustibility

QI = calorific load of the building

B = coefficient corresponding to the situation and importance of the fire sector

L = coefficient of time necessary to start the extinction

W = coefficient of resistance to fire of the supporting structure of the construction

Ri = coefficient of risk reduction

Calculation of the risk of the content IR

Damage to people and materials is given

IR = H. D. F

H = coefficient of damage to people

D = coefficient of danger to property

F = coefficient of influence of smoke

EVACUATION METHODS

EVACUATION SIGNALS

It is important to have a general communication system, with which the evacuation signal can be transmitted to the entire building. The different means used to give the alarm signal can be: a siren, a recorded message in the public address system. Whatever the alarm signal, it is important that it is perfectly identified by everyone.

AUXILIARY SIGNALS: They help and provide information about the auxiliary equipment.

DANGER AND WARNING SIGNS: They warn of possible dangers that may entail the use of any material or tool.

PROHIBITION SIGNS: preventing certain activities that endanger one's own health or that of other workers. In short, they are signs that Prohibit.

EMERGENCY LIGHTING: ensures, in the event of a failure in the normal power supply, the lighting in the premises and accesses to the exits, for an eventual evacuation of the public or to illuminate other points that are indicated.

EXTINGUISHER

It is any device intended to extinguish fires.

PORTABLE EXTINGUISHER: It can be transported by hand or on wheels by a single person.

DRY CHEMICAL EXTINGUISHER (external cartridge)

CHARACTERISTICS OF AN EXTINGUISHER: Manometer, hose, container, base, siphon tube, extinguishing agent, pressurizing agent, transport handle, activation lever, valve, nozzle.

MAN IN THE BUILDING INTERPRET: The people who are on the first levels leave the building and can be saved, but the people who are on the last levels are in unsustainable conditions and can no longer survive due to the amount of people who leave at speed.