The death of a person caused by a fire, in addition to the factors of death, sudden death and burning caused by the external force, is mostly due to the smoke, temperature and other factors that caused the death of the person.

Most of the combustion in the fire is organic matter, and the mixture of combustion products and air in the fire site forms smoke and smoke. Its main components are carbon monoxide, carbon dioxide, water vapor, sulfur dioxide and phosphorus pentoxide. However, in the incomplete combustion state, a large amount of intermediate products will be generated , especially when some of the macromolecular synthetic materials reach different temperatures in the fire field, different intermediate substances will be generated. Commonly, hydrogen sulfide, ammonia, and cyanide are generated. Hydrogen, benzene, formaldehyde, hydrogen chloride, chlorine and phosgene and other substances.

Modern polymer synthetic materials mainly include chemical textiles, such as clothes, curtains, carpets, etc., as well as flammable and flammable materials that are widely used in modern decoration, such as various types of sheet materials, plastics, chemical fiber, and other polymer materials. These materials will not only encourage the fire to increase the temperature of the fire in the fire, but also prolong the burning time, and decompose a large number of toxic gases such as carbon monoxide and nitrogen oxides, which can cause people to poison and die in a very short time. A large amount of data shows that toxic smoke is the biggest killer of death caused by fire.

The following describes the cause of death in fire:

One, chemical suffocation died.

Inhalation of carbon monoxide and hydrogen sulfide causes chemical asphyxiation death. Carbon monoxide and hemoglobin affinity for oxygen than the large 210-fold, when the air content of 0.1% carbon monoxide, 50% is formed in the blood carboxyhemoglobin and 50% oxyhemoglobin, causing severe CO poisoning, wherein when the carbon monoxide concentration reaches 1.28 %, people die immediately in such an environment for 3 minutes. The oxygen content in the smoke within a few minutes of the fire scene will be much lower than 21%, and the carbon monoxide content will be much higher than 0.1%, which can cause people to die in a short time; it has a very strong cytotoxic effect and enters the body will rapidly bind to cytochrome oxidase to generate high iron cyanide cytochrome oxidase, cytochrome loss of the ability to transfer electrons, the respiratory chain disruptions, cell death, resulting in the death of people short.

Second, simply suffocate death.

The process of gas exchange between the human body and the outside world is inhalation of oxygen and exhalation of carbon dioxide, which is achieved through the lungs. This includes lung ventilation and lung ventilation. Insufficient lung ventilation will reduce the oxygen content of the lungs and increase the carbon dioxide content. When the lungs are insufficiency, the oxygen content in the blood will decrease, and the carbon dioxide content will increase, causing suffocation and death. When a fire occurs , the combustion process of combustibles consumes a lot of oxygen, and its oxygen content will decrease. When the oxygen content in the air is less than 6% , people will suffocate due to lack of oxygen in a short time. Therefore, in the absence of oxygen, the brain first affected, resulting in dysfunction, even if the oxygen content of between 6% to 14%, though not from lack of oxygen and died a short time, but also because of decreased activity or loss The ability to move can't escape the fire , and it is eventually burned to death (in a highly confined space such as a basement, oxygen content can be as low as 3% ).

Third, smoke and suffocation died.

When smoke containing a large amount of smoke is inhaled by people in the fire site , it will adhere to the nasal cavity, oral cavity and trachea , enter the bronchi, bronchioles and small bronchi , and even spread into the lungs to adhere to the alveoli , so the deceased in the fire A large amount of smoke and dust will be found on the nasal cavity, oral cavity, upper surface of the tongue, and trachea . Sometimes it will be a thick layer . In severe cases it will block the nasal cavity and trachea , resulting in insufficient ventilation of the lungs and eventually suffocating death.

Fourth, thermal damage suffocated to death.

After a fire occurs , the temperature of the flue gas diffused from the fire can be as high as several hundred degrees, the temperature of the flame can reach more than 1000 °C , and the flame temperature of ethers and some combustible gases can reach 2000 °C or more. When a person inhales high-temperature smoke , smoke flows through the nasal cavity, throat, and trachea into the lungs and burns the nose, throat, trachea, and even the lungs , causing blistering, edema, or congestion in the mucosal tissue, causing the wounded to suffocate. death. In addition, flue gas heat damage caused by fire contains water vapor is more serious, so those injured in the course of treatment should be promptly performed a tracheotomy to maintain airway patency.

Fifth, mucous membrane irritation and death.

Some products of combustion can have a strong irritant effect on the human throat, trachea, bronchus and lungs , making it impossible for people to breathe normally and suffocate.

Anesthesia leads to death.

Some gases ( such as nitrous oxide, ethers ) do not cause suffocation by inhalation, but they are used by the anesthesia of the human body. People cannot escape the scene and are killed by fire or other factors due to the decreased ability of anesthetic consciousness.

Seven, high temperatures lead to death.

The temperature of fire smoke can be as high as several hundred degrees, and the temperature of smoke can be as high as 1000 degrees in a highly enclosed space ( such as a basement ) . People's patience with high-temperature flue gas is limited , can endure at 65 °C for a short period of time; at 120 °C , it can produce irreparable damage within 15 minutes; at 140 °C , it can tolerate 5 minutes; 170 °C can be tolerated 1 minute; the temperature can no longer tolerate for more than 1 minute, there will be a strong sense of pain, heart rate, muscle spasm, shock, can not be escaped from the fire and burned to death.

Therefore, the fire scene is very difficult, and only the knowledge and skills of mastering escape can lead to danger.

Related reading: Fire escapes ten points in mind