Firefighters: What is the last barrier between you and cancer?

There is no doubt that there are many poisonous and harmful carcinogens on the fire. The vast majority of harmful substances enter the body through the respiratory system and are therefore essential for fire protection for firefighters.

At present, the equipment that the fire brigade is equipped with to completely avoid inhalation of harmful substances is only empty calls. I hereby emphasize that the fire field is empty and the best way is to call back. Obviously, this is not realistic. Some small fires, such as garbage, haystacks, etc., as well as the stage of clearing the fire scene and the late phase of fire adjustment, are generally not empty calls. To reduce the inhalation of harmful substances, it is recommended that everyone Wear other respiratory protection products.

However, there are many kinds of respiratory protection products and brands are miscellaneous, which one can play a protective role. This article will introduce the system.

The so-called "know-to-know-the-to-know-know-to-know-to-know-to-know-what-you-know-to-know-the-were-you-to-know-the-first-we-know-fire-fume.

Fire hazard is mainly caused by three factors: heat, smoke, and oxygen deficiency. For most fires, the proportion of damage caused by smoke is the largest, and more than 85% of deaths are due to inhalation of smoke and toxic gases and coma and death.

Another article of the public number has just been, we made two conclusions about the fire smoke, detailed introduction to the composition and harm of fire smoke, I only briefly introduce here.

Knowledge point one: smoke

The composition and amount of fire smoke depend on the chemical composition of the combustibles and the combustion reaction conditions. On the whole, fire smoke consists of three parts: gas generated by pyrolysis and combustion, suspended particulates, and remaining air.

In modern homes, combustibles are mostly organic and there are a few metals. The chemical composition of organic matter is mainly carbon ( C ) hydrogen ( H ) oxygen ( O ) nitrogen ( N ), in addition to sulfur ( S ) phosphorus ( P ) and halogen ( F , Cl , Br , I ) and other elements. The main products of combustion include carbon monoxide, carbon dioxide, water vapor, sulfur dioxide, and phosphorus pentoxide. In the incomplete combustion state, a large amount of intermediate products are generated.

The aerosol particles generated in the fire smoke are called smoke particles, and usually include free carbon, tar particles, condensed droplets of high-boiling substances, and the like.

The hazards of fire smoke mainly include oxygen deficiency, poisoning, light reduction, dust and high temperature.

Hypoxia

The combustion consumes a lot of oxygen, and the gas in the smoke is not toxic, but even non-toxic gases can hinder people's normal breathing and reduce the concentration of oxygen in the air.

Poisoning

Modern buildings include a large number of macromolecular synthetic materials. When the temperature of the fire reaches a different level, a variety of toxic and harmful intermediate products are generated. The damage of toxic gases to the human body is divided into acute poisoning and chronic poisoning. The main causes of acute damage are hydrogen sulfide, ammonia, formaldehyde, hydrogen cyanide, chlorine, hydrogen chloride, phosgene, etc., resulting in chronic damage of benzene series, polycyclic aromatic hydrocarbons, dioxin and other carcinogens.

Light reduction

Smoke in the fire has a complete shielding effect on visible light, so that the visibility of the fire field is greatly reduced. Some gases such as hydrogen chloride, ammonia, chlorine and sulfur dioxide have a strong stimulatory effect on the eyes, making it impossible for people to blink and seriously affecting escape.

Dust

According to the particle size, the dust can be divided into dust and dust. The particle size of the dust drop is greater than 10 micrometers, and it can naturally fall by its own weight . The particle size of the fly dust is less than 10 micrometers, and the granular body is light and can float in the atmosphere for a long time. Particles larger than 5 μm can be blocked by nasal hair and mucus in the respiratory tract; particles smaller than 0.5 μm generally adhere to the surface of the upper respiratory tract and discharge with the sputum; particles with a diameter of 0.5-5 μm are the most harmful to the human body, and it will not only Deposited in the lungs, you can also directly into the blood to reach all parts of the body.

Smoke particles are also attached with various harmful substances on the surface. Once they enter the human body, they will cause various respiratory diseases. Particles with different particle sizes enter the lungs as they enter the lungs, and are trapped in different parts of the respiratory tract by collisions, diffusions, and sediments. Floating particles larger than 5 μm are mostly trapped in the upper respiratory tract, and less than 5 μm in size remains in the bronchioles. And alveoli. The deposition rate of 0.01 to 1 micron airborne dust was highest in the alveoli.

high temperature

In the fire, the temperature of fire smoke can sometimes reach several hundred degrees, far beyond the limit that the human body can withstand. Inhalation of high-temperature flue gas can cause burning of the respiratory system. In severe cases, it can lead to suffocation. High-temperature fire smoke should also include water to prevent vaporization of vapors in the event of a fire. Because water carries a large amount of heat with a large heat capacity, it can easily cause burns.

In all five aspects, only empty calls can protect us from all the hazards of fire smoke. Once again, we must say that we must wear empty calls when entering the fire. It is best to wear empty calls throughout.

Not all occasions are suitable for empty calls, such as clearing fires, fire investigations, some outdoor garbage dumps, weeds and other small fires, we can also choose other respiratory protection products, mainly dust and chronic poison damage.

This article referring to the national standard GB2626 - 2006 "Respiratory protective equipment - self-absorption filter anti-particulate respirators" and GB2890 - 2009 "Respiratory protection - self-absorption filter respirators," as we specifically describes the types of respiratory protective equipment, scope, help Everyone chooses the right product.

Knowledge point two: mask classification

GB2626 - 2006 "Respiratory protective equipment - self-absorbing filter type particulate respirator" according to the mask structure is divided into disposable mask, replaceable half mask and full-face mask three categories, GB2890 - 2009 "Respiratory protection - self-absorption filter antivirus The mask is divided into a full face mask and a half face mask according to the structure. According to the mask and the filter connection can be divided into catheter type and direct type.

The half mask and full face mask of the dust mask and gas mask are structurally universal and only need to replace the filter element. Filter elements include canisters, filter cartridges, filter cartridges, filter cotton, and filter media.

Knowledge Point 3: Protection Standards

Smoke and toxic gases exist in the fire field at the same time. The filter cotton and the filter box can be used in combination to achieve the effect of dust removal and poisoning.

Disposable masks are actually masks that we usually wear. There is a recommended standard GBT 32610-2016 “Protective masks for daily protection”, but this is a national standard for civil use. This article does not refer to it.

GB2626 - 2006 "Respiratory protective equipment - Self-priming filter particulate respirator" filter elements are divided into KN and KP categories, KN category is only suitable for filtering non-oil particles, KP category is suitable for filtering oily and non-oily particulate matter. According to the level of filtration efficiency, the level of filter elements is graded according to Table 1 .

The 90 , 95 , and 100 here represent the filtering efficiency. We usually say that the N95 mask is actually KN95 , which means that the efficiency of non-oil particles in mask filtering is above 95% .

The standard also provides regulations on leakage, respiratory resistance, airtightness, vision, headbands, etc. Interested friends can understand for themselves, and we need to know so much about choosing protective equipment.

The choice of gas mask requires a certain understanding of the filter element. GB2890 - 2009 "Respiratory protection - self-absorption filter gas mask" stipulates that the filter type is divided into ordinary filter, multi-function filter, integrated filter, special filter, They are represented by the letters P , D , Z , and T , respectively .

Common filters include:

Type A : used to protect organic gases or steam;

Type B : used to protect inorganic gases or steam;

Type E : used to protect sulfur dioxide and other acid gases or steam;

Type K : organic derivatives used to protect ammonia and ammonia;

CO type: used to protect carbon monoxide gas;

Hg type: used to protect mercury vapor;

H2S type: used to protect hydrogen sulfide gas.

The multifunctional filter is capable of protecting the above two or more types of filters. The integrated filter is an ordinary filter or multi-function filter with a filter function. Special filter elements are used to protect filters that are not specified in this standard and are specified by the manufacturer as gases or vapors.

The grade of the filter is divided into different protection times:

Level 1 : Protection time for general ability;

Level 2 : Protection time for medium capacity;

Level 3 : Protection time for higher ability;

Level 4 : Special protection time.

The filter performance of the integrated filter is divided into the following:

P1 : General capacity filtering efficiency;

P2 : Medium capacity filtration efficiency;

P3 : high-capacity filter efficiency;

The marking of the filter consists of the filter type, filter grade, and filter performance level.

E.g:

Grade 1 A common filter is marked as: PA-1 ;

The grade 2 multi-function filter with protective A and B types of gas is marked as: DA/B-2 .

Knowledge point four: how to choose

After having a general understanding of fire smoke and respiratory protection products, the following is the key point. Do not look at the front as far as the following is enough, how to choose the right respiratory protection products for us? To comprehensively consider the cost-effectiveness, comfort, use of occasions and other aspects, the following are my personal recommendations, for reference only.

Once again, there is no filter element that can filter out all the toxic and harmful substances in the fire. For their own health, it is recommended that everyone talk back.

First eliminate the full face mask, it is really not necessary, large size is not convenient to carry, generally we choose to wear a mask when the basic is also no stimulating effect on the eyes. After all, since they have already worn a full-face mask, are they still backsliding ?

The foregoing mentioned that we wear respiratory protective equipment mainly for dust and chronic toxic damage, and carcinogens such as benzene series, polycyclic aromatic hydrocarbons, and dioxins are mostly adsorbed on the smoke in the fire. Therefore, it is recommended to use a disposable dust mask or half mask in general . It is recommended to use KP95 or above.

With the disposable mask to facilitate the carrying, I perennial in the clothes on the clothes jacket pocket two, and the low price, as long as it is a regular channel to buy are very reliable, here is not recommended brand. As for whether or not you need to choose a mask with an exhalation valve, it depends on personal preference. My breath is a smooth, breath-taking valve.

Choosing a dustproof half mask is recommended for use with a filter cartridge. Although the filter can be used for a long time, it is heavier and can affect a certain field of vision. Filter elements are multi-functional, including the A/B type is the best, but the multifunctional price will be twice that of the ordinary filter. If you use ordinary filter, type A can be used, mainly for the protection of benzene, formaldehyde, chlorine, acetone, alcohols, aniline, carbon dioxide, carbon tetrachloride, chloroform, methyl bromide, methyl chloride, nitro Organic gases such as alkanes and chloropicrins are more likely to cause chronic damage to organic gases than B -type protective inorganic gases. Recommend a domestic brand Haigu, all products, have official website, you can view.

Since it is the introduction of respiratory protection products, it is certainly not possible to go around 3M , because it is an American brand, so the production according to the NIOSH (Institute of Occupational Safety and Health) standards, the classification of filter elements and domestic differences.

Although the price of 3M products is not cheap, but the shape of the gas mask is really cool, like to install X is not bad money friends can buy.

statement

I am also a non-professional mask production technician. The above is only for personal advice. It is for reference only, and there are mistakes and mistakes. Please also point out enthusiastically.

This article is reproduced from WeChat public number: Orange Rescue.