Chapter I Dangerous Characteristics, Classification, Storage and Transportation Requirements of Flammable and Explosive Chemicals

All chemicals with explosive, flammable, toxic, corrosive, radioactive and other dangerous properties can cause combustion and explosion under certain conditions in the process of transportation, loading and unloading, production, use, storage and storage, resulting in accidents such as personal injury and property loss, which are collectively referred to as chemical dangerous goods. At present, there are about 2200 common and widely used species.

China State Bureau of Technical Supervision issued the List of Dangerous Goods (GB 6944-86) and the List of Dangerous Goods (GB12268-90-90) in 1986 and 1990 respectively, which classified dangerous goods into nine categories and specified their names and numbers.

1 class: explosives;

The second category: compressed gas and liquefied gas;

Class 3: flammable liquids;

Class 4: flammable solids, spontaneous combustion articles and flammable materials when wet;

Category 5: oxidants and organic peroxides;

Category 6: toxic and infectious substances;

Class 7: radioactive substances;

Class 8: corrosive products;

Category IX: Miscellaneous.

Because a chemical hazardous substance often has a variety of dangers, in the specific classification process, we should master the principle of "rearrangement", that is, according to the main dangers of each chemical substance's characteristics, determine which category it belongs to.

For example, the toxic and corrosive products in the above nine categories seem to have little to do with fire prevention from the classification name, but they are not. First of all, most of these two kinds of chemicals are organic compounds, and most of the organic compounds based on carbon and hydrogen are flammable, which is one of the characteristics of organic compounds. Most organic toxic substances are not only toxic, but also flammable, and some have low flash points (such as allyl cyanide, allyl sulfur, ethyl pyridine, etc.). ), but it is classified as a toxic substance because of its outstanding toxicity; There are also highly toxic organic compounds (such as acrylonitrile), which are classified as flammable liquids because of their high combustion risk; Many organic corrosive products are corrosive and flammable at the same time, and are classified as corrosive products because of their obvious corrosiveness. Look at the inorganic compounds in these two categories. Although some are nonflammable, they are also oxidizing (such as nitric acid, perchloric acid, hydrogen peroxide, bleaching powder, etc.). ), can promote the burning and even explosion of flammable and combustible substances. Or release flammable and toxic gases (such as cyanide, etc. ) due to acid decomposition; Or gas (such as metal compound of phosphorus, etc.). ) is highly toxic and can spontaneously ignite when it meets water, which is directly or indirectly related to fire prevention. In addition, some chemicals, such as highly toxic hydrogen cyanide, liquid chlorine, flammable hydrogen, liquid hydrocarbon gas, combustion-supporting compressed air and oxygen, nonflammable low-toxic refrigerant Freon, and even nontoxic carbon dioxide and nitrogen, must be stored in pressure-resistant steel cylinders. Once the cylinder is heated, the pressure in the cylinder will increase, which may cause combustion and explosion. Therefore, regardless of its original characteristics, it will be included in the category of compressed gas and liquefied gas of hazardous chemicals.

The so-called flammable and explosive chemicals refer to the compressed gas, liquefied gas, flammable liquid, flammable solid, flammable materials that spontaneously ignite when wet, oxidants and organic peroxides, and some flammable and explosive chemicals in the National Standard GB12268-90 List of Dangerous Goods.

At present, there are more than 1000 kinds that are common and widely used. The Ministry of Public Security issued the Measures for the Supervision and Management of Fire Safety of Flammable and Explosive Chemicals 1994 (Ministry of Public Security

Flammable and explosive chemicals have great fire risk. Once a disaster occurs, it will often cause great harm, great influence and great loss, and it is very difficult to put out the fire. For example, on August1989 12, the oil tank of Huangdao oil depot in Qingdao, Shandong Province exploded and caught fire. Before and after the fire, it burned for/kloc-0.04 hours, burning 36,000 tons of crude oil and five large oil tanks. The fire caused direct economic losses of 35.4 million yuan, of which 14 fire officers and soldiers died and 56 were injured. Five oil depot workers died and 12 people were injured. At about 4 pm on March 5th, 1998, the valve at the bottom of a 400 cubic meter spherical gas storage tank in the gas storage tank area of the management station of Xi 'an Gas Company in Shaanxi Province burst, resulting in a large amount of liquefied petroleum gas leakage. In the process of organizing relevant personnel to block the carrier, at about 6 pm, the liquefied petroleum gas station suddenly exploded and caught fire, causing 1 1 deaths (including 7 fire officers and soldiers). 3 1 person was injured (9 of them were seriously injured and 3 died in the rescue process), 2 400 m3 spherical tanks in the tank farm were destroyed by explosion, 4 100 m3 horizontal tanks were scrapped and 7 LPG tankers were destroyed. A large number of facts and blood lessons tell us that units and individuals engaged in the production, use, storage, management and transportation of flammable and explosive chemicals must establish the idea of "safety first" and master their characteristics and necessary knowledge of fire prevention and extinguishing.

The first section compressed gas and liquefied gas

Compressed gas and liquefied gas refer to compressed, liquefied or pressure-dissolved gases stored in pressure-resistant containers. The gaseous gas in a steel cylinder is called compressed gas, and the liquid gas is called liquefied gas.

I. Characteristics

1. inflammable and explosive

More than half of the compressed gases and liquefied gases listed in the Catalogue of Fire Safety Supervision and Management of Flammable and Explosive Chemicals are combustible gases. The main dangerous characteristics of combustible gas are inflammable and explosive. Combustible gases within the combustion concentration range will catch fire or explode when they meet the fire source, and some even explode with very little energy. Compared with flammable liquids and solids, flammable gases are easier to burn and burn faster. The gas composed of simple components is more flammable than the gas composed of complex components, with faster combustion speed, higher flame temperature and greater risk of fire and explosion. The explosion limits of hydrogen, carbon monoxide and methane are 4. 1%~74.2%, 12.5%~74% and 5.3%~ 15% respectively. At the same time, because the filling container is a pressure container, it is also prone to physical explosion when heated or radiated on fire.

2. Diffusibility

Compressed gas and liquefied gas are very easy to diffuse because of their large molecular spacing and small interaction force, and can spontaneously fill any container. The diffusivity of gas is affected by specific gravity: gas lighter than air can diffuse infinitely in the air and easily form explosive mixture with air; After diffusion, gases heavier than air often gather on the ground, ditches, tunnels, dead corners of factories and so on. , and lasts for a long time, burning or exploding in case of fire. Mastering the specific gravity and diffusivity of gas is of practical significance for guiding fire supervision and inspection, evaluating fire risk, determining fire prevention distance and selecting vent position.

3. Shrinkage and expansibility

Compressed gas and liquefied gas expand with heat and contract with cold much more than liquid and solid, and their volumes expand and contract with the rise and fall of temperature. Therefore, in the process of storage, transportation and use, containers (cylinders) should pay attention to fire prevention, sun protection and heat insulation. When filling gas into containers (steel cylinders), attention should be paid to the limit temperature and pressure, and the filling quantity should be strictly controlled to prevent accidents caused by overload, overtemperature and overpressure.

4. Electrostatic characteristics

When compressed gas and liquefied gas are ejected from nozzles or damaged places at high speed, static electricity will be generated due to strong friction. Electrification is also one of the parameters to evaluate the fire risk of compressed gas and liquefied gas. Mastering its electrification situation is helpful to guide and check whether the preventive measures such as equipment grounding and flow control are implemented in actual fire supervision and inspection.

5. Corrosion toxicity

Mainly some gases containing hydrogen and sulfur have corrosive effects. Such as hydrogen, ammonia, hydrogen sulfide, etc. , it will corrode the equipment, and in severe cases it will lead to cracks and air leakage. For such gas containers, certain anti-corrosion measures should be taken and their compressive strength should be tested regularly, just in case. Compressed gas and liquefied gas, except oxygen and compressed air, are mostly toxic.

Step 6 suffocate

Both compressed gas and liquefied gas have certain asphyxiation (except oxygen and compressed air). Flammability, explosiveness and toxicity are easy to attract attention, while asphyxiation is often ignored, especially those non-flammable and non-toxic gases, such as carbon dioxide, nitrogen, helium, argon and other inert gases, which will suffocate people once leaked.

7. Oxidation

There are two kinds of oxidizability of compressed gas and liquefied gas: one is clearly classified as combustion-supporting gas, such as oxygen, compressed air and nitrous oxide; One kind is toxic gas, which is nonflammable in itself, but highly oxidizing, and can burn or explode when mixed with combustible gas, such as chlorine mixed with acetylene, chlorine mixed with hydrogen can explode when exposed to light, fluorine gas can explode when exposed to hydrogen, grease can spontaneously ignite when exposed to oxygen, and iron can also burn in oxygen and chlorine. Therefore, the oxidizability of gases, especially chlorine and fluorine, can not be ignored in fire supervision, and they are classified as toxic gases. In addition to their toxicity, attention should also be paid to their oxidation, and they should be separated from other combustible gases when stored, transported and used.

Second, the fire precautions

1. Overfilling is strictly prohibited to prevent cylinders from being heated.

2. Compressed gas and liquefied gas are not allowed to leak. The reason is not only highly toxic and flammable, but also because some gases will react with each other and cause explosions. Therefore, cylinders with conflicting contents should be stored in different warehouses. For example, hydrogen bottles and liquid chlorine bottles, hydrogen bottles and oxygen bottles, liquid chlorine bottles and liquid ammonia bottles are not allowed to be mixed in one room. Combustible gas shall not be stored with other kinds of dangerous chemicals. In addition, the gas cylinders should be placed upright and tidy, and it is best to enclose and fix them with a frame or fence, and leave a passage.

3. Combustible substances such as grease are easily ignited or even exploded under the impact of high-pressure pure oxygen. Therefore, it is forbidden to contact oxygen cylinders with grease. If the cylinder is contaminated with grease, it should be wiped clean with carbon tetrachloride immediately.

4. The warehouse should be cool and ventilated, away from heat sources and kindling, to prevent sun exposure, and heating is strictly prohibited. Explosion-proof lighting should be used for warehouse lighting. Flammable materials shall not be piled up around the warehouse.

5. Pay attention to the packaging shape when the cylinders are put into storage for acceptance, and there is no obvious trauma; Complete accessories; Closed tightly, no air leakage; It is not allowed to extend the service beyond the service period.

6. When loading and unloading, be sure to handle it with care. It is forbidden to collide, throw, slide down the slope or roll on the ground. Don't aim the cylinder valve at people when handling, and pay attention to prevent the cylinder helmet from falling. When handling oxygen cylinders, work clothes and loading and unloading tools must not be stained with oil.

7. In the process of storage and transportation, the valve of gas cylinder should be tightened to avoid leakage. If the gas cylinder leaks during storage, the warehouse door should be quickly opened for ventilation, the valve of the gas cylinder should be tightened, and the gas cylinder should be moved to a safe place immediately. If it is toxic gas, wear a gas mask. In case of fire, the cylinder should be removed from the fire site as soon as possible. If it cannot be transported, a large amount of water can be used to cool the cylinder to prevent the cylinder from exploding due to high temperature. Firefighters should stand against the wind and stand on the side of the cylinder.

8. The safety helmet on the gas cylinder must be worn during transportation. Generally, gas cylinders should be laid flat, with the bottle mouths facing the same direction and not crossed; The height shall not exceed the vehicle guardrail, and it shall be fastened with triangular wooden mats to prevent rolling.

9. In order to distinguish the gas filled in the cylinder, the relevant state departments have uniformly stipulated the logo of the cylinder, including the color of the outer surface of the cylinder, the color of the words used and the text. , should be implemented in accordance with the provisions.

10. All kinds of steel cylinders must be inspected regularly in strict accordance with state regulations. If serious corrosion or other serious damage is found in the use of gas cylinders, they should be inspected in advance.

1 1. When storing and transporting gas cylinders at ordinary times, check:

(1), whether the paint color and logo on the gas cylinder are consistent with the names on various documents, whether the packaging, logo and shockproof aprons are complete, and the validity period of the gas cylinder seal logo.

(2) Whether the safety helmet is complete and tight, and whether the bottle wall is corroded, damaged, sunken, blistered and scarred.

(3), listen to the cylinder whether there is a "hissing" air leakage sound.

(4) Use the sense of smell to detect whether there is a strong pungent smell or peculiar smell at the scene.

Flammable liquid in the second quarter

Flammable liquids refer to flammable liquids, liquid mixtures or liquids containing solid substances, but do not include liquids that have been classified into other categories because of their dangerous characteristics. The flash point of closed cup test is equal to or lower than 665438 0℃.

According to the flash point, it can be divided into three categories:

1. Low flash point liquid refers to liquid with flash point.

2. Medium flash point liquid refers to the liquid whose flash point is-18℃ ≤ 23℃ in the closed cup test.

3. The liquid with high flash point refers to the liquid with flash point of 665438 0℃ or lower in the closed cup test at 23℃.

I. Characteristics

1. Flammability

The combustion of combustible liquid is a combustible mixture formed by its volatile vapor and air. When it reaches a certain concentration, it encounters a fire source, which is essentially an oxidation reaction between liquid vapor and oxygen. Because of the low boiling point of flammable liquid, flammable liquid is easy to volatilize flammable vapor, and the energy required for ignition is extremely small, so flammable liquid is highly flammable.

2. The explosiveness of steam

Flammable liquid is volatile, and volatile vapor is easy to form explosive mixture with air, so flammable liquid is in danger of explosion. The more volatile, the greater the risk of explosion. The evaporation rate of different liquids varies with temperature, boiling point, specific gravity and pressure.

3. Thermal expansion

Flammable liquids have the same thermal expansion as other liquids. Flammable liquids stored in closed containers will expand in volume and increase in vapor pressure after being heated. If the pressure limit of the container is exceeded, it will cause the container to expand and burst. Therefore, using the thermal expansion of flammable liquid, we can check the container of flammable liquid to see whether there is a gap of not less than 5% in the container, whether it is stored in a cool place in summer or whether cooling measures are taken to protect it.

4. Asset liquidity

Generally, the viscosity of flammable liquid is very small, which is not only easy to flow, but also increases the concentration of flammable liquid vapor in the air, thus increasing the risk of combustion and explosion, even if the container has only tiny cracks.

5. Electrostatic characteristics

Most flammable liquids are dielectrics, which will generate static electricity during filling, transportation and flow. When static electricity accumulates to a certain extent, it will discharge, causing fire or explosion. The electrostatic characteristics of flammable liquids, in the actual fire supervision and inspection, can determine the fire risk of flammable liquids, and can check whether preventive measures to eliminate electrostatic hazards have been taken, such as whether the transportation pipelines with good materials are used, whether the equipment and pipelines are reliably grounded, and whether the flow rate is restricted.

6. Toxicity

Most flammable liquids (or vapors) are toxic by themselves. Unsaturated aromatics and volatile petroleum products are more toxic than saturated hydrocarbons and volatile petroleum products.

In addition, petroleum products also have boiling splash phenomenon, that is, heavy oil products with wide boiling point range have high viscosity, and the oil products contain emulsified or suspended water or water layer under the oil layer. After the fire, under the action of radiant heat, a high temperature layer will be generated, which will lead to boiling or splashing of oil. Boiling oil refers to crude oil, residual oil, heavy oil and other oil products with water content of 0.3%~4%.

Second, the fire precautions

1. For flammable liquids with flash point lower than 23℃, the storage temperature generally does not exceed 30℃, and low-boiling varieties should be cooled and refrigerated. Store in large quantities (such as benzene, alcohol, gasoline, etc.) ) can generally be stored in storage tanks. Storage tanks can be stored in the open air, but cooling measures should be taken when the temperature is higher than 30℃. Mechanical equipment must be explosion-proof and have grounding devices to guide static electricity.

2. In the process of loading and unloading, it is forbidden to crush, rub, drag and other operations that endanger safety. It is forbidden to use iron tools that are easy to generate sparks and wear shoes with nails when working.

3. In general, it shall not be mixed with other dangerous chemicals. A small amount of bottled flammable liquids in the laboratory can be stored in dangerous goods cabinets according to their properties, and items with conflicting properties such as oxidants are not allowed to be mixed in the same compartment.

It's best to go in and out of the warehouse for transportation in the morning and evening when the weather is hot. In the process of transportation, pumping and filling, there should be a good grounding device to prevent electrostatic accumulation. Tank cars transporting flammable liquids should have grounding chains, and the tank body can be provided with perforated partitions to reduce static electricity generated by vibration.

The vapor of most flammable liquids has certain toxicity, which will invade the human body from the respiratory tract and cause harm. Special attention should be paid to the packaging of flammable liquids. Ventilation measures should be strengthened during operation. In summer or in case of fire, the vapor concentration of air poisoning increases, and more attention should be paid to prevent poisoning.

In the third quarter, flammable solids, spontaneous combustion items and flammable items when wet

I. Characteristics, classification and fire prevention measures of flammable solids

Flammable solids refer to solids with low ignition point, sensitive to heat, impact and friction, easily ignited by external fire sources, burning rapidly, and possibly emitting toxic smoke or gas, but do not include substances that have been listed as explosives.

1. feature

(1) has a low ignition point and is easy to ignite.

The ignition point of combustible solids is relatively low, generally below 300℃, and it can cause combustion as long as there is a small energy ignition source at room temperature. Some flammable solids can also cause combustion when subjected to external forces such as friction and impact.

(2) Flammable and explosive in case of acid and oxidant.

Most flammable solids contact with acids and oxidants, especially with strong oxidants, which will immediately cause fire or explosion.

(3) itself or combustion products are toxic

Many flammable solids are toxic by themselves or produce toxic substances after combustion.

(4) Spontaneous combustion

Celluloid, nitrocellulose and their products in flammable solids are prone to spontaneous combustion and fire when accumulating heat.

classify

Combustible solids can be divided into two categories according to the ignition point and flammability: first-class combustible solids and second-class combustible solids. The first-class combustible solid has low ignition point and self-ignition point, is easy to burn and explode, has high combustion speed and high toxicity of combustion products; The flammability of secondary combustible solids is worse than that of primary combustible solids, and the combustion speed is slow, and some combustion products are less toxic.

3. Fire prevention measures

(1) Some varieties, such as nitrocellulose products, should be ventilated and cooled at ordinary times to prevent damp and mildew, and pay attention to the storage period.

(2) For nitrocellulose containing water or ethanol as stabilizer, always check whether the package is intact, and repair it in time if it is found damaged; Always check the drying condition of stabilizer, add stabilizer when necessary, and the wetting must be uniform. Special attention should be paid to careful handling to prevent the packaging from being damaged.

(3) In storage, different kinds of accidents should be treated differently. If red phosphorus is found smoking, it should be rescued from the warehouse immediately and put out with yellow sand and dry powder, because red phosphorus can be rescued in time from smoking to fire. However, if bulk sulfur is found, it should be put out with water in time; However, magnesium, aluminum and other metal powders can only be put out with dry sand and dry powder, and water, acid-base fire extinguishing agent, foam fire extinguishing agent and carbon dioxide are strictly prohibited.

Second, spontaneous combustion items

Refers to articles with low spontaneous combustion point, which are prone to oxidation reaction in the air, release heat and burn by themselves. Spontaneous combustion materials include ignition materials and self-heating materials. Ignition substance refers to liquid, solid or liquid mixture that can burn by itself when it is in contact with air for less than 5 minutes. Self-heating substance refers to a substance that burns itself when it comes into contact with air without an external heat source.

1. feature

(1) Spontaneous combustion in air

Most pyrophoric materials are very active and highly reducible. When they come into contact with oxygen in the air, they will generate a lot of heat, reach the self-ignition point and explode.

(2) Flammability and explosiveness when wet

Some spontaneous combustion materials will decompose when exposed to water or moisture, causing spontaneous combustion or explosion.

(3) spontaneous combustion of accumulated heat

classify

According to the difficulty of spontaneous combustion, spontaneous combustion can be divided into two categories: primary spontaneous combustion and secondary spontaneous combustion.

3. Fire prevention measures

There are not many kinds of spontaneous combustion articles, and the chemical structure is irregular. At the same time, because different substances have different molecular compositions and properties, the causes of spontaneous combustion and how to prevent spontaneous combustion are also different. Therefore, corresponding measures should be taken according to the different characteristics of different spontaneous combustion articles to ensure the safety of materials. The requirements are as follows:

(1) Yellow phosphorus should always be soaked in water during storage and transportation; Waterproof triethyl aluminum and other packages must be tight and free from moisture.

(2) According to the different characteristics and seasonal climate of spontaneous combustion articles, regularly check whether there is abnormal appearance and smell in the warehouse and between stacks, and whether there is leakage or damage in the packaging, and properly handle it in time.

(3) Transportation should be treated differently according to the nature of each variety. The first-class spontaneous combustion articles (except yellow phosphorus) packed in iron drums should be firmly connected with iron pieces, and each layer should be firmly padded with wooden mats to prevent friction and movement.

Three. Flammable substances when wet

Refers to the articles that react violently with water or moisture and release a lot of combustible gas and heat. Some will burn or explode without an open flame.

1. feature

(1) Flammability in water-this is the commonality of this kind of substances.

(2) It is explosive when it meets oxidant and acid-this chemical reaction is more violent and dangerous than when it meets water.

(3) spontaneous combustion risk

(4) Toxic and corrosive.

classify

Flammable articles exposed to moisture are divided into two danger levels: first-class flammable articles exposed to moisture and second-class flammable articles exposed to moisture.

3. Fire prevention measures

(1) These items are strictly prohibited to be stored in the open air. The warehouse must be dry to prevent water leakage or rain and snow immersion. Pay attention to the smooth sewer to ensure that there is no water in the rainstorm or flood season.

(2) Items that emit acid mist such as hydrochloric acid and nitric acid shall not be stored near the warehouse.

(3) Active metals such as potassium and sodium are absolutely not allowed to be exposed to the air, and must be immersed in kerosene for preservation, and the container shall not leak.

(4) Do not mix with other dangerous chemicals, especially acids, oxidants, water-containing substances and deliquescent substances.

(5) In the absence of rain-proof equipment, it is forbidden to work in rainy and snowy days. Transport vehicles and ships must be dry and have good rain-proof facilities.

(6) When the calcium carbide bucket is put into storage, check whether the container is in good condition and deflate the iron bucket that is not filled with nitrogen.

(7) It is forbidden to use water-based, acid-base and foam extinguishing agent when extinguishing fire; Active metal fires cannot be put out with carbon dioxide.

Section 4 Oxidants and Organic Peroxides

Oxidant refers to a substance that is in a high oxidation state, strong in oxidation, easy to decompose and gives off oxygen and heat. Including inorganic substances containing peroxy groups, which are not necessarily flammable, but can cause combustible materials to burn, can form explosive compounds with soft powdery combustible materials, and are sensitive to heat, vibration or friction.

Organic peroxide refers to an organic substance containing peroxy groups in its molecular composition, which is flammable, explosive, easy to decompose and extremely sensitive to heat, vibration or friction.

1. feature

The harmful characteristics of oxidants are mainly manifested in eight aspects:

(1) strong oxidation; (2) thermal shock decomposition; (3) Flammability; (4) Spontaneous combustion of combustible materials; 5] decomposability of interaction with acid; [6] Decomposability of interaction with water; (7) Decomposition of interaction between strong oxidant and weak oxidant; It is corrosive and toxic.

Characteristics of organic peroxides:

(1) Decompose explosives; (2) Flammability; (3) harmfulness.

classify

Oxidants are generally divided into two levels: primary oxidant and secondary oxidant.

3. Fire prevention measures

(1) The warehouse shall not be leaked, and acid mist shall be prevented from invading. It is strictly prohibited to transport with acids, inflammables, organics, reducing agents, spontaneous combustion articles and inflammable articles when wet.

⑵ Different kinds of oxidants should be transported in suitable warehouses according to their properties and fire extinguishing methods.

(3) During storage and transportation, try to avoid friction and collision and prevent explosion. Special attention should be paid to chlorates, organic peroxides and other substances.

(4) Before and after storage in the warehouse and before and after loading and unloading of transport vehicles, cleaning and cleaning shall be carried out. Strictly prevent impurities such as organic matter and combustible materials from being mixed.

Section 5 Poisons and Corrosives

1. Combustible combustion-supporting toxic substances refer to flammable or combustion-supporting substances that accumulate to a certain amount after entering the human body, can have biochemical effects or biophysical changes with body fluids and tissues, disturb or destroy the normal physiological functions of the body, cause temporary or permanent lesions, and even endanger life.

Most toxic substances are decomposed by acid and heat, releasing toxic gas or smoke. Among them, organic toxic substances are flammable, which will ignite and explode when exposed to open flames, heat sources and oxidants, and release toxic gases at the same time. Liquid poisons are also easy to volatilize and leak, polluting the environment. Poisons are divided into one kind of poison (drama medicine) and two kinds of poison (drugs) according to toxicity. According to the chemical composition of poisons, poisons can also be divided into two categories: inorganic poisons and organic poisons. According to the degree of poisoning danger in storage and transportation, the packaging of toxic substances is divided into class I, class II and class III.

The main danger of toxic substances is toxicity. Toxicity is mainly manifested in the harm to human body or other animals. The main ways of poisoning to human body or other animals are respiratory tract, digestive tract and skin, and respiratory system poisoning, digestive system poisoning and skin poisoning to human body or other animals. The dangerous characteristics of flammable and toxic substances are not only toxic, but also have fire hazards, which are mainly manifested in: (1) flammable when wet; (2) oxidation; (3) Flammability; (4) explosive.

Second, combustible combustion-supporting corrosive products

Combustible combustion-supporting corrosives can be divided into three categories according to their chemical properties:

1. Inflammable combustion-supporting acidic corrosive products.

2. Combustible combustion-supporting alkaline corrosion products.

3. Combustible combustion-supporting other corrosive products.

Hazard characteristics of combustible combustion-supporting corrosives;

1. corrosiveness. Mainly reflected in three aspects: first, the harm to human body; The second is the destruction of biology; The third is the corrosiveness to metals.

2. Toxic. Among corrosive substances, some can volatilize highly corrosive and toxic gases, such as Br2 and HF.

3. Fire hazard. Mainly reflected in three aspects: first, oxidation; The second is flammability; The third is the flammability of decomposition in water.

It is not easy to find more than five short pieces. If it is a composition, then find a composition to read.

Go to the encyclopedia. It might help.