How to judge the danger of flammable substances?
The danger of flammable substances can be judged roughly based on their ignition point. The lower the ignition point, the greater the risk. However, even a substance with a higher ignition point is dangerous when heated or at a temperature above its ignition point. Therefore, attention must be paid.
2 Classification of flammable substances
1 special flammable substance
It is a liquid at 20 ° C, a substance which can be liquid at 20-40 ° C, and a substance whose ignition temperature is below 100 ° C or a flash point of below 20 ° C and a boiling point of below 40 ° C. Such as ether, pentane and other substances.
2 highly flammable substances
A substance with high flammability at room temperature.
(The ignition point is below 20 °C)
Such as: petroleum ether, ethanol and other substances.
3 moderately flammable substances
A substance that is highly flammable when heated.
(flame point is about 20-70 ° C)
Such as: kerosene, acetic acid and other substances.
4 low flammable substances
When heated at a high temperature, a substance that ignites due to decomposition of a gas (a substance having a burning point of 70 ° C or higher). Such as: lubricants, soybean oil and other substances.
Analysis of the concept of 3 burning point and ignition point
The ignition point is for liquids.
The ignition point refers to the lowest temperature at which the liquid vapor is mixed with air on the liquid surface to form a vapor concentration that can ignite, and is called the ignition point of the liquid substance.
The fire point is aimed at combustibles.
The point of ignition (ignition temperature) is the lowest temperature at which a combustible material is heated in the air to ignite on its own.
The ignition point or ignition point of a substance, under the same measurement conditions, results in a slight deviation, so it is difficult to say that it is a fixed constant of matter, but both are important physical properties of the substance.
4 special flammable substances
What are included?
Ether, carbon disulfide, acetaldehyde, pentane, isopentane, propylene oxide, divinyl ether, carboxyl nickel, aluminum alkyl, and the like.
These substances are extremely low in ignition temperature and ignition point, so they are easy to catch fire.
Note: Not limited to the above examples!