What Is The Closed Cup Flash Point Of Diesel?

What is the meaning of diesel closed cup flash point? What is the significance?

1. What is the closed cup flash point


First, it is necessary to make clear what the flash point is. The flash point is a safety indicator for the storage, transportation, and use of flammable liquids, as well as a volatile indicator of flammable liquids.

Under the specified test conditions, the minimum temperature at which a certain ignition source is used to cause liquid vaporization and ignition.

Flashing refers to the phenomenon that when sufficient vapor is generated on the liquid surface and mixed with air to form combustible gas, it will produce a short flash when meeting the fire source, which is called a flash.

The lowest temperature at which a flash occurs is called a flash point.

Diesel oil

The open cup method and closed cup method are two methods for measuring flash points. Generally, light oil products such as kerosene and diesel oil adopt the closed cup method, while heavy oil products such as lubricating oil, heavy oil, and residual oil adopt the open cup method.

Under specified conditions, heat the sample. When the sample reaches a certain temperature, the mixture of steam and the ambient air of the sample will flash once it contacts the flame. The minimum temperature of the sample when flash occurs.

2. Difference between closed cup flash point of diesel oil ≤ 60 ℃ and>60 ℃


Diesel oil is a kind of light petroleum, which is the main fuel for diesel engines. The freezing point of diesel oil is divided into light diesel oil and heavy diesel oil,

The boiling point range of light diesel oil is about 180 ° C~370 ° C, and that of heavy diesel oil is about 350 ° C~410 ° C,

Light diesel has six brands of 5, 0, – 10, – 20, – 35, and – 50, and heavy diesel has three brands of 10, 20 and 30.

At present, the closed cup flash point of most diesel sold on the market is more than 60 ℃. According to the National Sixth New Standard, the closed cup flash point of No. 0 diesel has reached more than 60 ℃, and 10, 20, and 30 brands also exceed this value; However, diesel fuel is – 10, – 20, – 35, – 50 and other products, and its closed cup flash point is less than 60 ℃.

Diesel engine

3. Flashpoint is a safety index for storage, transportation, and use of flammable liquid


The hazard level of oil products is classified according to the flash point:

Flammable products with a flash point below 45 ℃, such as gasoline and kerosene; Those with a flash point above 45 ℃ are combustible.

According to fire engineering design and application, flammable liquids are divided into three categories according to different flash points. Namely:

Class A liquid: liquid with a flash point less than 28 ℃. (such as crude oil, gasoline, etc.)

Class B liquid: liquid with a flash point greater than or equal to 28 ℃ but less than 60 ℃. (such as jet fuel and kerosene for lamps)

Class C liquid: liquid with a flash point greater than or equal to 60 ℃. (Heavy oil, diesel oil, lubricating oil, etc.)

It is of great significance in fire protection: the flash point is an important basis for the fire hazard classification of flammable liquid production and storage sites, and it is also the basis for the classification of Class A, B, and C hazardous liquids.

Diesel gas station

The determination and selection of fire resistance rating, floors, floor area, safe evacuation, fire separation, explosion-proof facilities, etc. of the flammable liquid production, storage plant, and warehouse shall be determined according to the flash point; The layout and fire separation of liquid storage tanks and storage yards, the layout and fire separation of flammable and combustible gas storage tanks, and the layout and fire separation of liquefied petroleum gas storage tanks shall also be based on the flash point.

In addition, flash point is also the basis for selecting fire extinguishing agent and determining fire extinguishing intensity.

At the gas station, the fuel dispenser is the terminal equipment for adding diesel or gasoline to the car. The operator knows about the flash point, Better fire prevention measures.

4. Diesel oil with a closed cup flash point ≤ 60 ℃ is classified as hazardous chemicals


Other diesel fuels are not included in the supervision of hazardous chemicals.

In the past, diesel oil was classified as a hazardous chemical, depending on its brand. Among them, 10, 20, and 30 heavy diesel oils are not hazardous chemicals.

The diesel management, such as transportation, warehousing, and operation, is mixed, which interferes with the normal industry competition.

Oil barrel

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