What is meant by flammability range?
Flammability limits or explosive range: The entire range of concentrations of a mixture of flammable vapor or gas in air (expressed as volume percent) over which a flash will occur or a flame will travel if the mixture is ignited.
What are the levels of flammability?
Classification of flammability
| Rating | Degree of flammability |
|---|---|
| 1 | Materials that must be preheated before they ignite |
| 2 | Materials that must be moderately heated or exposed to relatively high ambient temperatures before they ignite |
| 3 | Liquids and solids that can ignite under almost all temperature conditions |
What is LFL and UFL?
The lower flammability limit (LFL) identifies the smallest mixture able to sustain a flame. The upper flammable limit (UFL) identifies the richest flammable mixture. A quantifiable difference exists between the flammability limit and explosive limit.
What is flammability diagram and its applications?
Flammability diagram or flammability composition diagram is one of the important documents used across the world to understand and prevent fire and explosion. They are mainly used for the hydrocarbon mixture and so a key to the cargo and ship’s safety on tankers.
How do you calculate flammability?
Flammability is determined by the flash point of a material. Flash point is the minimum temperature at which a liquid forms a vapor above its surface in sufficient concentration that it can be ignited. Flammable liquids have a flash point of less than 100°F. Liquids with lower flash points ignite easier.
What is high flammable limit?
The upper flammability limit (UFL) is defined as the highest possible concentration of a substance in air at which a flammable mixture is formed (Crowl and Louvar, 2013).
How is flammability measured?
The materials are placed over a Bunsen burner either vertically or horizontally, depending on the specification. During a vertical flammability test, a material is observed for the length of time it burns after the igniting flame is removed, how much of the specimen burns and whether or not it drips flaming particles.
What does a flammability rating of 2 mean?
0 Not combustible. Instability (Yellow) (Reactivity) 4 Danger- Explosive material at room temperature. 3 Danger – May be explosive if shocked, heated under confinement, or mixed with water. 2 Warning – Unstable or may react violently if mixed with water.
What is LEL and UFL?
Below the explosive or flammable range the mixture is too lean to burn and above the upper explosive or flammable limit the mixture is too rich to burn. The limits are commonly called the “Lower Explosive or Flammable Limit” (LEL/LFL) and the “Upper Explosive or Flammable Limit” (UEL/UFL).
What is flammability upper & lower flammability limit?
The upper flammability limit is defined as the concentration of the most concentrated mixture that is flammable and the lower flammability limit as the concentration of the most dilute fuel-air or fuel-diluent mixture that is flammable.
What is a flammability diagram?
Flammability diagram. Flammability diagrams show the control of flammability in mixtures of fuel, oxygen and an inert gas, typically nitrogen. Mixtures of the three gasses are usually depicted in a triangular diagram, known as a ternary plot. Such diagrams are available in the speciality literature.
What is the LOC on a flammability diagram?
The LOC is the line that shows any gas mixture containing oxygen below the LOC is not flammable. The shape and size of the flammability zone on a flammability diagram change with a number of parameters, including fuel type, temperature, pressure and inert species. Thus the flammability limits and the LOC also change with these parameters.
How do you find the flammability of a gas?
A general way to represent the flammability of a gas or vapor is by a triangle diagram shown below. Concentrations of fuel, oxygen and inert material are plotted on the three axes. Each apex of the triangle represents either 100% fuel, oxygen or nitrogen.
What are the flammability limit mixtures for hydrocarbon gas in air?
The lower and upper flammability limit mixtures for hydrocarbon gas in air are represented by the points C and D. As the inert gas content increases, the flammable limit mixtures change as indicated by the lines CE and DE, which finally converge at the point E.