What is the explosive limit range?
The explosive limits of flammable liquids, such as petrol, are the range in which enough vapour or gas is present to burn or explode. For example, an unleaded petrol may have a lower explosive limit of 1.4% and an upper explosive limit of 7.6%. Acetone may have an LEL of 2% and a UEL of 13%.
What does 100% LEL mean?
One hundred percent lower explosive limit (100% LEL) denotes an atmosphere in which gas is at its lower flammable limit. The relationship between percent LEL and percent by volume differs from gas to gas.
What is upper explosive limit?
The highest concentration of a gas or vapor (percentage by volume in air) above which a flame will not spread in the presence of an ignition source (arc, flame, or heat). Concentrations higher than UEL are “too rich” to burn.
What does 10% of LEL mean?
Atmospheres with a concentration of flammable vapors at or above 10 percent of the lower explosive limit (LEL) are considered hazardous when located in confined spaces. However, atmospheres with flammable vapors below 10 percent of the LEL are not necessarily safe. Such atmospheres are too lean to burn.
What is explosive capacity?
The index of the capacity of an explosive to be initiated into detonation in a sustained manner. It is defined by the power of the detonator which is certain to prime the explosive to a sustained and continuous detonation.
What is the explosive limit of h2?
Hydrogen can be explosive at concentrations of 18.3- 59% and although the range is wide, it is important to remember that gasoline can present a more dangerous potential than hydrogen since the potential for explosion occurs with gasoline at much lower concentrations, 1.1- 3.3%.
What is 100% LEL of methane?
We generally consider its LEL (lower explosive level) to be 5% by volume (5% bv). The mixture is too lean to burn if less than 5% methane is present. But at 5%, we can burn or explode if there is an ignition source. So we call 5% bv methane the same as 100% LEL.
How many ppm is 1% LEL?
The LEL of a gas is the lowest concentration of that gas which can combust. A reading in %LEL measures the percentage of that LEL value. For example, for methane, the LEL is 5% by volume. 50% LEL is half of that value, or 2.5% by volume.
What does 50% LEL mean?
The Occupational Safety and Health Administration permissible exposure limit, National Institute of Occupational Safety and Health (NIOSH) recommended exposure limits, and the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value is 5 ppm (21 mg m−3) on a time-weighted average (TWA) ...
What is the least explosive limit?
The LEL for hydrogen is 4%, and it remains quite flammable all the way up to 77% in air (77% is the UEL, or upper explosive/flammable limit). Sparks, static discharge arcs, and similarly-hot surfaces can ignite hydrogen-air mixtures at or above 4%.
What is the LEL for hydrogen?
The minimum ignition energy of hydrogen in air is one of the lowest among known substances at 0.02 mJ, and hydrogen-air mixtures can ignite with 1/10 the effort of igniting gasoline-air mixtures. Because of this, any possible ignition source has to be scrutinized.
Is hydrogen the most explosive gas?
E.g. Methane (CH4) L.E.L. = 5 % (=50000 ppm) and U.E.L.
How many ppm is 5% LEL?
% LEL means the lower limit of explosion, that is, in which concentration will the combustible gas explode when it meets fire. It is worth noticing that this unit is not a natural unit, but the lower limit of the explosion is divided into one hundred parts, one part for 1% LEL.
What is 1% LEL?
Methane is measured in % LEL or % by volume (vol. -%). Methane is also measured in ppm (parts per million). The LEL monitoring serves the safety of individuals, because it can be stated that 100% LEL corresponds to 100% risk of explosion.
Is methane ppm or LEL?
There are three fundamental types: mechanical, nuclear, and chemical. A mechanical explosive is one that depends on a physical reaction, such as overloading a container with compressed air.
What are the 3 types of explosives?
High explosives have a quality called “brisance” which is their ability to shatter objects. This makes them useful for mining rock or artillery shells, but unwanted as artillery propellants, where low explosives are preferred because they are gentler on the guns.
What is highly explosive?
There are two major categories, high explosives and low explosives. High explosives are further divided into initiating, or primary, high explosives and secondary high explosives.
What are the two 2 types of explosive?
Hydrogen is more flammable but oxygen is not far behind, oddly Water ( made of hydrogen and oxygen ) is and fire quencher. and the color of the flames comes in the different chemicals in the fuel of the fire, for example, salt makes the flame green, I think baking powder makes another color I'm not sure which.
Is h2 or o2 more flammable?
Helium's inert nature makes it non-flammable, ensuring a safe environment. Unlike other gases such as hydrogen or methane, helium does not readily react with oxygen or other substances to produce a flame. This is because helium is a noble gas, meaning it has a full outer electron shell and is highly stable.
Why is helium not flammable?
The process of burning in this case is the oxidation of hydrogen or combination of the hydrogen and oxygen molecules. The result of the oxidation of hydrogen, its combustion product, is simply H2O or water. The reason that water (in any state) is not flammable is that it is already the product of combustion.
Why is water not flammable?
20% LEL is the High Alarm, a distress signal. Not explosive yet. 100% LEL means the gas concentration has reached the lower explosive limit and became explosive.
What is 20% LEL methane?
10% LEL equates to 1/2 % natural gas. If an LEL CGI alarms or reads 10% at any time in the FREE AIR (unconfined area) in any part of the building, evacuate the building. CGI readings of 60% LEL or higher in the FREE AIR or 3% natural gas must be considered very serious and the hot zone should be expanded.
What is 10 LEL of natural gas?
L.P.G., therefore, does not present an IDLH hazard at concentrations below its lower explosive limit (LEL). The chosen IDLH, based on the “estimated” LEL for L.P.G. (19,000 ppm), is the concentration above which only the “most protective” respirators are permitted.
What is the LEL limit of LPG?
5% methane by volume. Any reading above the LEL is consider explosive, so the reason the alarm goes off so early, is to allow time for the worker to exit the space. 5% of LEL – low alarm, no entry permitted, but allowed to remain in space if already there. 10% of LEL – high alarm, exit space immediately.
How many ppm is 1% gas?
Parts-per-million (abbreviated ppm) is the ratio of one gas to another. For example, 1,000 ppm of CO2 means that if you could count a million gas molecules, 1,000 of them would be of carbon dioxide and 999,000 molecules would be some other gases.
Is 5% LEL safe?
Lower Explosive Limit (LEL) The lower explosive limit in air measured in percent by volume at room temperature. The minimum concentration of gas or vapor in the air below which the substance will not burn or explode. Below this concentration, the mixture is too "lean" to ignite or explode.
How much gas is 1000 ppm?
The Lower Explosive Limit (LEL) is a concentration of 1.3%. That is to say; where petrol vapours amount to 1.3% concentration in an atmosphere and an ignition source is present, an explosion will occur.
What does 25% LEL mean?
Kerosene has a flash point of 110 degrees Fahrenheit. Gasoline has a flash point of -40 degrees. This means that at 110 degrees or higher kerosene gives off flammable vapors and can ignite. However, gasoline requires a temperature of only 40 degrees to vaporize to cause an explosion or fire.
What is the explosive limit of petrol?
The LEL of a gas is measured as a percentage of volume. If you're using an LEL gas detector, the display will show a 0-100% LEL readout. For example, hydrogen gas has an LEL of 4% by volume in the air. When the volume of hydrogen gas has reached the point of 2% by volume, then the detector will read 50% LEL.
What is more flammable than gasoline?
Acetylene, C2H2, 1.25%vol / 50 %LEL in Air (103 SL)
What is LEL measured in?
Hydrogen is very reactive, but it needs an element (like oxygen), or a compound to react with. But hydrogen is so reactive, it can combine explosively with other elements. Hydrogen and fluorine explode on contact with no spark or a energy source.
What is the LEL for acetylene?
Hydrogen can be explosive with oxygen concentrations between 18 and 59 percent while gasoline can be explosive at oxygen concentrations between 1 and 3 percent. This means that gasoline has greater risk for explosion than hydrogen for any given environment with oxygen.
Can hydrogen explode without a spark?
Hydrogen is highly flammable for a couple of reasons. First of all, the hydrogen-oxygen bond is VERY strong. In other words, LOTS of energy is released when hydrogen forms a bond with oxygen. By contrast, the hydrogen-hydrogen bond is fairly weak.
What is more flammable than hydrogen?
What is the value of 1 ppm? 1 PPM is equal to 0.0001 percent of the solution. It is equal to 1 milli- of other units such as a milligram per liter of water, milligram per kilogram, etc. It is also the 1/1,000,000 fraction of something.
Why is h2 flammable?
Here is a formula, PPM=%LEL×LEL(vol%)×100, taking methane as an example, how much PPM is methane in 20%LEL, according to the calculation formula: 20(%LEL)×1(%VOL)×100=2000PPm.
What is 1 ppm equal to?
LNG has a higher flammability range in air (Table 1.1) and a higher auto-ignition temperature than other liquid fuels (Table 1.2). The upper flammability limit and lower flammability limit of methane, the dominant component of LNG vapour, are 5% and 15% by volume, respectively.
What is 20 LEL in ppm?
One hundred percent lower explosive limit (100% LEL) denotes an atmosphere in which gas is at its lower flammable limit. The relationship between percent LEL and percent by volume differs from gas to gas.
What is LNG Lower Explosive Limit?
Using the LEL (Lower Explosive Limit) in %V/V, it can be converted to g/m3 by multiplication by the molecular weight and dividing by another constant 2.4, so for acetone this would be 58.1 x 2.5/2.4 = 60.52g/m3.
What does 100% LEL mean?
Think of 1 ppm as 1/1,000,000 which equals 0.000001 or 0.0001%. Dividing 1 by 10,000 and then interpreting the results as a percentage will net you the same result.
How do you convert LEL to G m3?
ANFO belongs to the group of non-ideal high explosives (NIHEs), which differ from conventional explosives, as these explosives are characterised by high porosity and low density, as well as by the fact that the fuel and the oxidising agent are not combined in a single molecule and can form separate phases.
How do you convert ppm to percent in LEL?
It is made by combining toluene with a mixture of nitric acid and sulfuric acid. 2,4,6-Trinitrotoluene is also known by other names such as sym-trinitrotoluene, TNT, and 1-methyl-2,4,6-trinitrobenzene. 2,4,6- Trinitrotoluene is produced in the United States only at military arsenals. It is not produced commercially.
Is ANFO high explosives?
Trinitrotoluene (TNT) (118-96-7) is used as a high explosive for military and industrial applications. It is also an intermediate in the production of dyes and photographic chemicals. Ingestion, inhalation, and dermal contact are possible routes of exposure.
What is TNT made of?
One of the most powerful explosive chemicals known to us is PETN, which contains nitro groups which are similar to that in TNT and the nitroglycerin in dynamite. But the presence of more of these nitro groups means it explodes with more power.
Is TNT a high or low explosive?
Some high explosives have the general formula Ca Hb Nc Od. The oxidiser (O) and the fuel (C, H) are present in the same molecule. Nitrogen atoms are present so that there is the highly exothermic production of hot N2 gas.
What's the strongest explosive?
Nitroglycerine is an explosive liquid which was first made by Ascanio Sobrero in 1846 by treating glycerol with a mixture of nitric and sulphuric acid.
What is explosive formula?
Azidoazide azide has been called “the most dangerous explosive material in the world.” It is also No. 3 in K. S. Lane's list “The 10 Most Dangerous Chemicals Known to Man”.
What liquid is highly explosive?
An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure.
What is the most explosive element?
Black powder is a low explosive material comprised of potassium nitrate (saltpeter), sulfur and charcoal. While used as a propellant in fireworks and pyrotechnics, it is also used in some ammunition and muzzleloaders.
What is the difference between explosive and explosion?
Like gasoline and natural gas, hydrogen is flammable and can behave dangerously under specific conditions. Hydrogen can be handled safely when simple guidelines are observed and the user has an understanding of its behavior.
Is black powder a high explosive?
Hydrogen used in the fuel cells is a very flammable gas and can cause fires and explosions if it is not handled properly. Hydrogen is a colorless, odorless, and tasteless gas.
Is 100% hydrogen flammable?
Of all the elements, helium is the most stable; it will not burn or react with other elements.
Is H2 highly explosive?
Helium-3 is a stable and lighter isotope of natural helium. It is an inert, nontoxic and nonflammable gas. Il is colorless, tasteless and ordorless. Helium-3 is osbtained from tranformation of tritium 3H into 3He after β (beta) emission.
Is helium very explosive?
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.
Is helium-3 flammable?
The Occupational Safety and Health Administration permissible exposure limit, National Institute of Occupational Safety and Health (NIOSH) recommended exposure limits, and the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value is 5 ppm (21 mg m−3) on a time-weighted average (TWA) ...
What is LFL and UFL?
The minimum concentration of a substance that propagates a flame through a homogeneous mixture of the substance and air under the specified test conditions. The LFL is sometimes referred to as LEL (Lower Explosive Limit). For the purposes of this definition, LFL and LEL are identical.
What is the least explosive limit?
That concentration of a combustible material in air below which ignition will not occur. It is often, interchangeably called Lower Explosive Limit (LEL) and for dusts, the Minimum Explosible Concentration (MEC).