Computed values of Flash Point (FP) as a function of pressure for all the substances of Table 1. In all cases, the FP decreases with decreasing pressure. In particular, in going from 1 atm to 0.4 atm, the FP decreases of about 10 °C for all the substances.
What happens when the flash point is above the fire point?
At flash point, more vapor may not be produced rapidly enough to sustain combustion. Hence, the fire is mostly not sustained. At some temperature above the flash point, the liquid will produce enough vapour to support combustion. (This temperature is known as the fire point).
What does flash point mean in chemistry?
Flash Point. Flash point is the lowest temperature at which a chemical can vaporize to form an ignitable mixture in air. A lower flash point indicates higher flammability. Measuring a flash point (open-cup or close-cup) requires an ignition source. At the flash point, the vapor may cease to burn when the ignition source is removed.
What does a lower flash point indicate?
A lower flash point indicates higher flammability. Measuring a flash point (open-cup or close-cup) requires an ignition source. At the flash point, the vapor may cease to burn when the ignition source is removed.
What factors affect the flash point of an oil?
Distillation: Higher the boiling range of the oil, higher will be its flash point. Adulteration: If the oil adulterated with lighter fuel the flash point will be very less. In the search of sincerity. Author has 167 answers and 403.8K answer views 5 y What is a fire point?
What are the factors affecting the value of flash and fire point?
Note: There are different types of factors affecting the fire point of a fuel. Some of them are pressure, oxidant, apparatus sheltering etc. The apparatus must be shielded from sunlight as sunlight causes an increase in the temperature of the fuel before we start the heating.
Is flash point affected by pressure?
1. Computed values of Flash Point (FP) as a function of pressure for all the substances of Table 1. In all cases, the FP decreases with decreasing pressure. In particular, in going from 1 atm to 0.4 atm, the FP decreases of about 10 °C for all the substances.
Can you increase flash point?
Solvents such as acetone, methanol, ethylacetate, ethanol and xylene, to name a few, increases flash points by 50° C. to 60° C., by addition of 12-14% terpineol.
How does flash point depend on the vapor pressure?
In general, a low boiling point indicates a high vapor pressure and, possibly, an increased fire hazard. Flashpoint is the minimum temperature at which the vapor concentration near the surface of the liquid is high enough to form an ignitable mixture.
Does pressure increase flammability?
Temperature, pressure, and the concentration of the oxidizer also influences flammability limits. Higher temperature or pressure, as well as higher concentration of the oxidizer (primarily oxygen in air), results in lower LFL and higher UFL, hence the gas mixture will be easier to explode.
What makes something more flammable?
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.
How do I check flash points?
This test procedure utilizes an open metal container that is filled with the sample oil. The oil is then heated at a prescribed rate and periodically a small pilot flame (ignitor) is passed over its surface. This continues until a flash appears. The oil temperature is then recorded as its flash point.
What is difference between flash point and fire point?
If the temperature is at or above the flash point, the vapor will ignite and an easily detectable flash can be observed. The flash produced need not sustain for long time. Whereas, fire point is the minimum temperature at which vapor of the fuel steadily burns at least for five seconds once ignited.
What is low flash point fuel?
Low-flashpoint fuel means gaseous or liquid fuel having a flashpoint lower than otherwise permitted under SOLAS regulation II-2/4.2. 1.1. Sample 1. Low-flashpoint fuel means gaseous or liquid fuel having a flashpoint lower than otherwise permitted under SOLAS regulation II-2/4.2.
What affects vapor pressure?
Vapor pressure is the pressure caused by the evaporation of liquids. Three common factors that influence vapor press are surface area, intermolecular forces and temperature. The vapor pressure of a molecule differs at different temperatures.
What is the relationship between volatility and vapor pressure?
If two substances are compared at the same temperature, the more volatile one will have the higher vapor pressure. The vapor pressure of water is the pressure at which water vapor is in thermodynamic equilibrium with the condensed state.
At what temperature does oil ignite?
ExamplesFuelFlash pointAutoignition temperatureGasoline (petrol)−43 °C (−45 °F)280 °C (536 °F)Diesel (2-D)>52 °C (126 °F)210 °C (410 °F)Jet fuel (A/A-1)>38 °C (100 °F)210 °C (410 °F)Kerosene>38–72 °C (100–162 °F)220 °C (428 °F)4 more rows
What is the flash point?
flash point, the lowest temperature at which a liquid (usually a petroleum product) will form a vapour in the air near its surface that will “flash,” or briefly ignite, on exposure to an open flame. The flash point is a general indication of the flammability or combustibility of a liquid.
How additives affect the pour point of diesel fuel and fuel oil?
Results showed that copolymer ethylene-vinyl acetate 28% at a concentration of 500 ppm reduced pour point temperature by 12°C for diesel and that copolymer ethylene-vinyl acetate 19% at a concentration of 300 ppm reduced pour point temperature by 9°C for fuel oil.
Why is flash point important?
Flash point is an important factor in relation to the safety of spill cleanup operations. Gasoline and other light fuels can ignite under most ambient conditions and therefore are a serious hazard when spilled.
What is a flash point?
The flash point is a safety-related characteristic and defines the minimum temperature at ambient pressure at which a vapor-air mixture can be ignited in a closed space [58].
What is the flash point of diesel fuel?
Flash point of diesel fuels is measured according to ASTM D 93—Flash-Point by Pensky-Martens Closed Cup Tester. The sample is stirred and heated at a slow, constant rate in a closed cup. At specific temperature intervals (1 or 2 °C), the cup is opened and an ignition source is moved over the top of the cup. The flash point is the lowest temperature at which the application of the ignition source causes the vapors above the liquid to ignite.
How to determine flash point of oil?
The flash point of an oil product can be determined by several methods, depending on the oil product and the quantity available. Lower viscosity products, including light fuel oils and most fresh crudes, are measured by the Tag closed-cup method. This follows ASTM method D 1310.7 Though accurate, the Tag method uses a comparatively large volume of oil, 50 to 70 mL. Smaller volumes, 1–2 mL, can be measured by ASTM D6450. 8 The practical working range of these two methods is –10°C to approximately 100°C. With subambient cooling, using dry ice baths and/or liquid nitrogen baths, much lower flash point temperatures can be measured, but this is often not necessary for emergency response considerations.
What is the standard test material for assuring quality control for a lower temperature flash point apparatus?
The standard test material for assuring quality control for a lower-temperature flash point apparatus historically has been para-xylene; however, heavier normal alkane standards, n-decane, n-undecane, n-tetradecane, and n-hexadecane have also been found to be suitable and offer a wider range of test temperatures. 11
Does flash point require ignition?
Measurement of flash point does not require production of a stable flame, it only requires ignition of vapor and fuel. 5 The actual measurement which defines ignition is usually a temperature rise 6 produced by the combustion. View chapter Purchase book.
What is the flash point of a liquid?
Flash point, the lowest temperature at which a liquid (usually a petroleum product) will form a vapour in the air near its surface that will “flash,” or briefly ignite, on exposure to an open flame. The flash point is a general indication of the flammability or combustibility of a liquid.
How are flash points measured?
Flash points are measured by heating a liquid to specific temperatures under controlled conditions and then applying a flame. The test is done in either an “open cup” or a “closed cup” apparatus, or in both, in order to mimic the conditions of storage and the workplace.
Why is kerosene used in gasoline?
Before gasoline became important, kerosene was the main petroleum product (used mainly as fuel for lamps and stoves), and there was a tendency on the part of petroleum distillers to leave as much as possible of the commercially worthless gasoline in the kerosene in order to sell more product.
What is combustion reaction?
combustion, a chemical reaction between substances, usually including oxygen and usually accompanied by the generation of heat and light in the form of flame. The rate or speed at which the reactants combine is high, in part because of the nature of the chemical reaction itself and in part because…
What is petroleum gas?
petroleum, complex mixture of hydrocarbons that occur in Earth in liquid, gaseous, or solid form. The term is often restricted to the liquid form, commonly called crude oil, but, as a technical term, petroleum also includes natural gas and the viscous or solid form known as bitumen, which is found…
What is an encyclopedia editor?
Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. ...
What is a flash point?
Flash point is a temperature at which a volatile substance ignited when presented with an ignition source.
What are the factors that affect the flash point temperature of oil?
Any contaminants like Water, Solvents like Kerosene & Diesel, etc and of course based on atmospheric pressure also. These kind factors will impact flash or fire point temperature of oil.
What is the difference between fire point and flash point?
Flash Point is the temperature of oil in a heated container that generates enough vapours to ignite for a fraction of a second when exposed to an open flame. Fire Point is the temperature of oil in the heated container that generates enough vapours to sustain fire (continue to burn).
What is the flash point of diesel fuel?
Flash point minimum temperatures are required for proper safety and handling of diesel fuel. Due to its higher flash point temperature, diesel fuel is inherently safer than many other fuels, such as gasoline.The flash point of diesel fuel varies from 126 t0 205 degree fahrenheit (52 to 96 degree celsius ) depending upon the type of diesel fuel. The fire point of a fuel is the temperature at which the vapour produced by that given fuel will continue to burn for at least 5 seconds after ignition by an open flame. At the flash point, a lower temperature, a substance will ignite briefly, but vapor might not be produced at a rate to sustain the fire.Fire point can be assumed to be 10 degree celsius higher than flash point.
What happens to the temperature of a fluid as the temperature increases?
The fluids have the specific vapour pressure, which varies which the change in the liquid temperature. As the temperature increases, vapour pressure increases . The increase in the vapour pressure, increases the concentration of the vapour of fluid in the air.
What is the flash point of transformer oil?
Flash point of transformer oil is the minimum temperature at which the oil gives of vapor , the value of flash point for transformer oil ( mineral oil) is generally 140°C.
How to measure flash point?
The flash point of a liquid can be measured by two processes: 1) open cup 2) closed cup. In the open cup, the sample is heated and the flame brought over a surface over a period of time. In this measurement, the flash point usually coincides with the fire point.
What is a closed cup test?
There are two types of closed cup testers: non-equilibrial, such as Pensky-Martens, where the vapours above the liquid are not in temperature equilibrium with the liquid, and equilibrial , such as Small Scale (commonly known as Setaflash), where the vapours are deemed to be in temperature equilibrium with the liquid. In both these types, the cups are sealed with a lid through which the ignition source can be introduced. Closed cup testers normally give lower values for the flash point than open cup (typically 5–10 °C or 9–18 °F lower) and are a better approximation to the temperature at which the vapour pressure reaches the lower flammable limit. In addition to the Penskey-Martens flash point testers, other non-equilibrial testers include TAG and Abel, both of which are capable of cooling the sample below ambient for low flash point materials. The TAG flashpoint tester adheres to ASTM D56 and has no stirrer, while the Abel flash point testers adheres to IP 170 and ISO 13736 and has a stirring motor so the sample is stirred during testing.
What is a flash point?
The flash point is a descriptive characteristic that is used to distinguish between flammable fuels, such as petrol (also known as gasoline ), and combustible fuels, such as diesel .
What is the flash point of a volatile substance?
In chemistry, the flash point of a volatile material is the lowest temperature at which its vapors ignite if given an ignition source . The flash point is sometimes confused with the autoignition temperature, the temperature that causes spontaneous ignition.
What determines the concentration of a flammable liquid in the air?
Hence, temperature determines the concentration of vapor of the flammable liquid in the air. A certain concentration of a flammable or combustible vapor is necessary to sustain combustion in air, the lower flammable limit, and that concentration is specific to each flammable or combustible liquid. The flash point is the lowest temperature ...
What is the flash point of diesel fuel?
Diesel fuel flash points vary between 52 and 96 °C (126 and 205 °F). Diesel is suitable for use in a compression-ignition engine. Air is compressed until it heats above the autoignition temperature of the fuel, which is then injected as a high-pressure spray, keeping the fuel-air mix within flammable limits.
What is the temperature of a closed cup?
Closed cup testers normally give lower values for the flash point than open cup (typ ically 5–10 °C or 9–18 °F lower) and are a better approximation to the temperature at which the vapour pressure reaches the lower flammable limit.
What is the temperature of gasoline?
220 °C (428 °F) Vegetable oil (canola) 327 °C (621 °F) 424 °C (795 °F) Biodiesel. >130 °C (266 °F) Gasoline (petrol) is a fuel used in a spark-ignition engine. The fuel is mixed with air within its flammable limits and heated by compression and subject to Boyle's Law above its flash point, then ignited by the spark plug.
Why is fire not sustained?
Hence, the fire is mostly not sustained. At some temperature above the flash point, the liquid will produce enough vapour to support combustion. (This temperature is known as the fire point). It is used to measure how volatile a liquid is and the level of risk it could pose. They are measured by heating a liquid to specific temperatures ...
What is a closed cup tester?
Closed cup measurement: There are two types of closed cup testers: Non-equilibrial, such as Pensky-Martens, where the vapours above the liquid are not in temperature equilibrium with the liquid, and equilibrial, such as Small Scale (commonly known as Setaflash), where the vapours are deemed to be in temperature equilibrium with the liquid. In both these types, the cups are sealed with a lid through which the ignition source can be introduced. Closed cup testers normally give lower values for the flash point than open cup (typically 5–10 °C or 9–18 °F lower) and are a better approximation to the temperature at which the vapour pressure reaches the lower flammable limit.
What is the temperature of a closed cup?
Closed cup testers normally give lower values for the flash point than open cup (typ ically 5–10 °C or 9–18 °F lower) and are a better approximation to the temperature at which the vapour pressure reaches the lower flammable limit.
Why is kerosene used in gasoline?
Before gasoline became important, kerosene was the main petroleum product (used mainly as fuel for lamps and stoves), and there was a tendency on the part of petroleum distillers to leave as much as possible of the commercially worthless gasoline in the kerosene in order to sell more product.
What are the two types of flash points?
There are two basic types of flash point measurement: Open cup and Closed cup. Open cup measurement: In open cup devices, the sample is contained in an open cup which is heated and, at intervals, a flame brought over the surface.
Is flash point an empirical measurement?
Generally, flash point is an empirical measurement rather than a fundamental physical parameter. The measured value will vary with equipment and test protocol variations, including temperature ramp rate (in automated testers), time allowed for the sample to equilibrate, sample volume and whether the sample is stirred.
What is a flash point of 93 degrees?
A liquid with a flash point between 23 and 60 Celsius degrees will be classified as flammable liquid category 3. A liquid with a flash point above 93 Celsius degrees does not meet GHS classification criteria and will not be regarded as a flammable liquid or a hazardous chemical. Under dangerous goods regulations, ...
What is a flash point?
Little Pro on 2016-01-13 50973. Flash point is the lowest temperature at which a chemical can vaporize to form an ignitable mixture in air. A lower flash point indicates higher flammability. Measuring a flash point (open-cup or close-cup) requires an ignition source. At the flash point, the vapor may cease to burn when the ignition source is ...
What is the flash point of a chemical?
a chemical only contains volatile organic components with flash-points above 100 °C for aqueous solutions, or. the estimated flash-point is above 200 °C, or. the flash-point can be accurately predicted by interpolation from existing characterised materials.
How to predict flashpoints?
the flash-point can be accurately predicted by interpolation from existing characterised materials.
Where to find flash point on SDS?
You can often find it in the section 9 of a safety data sheet (SDS). It shall be note that flash point is different from auto-ignition temperature at which a chemical can burn without an ignition source.
What is the FP of biodiesel?
FP is the safety measure of fuel for storage. It is the point at which fuels are flammable [28]. According to the Australian standards and EN14214 standards, the minimum FP temperature for biodiesel should be 120°C whereas it should be 130°C according to US standards. To measure the FP value of the fuel according to the ASTM D93 method, an HFP 380 Pensky-Martens FP analyzer was used. Table 14.5 shows the FP temperature of different biodiesel fuel. All the biodiesel have a higher FP than diesel fuel which indicates that biodiesel is safer to transport and store [14,29–33]. Among all the biodiesels, JBD has the maximum FP (184.5°C), and BBD has the minimum FP temperature (141.5°C). All the values are within the specified limits.
How does escaping gas work?
If adequate isolation capabilities are available and employed in a timely fashion, the initial release will be characterized by high flow and momentum, that decreases as isolation is applied or supplies are exhausted. Within a few pipe diameters, from the release point, the released gas, pressure decreases. Escaping gases are normally very turbulent and air will immediately be drawn into the mixture. The mixing of air will also reduce the velocity of the escaping gas jet. Obstacles such as overhead platforms, pipe racks, structures, etc., will disrupt momentum forces of any pressurized release. These releases, if not ignited, will then generally form a vapor cloud that would naturally disperse in the atmosphere or if later then ignited, cause an explosive blast if the cloud is in a relatively confined area. Where turbulent dispersion processes are prevalent (e.g., high pressure flow, winds, congestion, etc.) the gas will spread in both horizontal and vertical dimensions while continually mixing with available oxygen in the air. Initially, escaping gases are above the UEL, but with dispersion and turbulence effects, they will rapidly pass into the flammable limits. If not ignited and given an adequate distance for dilution by the environment, they will eventually disperse below the LEL. Various computer software programs are currently available that can calculate the turbulent gaseous jet dispersion, downwind explosive atmospheric locations, and volumes for any given flammable commodity, release rates, and atmospheric date input (i.e., wind direction and speed).
How do liquids dissipate?
If they are highly volatile, dissipation by vaporization may occur when the vaporization rate equals the spread rate. Depending on the viscosity of nonvolatile liquids, they will spread out immediately and form into a “pool” of liquid that is somewhat localized to the immediate area. The higher the viscosity, the longer time it will take to spread. As a general estimate, 3.8 L (1 gal.) of an unconfined liquid on a level surface will cover approximately 1.8 m 2 (20 ft 2 ), regardless of viscosity. A pool on calm water will spread under the influence of gravity until limited by surface tension, typically giving a minimum oil slick thickness of 10 mm (0.04 in.) on the water. A pool on the water will also drift in the direction of the wind and current. If no ignition occurs, the lighter ends will evaporate and eventually the residual oil will be broken up by wave action and bacteriological digestion. During the evaporation of the lighter fractions, combustible vapors may form immediately above the oil spill for a short distance.
What is the volumetric flow rate of component D?
The volumetric flow rate of component D is 6785 BPD.
What is FP i?
FP i is the flash point temperature of component i, in °F. The flash point blending index is blended based on wt% of components.
How do gases release?
If released under atmospheric conditions, the gas will either rise or fall, depending on its vapor density and will be carried into the path of the prevailing wind (if existent at the time). The vapor density for most common petroleum and chemical materials is greater than 1 and therefore they will not readily rise and dissipate. In the absence of wind, heavier gases will collect in low points in the terrain or will not dissipate from congested areas. These atmospheric releases, if ignited, will burn relatively close to the source point, normally in a vertical position with flames of short length. For the lighter gases, the height of a gas plume will mostly be limited by atmospheric conditions, such as ambient wind speed. If gases are ignited, the height of the plume will rise due to the increased buoyancy of the high-temperature gases from the combustion process.
What is BI FPi?
where xvi is the volume fraction of component i, and BI FPi is the flash point index of component i that can be determined from the following correlation ( Riazi, 2005 ):
What happens to the liquid fuel at the flashpoint?
This is due to the liquid fuel cannot evaporate enough into the vapour to form a combustible vapour-air mixture. So this Flashpoint is the minimum temperature at which the liquid fuel can enough vapour-air mixture to form a combustible mixture.
What are the two characteristics of liquid fuels?
As we have discussed the important qualities of the Spark-Ignition Engine Fuels and Compression-Ignition Engine Fuels, The flash point and the fire point are the two important characteristics of the liquid fuels.
What are the two important characters to consider for the spark ignition engines and the compression ignition engines?
For selecting the suitable fuel for the internal combustion engines, flash point and the fire points are the two important characters to consider for the spark ignition Engines and the Compression Ignition Engine fuels.
What is the flash point of diesel fuel?
The flash point of diesel fuel varies from 52°C to 96°C (126°F to 205°F)depending upon the type of diesel fuel.
Which fuel has a low fire temperature?
General Trivia: Petrol (gasoline) has a very low fire and flash point temperatures because it is very volatile and it readily catches fire due to the vapours produces by the fuel at even below room temperatures, which easily mixes with the air and ignites instantly. On the other hand, Diesel has contrasting behaviour.
Is the fire point of petrol higher than the flashpoint?
The fire point for petrol also will be higher than the flashpoint of petrol.
What is the flash point test?
The flash point test dates back to the mid-19th century as one of the earliest identifiers of an oil’s physical properties. It was originally used to determine the fire hazards of fuels and oils being stored and transported. The flash point test measures the tendency of an oil to form a flammable mixture with air.
What is the temperature range of a flash point?
ASTM D93, Flash Point by Pensky-Martens Closed Cup Tester, is used for petroleum products with a temperature range of 40 to 360 degrees C (104 to 680 degrees F) and biodiesel with a temperature range of 60 to 190 degrees C (140 to 374 degrees F).
What is the purpose of flash point and volatility?
Flash point and volatility tests serve a purpose, just for different conditions. They are also related. After all, for an oil to reach its flash point, it must first volatize. While the flash point tells you very little about an oil’s volatility, an oil’s volatility can tell you a lot about its flash point. Volatility testing has proven that ...
What is the determining point of oil?
Ignition is the determining point. The lowest measured temperature at which the oil will ignite or flash is recorded as its flash point. If the test is performed over a longer period of time, the oil’s fire point can be obtained. The fire point is when ignition is sustained for five seconds. Several methods can be employed to determine an oil’s ...
Overview
The flashpoint of a material is the "lowest liquid temperature at which, under certain standardized conditions, a liquid gives off vapours in a quantity such as to be capable of forming an ignitable vapour/air mixture". (EN 60079-10-1)
The flash point is sometimes confused with the autoignition temperature, the temperature that causes spontaneous ignition. The fire point is the lowest temperature at which the vapors keep bu…
Fuels
The flash point is a descriptive characteristic that is used to distinguish between flammable fuels, such as petrol (also known as gasoline), and combustible fuels, such as diesel.
It is also used to characterize the fire hazards of fuels. Fuels which have a flash point less than 37.8 °C (100.0 °F) are called flammable, whereas fuels having a flash point above that temperature are called combustible.
Mechanism
All liquids have a specific vapor pressure, which is a function of that liquid's temperature and is subject to Boyle's Law. As temperature increases, vapor pressure increases. As vapor pressure increases, the concentration of vapor of a flammable or combustible liquid in the air increases. Hence, temperature determines the concentration of vapor of the flammable liquid in the air. A certain concentration of a flammable or combustible vapor is necessary to sustain combustion i…
Measurement
There are two basic types of flash point measurement: open cup and closed cup. In open cup devices, the sample is contained in an open cup which is heated and, at intervals, a flame brought over the surface. The measured flash point will actually vary with the height of the flame above the liquid surface and, at sufficient height, the measured flash point temperature will coincide with the fire point. The best-known example is the Cleveland open cup (COC).
Examples
Gasoline (petrol) is a fuel used in a spark-ignition engine. The fuel is mixed with air within its flammable limits and heated by compression and subject to Boyle's Law above its flash point, then ignited by the spark plug. To ignite, the fuel must have a low flash point, but in order to avoid preignition caused by residual heat in a hot combustion chamber, the fuel must have a high autoignition temperature.
Standardization
Flash points of substances are measured according to standard test methods described and defined in a 1938 publication by T.L. Ainsley of South Shields entitled "Sea Transport of Petroleum" (Capt. P. Jansen). The test methodology defines the apparatus required to carry out the measurement, key test parameters, the procedure for the operator or automated apparatus to follow, and the precision of the test method. Standard test methods are written and controlled b…
See also
• Autoignition temperature
• Fire point
• Safety data sheet (SDS)