The Cleveland open-cup method is one of three main methods in chemistry for determining the

flash point The flash point 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 fl ...

of a

petroleum Petroleum, also known as crude oil, or simply oil, is a naturally occurring yellowish-black liquid mixture of mainly hydrocarbons, and is found in geological formations. The name ''petroleum'' covers both naturally occurring unprocessed crude ...

product using a Cleveland open-cup apparatus, also known as a Cleveland open-cup tester. First, the test cup of the apparatus (usually brass) is filled to a certain level with a portion of the product. Then, the temperature of this chemical is increased rapidly and then at a slow, constant rate as it approaches the theoretical flash point. The increase in temperature will cause the chemical to begin to produce flammable

vapor In physics, a vapor (American English) or vapour (British English and Canadian English; see spelling differences) is a substance in the gas phase at a temperature lower than its critical temperature,R. H. Petrucci, W. S. Harwood, and F. G. H ...

in increasing quantities and density. The lowest temperature at which a small test flame passing over the surface of the liquid causes the vapor to ignite is considered the chemical's

. This apparatus may also be used to determine the chemical's fire point which is considered to have been reached when the application of the test flame produces at least five continuous seconds of ignition. Temperature range of this apparatus is 120 to 250 degree c{{Cite book , editor-last = Wray , editor-first = Harry A. , title = Manual on flash point standards and their use: methods and regulations , publisher = ASTM International , date = September 1992 , location = Baltimore, MD , isbn = 0-8031-1410-9 The other principal methods of establishing chemical flash points are the

Pensky–Martens closed-cup test The Pensky–Martens closed-cup flash-point test is a test for the determination of the flash point of flammable liquids. It is standardized as ASTM D93, EN ISO 2719 and IP 34 The United States Environmental Protection Agency (EPA) has also publi ...

and the

Tagliabue cup Tagliabue is a surname. Notable people with the surname include: *Benedetta Tagliabue (born 1963), Italian architect *Carlo Tagliabue (1898–1978), Italian baritone * Elena Tagliabue (born 1977), Italian alpine skier * Gerald Tagliabue (born 1935) ...

method (often called simply the "Tag method").

References

Combustion Chemical tests