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Flashpoint

It’s a Factor for Your Everyday Safety

by Michael A. Collier

In the latter half of the 19th century, the primary use of petroleum was in the form of kerosine, which was used for light and heat. Because there were no specifications or controls on this kerosine during those times, numerous problems developed, usually related to fires. Thus began the evolution of flash-point measurement.

A liquid’s flash point is an indication of the temperature at which sufficient flammable vapors have evaporated to allow for ignition and the propagation of flame when exposed to an ignition source. Once the hazards of kerosine became evident, regulations were enacted to control flammable liquids by the flash point. Several different types of flash point apparatus were used in the late 1800s for this purpose, however, none of them were officially standardized.

ASTM’s Flash Point Standards

The first ASTM standard for flash point was published in 1918 (1) as D 56, Test Method for Flash Point by Tag Closed Cup Tester. Just three years later, two more flash point test methods were published: D 92, Test Method for Flash Point by Cleveland Open Cup Tester, and D 93, Test Method for Flash Point by Pensky-Martens Closed Cup Tester. All three of these standards are still in frequent use, with D 93 as the most prevalent, and the one most often cited in regulations and specifications.

The knowledge of a liquid's flash point is a critical factor in the handling and use of all flammable liquids, even if only to demonstrate that it does not have a flash point and thus is non-flammable. You might be surprised to learn that items such as cosmetics, perfumes, paints, adhesives, household cleaning products, food products, pesticides and many more all contain materials that may be flammable. Thus a flash point test may be required, and a statement of the hazard level may be indicated on the packaging.

The most predominant flammable liquids are fuels such as gasoline, kerosine, diesel, heating oil, and aviation fuel. Other forms of fuels are used for marine vessels, power generation and other applications.

Flash Point in Transport

Thousands of gallons per day of these fuels are transferred and transported throughout the world by various modes. Tanker trucks and cars are a common sight on the highway and the railroad. These tankers must display a safety placard which indicates the level of the hazard of the material being carried. This is vital information that can be immediately utilized in the event of a spill.

In many cases these tankers are filled or dispensed at locations where the fuel is transferred either into or out of the tankers through the use of hose connections, sometimes even into fully boarded aircraft. The flammability level must be known so that the appropriate safety precautions are taken when handling these fuels, thus a flash point test is conducted to establish the flammability hazard level.

Another fuel transportation mode is the pipeline. Although safer than over-the-road transportation, which is subject to accident, pipeline transportation has its own hazards. Many times the same pipeline is utilized to transfer different types of fuels. Some, such as gasoline, are much more flammable than kerosine or diesel, and there exists the potential that the more flammable material could be mixed in with these. If such a situation should occur and a more flammable fuel were to be filled into systems that are not designed for them, serious hazards could result. Likewise, ships are utilized to transport various fuels and even crude oil from port to port. These same ships may carry a different type of fuel than that which was carried in a previous journey. Flash point is the measurement used to determine if the shipment has somehow been mixed with another fuel.

Engine Design

Engine manufacturers for automobile, truck, aviation, locomotive and marine vessels design their engines based on the properties of the fuels they are intended to consume. As well, fuels are formulated with additives to meet the requirements of the engines. Flash point is a key criterion in these properties. If the flash point is too high, the engine may not combust the fuel properly, resulting in difficult startup or incomplete combustion. On the other side, using a fuel with a flash point that is too low might result in premature ignition, or worse. Both conditions could cause severe engine or burner damage.

To ensure that a fuel is capable of meeting the standard performance for the intended application, many specifications for fuels have been published as ASTM standards. Flash point is one of the key parameters in these specifications.

Conclusion

Because the flash point is required for regulations and fuel specifications, producing refineries must constantly monitor the production of these fuels. It may seem that determining the flash point on all of the thousands of gallons per day, on all the different type of products produced around the world, is an overwhelming task. Even though flash point determinations are not laborious, throughout the first 50 years of the existence of these standards, flash point testing was a time-consuming process. Fortunately, technological advances have allowed for the development of automated flash point determination apparatus that not only reduce the operator’s time required for testing, but also remove some of the subjectivity involved. More recently developed flash point standards have also reduced the amount of sample required for each test, an environmental concern, and reduced the time period for the test.

ASTM flash point standards are under the jurisdiction of ASTM International’s Committee D02 on Petroleum Products and Lubricant’s Subcommittee D02.08 on Volatility. Flash point standards are also developed in conjunction with the International Organization for Standardization (ISO), within their technical committees 28 and 19, as well as other standards developing organizations. Subcommittee D02.08 has been revising their flash point methods over the last 10 years to update these standards to current test materials and automated test apparatus. In 1991, certified reference materials were developed for each of the flash point test methods; this allows for the verification of proper performance of the test methods. Subcommittee D02.08 expects that flash point determinations will continue to play a critical role in the future with development of new and alternative fuels and other materials. //

Reference

1 Wray, Harry A., Manual on Flash Point Standards and Their Use.
ASTM, West Conshohocken, Pa., September 1992.

Copyright 2004, ASTM International

Michael A. Collier, a product manager for Petroleum Analyzer Company, Houston, Texas, is secretary of Committee D02 on Petroleum Products and Lubricants and vice-chairman/secretary of Subcommittee D02.08 on Volatility. He has been a member of Committee D02 since 1988.