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Committee on Hazard Potential of Chemicals Developing Resistivity and Flammability Standards

Subcommittee E27.04 on Flammability and Ignitability of Chemicals has recently begun developing two new standards, WK5909, Powder Resistivity Test, and WK5917, Test Methods for Determining Flammability Limits Using Pressure Criteria. Information on either work item can be accessed by visiting the ASTM International Web site and entering the work item number into the site search box on the ASTM home page. Subcommittee E27.04 is under the jurisdiction of Committee E27 on Hazard Potential of Chemicals.

WK5909 — Powder Resistivity Test

The ability to determine the resistivity of a material is important because the development of a hazardous electrostatic discharge is a strong function of resistivity. According to Larry Floyd, Ciba Specialty Chemicals, “Liquids and powder solids with high resistivities can develop a static potential that is difficult to dissipate, and can be the source of static electric discharges resulting in fires and explosions.”

While a poll taken of E27.05 membership indicates that two test methods are currently being used for powder bulk resistivity — ASTM D 257, Test Methods for DC Resistance or Conductance of Insulating Materials and British standard BSI 5958, Code of Practise for Control of Undesirable Static Electricity — neither adequately addresses the issue of powder resistivity. Therefore, the subcommittee is hoping to develop the proposed WK5909 into a standard that will specify 1) preparation of the powder sample (moisture content, particle size distribution), 2) test conditions (humidity, temperature), and 3) test procedure and instrument .

For further technical information on WK5909, contact Larry Floyd, Ciba Specialty Chemicals, McIntosh, Ala. (phone: 251/436-2747).

WK5917 — Determining Flammability Limits

According to Erdem Ural, president, Loss Prevention Science and Technologies, Inc., there is currently a need for a good standard test method to determine flammability limits at standard conditions, as well as at the process temperature and pressure. Subcommittee E27.04 hopes to address this need in developing WK5917, which will also cover measurement of Kg, Pmax and burning velocity.

Ural explains the importance of the proposed new standard by saying, “Flammability limits are used widely in fire protection engineering and explosion protection. Kg, Pmax and burning velocity are used in designing explosion prevention and protection systems.”

The task group working on WK5917 invites all interested parties to participate in the development of the standard, and is particularly interested in anyone who would be willing to participate in round robin studies.

For further technical information on WK5917, contact Erdem Ural, Loss Prevention Science and Technologies, Inc.,Stoughton, Mass. (phone: 781/ 344-7656). Committee E27 meets April 19-21 during the April 2005 Committee Week in Reno, Nev. For membership or meeting details, contact Scott Orthey, ASTM International (phone: 610/832-9730). //

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