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New Methodology Proposed for Fire-Stop Materials

Fire-rated walls or assemblies are designed to reduce the spread of fires in buildings. When builders pierce fire-rated walls to insert electric conduits or pipes, they use fire-stop materials to seal the opening and restore the wall’s fire rating. These materials are sold as foam, caulk, putty, mortar, devices, or boards. Because of their fire-protective properties, fire-stop materials are often specified in building codes.

It is essential that fire-stop products last as long as the fire-rated assembly. To evaluate this issue, ASTM Subcommittee E06.21 on Serviceability is developing a “Standard Specification for the Serviceability of Materials Used in All Penetration Fire Stops After Exposure to Severe Environmental Conditions.” The subcommittee is part of Committee E06 on Performance of Buildings.

Currently on ballot at ASTM International, the proposed specification will provide a uniform methodology for testing the effects of environmental exposure on fire-stop materials. “The standard was broadened to include all the types of fire-stop materials that go into construction,” said Richard Licht, a chemist and subcommittee member. Testing the affects of temperature, humidity, and aging on these materials varies among manufacturers and could result in performance variations, said Licht. A Codes and Standards manager with 3M Company, St. Paul, Minn., Licht drafted the standard with input from consultants, architect/engineers, fire-testing laboratory personnel, and manufacturers of fire-stopping materials, fire-rated gypsums, and wall boards.

The proposed standard is based in part on an Underwriters Laboratories standard for intumescent materials, he said. “When you have insulation or cable jacketing or other types of combustible materials going through a fire-rated wall,” he explained, “they are going to burn away. So you need an intumescent material, or a material that expands with heat, to seal those openings.

“You need to be assured that these materials will still be able to function 10, 15, 20 years from now,” he averred. “While this standard is not designed to determine the expected life of these materials this standard could be the starting point for another standard that could predict expected life based on the ahrrenuis function.” Subjecting the products to standard exposures for temperature, C02/S02, temperature cycling, water immersion, and other factors simulating severe environmental exposure will allow end users to estimate how the fire-stop materials will perform decades in the future, Licht concluded.

For further technical information, contact Richard R. Licht, 3M Company, St. Paul, Minn. (phone: 651/733-7079). Committee E06 meets Oct. 13-16 in Norfolk, Va. For meeting or membership details, contact Stephen F. Mawn, manager, ASTM Technical Committees (phone: 610-832-9726). //

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