 Committee on Building Seals and Sealants Launches Activities on Fatigue Resistance, Pedestrian Walkways
ASTM International Committee C24 on Building Seals and Sealants is now working on two proposed new standards, WK6920, Fatigue Resistance of Structural Silicone, and WK6999, Specification for Horizontal Joint Seals Used in Pedestrian Walkways.
WK6920
WK6920, which is under the jurisdiction of ASTM Subcommittee C24.20 on General Sealant Standards, is intended to serve as an enhancement to current performance requirements for structural silicones and to help users ascertain that current and new products are sufficiently resilient to withstand years of fatigue imposed on systems by thermal expansion and contraction, as well as other imposed loads.
According to Errol Bull, technical marketing engineer, GE Advanced Materials, Silicones, WK6920 will increase the safety level in silicone structural glazing construction. “Since SSG construction techniques can have life safety implications, such as falling glass, to pedestrians and building occupants, it is imperative to allow only products that have a performance profile that can withstand the loads imposed to such a system and which can withstand such loads for the duration of the intended service life,” says Bull. “This standard can screen out products that are not appropriate for use in SSG systems.”
Bull also notes that each structural silicone adhesive/sealant has a unique property profile and that fatigue is a characteristic that has not yet been addressed within the ASTM performance requirements for such materials.
All interested parties are invited to participate in the further development of WK6920.
CONTACT:
Technical Information:
Errol Bull, GE Advanced Materials, Waterford, N.Y.
Phone: 518/233-3443
ASTM staff: Scott Orthey
Phone: 610/832-9730
Upcoming Meeting: June 12-16,
June Committee Week, Reno, Nev.
WK6999
In the past, the only measurement used to determine whether sealants could endure a great deal of foot traffic was hardness. Because research presented at symposia and from the field has shown that other factors need to be considered in the design and use of traffic sealants, Committee C24 has a new proposed standard that encompasses a wider range of factors. The standard, WK6999, Specification for Horizontal Joint Seals Used in Pedestrian Walkways, is under the jurisdiction of Subcommittee C24.10 on Specifications, Guides and Practices.
WK6999 will quantify wet applied horizontal joint sealants based on the following factors:
• Weatherability;
• Movement capability;
• Puncture resistance;
• Compression deflection;
• Resistance to dynamic loads;
• Adhesion through immersion and movement;
• Resistance to chemicals;
• Tear resistance;
• Abrasion resistance; and
• Rheology at application.
Incorporating these factors will give system designers greater flexibility in creating joints that will be ideally suited for specific situations. “There is no single product that does everything in horizontal seals today and it is not likely that this will change,” says Larry Carbary, associate industry scientist, Dow Corning Corporation. “The proposed new standard will allow materials to have ratings according to what they are capable of performing and it will allow the specifier to design a system that can perform up to expectations.
“Committee C24 is writing the standard and the test methods to accompany it, but we are interested in greater participation, particularly from members of Committee E06 on Performance of Buildings,” says Carbary. “Also, assistance is needed to write test methods and perform round robin testing within the next two years, so that a meaningful specification can be developed.” The committee hopes to bring the proposed specification to ballot in December 2006.
CONTACT:
Technical Information:
Larry Carbary, Dow Corning, Midland, Mich.
Phone: 989/496-8696
ASTM staff: Scott Orthey
Phone: 610/832-9730
Upcoming Meeting: June 12-16,
June Committee Week, Reno, Nev.
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