Class C Debate Resurfaces with Ongoing ANSI Z97.1 Revisions
September 23, 2009

The publication of ANSI Z97.1-2004, Safety Glazing Materials Used in Buildings - Safety Performance Specifications and Methods of Test was not without controversy, as debating, re-balloting and appealing centered around whether the standard should continue to include Class C, which classifies wired glass as a safety glazing material. The proposal to eliminate the Class C, which saw much support, failed to earn the 2/3-majority vote necessary to pass. Now, revisions are underway to update the standard and once again the issue of whether Class C should remain in the standard has risen.

According to Jeff Griffiths, director of business development for SaftiFirst/O'Keeffe's Inc., one concern with the Class C is that the 100 foot-pound impact resistance standard it requires is below that of the Consumer Products Safety Commission (CPSC) standard of 150 foot-pound for safety glazing. Safti is currently lobbying for ANSI committee members to vote negatively on ballot B09-0130.01.R as it includes Class C.

"The CPSC performance requirements are the basis for post 2003 International Building Code requirements. Despite being woefully inadequate, the inclusion of the 100 ft-lb rating within a recognized safety-glazing standard has been used by wired glass manufacturers to substantiate the use of their product in fire-rated doors and sidelites," says Griffiths. "The continued inclusion of this performance class within the ANSI safety glazing standard undermines the legitimacy and relevance of the overall test standard. It also allows glazing manufactures and distributors to misrepresent the true shortcoming of their product with respect to impact safety by simply saying that their product meets ANSI impact standards."

While there are those against the inclusion of Class C, the standard is also supported.

"There are many non-hazardous locations in a building where wired glass can still be used and as a result it is both appropriate and responsible for the ANSI Z97.1 Accredited Standards Committee to retain Class C in the standard to ensure that a standard continues to exist for the product," explains Thom Zaremba, an industry consultant. "While the building codes have, appropriately, limited the number of applications where wired glass can be used in favor of new and more technically sophisticated products, that fact bears no real relevance to whether or not an impact standard against which to test wired glass should continue to exist."

Voting is currently underway to revise the standard with ballots due by October 16. The ANSI Z97.1 committee plans to submit the revised document to ANSI later this year.

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