Volume 45, Issue 6 - June 2010

feature


A Look at the Revised
ANSI Z97.1 Standard Changes in the 2009 Updated Standard
by Kevin Olah and Julia Schimmelpenningh


After five years of conscientious work by the members of the American National Standards Institute’s (ANSI) Accredited Standards Committee (ASC) Z97, the update to the American National Standard for Safety Glazing Materials Used in Buildings – Safety Performance Specifications and Methods of Test (ANSI Z97.1) has been completed. The 2009 edition is now available for public sale and distribution.

The 2009 version contains several modifications and new material over the previous version. The modifications add clarity of purpose, intent and procedures. Depending on the need, sections have been re-written and new sections added to provide additional assurance that the intended safe-break characteristics have been achieved before a test specimen may be declared compliant or “qualified” under ANSI Z97.1. Documents that were referenced in the Standard also were reviewed and updated.

Background to the Update
Due to historical precedence and a desire for harmonization with the influential Standard CPSC 16 CFR 1201 – Safety Standard for Architectural Glazing Materials the Accredited Standards Committee (ASC) struggled at the front end of the revision cycle with the scope and limitations of the document. Several international standards were studied during this revision process to gain a better understanding of global positions and intent for safety glazing. In the end, the 2009 update is a Standard that, if enforced, will lead to a reduced number of cutting and piercing injuries sustained by humans who accidentally impact properly specified and installed safety glazing materials.

The Standard is written specifically for architectural glazing materials subjected to accidental human impact. The committee recognized that safety glazing configurations, tested and deemed to pass in accordance with this Standard, may be used in applications other than those specifically identified in the scope—for
example in furniture, shelving and signage. It remains the responsibility of the specifying parties to ensure that the test method chosen, product impact classification and interpretation of results are appropriate for their particular application.

Let’s take a visual cruise through the document so that you become aware of the portions of the Standard that have been modified.

Noteworthy Changes
The noteworthy changes in the Standard start with the Forward section. Although not technically part of the Standard, it gives guidance on how the Standard should be used and how to provide feedback, comments and requests for interpretation to ASC. A section related to the currency of referenced documents within the Standard has been added to the Forward. In the past, confusion over what version of a referenced Standard should be used—the cited or newest version—has been a concern of ASC. Since referenced Standards sometimes change between version publications, the committee borrowed a “best practice” from the International Code Council (ICC). A table of references and the applicable year is included in an annex to the Standard.

As with every publication of the ANSI Z97.1 Standard, the participants in the update are identified. The people on this list deserve the credit for gaining consensus on some tough issues.

As the Standard opens, the first sections are the Scope, Purpose and Limitations of the document. Small, but significant, wording changes are included in these sections. Specifically, the products that have not been, or no longer are, considered safety glazing in accordance with this Standard are noted.

The Reference and Definition sections have benefited from minor adjustments, updates and consistency.

Specimens are then grouped in Table 1 by product type. This table defines the tests that need to be completed for each product type. A center-punch fragmentation test for tempered glass is now included in the document, essentially ensuring that any glass product not broken by the force of the shot-bag impact still will break in accordance with the safe-break criteria of this Standard. The specifics of the center-punch fragmentation test, including method of test and interpretation of results, also are added to the 2009 version of ANSI Z97.1.

Due to the international acceptance of ANSI Z97.1, a modification to the Thickness of Specimens section is incorporated. This allows compliance of glazing that may not fall within the strict minimum and maximum thickness values of ASTM C 1036 - Standard Specification for Flat Glass.

The Methods of Test section has been revised extensively with new, enlarged images and corresponding text that ease readability significantly. There still are three classes of impact: A, B and C. The Adjustments in the Limitations section relegates Class C to a product test method and clarifies the intent of the 2004 version regarding the safety rating of Class C-compliant materials.

One of the biggest changes in the 2009 document is the inclusion of Table 2, “Applicable Interpretation of Results from Shot Bag Impact.” This table was inserted to assist in the understanding of the Interpretation of Results section. As this section has been revamped and restructured, the committee felt that the addition of Table 2 would provide needed guidance and clarity. The methodology, particle weight determination and interpretation of results for the center-punch fragmentation test mentioned earlier are contained in this section.

The next section of the Standard describes the weathering requirements for glazing products. The only product exempt from weathering is tempered glass. All other glazing types applicable to this Standard—laminated glass, organic coated glass and plastics—must demonstrate acceptability after exposure to weathering conditions in order to comply.

Essentially, the Weathering section requires either natural or accelerated weathering be completed on glazing samples produced with the thinnest materials expected to be submitted for qualification. Samples are evaluated in clear form as they are considered to be the most sensitive to change. Samples not available in clear form are submitted as is. Clear products qualify colored products.

The Standard allows for weathering in South Florida or via accelerated form with xenon bulbs. The mounting conditions for natural exposure, as well as the chamber conditions for the xenon, are clearly spelled out with references in the Weathering section. The tests to be conducted on the various products also are defined clearly.

Laminated glass and organic coated glass must meet new requirements in the 2009 version. Although visual inspection of the glazing still is a critical part of the Standard, quantitative measurements for visible transmittance, yellowness, haze and Delta E are added.

For plastic safety glazing products, dimensional stability and testing via Charpy Impact continue to be included in the new version of the Standard. With the discontinuation of ASTM D 756 Practice for Determination of Weight and Shape changes of Plastics Under Accelerated Service Conditions, an enhanced section on the exposure of products for indoor use has been added. Much of the applicable practice from the discontinued ASTM Standard was re-written and incorporated into ANSI Z97.1-2009.

Unchanged Elements
With all of the changes mentioned above, what stays the same? The impactor, a leather punching bag filled with lead shot, is still used. The target weight of the impactor remains consistent at 100 pounds. The largest size that can be tested remains at 34 by 76 inches. Smaller sizes can be tested but will carry a “limited” designation to them. The impact location, drop heights and framing mechanism for the glazing all remain the same. Bent glass laminates are still included in the Standard; however, Standardized radius is provided for the test. There still are two classifications for safety glass: Class A with a 48-inch drop height and Class B with a 18-inch drop height. Class C remains in the Standard with a 12-inch drop height and remains applicable only to fire-rated wired glass. The size limitations for product use continue to be left out of the Standard and left to the discretion of the authority having jurisdiction over safety glazing requirements. The marking of glazing in accordance to the Standard also remains unchanged. However, the fabricator is cautioned that composite testing—testing that qualifies specimens to both ANSI Z97.1-2009 and CPSC 16 CFR 1201—may require modified marking or logos based on changes within the certification provisions of the Consumer Product Safety Commission (see March 2010 USGlass, page 34).

The Next Cycle
ASC was not able to address every modification brought forth for consideration to the Standard during this cycle, just as it was not able to address every change in the last cycle. The committee strives to improve the Standard in such a way that it is useful and understood by the specifiers, users and fabricators.

ANSI Z97.1 is a continuous Standard, which means it is constantly under review. ANSI sets a five-year time limit on the update-and-revision process of a Standard to ensure that it is in harmony with industry evolution, market demands and use. The Steering Committee of ASC Z97 is planning on meeting in June 2010 to discuss the structure and procedures for the next revision of the Standard.

ASC Z97 operates the committee in accordance with the essential procedures published and prescribed by ANSI. Membership in ASC is open, and new participants are welcome.

The ANSI Z97.1-2009 Standard, a redline version (indicating modifications and additions to the 2004) and the 2004 version may be purchased at www.ANSIZ97.com.

Kevin Olah is manager of homologation at Guardian Industries in Auburn Hills, Mich., and serves as chair of ASC Z97. Julia Schimmelpenningh is global applications manager at Solutia Inc. and serves as ASC Z97 Secretary. Their opinions are solely their own and not necessarily those of this magazine. is manager of homologation at Guardian Industries in Auburn Hills, Mich., and serves as chair of ASC Z97. Julia Schimmelpenningh is global applications manager at Solutia Inc. and serves as ASC Z97 Secretary. Their opinions are solely their own and not necessarily those of this magazine.

USG
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