Laminated Glass – Safety Glass Testing

Use of safety glass

 

ANSI Z97.1; CGSB 12.1; CPSC 16 CFR 1201; EN 12600 and ISO 29584
 

What is safety glass? When fractured, safety glass breaks in a way that minimizes potential cutting or piercing injuries when tested under specific protocols. Its use is required by various Authorities Having Jurisdiction (AHJ) in all parts of the world.
 

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Although configurations and performance requirements may vary, the objective remains constant––safety glass reduces or eliminates serious injuries from broken glass. These injuries are defined in some regulations as cutting and piercing injuries, and in others as protection by means of glass shard containment after breakage occurs. Another constant is the assumption that safety glass is broken by accidental impact.  Resistance to breakage and penetration of glass via intentional impact is addressed as security glazing and has different test methodology and pass/fail criteria.

As safety glass is intended to address accidental impact, applications such as doors, sidelights, shower doors and floor-to-ceiling glazing are typically covered by these regulations. These tend to be locations where humans can accidently make abrupt contact with glazing and cause breakage. 

 

Requirements for safety glass

The danger of falling glass has been recognized and constitutes the necessity of requiring units of safety glass with glass shard containment capability in overhead and sloped applications such as skylights, atriums and elevators. Normally governing bodies for construction (building codes, building ministries etc.) will determine the minimal applications that require safety glazing. Of course, during design, any area slated for glass installation should be reviewed and the potential for human or other mechanical impact, fall-out, or fall-through should be considered when selecting the appropriate glass.

 

Tests for safety glass

Tests for safety glass are typically administered by a swinging pendulum of a weighted object meant to simulate human impact. The impactor is usually a defined object with specified shape, hardness and mass. The force on the safety glass is adjusted by the drop height. The regulations clearly specify the impactor and its characteristics, as well as the drop height necessary to generate the desired force.  

Guidelines are provided to assess the glass after impact to determine its safety classification. Many test procedures require the glass to break before it can be classified. In these programs, the specimen must be taken to failure to assess it as safety glazing. It is not sufficient to sustain the impact without breaking; the premise of most standards is to determine the characteristics of the glass after breakage has occurred. Some standards allow for the interpretation of expected mode of breakage after impact as well if the specimens are unbroken after the test sequence is complete.  

 

​Additional tests

Additional tests of radiation and boil may be required of the laminated glass. This provides indications related to processing quality and durability of the product over time. These tests are typically run in parallel with the impacted specimens to determine if a given configuration will qualify as safety glazing.  In some instances these requirements are separated from the standard containing the impact test, but may still be required by the AHJ.

Each country or region has adopted their own version of a safety glazing standard, but all have evolved from ANSI Z97.1. Some commonly referenced standards are indicated below and typical configurations of laminated glass with Saflex® or Vanceva® interlayers needed to meet the impact requirements are presented.

 

American National Standards Institute (ANSI) Z97.1

For safety glazing materials used in buildings– safety performance specifications and methods of test
 
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Laminated Glass with Saflex or Vanceva interlayers for ANSI Z97.11
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1. Glass thickness is determined by overall laminate need.  Typical testing is completed with 2.7 mm (Lami) through 12 mm (1/2 in) thickness.

 

Consumer Product Safety Commission (CPSC) 16 Code of Federal Regulations (CFR) Part 1201

This federally mandated standard has adopted the ANSI Z97.1 methodology and criteria for classification.
Laminated Glass with Saflex or Vanceva interlayers for for CPSC 16 CFR 1201[1]

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[1] Glass thickness is determined by overall laminate need.  Typical testing is completed with 2.7 mm (Lami) through 12 mm (1/2 in) thickness.

[1] Laminates prepared with Saflex and Vanceva laminates in the cited configurations have been demonstrated to pass all required testing for CPSC 16 CFR 1201 when properly laminated.

 

Canadian General Standards Board (CGSB) 12.1–safety glass

This standard has harmonized with ANSI Z97.1 – 2015 on methodology and criteria for classification. 

Laminated glass with Saflex or Vanceva interlayers for CGSB 12.1[1]  
 

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[1] Laminates prepared with Saflex and Vanceva laminates in the cited configurations have been demonstrated to pass all required testing for CPSC 16 CFR 1201 when properly laminated.
[2] Glass thickness is determined by overall laminate need.  Typical testing is completed with 2.7 mm (Lami) through 12 mm (1/2 in) thickness.

 

EN 12600 Glass in building – Pendulum test – impact test method and classification of flat glass

The Impactor is a mechanism consisting of two identical stacked tires weighing 50 kg (110 lbs) versus the shot bag used in previously discussed test protocols. 
 
EN 12600 there are 3 drop height classifications as seen in the following table:
 

Classification Drop Height (mm) Drop Height (inches) Force
3 190 7.5 9.5 N (69 lbf)
2 450 18 22.5 N (163 lbf)
1 1200 47 60 N (434 lbf)

 
The classification is further defined by mode of breakage in accordance with the following table:
 

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The performance is reported with a three character designation:
X (Y) Z
Whereas: 
X = highest drop height in which the specimen doesn’t break or breaks as break type (a) or break type (b) as described above.
Y = describes the mode of breakage from above chart using the letters A, B or C
Z = highest drop height in which the specimen breaks in accordance with break type (a) above.

Ratings from testing completed in accordance with this standard are 1(B)1, 2(C)2, 1(C)3 etc…

 

A rating of 1B1 is the highest performance level outlined in EN 12600.

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* Mode of breakage for laminated glass is (B)

 

Laminated glass with Saflex or Vanceva interlayers for EN 12600

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ISO 29584 - Glass in building – Pendulum impact testing and classification of safety glass
ISO 29584 is based on the practice and classification system defined in ANSI Z97.1 and EN 12600.  This method allows either the shot bag or twin tire impactor to be used.

 
[1] Glass thickness is determined by overall laminate need.  Typical testing is completed with 4 mm (Lami) through 12 mm (1/2 in) thickness.

 

Laminated glass with Saflex or Vanceva interlayers for ISO 29584

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[1] Glass thickness is determined by overall laminate need.  Typical testing is completed with 4 mm (Lami) through 12 mm (1/2 in) thickness.