During an earthquake, glazing is one of the non-structural elements most likely to injure building occupants. When a window, partition or frame fails suddenly, people may be exposed to glass fragments propelled with significant kinetic energy. FEMA E-74, Reducing the Risks of Nonstructural Earthquake Damage – A Practical Guide (2011), describes this mechanism in detail: glazed elements that are not designed to accommodate seismic movement can become dislodged and fall far from their original position, creating a particular hazard along evacuation routes. A safety film applied to the glazing can help reduce this risk, provided you understand exactly what it can—and cannot—do.
How fragment retention works
When glass breaks under seismic stress, it does not fail uniformly. Tempered glass breaks into many small pieces with less sharply cutting edges, but those pieces can still be dangerously projected through the space. Annealed glass fractures into long, sharp shards. In both cases, the rapid dispersal of fragments significantly increases the risk of injury.
A safety film provides fragment retention: it remains bonded to the glazing when the glass breaks and holds the pieces in place or in a cohesive mass. It does not prevent the glazing from breaking, but it limits the immediate consequences for occupants.
FEMA E-74 (2011) identifies glazing as a significant source of non-structural risk during earthquakes, especially when it is positioned above walkways or evacuation routes. The guide presents glazing retention measures as one way to mitigate non-structural damage, with the suitability of each measure assessed in the specific context of the project.
Factors that determine film performance
The performance of a safety film in a seismic context depends on several interrelated factors:
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Film thickness and composition: thicker films (300 μm and above) generally provide greater tear-out resistance than thinner films, provided they are compatible with the substrate glazing and used with a suitable attachment system. Break strength, expressed in kg/cm, is the key technical parameter for comparing products.
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Perimeter anchoring: a film simply applied to the glass may peel away under the bending stresses caused by seismic movement. Depending on the structural configuration and project requirements, anchoring the film to the frame or sash—using a structural sealant or metal profile—may be considered to improve the overall system's integrity. This decision must be assessed case by case by a qualified installer or design office.
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Glazing type: film performance varies depending on whether it is applied to single annealed glass, insulating glass, tempered glass or laminated glass. The application surface (interior or exterior), glazing area and geometry also affect the results.
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Installation quality: air inclusions, contaminants or poor adhesion reduce retention performance. Installation by a qualified professional is essential.
What the film does not replace
A safety film is not a structural earthquake-protection measure. It does not improve the building's structural integrity, the strength of the frame, the anchoring of the joinery to the façade or the forces exerted on the structure. These matters fall under architectural design and the specifications prepared by specialist seismic engineers.
Likewise, applying a film to existing, untested glazing does not give it a certified impact-resistance classification. EN 12600 characterises resistance to pendulum impacts on flat glass, while EN 356 covers resistance to forced entry. Specific standards exist for seismic applications in some countries, particularly in areas with high seismic activity. Consult an installer or design office whenever compliance with a recognised standard is required.
Who can benefit from this solution?
Installing a safety film to retain glazing during an earthquake may be relevant for several types of buildings, depending on the project characteristics, the site's seismic exposure and the applicable regulatory requirements:
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Public-access buildings: schools, hospitals, theatres and stations, where high occupancy increases the collective risk associated with broken glass. The suitability of a film solution must nevertheless be assessed against the structural diagnosis and compliance requirements applicable to each facility.
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Commercial and office buildings in seismic zones: open-plan offices, glazed entrance halls and transparent partitions with large areas of non-structural glazing.
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Buildings whose window systems were not designed for current seismic loads: in this case, a prior inspection by a qualified professional is essential to assess film compatibility with the existing glazing and whether reinforced anchoring is appropriate.
For an initial overview of the available options, see the articles about safety films for glazing (https://solarscreen.eu/fr/blog/category/safety/) and explore the technical specifications of the transparent Protector Architectural protection film (https://solarscreen.eu/fr/products/protector-architectural/), designed for a wide range of glazing safety applications.
Selecting the right film—based on thickness, anchoring and compatibility with the substrate glazing—requires a case-by-case assessment. An authorised installer can inspect the existing glazing and recommend the appropriate solution based on the site's seismic exposure.