UNI 7697: The Complete Guide to Safety Glass Standards for Building Construction

When selecting glass for a building, the choice is not merely an aesthetic matter, but also one of safety. The UNI 7697 standard is the mandatory technical reference in Italy and Europe for anyone, from designers to window fitters to builders, involved in selecting the correct glass for building applications.

At Lumyra Glass, we use only compliant safety glass: every glazing we create originates from strict adherence to these criteria, because we believe that safety and quality are essential.

In this article you will find everything you need to know about UNI 7697 standards: what it is, the criteria that influence glass selection, the types of safety glass permitted, and the main innovations introduced by the 2021 revision.

What is UNI 7697?

UNI 7697, titled "Safety criteria in glass applications," is the Italian and European regulation that defines which type of glass to use based on intended use and installation location, with the objective of ensuring the safety of people, animals and property.

Established in Italy in 1977 to fill a regulatory gap in the glass applications sector, the standard has undergone successive revisions to follow the technical and regulatory evolution of the sector, culminating in the most recent version: UNI 7697:2021.

It covers almost all glass applications in buildings, including windows and glass doors, entrance doors, railings and partition walls. When a specific technical standard exists for an application, UNI 7697 refers directly to it. For all other applications not regulated by specific standards, UNI 7697:2021 constitutes the guiding criterion to be applied.

UNI 7697: Glass Selection Criteria for Building Construction

To select the correct glass, the standard imposes evaluation of three main factors: the type of glazing, the actions that may cause its breakage, and the resulting risks.

Types of Glazing

According to UNI 7697 standards, glazing can be subdivided based on 4 criteria:

• Application: A distinction is made between internal glazing, which separates two internal spaces, such as partition walls in offices, and external glazing, which separates the internal environment from the external one, such as sliding glass panels on terraces.
• Orientation: Glazing can be vertical, such as facades and windows, horizontal, such as glass floors or flat skylights, or inclined, such as glass greenhouses.
• Accessibility: Glazing is subdivided into accessible, when people can come into contact with it, such as a window pane, and non-accessible, when people cannot touch it in any way, as in the case of a skylight.
• Protection: For applications that involve risks in case of breakage, such as in the case of a glass balustrade that could fall from a significant height and injure passers-by, protective measures are adopted. Instead, in low-risk applications without projections outside the building, such as doors or glass doors, whose breakage entails only the replacement of the pane itself, glazing is considered unprotected.

Actions and Stresses

Stresses are the set of physical forces that may cause a glass pane to break: UNI 7697 standard classifies them as static, such as dead load or snow, dynamic, such as wind or vibrations, and exceptional, such as explosions or projectile impact.

Each type of action requires a specific mechanical resistance of the glass, which must be verified during the design phase.

Types of Damage in Case of Breakage

An aspect often underestimated is the assessment of potential damage in case of breakage. Standard 7697 identifies three risk categories:

• Physical damage to people, animals or property: When fragments resulting from breakage can cause serious injuries.
• Fall into the void: Imagine a glass balustrade on a terrace on the fourth floor, where, in case of breakage, only the laminated glass retains fragments in the interlayer film, preventing shards from falling on people below. This is why the standard makes it mandatory from a height of one meter.
• Social damage: When breakage damages collective assets, such as works of art or public infrastructure.

Guide to Glass Selection According to UNI 7697

According to UNI 7697 standard, only two types of glass ensure the required safety: laminated safety glass and tempered glass, both governed by UNI EN 12600.

Laminated Glass

Laminated glass consists of two or more panes bonded by one or more plastic interlayer films, typically Polyvinyl Butyral (PVB) or SentryGlas® Plus (SGP). In case of breakage, fragments remain anchored to the film, preventing the fall of dangerous shards.

It is mandatory in all applications at a height greater than one meter above the walking surface, such as railings, balusters, continuous facades and skylights, to ensure the safety of passers-by.

Tempered Glass

Tempered glass is subjected to a heat treatment that increases its mechanical resistance. In case of breakage, it shatters into small non-cutting blunt fragments, dramatically reducing the risk of injuries.

It is suitable for applications at heights below one meter, such as doors, glass doors, sliding glass panels and internal partitions.

At Lumyra Glass, we use tempered glass for all sliding and packaged glazing, in full compliance with the criteria established by UNI 7697 standard.

Laminated Glass vs. Tempered Glass

Installation Direction

The standard also indicates the correct side for installing the safety glass pane in insulating glazing units. Safety glass must not be positioned on the side exposed to the action that may cause its breakage, but rather on the opposite side, where people or elements to be protected are located.

Incorrect installation can nullify the safety properties of the glass, making the glazing non-compliant with the standard and potentially dangerous in case of impact.

UNI 7697:2021: Innovations from the Revision

The updated version of the standard introduces some significant changes that every professional in the sector must know.

Heat Soak Test (HST) Now Mandatory

The Heat Soak Test is a thermal process applied to tempered glass that eliminates panes destined to break, that is, those containing nickel sulfide (NiS). This treatment makes it possible to minimize spontaneous glass breakage, ensuring greater safety and durability.

While previously HST was only recommended, it is now mandatory.

Laminated Glass for Sports Fields

Prior to 2021, monolithic tempered glass was permitted in covered sports facilities (such as padel and squash courts). The updated standard has made laminated safety glass mandatory in these contexts, eliminating the risk of fragment falls on players.

Schools and Universities: Tempered or Laminated Glass?

The glass to be used for school buildings varies based on school type:

• Primary and secondary schools: It is mandatory to use laminated glass for both internal and external panes of the insulating glazing unit, since younger students are more exposed to risks.
• Universities: For external panes, tempered glass is also permitted.

Summary of UNI 7697:2021 Innovations
 

Conclusion

UNI 7697 standard is fundamental to building a truly safe structure. Complying with it means protecting the people who live and work in those spaces, concretely reducing the risk of injuries.

However, correctly applying the standard requires professional expertise: the tables and charts in the standard are indeed support tools, but it is the judgment of the designer, trained in knowledge of the specific context and conditions of use, that makes the difference between a building that is simply compliant and one that is truly safe.

At Lumyra Glass, our commitment to respecting UNI 7697 and other standards is an integral part of our production philosophy: we hold various certifications, including CE marking, certification from the Giordano Institute and numerous UNI certifications, such as wind resistance (UNI EN 1932) and water tightness (UNI EN 1027). Every glazing we create is designed with glass suitable for the specific application, in full compliance with UNI 7697:2021.

Are you a designer, window fitter or construction company? Contact us for free technical consultation: we create personalized projects for your specific application, using exclusively glass compliant with UNI 7697.

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