Fire-rated Glazing Supports Safer School Design

Building materials and architectural systems intended to provide added safety and security, such as protection from storms or defense against fire, are often required to meet certain testing standards. These standards simulate how a material or system might perform when subjected to similar situations in application. They help specifiers choose products that will meet or exceed a baseline of building safety.

Model building codes detail what types of rated glazing are necessary in a wide range of contexts. Despite this information, it can sometimes be difficult to know which code-compliant designs are possible given the rating needed for an application. Knowing how to achieve more occupant-centered, code-compliant designs can help projects more readily pass inspections and avoid costly reworks.

Although building code requirements often address fire and other threats to life safety, these codes are not all encompassing. Currently, there is a lack of code-driven standards around safer school design. This can make choosing the right security-rated glazing difficult.

Achieving enhanced security as well as fire- and life-safety code compliance are both crucial components of safer school design. The National Fire Protection Association (NFPA) estimates that an average of over 7,000 fires occur on school grounds annually—and that most of them happen during school hours. Further, the Partner Alliance for Safer Schools, in their K-12 guidelines, recommends that all security improvements meet fire and building code requirements.

As such, knowing the basics of fire-rated glass design and how code requirements can impact security is crucial to effective safer school design.

What are the types of fire-rated glazing and where can it be used

In general, fire-rated glazing is separated into two distinct categories: fire-protective and fire-resistive. Each type is rated in increments of time—most commonly from 20 minutes to 180 minutes—according to fire tests with standard maximum temperatures and pre-determined temperature rise criteria. For both categories, fire-rated glazing and assemblies tested beyond 20 minutes will also need to pass the hose stream test to ensure they stay intact from the pressure of a fire hose and the thermal shock of a drastic temperature change.

Fire-protective glazing blocks the spread of fire and smoke. It is not tested to document its ability to block the spread of conductive and radiant heat. As such, according to model building codes, fire-protective glass is typically limited to windows and openings that are less than 25% of the total wall area as well as specific places within fire door assemblies. The limitations on the use of fire-protective glazing are subject to applicable building code requirements, so it is encouraged that designers consult with local codes to determine how they can best use this material.

Fire-resistive glazing provides an added layer of protection by blocking the spread of fire, smoke and both conductive and radiant heat. Tested to standards such as ASTM E119: Standard Test Methods for Fire Tests of Building Construction and Materials and UL 263: Fire-resistance Ratings, this glazing’s size and use within door and wall assemblies glazing is not limited within model building codes. As a result, fire-resistive glazing can be used in wall applications requiring a 60-minute or greater fire rating that must meet temperature-rise criteria, such as stairwells, exit access corridors, or other fire barriers dividing interior construction.

Additionally, manufacturers, like Technical Glass Products (TGP), can help guide specifiers through building code requirements to help ensure they are choosing the right glazing systems for their intended designs. This is incredibly important because fire- and life-safety requirements can vary by location and when a building was constructed or renovated. In addition to manufacturer guidance and resources, it is encouraged that designers and specifiers refer to local building codes and consult with an Authority Having Jurisdiction (AHJ) when determining code requirements.

In general, fire-rated materials are often required along paths of egress, including walls, openings and fire door assemblies. These materials may also be necessary to support compartmentalization strategies in large interior spaces. Fire ratings may also be required for classroom doors, regardless of the presence of fire mitigation systems in certain jurisdictions, as well as exterior walls and windows in proximity to neighboring buildings or within certain building return conditions.

How do fire- and life-safety code requirements impact safer school design?

When a school building plan seeks to provide open sightlines and plenty of access to natural light, building professionals can facilitate code-compliant designs with fire-rated glazing. With its ability to cover a wide range of applications, there is the potential for the use of fire-rated glazing to overlap in areas where best practices for safer school design recommend security-rated products. These areas may include secure entry vestibules, classroom doors and exterior windows.

Due to instances where active shooters triggered fire alarms then attacked occupants as they fled the building, security-rated components may be advantageous in stairwells and on stories above the first floor. In a recent American School & University webinar, Julia Schimmelpenningh notes these applications support strategies to minimize attack perches—places inside a building where active shooters have attacked occupants exiting in response to an alarm.

In these instances, multifunctional, fire-rated glazing is a viable option. It either uses components that are known to be compatible or assemblies that are tested as a complete system, which helps ensure one type of protection does not compromise the other. This is important since many security-rated products are plastic-based and may compromise or entirely negate a fire-rated component’s ability to perform as intended during a fire. Using compatible components or assemblies tested as a full system supports safer school design by limiting the potential for unintended consequences.

Because glass supports open sightlines and access to daylight, safer school designs often benefit from security-, fire- or multifunctional, fire-rated glazing. These materials can promote occupant well-being and support positive student outcomes while also maintaining a baseline of fire and life safety as well as enhanced security. When these systems come from industry-leading manufacturers, like Technical Glass Products (TGP), building professionals can expect they will meet intended performance criteria.