IBC Code Requirements You Need to Know for Glass Guardrails

Jun 10, 2022

Most people don’t pay attention to the guard railings until they actually need the support of this type of fall protection. Railings are installed in all public areas where It is a federal requirement,for both commercial and residential locations where there is a fall hazard of more than 30” from the walking surface.

However, for interior space designers and architects, it’s vitally important that they know the federal requirements that govern the use of different types of guardrails.

The International Building Code (IBC) is responsible for creating the different types of regulations and requirements that both architects and designers must comply with.

The Role of the International Building Code (IBC)

The International Building Code (IBC) is a model building code that was created by the International Code Council, and it has been widely adopted by most jurisdictions throughout the United States. The IBC creates code requirements that address both health and safety concerns for buildings and different fixtures like handrails or guardrails.

It continues to make improvements and release amended versions of the eponymous International Building Code, laying out the guidelines and requirements that architects must follow.

Updated editions are published every three years, with the latest version being released in 2021. Many other organizations, such as the ADA, OSHA, or the National Fire Protection Association, to align their publishing schedules with the IBC.

It’s important to note that the IBC only publishes requirements that relate to commercial spaces. For residential spaces, a separate model code, entitled the International Residential Code, are published.

The Use of Glass in Modern Buildings

Glass is one of the most widely used materials in modern architecture. It not only has a clean contemporary look, it allows natural light in, and lets occupants view the outside world while protecting them from external elements and providing various levels of safety.

But the use of glass in buildings must comply with different problems, such as energy efficiency, life safety, and protection from the elements. The International Building Code (IBC) provides guidelines that focus on all three of these areas.

Railing systems in many cases can be seen as an extension of the building façade both aesthetically and functionally. Glass railings have the same performance requirements as other railing systems with additional safety criteria for the glass itself.

In the following article, we are going to discuss the important building codes associated with glass guardrails.

Using a Top Rail is a Requirement – With an Exception

IBC 2021 requires all-glass systems to be designed with top rails to prevent falls in case the glass breaks. The requirement was introduced in the 2015 iteration of the IBC, and is designed to improve safety.

A top rail is required for all glass baluster panels. The glass, in such types of guardrails, is generally designed to be load-bearing. The IBC requires such installations to add a top rail that needs to be attached to a minimum of three glass balusters.

This is designed to offer maximum safety; in the event of one glass baluster panel failing, the top railing will still be there to prevent a fall, and shall provide enough coverage across the opening.

However, there’s an exception to this requirement; laminated glass balusters. In case the glass baluster is laminated and has been impact-tested to be used as a barrier in compliance with ASTM standard 2353 (The American Society for Testing and Materials), then a top rail isn’t a requirement.

As per Section 2407.1.2, “A top rail shall not be required where the glass balusters are laminated glass with two or more glass plies of equal thickness and the same glass type when approved by the building official. The panels shall be designed to withstand the loads specified in Section 1607.8.”

It’s important to note that top rails aren’t a requirement for infill panels, in situations where the glass is in a non-load bearing position and has support from fixed structural metal rails.

Glass Lamination Requirements

IBC 2021 also provides instructions for the type of glass to be used. First introduced with the 2015 code, the IBC recommends that all glass used in  guards must be:

  • Laminated
  • Should be fully tempered or heat-strengthened
  • Should meet the safety glazing requirements of the Cat. I (16 C.F.R. 1201) or Class A (ANSI Z97.1).

This is designed to not only protect people from falling a level below in case the glass breaks, but it also protects occupants from the risk of shattering glass from above. These requirements originated due to several instances where monolithic glass railings were breaking.

Monolithic glass is only allowed when there isn’t a walkway under the glass, or if the walking surface offers permanent protection from the risk of falling glass.

Load Requirements

Section 2403.4 states, “Where interior glazing is installed adjacent to a walking surface, the differential deflection of two adjacent unsupported edges shall not be greater than the thickness of the panels when a force of 50 pounds per linear foot (plf) (730 N/m) is applied horizontally to one panel at any point up to 42 inches (1067 mm) above the walking surface.

Essentially, what this means is that glass guards must be able to comply with two discrete load requirements, including a linear load of 50 pounds per linear foot, as well as a concentrated load of 200 pounds, as specified in IBC Section 1607.8.

More importantly, glass used in guardrails must be manufactured using a safety factor of four, as per section 2407.1.1. To ensure compliance, manufacturers can divide the conventional glass strength values by four. Keep in mind that this only applies to glass materials used in the guardrails, not other materials.

Glass Edges

One of the major issues that arise with the use of laminated glass is the exposed edges. For this purpose, there are standards by both the IBC and the ASTM. In situations where a top rail, such as an aluminum railing, isn’t required, the quality of the exposed edges is incredibly important.

Generally, architects expect the quality to be similar across both laminated and monolithic glass. Edge tolerances are specified for glass railing systems in the ASTM:

ASTM C1036: Standard specifications for flat glass

ASTM C1048: Standard specification for heat-strengthened and fully tempered flat glass

ASTM E2353-06: Specifications for glass performance in permanent glass railing systems and balustrades

ASTM E2358-04: Specifications for glass performance in permanent railing systems and balustrades


The International Building Code requires all glass used as guards to be permanently marked with the manufacturer’s mark. The marking must also include the type and the thickness of the glass, as well as the name of the installer and the manufacturer. The safety glazing standard used must also be added. 

For labels on laminated glass, the building code officials can also give approval for a certificate or provide any other form of evidence instead of a permanent label, as per Section 2403.1 and Section 2406.3 and 2406.3.

In areas with a higher windload, such as in the Miami-Dade area, the building code also provides safety requirements to prevent the exterior glass guards from shattering and becoming windborne debris missiles.

As per Section 2404.1, Windloads in Vertical Glazing Applications, only laminated glass must be used in guards. If there’s a top rail attached, the glass must also meet the requirements specified in the Windloads Section (2404.1).

Authority Having Jurisdiction

Even though the universal adoption of the International Building Code would be ideal, the fact remains that it’s a model code. To ensure that the design meets the code, it’s important to discuss with the Authority Having Jurisdiction (AHJ).

Depending upon the location, this could either be the fire marshal, the accessibility reviewer, or the building inspector. It’s best to get in touch with the railing supplier to gain a better understanding of the right authority.

Contact GRECO Architectural Metal Products – Your Glass Railing Experts

If you’re looking for a reliable solution for your glass guardrails, get in touch with GRECO’s engineering team. GRECO designs, engineers, manufactures and installs all types of architectural railings and metal products, strictly in line with the current building codes. GRECO can help designers select and design the perfect glass railing for the project.

Being an industry leader in this space, GRECO offers the latest designs, top-notch customer service, and technical support to help architects and builders install railings withou