How does the building code define railings and glass guards? While the term “railing” is used throughout the code, it is not defined in the building code. Instead, the IBC defines the term “guard.” A guard is defined in Section 202 as a building component or system of building components located at or near the open sides of elevated walking surfaces that minimizes the possibility of a fall from the walking surface to a lower level. ASTM E2353 Standard Test Methods for Performance of Glass in Permanent Glass Railing Systems, Guards & Balustrades defines guardrail similarly. Other related terms to understand and differentiate include: