UL 263:2021 PDF Download

The UL 263:2021 standard establishes fire testing methods for various building assemblies and structural units. These tests apply to masonry units, composite assemblies, walls, partitions, columns, girders, beams, slabs, and composite floor and roof assemblies. The purpose of these tests is to evaluate the ability of these assemblies to withstand fire exposure and retain their structural integrity.

The classifications provided in the standard are specific to the performance of assemblies during the fire exposure period and should not be interpreted as determining their suitability for use after a fire. The tests assess the assembly's resistance to heat and, in some cases, a hose stream, while under load if it is load-bearing. The standard defines the conditions for a standard fire exposure, including specified temperatures and duration, and in some cases, the application of a fire hose stream. It is important to note that these tests may not represent all fire conditions that can occur in practice.

During the test exposure, the standard measures the transmission of heat and hot gases through the assembly, as well as the load-carrying ability of load-bearing elements and individual assemblies. However, the standard does not cover data accumulation for assemblies constructed with different components, evaluation of smoke or toxic gas generation, measurement of smoke passage control, simulation of fire behavior for joints or connections, measurement of flame spread on the surface, or the effect of conventional openings in the assembly on fire endurance. These aspects are outside the scope of this standard.

The tests described in UL 263 may be referred to as "Standard Fire Tests," with the performance expressed in terms of hourly classifications (e.g., 2-hour, 6-hour, 1/2-hour). The results of these tests serve as one factor for assessing the fire performance of building construction and assemblies. However, the application of these results to predict the performance of actual building construction requires careful evaluation of the test conditions. If a higher level of safety is desired, adjustments to the specified time classification period should be made.