Which standards are commonly used to establish fire resistance ratings for building assemblies?

• A. UL 263
• B. ASTM E119
• C. Both UL 263 and ASTM E119, which are used to establish fire resistance ratings.
• D. NFPA 251.

Answer: (C)

Fire resistance ratings come from standardized furnace tests that determine how long a building element can resist fire while preserving structural stability, integrity, and insulation. The two widely used test standards are ASTM E119 and UL 263. Both specify the fire exposure, specimen mounting, duration, and acceptance criteria, and they both yield ratings (like 1-hour or 2-hour) that codes rely on to define how long an assembly must withstand fire. While NFPA 251 also covers fire testing, the common references in modern standards and codes for establishing fire resistance ratings are ASTM E119 and UL 263.