Which statement about Heavy Timber Arch is false?

Which statement about Heavy Timber Arch is false?

• A. Constructed of large structural members
• B. 2x12 or larger
• C. Joists consisting of 2x6s and 1x6 Sheathing
• D. Adhere to 30 minute burn rule

Answer: (D)

Heavy Timber Arch relies on large timber members whose size itself contributes to fire resistance. When timber is exposed to fire, a char layer forms on the surface that insulates the inner wood and slows heat transfer, helping the structure maintain strength longer. Because of this inherent protection, fire resistance for heavy timber is typically specified in minutes or hours by the building code, not by a simple 30-minute rule. So the claim about following a 30-minute burn rule isn’t accurate for Heavy Timber Arch. The idea that it uses large structural members is correct, and cross sections like 2x12 or larger are consistent with heavy timber practices. Floors in such systems can involve built-up timber assemblies like 2x6 joists with 1x6 sheathing, which fits within heavy timber design approaches.

Heavy Timber Arch relies on large timber members whose size itself contributes to fire resistance. When timber is exposed to fire, a char layer forms on the surface that insulates the inner wood and slows heat transfer, helping the structure maintain strength longer. Because of this inherent protection, fire resistance for heavy timber is typically specified in minutes or hours by the building code, not by a simple 30-minute rule. So the claim about following a 30-minute burn rule isn’t accurate for Heavy Timber Arch. The idea that it uses large structural members is correct, and cross sections like 2x12 or larger are consistent with heavy timber practices. Floors in such systems can involve built-up timber assemblies like 2x6 joists with 1x6 sheathing, which fits within heavy timber design approaches.