NASCLA Accredited Commercial General ContractorWoodMedium
A construction project requires the use of fire-retardant treated wood (FRTW) for interior non-load-bearing partitions in a commercial occupancy. Which of the following statements about FRTW is true regarding its structural properties?
- AThe fire-retardant treatment process has no impact on the long-term durability or structural performance of the wood.
- BFRTW always has the same strength properties as untreated wood of the same species and grade.
- CFRTW is typically stronger than untreated wood due to the chemical impregnation process.
- DFRTW can exhibit reduced strength properties, especially at elevated temperatures or high humidity.
Show answer & explanationAnswer & explanation
Correct answer: D. FRTW can exhibit reduced strength properties, especially at elevated temperatures or high humidity.
Fire-retardant chemical treatments can sometimes reduce the strength properties of wood, particularly its modulus of elasticity and modulus of rupture. This effect can be exacerbated in environments with high temperatures and humidity, which can affect the long-term performance of the treated wood.
Why the other options are wrong
- A. The treatment process can impact long-term durability and structural performance, requiring specific design considerations and limitations.
- B. FRTW often has reduced strength properties compared to untreated wood, especially for certain treatments and environmental conditions.
- C. FRTW is generally not stronger; the treatment typically has a neutral or negative effect on strength.
Fire-Retardant Treated Wood (FRTW)
Wood impregnated with fire-retardant chemicals to reduce its flammability and rate of flame spread.
- Used to meet specific fire code requirements.
- Can affect structural properties, requiring design adjustments.
- Performance can be sensitive to environmental conditions (heat, humidity).
Memory trick: Fire treatment helps with flames, but your strength might not be the same.