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A contractor is installing drywall in a commercial office. To comply with fire codes for a rated wall assembly, which type of gypsum board must be used?

  1. ARegular gypsum board
  2. BSound-reducing gypsum board
  3. CMoisture-resistant gypsum board
  4. DType X gypsum board
Show answer & explanation

Correct answer: D. Type X gypsum board

Type X gypsum board (fire-rated drywall) contains special additives, typically fiberglass, in its core to increase its fire resistance. It is specifically designed and tested for use in fire-rated wall and ceiling assemblies to meet building code requirements.

Why the other options are wrong

  • A. Regular gypsum board does not have the enhanced fire resistance required for rated wall assemblies.
  • B. Sound-reducing gypsum board (QuietRock, etc.) is for acoustic performance, not primarily fire resistance.
  • C. Moisture-resistant gypsum board (greenboard) is for high-humidity areas, not fire resistance.

Type X Gypsum Board

A fire-resistant type of gypsum board containing special additives, usually fiberglass, in its core to enhance its resistance to fire, typically used in fire-rated wall and ceiling assemblies.

  • Fire-rated
  • Contains fiberglass
  • For rated assemblies

Memory trick: For a 'fire-rated wall', choose 'Type X' gypsum board, it's got that 'extra' fire protection.

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