Underwriters Laboratories (U.L.) is an organization referenced in the 1935-miami-dade-building-code as a provider of standards and certifications for building materials, particularly regarding fire resistance, structural integrity, and roofing specifications.
Role in the 1935 Miami-Dade Building Code
In Chapter 24: Masonry, the code accepts certificates furnished by Underwriters Laboratories in lieu of physical tests for certain materials, specifically hollow concrete blocks (p. 147).
Specific Applications
- Hollow Concrete Blocks: The Building Inspector may accept U.L. certificates for hollow concrete blocks used in exterior, party, or division walls, bypassing the requirement to test five units on-site (p. 147).
- “Special” Concrete Units: “Special” concrete blocks or tile must comply with the Underwriters Laboratories’ Standard for Hollow Concrete Building Units, dated September 26, 1930 (p. 148). U.L. certified units are explicitly considered “Special” units (p. 148).
- Fire Doors: Fire doors bearing the label of the Underwriters Laboratories, Incorporated, are accepted as meeting the requirements for one-hour fire-resistive doors, including tin-clad wood-core and sheet metal types (p. 293).
- Fire-Resistive Windows: Fire-resistive windows bearing the U.L. label are accepted as one-hour fire-resistive windows (p. 295).
- Roof Coverings: “Fire Retardant” roofings may be accepted if they meet Class A or B specifications of the Underwriters Laboratories, Incorporated, provided they bear the label and are laid in the manner prescribed (p. 295). “Ordinary” roofings may meet Class C specifications of the Underwriters Laboratories (p. 298).
The reliance on underwriters-laboratories highlights the code’s integration of third-party testing and certification to ensure material quality and fire-resistive-construction-requirements.
Related Entities
- american-society-for-testing-materials
- american-concrete-institute
- national-board-of-fire-underwriters