![]() ![]() The calculated fire resistance method is based on extensive research and testing of concrete masonry walls. The last two options listed above require justification to the building official that the proposed design is at least the equivalent of what is prescribed in the code.ĬALCULATED FIRE RESISTANCE RATINGS Background 18).įor prescriptive designs, the IBC provides a series of tables that describes requirements of various assemblies to meet the fire resistance ratings specified. More information on listing services for fire ratings is provided in NCMA FAQ 21-14, What is the difference between fire resistance ratings for masonry assemblies obtained through IBC versus a listing service such as UL or FM? (ref. The system also is somewhat inflexible in that little variation from the original tested wall assembly is allowed, including unit size, shape, mix design, constituent materials, and even the plant of manufacture. The listing service also monitors materials and production to verify that the concrete masonry units are and remain in compliance with appropriate standards, which usually necessitates a premium for units of this type. Private commercial listing services allow the designer to select a fire rated assembly that has been previously tested, classified and listed in a published directory of fire rated assemblies. The calculation method is fully described in ACI/TMS 216.1 and IBC Section 722, and determines fire resistance ratings based on the equivalent thickness of concrete masonry units and the aggregate types used to manufacture the units. The calculations are based on extensive research, which established relationships between the physical properties of materials and the fire resistance rating. Of these, the calculation method is an economical and commonly used method of determining concrete masonry fire resistance ratings. alternative means approved by the building official per Section 104.11 of the IBC. ![]() third party listing services, such as Underwriters Laboratory and.engineering analysis based on a comparison with tested assemblies.prescriptive designs such as those in Section 721 of the IBC.standardized calculation procedures, such as those in ACI/TMS 216.1 and in Section 722 of the IBC.METHODS OF DETERMINING FIRE RESISTANCE RATINGSīecause full-scale fire testing of representative test specimens is not practical in daily practice due to time and financial constraints, the IBC outlines multiple options for alternatives for fire rating determination: Also included are assemblies composed of concrete masonry and other components, including plaster and gypsum wallboard finishes, and multi-wythe masonry components including clay or shale masonry units. Included are methods for determining the fire resistance rating of concrete masonry walls, columns, lintels, beams, and concrete masonry fire protection for steel columns. The calculation procedure allows the designer virtually unlimited flexibility to incorporate the excellent fire-resistive properties of concrete masonry into a design. This TEK is based on both prescriptive details and tables as well as the calculated fire resistance procedure, which is practical, versatile and economical. The 2014 edition of the ACI/TMS 216.1 is referenced by the 20 IBC for concrete and masonry materials. ![]() 1), which outlines a procedure to calculate the fire resistance ratings of concrete masonry assemblies. This TEK is based on the provisions of Code Requirements for Determining Fire Resistance of Concrete and Masonry Construction Assemblies, ACI/TMS 216.1 (ref. 2, 3) governs materials and assemblies used for structural fire resistance and fire-rated separation of adjacent spaces. ![]() Concrete masonry is widely specified for fire walls and fire barriers because concrete masonry is noncombustible, provides durable fire resistance, and is economical to construct.Ĭhapter 7 of the International Building Code (IBC) (refs. ![]()
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