ACI Code Requirements for Determining Fire Resistance of Concrete and Masonry Construction Assemblies. for Determining. Fire Resistance of. Concrete and Masonry. Construction Assemblies. Reported by ACI/TMS Committee A. CI/TMS M An ACI /TMS. Find the most up-to-date version of ACI at Engineering
|Published (Last):||19 January 2013|
|PDF File Size:||7.93 Mb|
|ePub File Size:||9.40 Mb|
|Price:||Free* [*Free Regsitration Required]|
It is a multi-functional system in a single package: Table 4 contains sample calculations for the 93 pcf unit; calculations for the pcf units use the same methods.
The system also is somewhat inflexible in that little variation from the original tested wall assembly is allowed including unit size, shape, mix design, ingredients, and even the plant of manufacture. The strength, purity, thermal stability, and insulative qualities of Buildex aggregate make it an excellent performer in fire exposure, both in poured concrete and SmartWall masonry. The wci rating of walls with cmu using blended aggregates is determined per CBC Section These hourly fire resistance ratings can be established by three different methods: It is based on thousands of tests.
This is then added to the base concrete masonry wall equivalent thickness which is used in Table 1 to determine the fire resistance rating.
FIRE RESISTANCE RATING OF CONCRETE MASONRY ASSEMBLIES
The ratings are shown here in more detail to illustrate the difference in performance between different density units. Non-combustible Norlite masonry construction mitigates the spread of fires and the dangers of structural collapse. By drawing on this data, methods of calculation have been developed to determine fire resistive ratings. In many cases drywall, plaster or stucco finishes are added to concrete masonry walls. This adjustment recognizes the fact that the ASTM C test method for net volume of concrete masonry units typically results in slightly lower values for lightweight concrete masonry.
Expanded Shale, Clay or Slate. This adjustment makes the calculations conservative, and they are expected to more closely match “real world” testing lab results, both for lightweight and heavy weight units.
Fire Resistive Ratings
The fire resistance rating of multi-wythe walls Figure 2 is based on the fire resistance of each wythe and the air space between each wythe in accordance with the following Equation.
More importantly, the Standard is a document that has gone through a formal consensus process and is written in mandatory language, and therefore is now incorporated by reference into the national model codes.
The fire rating of the wall assembly is then the lowest of the two. The minimum required cover over the vertical reinforcement is 2 in. For partially acii concrete masonry walls using 8-inch thick cmu rated at 2 hours, the fire-resistance rating can be increased to 4 hours when ungrouted cores are filled with any of the following: The fire resistance rating of concrete masonry lintels is determined based upon the nominal thickness of the lintel and the minimum cover of 261.1 reinforcement in accordance with Table 5.
Concrete masonry units manufactured with Norlite aggregates are readily available throughout the Northeast. Also publishers of directories that list classified assemblies.
When calculating the fire resistance rating of a wall with finishes, two calculations are performed. Nominal Width Equivalent Thickness, inches 8 inch 4. The fire resistance rating of reinforced concrete masonry columns is based on the least plan dimension of the column as indicated in Table 4. It is based on extensive research which established a relationship between physical properties of materials and the fire resistance rating.
The equivalent thickness of a hollow unit is equal to the percentage solid times the actual thickness of the unit. Home About Projects Contact Us. To calculate the fire resistance rating of a concrete masonry unit, its equivalent thickness and the proportion of aco s used in its production must be known.
Customer Service Login Apply for account. Note that there may be situations where the wall needs to rated with the fire on only one side. For this illustration, river sand is blended with Buildex Expanded Shale Lightweight Aggregate to produce a 93 pound per cubic foot concrete masonry unit, which is the specified maximum density for SmartWall Systems. An alternative 2161 the calculation method is provided by private commercial listing services.
Gypsum wallboard and gypsum lath may be attached to wood or metal furring strips spaced a maximum of 24 in. For the most part, the contents of the Standard are not new, but rather are a compilation and refinement of the many acci previously published by the various segments of the masonry and concrete industry. If the mixes were made with a lightweight aggregate of different density from another source, the aggregate proportions and the resulting fire resistance ratings will vary from afi shown in Table 1.
Concrete masonry is widely specified for fire walls and fire separation walls because these elements are:. For the lightweight xci 93 and pcf 2116.1 the net volumes in Table 3 were reduced approximately 2.
The fire resistance rating of concrete masonry is typically governed by the heat transmission criteria. Units manufactured with a combination of aggregate types are addressed by footnote 2 which may be expressed by the following equation:.
The following proportions were used for blending Buildex and sand: Norlite, LLC S. For partially grouted walls where the unfilled cells are left empty, the equivalent thickness for fire resistance rating purposes is equal to that of an ungrouted unit.
Built In Fire Safety If the cells of hollow unit masonry are filled with approved materials, the equivalent thickness of the assembly can be considered the same as the actual thickness.
ACI Code Requirements for Determining Fire Resistance of Concrete and Masonry
Gypsum wallboard must be installed with the long dimension parallel to the furring members and all horizontal and vertical joints must be supported and finished. Finishes that are assumed to contribute to the total fire resistance rating of a wall must meet certain minimum installation requirements. The fire resistance ratings for lightweight units were calculated by linear interpolation using two steps, as illustrated in Table 4 below.
The listing service approach allows the designer to select a fire rated assembly which has been previously classified and 21.61 in a published directory of listed fire rated assemblies. For multi-wythe walls of clay brick and concrete masonry, use the values of Table 3 for cai brick wythe in the above equation.
American Society for Testing and Materials, It also includes assemblies composed of concrete masonry and other components including plaster and drywall finishes, and multi-wythe masonry components including clay or shale masonry units. Saratoga Street Cohoes, NY phone fax info norliteagg.
The third option, testing of representative elements of the construction in accordance with standard fire test methods 26.1 generally not practical due to the expense of the test and time required to build, cure, and test representative specimens.