FIRE-RESISTANCE DESIGN

Fire-resistance Ratings - ANSI/UL 263, BXUV


Guide Information for Fire-resistance Ratings

508.2.2.1508.3509509.2509.3509.4509.5509.6509.7509.7.1509.8602.1603.1702.1703703.2703.2.1703.2.3703.3704704.1704.11704.5704.6704.7704.9705705.1705.2705.3705.4705.5705.5.1705.5.2705.6705.6.1705.7706706.2.1706.3706.3.7706.4707707.12707.13707.13.1707.14.1707.4708708.1708.3708.4709709.3709.4710710.3711711.3711.3.1711.4712712.3712.3.1.1712.4712.4.1.1712.4.2714714.1714.2714.2.1714.2.2714.2.3714.5714.7716716.5.1716.5.2716.5.4716.5.4.1716.5.5716.6.2.1718718.1718.2718.5720721803.4.1803.4.2803.9.1.2805.1.1805.1.2909.11909.20909.20.2909.20.6.1910.4.4911.11007.61007.81017.11020.11020.1.31020.1.41020.1.7.11021.31022.210241024.11024.31024.5.21026.112071401.11403.21403.514061704.111704.122303.1.5.325012504.1.22603.52603.5.12603.5.73002.13005.3.13006.43104.103104.5T1017.1T601T602110.31(A)(1)110.31(A)(2)300.11(A)(1)518.4(C)645.4(5)695.14(E)695.14(F)(2)695.6(A)(2)(D)(2)700.10(D)(1)(4)700.10(D)(2)708.10(C)(2)(2)708.11(B)(1)708.20(B)110.31(A)(1)110.31(A)(2)300.11(A)(1)518.4(C)645.4(5)695.14(E)695.14(F)(2)695.6(A)(2)(D)(2)700.10(D)(1)(4)700.10(D)(2)708.10(C)(2)(2)708.11(B)(1)708.20(B)

Design Information Section

The Design Information Section supplements the individual published designs and is organized as follows:

I. INTRODUCTION
1. Rapid-rise Fire Test
2. Definitions
II. GENERAL
1. Metric Dimensions 12. Dampers
2. Loading of Test Specimens 13. Wood Structural Panels
3. Finish Ratings 14. Blanket Insulation
4. Nails and Screws 15. Sound Transmission Class (STC)
5. Interior and Exterior Applications 16. Impact Insulation Class (IIC)
6. Exposed Interior Finishes 17. Penetrations
7. Radiant Heating Cable and Panels 18. Curtain Wall/Floor Protection Systems
8. Coating Materials 19. Fire-resistant Joint Systems
9. Gypsum Board 20. Fire Doors, Frames and Hardware
10. Gypsum Board Joint Treatment (Taping) 21. Glazing, Wired Glass and Glass Blocks
11. Plaster 22. Exterior Wall Systems
III. FLOOR-CEILINGS AND ROOF-CEILINGS
1. Concrete 13. Enclosures for Fluorescent Recessed Luminaires (Troffers)
2. Fiber Reinforcement 14. Luminaires Certified for Fire Resistance
3. Steel Floor and Form Units 15. Restrained and Unrestrained Assemblies
4. Electrical Boxes for Concrete Floors 16. Air Ducts and Protection Systems
5. Nonmetallic Outlet Boxes for Ceilings 17. Blanket Insulation
6. Metallic Electrical Outlet Boxes 18. Wood Frame Construction
7. Steel Joists 19. Roof Coverings
8. Precast Concrete Units 20. Roof Insulation
9. Ceiling Control Joints 21. Uplift Resistance
10. Acoustical Materials 22. Steel Roof Deck Fasteners
11. Suspension Systems 23. Steel Floor Unit Fasteners
12. Fluorescent Recessed Luminaires (Troffers) 24. Use of Floor-Ceilings as Roof-Ceilings
IV. BEAMS
1. Beam Size 5. Unprotected Floors and Roofs
2. Composite and Noncomposite Beams 6. Adjustment of Thickness of Spray-applied Fire-resistive Materials for Restrained and Unrestrained Beams
3. Cavities 7. Restrained and Unrestrained Conditions
4. Beam Substitution  
V. COLUMNS
VI. WALLS AND PARTITIONS
1. Gypsum Board 7. Gypsum Board Joint Treatment (Taping)
2. Mineral Fiber Insulation 8. Nonmetallic Electrical Outlet Boxes
3. Wood Stud Wall Assemblies 9. Metallic Electrical Outlet Boxes
4. Steel Stud Wall Assemblies 10. Exterior Walls
5. Metal Thickness 11. Concrete Masonry Units
6. Wood Structural Panels  

This category covers fire-rating certifications based upon the test method and acceptance criteria in ANSI/UL 263 (ASTM E119), "Fire Tests of Building Construction and Materials." The ratings are expressed in hours and are applicable to floor-ceilings, roof-ceilings, beams, columns, walls and partitions.

The average furnace temperature from which these ratings are derived is 1000°F at 5 min., 1400°F at 15 min., 1550°F at 30 min., 1700°F at 60 min., 1850°F at 120 min., 1925°F at 180 min., and 2000°F at 240 min.

When a test assembly complies with the acceptance criteria, a detailed description of the assembly, its performance in the fire test, and other pertinent details such as specification of materials, certification coverage and alternate assembly details are included in a Report for the test sponsor. Sponsors may provide copies of the complete Test Report upon request. The Report also contains a summary of important features of the rated assembly. These summaries are also published in this Directory. Variations from the published specifications should be considered as not being investigated by UL.

NUMBERING SYSTEM FOR FIRE-RATED ASSEMBLIES

TYPES OF PROTECTION

Membrane Protection
Direct-applied Protection
Unprotected
Groups of
Construction

000-099

100-199

200-299

300-399

400-499

500-599

600-699

700-899

900-999
Floors-Ceilings:
A or B*
Concrete and
Cellular Steel
Floor
Concealed
Grid
System
(Reserved) Exposed Grid System (Reserved) Metal Lath Gypsum Board Misc. Spray-
applied
Fire-
resistive
Material
Unprotected
C - Glazing Systems (Reserved) (Reserved) (Reserved) (Reserved) (Reserved) (Reserved) (Reserved) (Reserved) Unprotected
D, E* or F*
Concrete and Steel
Floor Units
Concealed
Grid
System
(Reserved) Exposed Grid System Mineral and Fiber Boards Metal Lath Gypsum Board Mastic
and
Intumescent
Coatings
Spray-
applied
Fire-
resistive
Material
Unprotected
G or H*
Concrete and
Steel Joists
Concealed
Grid
System
(Reserved) Exposed Grid System Mineral and Fiber Boards Metal Lath Gypsum Board Misc. Spray-
applied
Fire-
resistive
Material
Unprotected
I
Non-load-bearing
Horizontal
Barrier
(Reserved) (Reserved) (Reserved) (Reserved) (Reserved) Gypsum Board (Reserved) (Reserved) (Reserved)
J or K
Concrete
Concealed
Grid
System
(Reserved) Exposed Grid System Mineral and Fiber Boards Metal Lath Gypsum Board Misc. Spray-
applied
Fire-
resistive
Material
Unprotected
L or M
Wood Joist or
Combination
Wood and
Steel Assemblies
Concealed
Grid
System
(Reserved) Exposed Grid System (Reserved) Metal Lath Gypsum Board Misc. Spray-
applied
Fire-
resistive
Material
Unprotected
Beams:
N or O* for
Floor-Ceiling
Concealed
Grid
System
(Reserved) Exposed Grid System Batts and Blankets or Mineral and Fiber Boards Metal Lath Gypsum Board Mastic
and
Intumescent
Coatings
Spray-
applied
Fire-
resistive
Material
Unprotected
Roof-Ceiling:
P, Q* or R*
Concealed
Grid
System
(Reserved) Exposed Grid System Mineral and Fiber Boards Metal Lath Gypsum Board Misc. Spray-
applied
Fire-
resistive
Material
Unprotected
Beams:
S or T* for
Roof-Ceiling
Building
Units
(Reserved) Exposed Grid System Mineral and Fiber Boards Metal Lath Gypsum Board Mastic
and
Intumescent
Coatings
Spray-
applied
Fire-
resistive
Material
Unprotected
Wall and Partition:
U, V or W
Building
or
Partition
Panel
Units
(Reserved) Insulating
and
Precast
Concrete
Wood Stud, Gypsum Board, Lath and/or Plaster Metal Stud, Gypsum Board, Lath and/or Plaster Misc. Metal Panels, Gypsum Board, Lath and/or Plaster Spray-
applied
Fire-
resistive
Material
Masonry and Precast Concrete
Columns:
X, Y or Z*
Building
Units
Pre-
fabricated
Mat Materials Batts and Blankets or Mineral and Fiber Boards Metal Lath and Plaster Gypsum Board Mastic
and
Intumescent
Coatings
Spray-
applied
Fire-
resistive
Material
Masonry

The prefix numbers with an asterisk (*) and the design numbers indicated as "Reserved" in the above table are for future expansion and to cater to new types of systems developed in the future.

1. Rapid-rise Fire Test

Fire-resistance designs for protecting structural members subject to petrochemical exposure fires are investigated to ANSI/UL 1709, "Rapid Rise Fire Tests of Protection Materials for Structural Steel," and are covered under Fire-resistance Ratings - ANSI/UL 1709 (BYBU). Systems complying with these requirements include an "XR" design prefix.

2. Definitions

Definitions of selected terms used to identify the types of protection referenced in the following Numbering System Table are:

Batts and Blankets — A category for a group of UL-certified products. The complete description of the products in the category and supplementary requirements for certification are covered under Batts and Blankets (BZJZ).

Building Units — A category for a group of UL-certified products. The complete description of the products in the category and supplementary requirements for certification are covered under Building Units (BZXX).

Category Control Number (CCN) — A unique four- or five-character alphanumeric designation assigned by UL to identify individual product categories (may also be referred to as a UL Category Code). For example, the product category Acoustical Materials is identified by the CCN BYIT.

Ceiling Radiation Damper — A device installed in a ceiling membrane of a fire-resistance-rated floor-ceiling or roof-ceiling assembly to automatically limit the radiative heat transfer through an air inlet/outlet opening. The complete description of the products and supplementary requirements for certification are covered under Air Terminal Units (BZGU), Ceiling Air Diffusers (BZZU) and Ceiling Dampers (CABS).

Code Authority — The Authority Having Jurisdiction, building official, code official, or other entity responsible for enforcing the locally adopted and enforced building, fire or life safety code.

Combination Fire/Smoke Damper — A device installed in ducts and air-transfer openings designed to close automatically upon the detection of heat and resist the passage of flame and smoke. The device is installed to operate automatically, controlled by a smoke-detection system and, where required, is capable of being positioned from a fire command center. The complete description of the products in the category and supplementary requirements for certification are covered under Dampers for Fire Barrier and Smoke Applications (EMME).

Concealed Grid System — Ceiling-suspension system for acoustical material that is not visible from the occupied space.

Corridor Damper — A device intended for use where air ducts penetrate or terminate at horizontal openings in the ceilings of fire-resistance-rated corridors, where the corridor ceiling is permitted to be constructed as required for the corridor walls. The complete description of the products in the category and supplementary requirements for certification are covered under Dampers for Fire Barrier and Smoke Applications (EMME).

Cross-laminated Timber (CLT) — A prefabricated engineered wood product consisting of not less than three layers of solid-sawn lumber or structural composite lumber where the adjacent layers are cross oriented and bonded with structural adhesive to form a solid wood element.

Direct-applied Protection — Various types of fire-resistive coating materials, including intumescent mastic and subliming coatings, and spray-applied fire-resistive materials, directly applied to the building element to provide protection from fire.

Exposed Grid System — Ceiling-suspension system for acoustical material that is visible from the occupied space.

Fire Damper — A device installed in ducts and air-transfer openings designed to close automatically upon detection of heat and resist the passage of flame. Fire dampers are certified for use in either static systems that will automatically shut down in the event of a fire, or in dynamic systems that continue to operate during a fire. A dynamic fire damper is tested and rated for closure under elevated temperature airflow. The complete description of the products in the category and supplementary requirements for certification are covered under Dampers for Fire Barrier and Smoke Applications (EMME).

Fire-resistant Joint System — An assemblage of specific materials or products rated in accordance with ANSI/UL 2079, "Tests for Fire Resistance of Building Joint Systems." Joint systems resist the passage of fire through joints between fire-resistance-rated assemblies for a prescribed period of time. See Joint Systems (XHBN).

Insulating Concrete — Nonstructural concrete with a unit weight less than 60 pcf.

Membrane Penetration — A breach in one side of a fire-resistance-rated floor-ceiling, roof-ceiling or wall assembly to accommodate an item installed into or passing through the breach.

Membrane Protection — Various rigid or semi-rigid boards installed adjacent to or around building elements to provide protection from fire.

Mineral and Fiber Boards — A category for a group of UL-certified products. The complete description of the products in the category and supplementary requirements for certification are covered under Mineral and Fiber Boards (CERZ).

Partition Panel Units — A category for a group of UL-certified products. The complete description of the products in the category and supplementary requirements for certification are covered under Units, Partition Panel (CJMR).

Prefabricated Building Columns — Structural building columns that include a fire-resistive protection system when delivered to the construction site. These products are certified and identified as Prefabricated Building Columns (CGHT). The complete description of the products and supplementary requirements for certification are covered under CGHT.

Smoke Damper — A certified device installed in ducts and air-transfer openings designed to resist the passage of smoke. The device is installed to operate automatically, controlled by a smoke-detection system and, where required, is capable of being positioned from a fire command center. The complete description of the products in the category and supplementary requirements for certification are covered under Dampers for Fire Barrier and Smoke Applications (EMME).

Through Penetration — A breach in both sides of a fire-resistance-rated floor-ceiling, roof-ceiling or wall assembly to accommodate an item passing through the assembly.

Through-penetration Firestop Systems — An assemblage of specific materials rated in accordance with ANSI/UL 1479 (ASTM E814), "Fire Tests of Penetration Firestops." Firestop systems maintain the fire-containment integrity of horizontal or vertical fire-resistive assemblies where through penetrations are located. See Through-penetration Firestop Systems (XHEZ).

Unprotected Fire-resistive Assemblies — Assemblies that do not require direct-applied coatings or suspended ceilings to protect the general floor or roof areas or structural elements.

Walls and Partitions — An assembly tested and intended to be used in a vertical orientation.

Wood Structural Panel — Wood structural panels include all-veneer plywood, composite panels containing a combination of veneer and wood-based material, and mat-formed panels such as oriented strand board and waferboard.

II. GENERAL

The following information is applicable to all fire-resistive designs described in this Directory. It is recommended that the users review this information in addition to the general guidelines provided for specific materials and construction types.

Authorities Having Jurisdiction should be consulted before construction.

Fire-resistance ratings apply only to assemblies in their entirety. Except for those separately rated structural members supporting tested assemblies, individual components are not assigned a fire-resistance rating and are not intended to be interchanged between assemblies but rather are designated for use in a specific design in order that the ratings of the design may be achieved. Unless otherwise specified in the individual design or certification, attachments to structural steel have not been investigated.

In order to remain within the design criteria the assembly must be constructed as specified in the published design. There are three potential types of acceptable modifications, as follows:

  • If a construction element is identified as "optional" or "may be provided" it is not mandatory and doesn't need to be included in the construction.
  • If a dimension is indicated as a minimum or maximum, the construction can include greater or lesser dimensions, respectfully.
  • The link at the top of each design entitled "See General Information for Fire-resistance Ratings - ANSI/UL 263" should be consulted. This link provides information on construction details, including clarifications and permitted variations.

All ratings are based on the assumption that the stability of the structural members supporting the assembly are not impaired by the effects of fire. The extent of damage of the test assembly at the rating time is not a criteria for the rating.

The specifications for materials in an assembly are important details in the development of fire-resistance ratings. Those materials provided with an "*" in the design text are eligible to be produced under the Follow-Up Service Program of UL. Information identifying such materials and the certified companies authorized to provide the materials are located in the product category section of this Directory. The appearance of the UL Certification Mark on the product is the only method provided by UL to identify products that have been produced under its Follow-Up Service.

1. Metric Dimensions

It is recommended that the "Metric Guide for Federal Construction," published by the National Institute of Building Sciences, be consulted for guidance regarding the use of metric-dimensioned building materials.

2. Loading of Test Specimens

ANSI/UL 263 requires the load applied to test samples to be based upon the limiting conditions of design as determined by nationally recognized structural design criteria. For some applications, the nationally recognized structural design criteria may be based upon the Allowable Stress Design (ASD) or the Load and Resistance Factor Design (LRFD) Method. For applications where these two design methods are available, the load applied to the test sample was determined in accordance with the Allowable Stress Design Method unless the rated assembly specifically references the Load and Resistance Factor Design Method. Also, unless otherwise stated, the load capacity of steel beams assumes the beams are fabricated from A36 steel.

ANSI/UL 263 permits samples to be tested with the applied load being less than the maximum allowable load as determined by the limiting conditions of a nationally recognized structural design criteria. The ratings for assemblies determined from tests where the applied load was less than allowed by the nationally recognized structural design criteria are identified as "Restricted Load Condition." The percent of the maximum load, the percent of the maximum stress, and the nationally recognized design criteria is identified in the text describing the structural element of rated assemblies with a restricted load condition. An example of the text used in an assembly with a restricted load condition and steel joist loaded to 80% of the maximum allowable is:

The design load for the structural member described in this design should not: (1) exceed 80% of the maximum allowable load specified in "Catalog of Standard Specifications and Load Tables for Steel Joists and Steel Girders," published by the Steel Joist Institute, or (2) develop a tensile stress greater than 24 ksi, which is 80% of the maximum allowable tensile stress of 30 ksi. (Note: The maximum allowable total load develops a tensile stress of approximately 30 ksi.)

Some restricted-load conditions have resulted from changes in product availability. An example is the substitution of K-Series joists for other series joists as described under Section III. FLOOR-CEILINGS AND ROOF-CEILINGS, Item 7, Steel Joists.

Assemblies tested with less than the maximum allowable load that would result from loading calculated using the Load and Resistance Factor Design Method or post-2015 AISC Specification criteria are identified as "Restricted Load Condition." The Percent Load Reduction and corresponding Load Restricted Factor for typical assemblies noted in Table I are based upon loading calculated in accordance with pre-2005 AISC ASD Specification criteria as compared to loading calculated in accordance with 2005 and later AISC Specification criteria in the United States. The calculations were performed for assemblies representing spans and member sizes of typical fire-test assemblies. The loads were calculated assuming a span of 13 ft for floors and roofs and 10 ft for walls. Calculations for wide-flanged steel beams assume a live-to-dead-load ratio of 3:1. A load restriction need not be applied for an unrestrained condition of any hourly rating nor applied for a restrained condition with an hourly rating of 1 hour or less.

Some fire-resistive designs are specified with a Restricted Load Condition. When using fire-resistive designs with a Restricted Load Condition, the factored resistance of the structural members or components should be reduced by multiplying the factored resistance by the Load Restricted Factor specified in the individual fire-resistive designs.

The Load Restricted Factor should be applied to the factored resistance of all structural members or components, including, but not limited to, factored moment resistance (Mr), factored shear resistance (Vr), factored tensile resistance (Tr) and factored compressive resistance (Cr).

Table I


Type of Assembly
Percent Load Reduction
(LRFD-ASD) / LRFD
Load Restricted
Factor
W8x28 - AISC
(W200x42 - CISC)
noncomposite steel beam
10% 0.9
W8x28 - AISC
(W200x42 - CISC)
composite steel beam
10% 0.9
Floor/Roof supported by open-web steel joists 4% 0.96
Floor supported by cold-formed steel channels 0% none
Floor supported by 2 x 10 in. (38 x 235 mm) wood joists 35% 0.65
Wall supported by 2 x 4 in. (38 x 89 mm) wood studs 18% 0.82
Wall supported by cold-formed steel studs 0 none
Steel columns * *
The ratings for floors supported by cold-formed steel channels and walls supported by cold-formed steel studs do not have a Load Restriction Factor as the associated loads in Canada and the U.S. are based on the same standard: CSA S136,  "North American Specification for the Design of Cold-Formed Steel Structural Members,"  and "North American Specification and Commentary for the Design of Cold-Formed Steel Structural Members."
* Unless otherwise specified in the individual designs, columns do not have a Load Restriction Factor, as those ratings are based on temperature limitations in accordance with ANSI/UL 263.

The engineer of record should be consulted whenever fire-resistive assemblies with Load Restricted Factors are selected. The indicated load reductions are based upon factored load effects that are governed by the reduced factored resistance of the structural elements. The selection of structural elements is, at times, based upon service limits, such as deflection and vibration. These factors and others, such as the change in material strength properties as a function of temperature, should be considered when selecting fire-resistive assemblies with Load Restricted ratings.

Unless stated in a design, it is recommended the Load Restricted Factors in Table I be used.

Assemblies developed from tests where the load applied on the sample was based upon calculations in accordance with the Load and Resistance Factor Design Method are identified in the individual certifications. These assemblies should not be considered "Load Restricted."

3. Finish Ratings

A finish rating is established for assemblies containing combustible (wood) supports. The finish rating is defined as the time at which the wood stud or wood joist reaches an average temperature rise of 250°F or an individual temperature rise of 325°F as measured on the plane of the wood nearest the fire. A finish rating is not intended to represent a rating for a membrane ceiling. The requirements for finish ratings are not included in ANSI/UL 263.

4. Nails and Screws

Nails are specified according to ASTM F547, "Standard Terminology of Nails for Use with Wood and Wood-Base Materials," or ASTM C514, "Standard Specification for Nails for the Application of Gypsum Board." Nails used to attach gypsum board to wood framing should be cement-coated box nails or cement-coated cooler nails unless specified otherwise in the individual designs. Screws meeting ASTM C1002, "Standard Specification for Steel Self-Piercing Tapping Screws for the Application of Gypsum Panel Products or Metal Plaster Bases to Wood Studs or Steel Studs," or ASTM C954, "Standard Specification for Steel Drill Screws for the Application of Gypsum Panel Products or Metal Plaster Bases to Steel Studs from 0.033 in. (0.84 mm) to 0.112 in. (2.84 mm) in Thickness," may be substituted for nails, one for one, when the head diameter, length, and spacing equal or exceed the requirements for the specified nails.

5. Interior and Exterior Applications

The fire-resistive designs and UL-certified materials are investigated with the understanding that their use is limited to interior applications unless otherwise specified in the individual designs or certification information (e.g., structural columns "Investigated for Exterior Use"). Where an exterior application of a UL-certified design is desired, the code authority should be consulted to ensure compliance with other code requirements applicable to exterior use.

6. Exposed Interior Finishes

The surface flammability and smoke-development characteristics of certified materials that may be used as exposed interior finishes are measured by the test method in ANSI/UL 723 (ASTM E84), "Test for Surface Burning Characteristics of Building Materials." The flame-spread index of such materials used in these designs is 200 or less. Such materials should also meet the interior finish provisions of the building code. Surface-burning characteristics certifications are contained in the UL Online Certifications Directory.

Interior finish materials including paint and wall coverings less than 0.036 in. thick and applied directly to the surfaces of walls and ceilings may be added to the exposed surfaces of fire-resistance-rated assemblies without restriction.

7. Radiant Heating Cable and Panels

The effect of the use of electrical radiant heating cable or wire on the fire-resistance performance of assemblies has not been investigated. Unless otherwise specified in the specific design, the use of electrical radiant heating panels in a fire-resistance-rated assembly is not permitted.

8. Coating Materials

Coating materials include products identified as: 1) Spray-applied Fire-resistive Materials and 2) Mastic and Intumescent Coatings.

The type of material is specified in each design. Materials that have been investigated for exterior application are so indicated in the individual designs and in the product category.

Unless specifically detailed in the individual designs or in the product certification information, the interaction of dissimilar fireproofing materials on the same structural element or at the intersection of structural members, and the adherence of one product to the other, has not been investigated under fire-test conditions.

Unless specifically detailed in the individual designs or in the product certification information, the impact of galvanization applied to structural steel members has not been investigated under fire-test conditions. Galvanization may impact the adhesion of spray-applied fire-resistive materials or mastic and intumescent coatings.

Spray-applied Fire-resistive Materials

The surfaces on which the material is to be applied must be free of dirt, oil and loose scale. Surfaces may be primed with the primers/paints covered under Primers for Structural Steel (CGJM).

The following method of determining the bond strength of the spray-applied materials only applies to galvanized steel, and primers or paints that are not covered under CGJM. Unless specifically prohibited in the individual designs, materials identified as Spray-applied Fire-resistive Materials (CHPX) may be applied to galvanized, primed or similarly painted wide-flange steel shapes and pipe and tube-shaped columns provided: (A) the beam flange width does not exceed 12 in.; (B) the column flange width does not exceed 16 in.; (C) the beam or column web depth (defined as inside of top flange to inside of bottom flange) does not exceed 16 in.; (D) the pipe outer diameter or tube width does not exceed 12 in.; (E) bond tests conducted in accordance with ASTM E736, "Standard Test Method for Cohesion/Adhesion of Sprayed Fire Resistive Materials Applied to Structural Members," should indicate a minimum average bond strength of 80% and a minimum individual bond strength of 50% when compared to the bond strength of the fire-resistive coating as applied to clean uncoated 1/8 in. thick steel plate (control sample). The average and minimum bond strength values should be determined based upon a minimum of five bond tests conducted in accordance with ASTM E736.

The bond tests need only be conducted when the fire-resistive coating is applied to a galvanized, primed or similarly painted surface for which acceptable bond strength performance between the galvanization, primer or other similar material and the fire-resistive coating has not been measured. A bonding agent may be applied to the galvanized, primed or similarly painted surface to obtain the minimum required bond strength where the bond strengths are found to be below the minimum acceptable values.

As an alternative to the bond test conducted on control samples applied to an uncoated steel plate, the following method may be used for unknown coatings in existing structures. Sections of galvanized or painted steel are to be coated with a bonding agent compatible with the sprayed material being used on the project. The treated and untreated substrates should be coated with material, cured, and subjected to five bond tests each, in accordance with ASTM E736. If the failure mode of the sections treated with the bonding agent is 100% cohesive in nature, it will be acceptable to use this bond test value as the control bond strength. The value obtained on the untreated galvanized or painted section should be compared to the control value using the minimum 80% average, 50% individual bond strength acceptance criteria established in ASTM E736.

If condition (E) is not met, a mechanical bond may be obtained by wrapping the structural member with expanded metal lath (minimum 1.7 lbs per sq yd).

If any of the conditions specified in (A), (B), (C) or (D) are not met, a mechanical break should be provided. A mechanical break may be provided by mechanically fastening one or more minimum 1.7 lbs per sq yd metal lath strips to the flange, web or tube and pipe surface either by weld, screw, or powder-actuated fasteners, on maximum 12 in. centers, on each longitudinal edge of the strip, so that the clear spans do not exceed the limits established in conditions (A), (B), (C) or (D) as appropriate. No less than 25% of the width of the oversize flange or web element should be covered by the metal lath. No strip of metal lath should be less than 3-1/2 in. wide.

As an alternative to metal lath, the mechanical break may be provided by the use of minimum 12 gauge steel studs with minimum 28 gauge galvanized steel disks if such a system is described in a specific design (usually a bottomless trench in an electrified floor design) for the fire-resistive coating being applied. The studs should be welded to the oversize element in rows such that the maximum clear span conforms to conditions (A), (B), (C) or (D) as appropriate. The spacing of studs along each row should not exceed 24 in. and a minimum one stud per 256 sq in. should be provided.

Where metal lath strips or steel studs and disks are used, acceptable bond strength as described in item (E) should also be provided. A bonding agent may be applied to the painted surface to obtain the required minimum bond strength where bond strengths to a painted surface are found to be below minimum acceptable values.

When non-UL certified steel deck is permitted as prescribed in protected deck designs (e.g., P700 series), painted or primed deck is to have min. 2.5 lb/sq. yd. galvanized or painted rib lath installed with ribs facing away from the deck and secured to the deck with #8 x 1/2 in. wafer-head screws spaced a maximum of 15 in. OC. Lath is permitted to follow the contour of the deck or span between the bottoms of the deck flutes. This guidance is to ensure proper adhesion of the fire-coating material to the deck as required by ASTM E736. Decks that are galvanized, painted or primed bearing the UL Certification Mark may also require the installation of lath to the deck. Refer to the individual designs to determine when lath is required and installation requirements when UL-certified steel floor and form units are used.

The dry density at which sprayed material should be applied to building elements is specified in the individual designs. Dry-density measurements may be determined by accurately measuring the thickness of a minimum 6 in. sq section randomly selected from the building, removing the material from the measure section, subjecting the samples to 120°F in an oven until constant weight is obtained, followed by accurate weighing of the dried sample, and calculating the density in lb per cu ft. Constant weight is usually obtained after 24 to 48 h exposure within a 120°F oven.

The spray-applied fire-resistive material thickness specification in a design should be considered the minimum average thickness of the individual thickness readings measured in accordance with ASTM E605, "Standard Test Methods for Thickness and Density of Sprayed Fire Resistive Material Applied to Structural Members." When spray-applied fire-resistive material is applied to metal lath, the spray-applied fire-resistive material thickness should be measured to the face of the lath unless specified otherwise in the individual designs.

Individual measured thickness, which exceeds the thickness specified in a design by 1/4 in. or more, should be recorded as the thickness specified in the design plus 1/4 in. For design thicknesses 1 in. or greater, the minimum allowable individual thickness should be the design thickness minus 1/4 in. For design thicknesses less than 1 in., the minimum allowable individual thickness should be the design thickness minus 25%.

The thickness of the spray-applied fire-resistive material should be corrected by applying additional material at any location where: (1) the calculated average thickness of the material is less than that required by the design or (2) an individual measured thickness reading is more than 1/4 in. less or more than 25% less (for design thicknesses greater than 1 in. and less than 1 in., respectively) than the specified thickness required by the design.

Areas of the structural frame and/or floor area are to be selected to obtain representative average thicknesses. Thickness readings on the floor or wall area are to be taken symmetrically over the selected area. The average of all measurements is to be considered the average thickness of the area. Thickness measurements on beams and/or columns are to be made around the member at sections within 12 in. of each other. The average thickness is to be considered the average of the readings taken at both sections.

Screw tips penetrating the steel roof deck in all P700 and P800 Series designs require spray-applied fire-resistive material. The spray-applied fire-resistive material specified in the design should be applied to cover the tips at a minimum thickness of 1/2 in.

Mixing and spraying instructions are included with each container of material.

Mastic and Intumescent Coatings

The surfaces on which the material is to be applied must be free of dirt, oil and loose scale. The certification information for materials identified as Mastic and Intumescent Coatings (CDWZ) should be consulted for specific recommendations regarding the application of the coating over primed painted surfaces.

The mastic and intumescent coating thickness specification in a design should be considered the minimum average thickness of the individual thickness readings measured in accordance with Technical Manual 12-B, "Standard Practice of the Testing and Inspection of Field Applied Thin-Film Intumescent Fire Resistive Materials; an Annotated Guide," published by the Association of the Wall and Ceiling Industries.

Extrapolation of member size and/or material thickness shown in the individual designs has not been investigated and would be considered to void the existing certified assembly.

The mastic and intumescent coating average thickness should not exceed the maximum thickness published in the individual designs and no individual thickness measurement should be less than 80% of the thickness specified in a design.

Mixing and spraying instructions are included with each container of material.

When mastic and intumescent coatings are exposed to fire, they expand and form an insulating char. Unless otherwise detailed in the individual designs, mastic and intumescent coatings are tested without any covering adjacent to the tested member that might interfere with the expansion of the coating. The effect on the fire-resistance rating of steel members (beams, columns, etc.) caused by any covering that would interfere with the expansion of a mastic and intumescent coating during a fire has not been investigated. Contact the manufacturer for their required clearance around structural members protected with mastic and intumescent coatings.

9. Gypsum Board

Vertically applied gypsum board is gypsum board that is applied with the long edges parallel to the framing members to which it is attached. Horizontally applied gypsum board applied is gypsum board applied with the long edges perpendicular to the framing members to which it is attached.

Gypsum board thicknesses specified in specific designs are minimums. Greater thicknesses of gypsum board are permitted as long as the fastener length is increased to provide penetration into framing that is equal to or greater than that achieved with the specified gypsum board thickness and fasteners.

Additional layers of gypsum board are permitted to be added to any design.

Most gypsum board products fall into three general categories: Regular, Type X, and proprietary products often referred to as Type C. These three categories of products each provide a different level of fire resistance. Regular and Type X board are described in ASTM C1396, "Standard Specification for Gypsum Board." Where fire-resistive performance is required, either a Type X board or a proprietary product is typically specified. Type X gypsum board is defined in ASTM C1396 as gypsum board that provides not less than a 1 hr fire-resistance rating for boards 5/8 in. thick and not less than 3/4 hr fire-resistance rating for boards 1/2 in. thick when applied parallel with and on each side of load-bearing 2 by 4 wood studs spaced 16 in. OC applied with 6d coated nails spaced 7 in, OC and with joints staggered 16 in. between sides when tested in accordance with ANSI/UL 263. Proprietary Type C boards have a better fire performance achieved through the use of proprietary modifiers in the gypsum core which reduces shrinkage under fire conditions, thereby allowing the boards to remain attached to the structural element for a longer period of time. Since proprietary Type C boards have a better fire performance than Type X boards, they also meet the ASTM C1396 definition for Type X board.

Most UL designs specify the manufacturer and product identification of the products intended for use in the design. For designs containing the statement, "See Gypsum Board (CKNX) Category for names of Classified Companies," any product in CKNX that meets the specifications described in the individual designs may be used. This statement is applicable to any gypsum board manufacturer who produces certified gypsum board meeting all requirements specified in the individual designs. It is not required that these design numbers appear in the individual company's certification found in CKNX.

For the addition of wood structural panels to fire-rated gypsum board wall assemblies, refer to Section VI. WALLS AND PARTITIONS, Item 6, Wood Structural Panels.

10. Gypsum Board Joint Treatment (Taping)

Except where specified otherwise under VI. WALLS AND PARTITIONS, and where otherwise specified in the individual designs, all gypsum board systems except those with predecorated or metal-covered surfaces have joints taped and joints and fastener heads covered with one coat of joint compound (fire taped). Base layers in multi-layer systems are not required to have joints or fastener heads taped or covered with joint compound.

11. Plaster

The proper aggregate and mix proportions are specified in each design. Thicknesses are measured from the outer face of the plaster base. When a finish coat is not specified, it is not included in the thickness dimensions, but it may be added. Materials investigated for exterior application are so indicated in the individual designs.

12. Dampers

Building codes include requirements for four types of dampers: fire dampers, smoke (leakage-rated) dampers, ceiling dampers, and corridor dampers. Dampers have been investigated for installation in wall or ceiling constructions in the maximum sizes and orientations (vertical or horizontal) indicated in their certification. Dampers have been investigated for the following applications:

Fire Dampers (EMME) are intended for use where air ducts and air-transfer openings traverse fire-resistance-rated walls and floors.

Leakage-rated (Smoke) Dampers (EMME) are intended for use where air ducts and air-transfer openings traverse smoke barriers.

Corridor Dampers (EMME) are intended for use where air ducts penetrate or terminate at horizontal openings in the ceilings of certain corridors, as required by the building code.

Air Terminal Units (BZGU), Ceiling Air Diffusers (BZZU) and Ceiling Dampers (CABS) are intended to function as a heat barrier in air-handling openings penetrating fire-resistive membrane ceilings. Additional details on duct outlet protection methods for membrane ceiling constructions, designated Systems A and B, is included under Section III. FLOOR-CEILINGS AND ROOF-CEILINGS, Item 16, Air Ducts and Protection Systems.

13. Wood Structural Panels

Wood structural panel are structural panel products composed primarily of wood and meeting the requirements of U.S. Department of Commerce Voluntary Product Standard PS 1, "Construction and Industrial Plywood," or U.S. Department of Commerce Voluntary Product Standard PS 2, "Performance Standard for Wood-Based Structural-Use Panels." Wood structural panels include all-veneer plywood, composite panels containing a combination of veneer and wood-based material, and mat-formed panels such as oriented strand board and waferboard. The panels bear the label of a code-recognized certification organization with a specific reference to the PS 1 or PS 2 standard. The panels are also marked "Exposure 1" or "Exterior." Some individual designs may limit the type of panel that can be used.

As an alternate, wood structural panels investigated in accordance with APA - The Engineered Wood Association Standard PRP-108, "Performance Standards and Policies for Structural-Use Panels," or PFS Research Foundation Standard PRP-133, "Performance Standards and Policies for Wood-Based Structural-Use Panels," and meeting the description for the panel type in the individual designs, may be used.

14. Blanket Insulation

For designs containing the statement, "See Batts and Blankets (BZJZ) Category for names of Classified Companies," any product in BZJZ that meets the specifications described in the individual designs may be used. This statement is applicable to any blanket insulation manufacturer who produces certified batts and blankets meeting all requirements specified in the individual designs. It is not required that these design numbers appear in the individual company's certification found in BZJZ.

15. Sound Transmission Class (STC)

In addition to the fire-resistance ratings, where indicated in the individual designs, the Sound Transmission Class (STC) rating is published for those designs where the sound transmission loss (STL) test was also investigated. ASTM E90, "Standard Test Method for Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements," is the test method used to investigate the sound transmission loss for the various designs. The STC rating applies to the assembly of materials as indicated in the individual designs.

16. Impact Insulation Class (IIC)

In addition to the fire-resistance ratings, where indicated in the individual designs, the Impact Insulation Class (IIC) rating is published for those designs where the impact noise test was also investigated. ASTM E492, "Standard Test Method for Laboratory Measurement of Impact Sound Transmission Through Floor-Ceiling Assemblies Using the Tapping Machine," is the test method used to investigate the impact noise of the design. The IIC rating applies to the assembly of materials as indicated in the individual designs.

17. Penetrations

Penetrations through all or a portion of an assembly can significantly affect the rating. Firestop systems developed to protect through- and membrane-penetrations are covered under Through-penetration Firestop Systems (XHEZ).

18. Curtain Wall/Floor Protection Systems

Perimeter Fire Containment Systems (XHDG) includes designs that have been investigated to protect the void created at the intersection of a fire-rated floor assembly and an exterior curtain wall assembly.

19. Fire-resistant Joint Systems

Joint Systems (XHBN) includes designs that have been investigated to protect the joints between fire-resistance-rated walls, floors, floor-ceiling assemblies and roof-ceiling assemblies.

20. Fire Doors, Frames and Hardware

See the individual categories under Fire Doors (GSNV) for products associated with fire doors, frames and associated hardware. This includes leakage-rated products investigated to limit the spread of smoke through these assemblies.

21. Glazing, Wired Glass and Glass Blocks

Fire-protection-rated Glazing Materials (KCMZ) contains information on wired glass and nonwired glazing investigated for fire resistance. Glass Blocks (KCJU) contains information on glass blocks investigated for fire resistance.

22. Exterior Wall Systems

Exterior Wall Systems (FWFO) contains information on the flame propagation on the exterior side of non-load-bearing wall assemblies investigated to ANSI/NFPA 285, "Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Non-Load-Bearing Wall Assemblies Containing Combustible Components."

III. FLOOR-CEILINGS AND ROOF-CEILINGS

The following guidelines are directed towards the materials and construction methods described for floor-ceiling and roof-ceiling assemblies. These guidelines are intended to supplement the specific description included with each design.

Specific guidelines for the application of beam designs to floor-ceiling and roof-ceiling assemblies are provided in this Directory under the heading "Beams."

1. Concrete

The concrete compressive strength specified in the designs may be reduced 500 psi to obtain the minimum value. The maximum compressive strength is not limited. The thickness is a minimum unless otherwise indicated.

The concrete's air dry unit weight is determined in accordance with ASTM C567, "Standard Test Method for Determining Density of Structural Lightweight Concrete." The unit weight specifications (unless stated as a range for individual designs) have a tolerance of plus or minus 3 pcf. If normal-weight concrete (145 to 155 pcf) is specified, the use of lightweight (90 to 120 pcf) is not recommended because its greater insulating properties could cause higher temperatures on supporting members. When lightweight concrete is specified, the use of normal-weight concrete is not recommended because its lower insulating properties could cause higher unexposed surface temperatures.

2. Fiber Reinforcement

Certified synthetic fiber reinforcements may be added to the concrete mix for the purpose of controlling shrinkage cracks.

These fibers are not intended to satisfy any structural requirements. The structural capacity of the concrete slab should be maintained in accordance with the requirements of ACI 318, "Building Code Requirements for Structural Concrete and Commentary."

The type of unit and the minimum steel thickness is specified in each design.

The steel floor and roof deck minimum thickness table is based upon an industry standard for steel deck. The load tables published by the steel deck industry are based upon the design thickness and a 5% tolerance is applied to derive the minimum thickness. The tolerance is in accordance with American Iron and Steel Institute specifications. For steel floor and roof deck, the minimum bare-metal thickness should be as follows:


Gauge

Design Thickness, in.
Min Thickness
Bare Metal, in.
28 0.0149 0.014
26 0.0179 0.017
24 0.0238 0.023
22 0.0295 0.028
20 0.0358 0.034
18 0.0474 0.045
16 0.0598 0.057

The effect on the fire resistance of the assembly when cellular sections are used as air-handling units has not been investigated.

Some steel units are provided with patterned indentations and are thereby considered to act compositely with the concrete topping. Moment and shear capacities are usually determined empirically from structural tests. The allowable load is provided in the manufacturer's catalogs. The loading for floors with noncomposite units (without indentations) is based on their section modulus. Some fire tests have been conducted on slabs utilizing the composite units but with the loading based on the section modulus of the steel. In such cases the design will specify noncomposite loading. Fire tests have generally shown that composite slabs deflect more than similar noncomposite slabs. Therefore, the ratings developed with composite units would not be jeopardized if noncomposite units of the same profile are used provided the loading is based on the section modulus of the noncomposite units.

When considering the substitution of a load-bearing steel stud wall or masonry wall for a beam specified in a floor-ceiling design, the following minimum conditions are to be met:

1. The hourly rating of the wall must be equal to or greater than the restrained hourly rating of the floor-ceiling assembly.
2. The structural capacity of the wall to be substituted must be equal to or greater than the structural capacity of the beam specified.
3. The bearing and connection of the deck should also be equivalent to that required in the specified design.
4. The level of restraint provided by the wall is to be validated to determine that if use of the restrained or unrestrained assembly is appropriate.
5. Openings between the load-bearing wall and steel floor units are to be protected with an appropriately rated joint system.

All considerations including but not limited to those noted above are to be validated by a design professional prior to making the substitution.

The steel form units used in floor or roof assemblies may be painted or galvanized when used in designs that include suspended ceilings (Designs G0--, G2--, G4--, G5--, P0--, P2--, P4--, P5--). In designs that specify the steel form units to be welded to supports with welding washers, the welding washers may be omitted when the steel form unit is 22 MSG gauge or heavier.

Normally, assemblies with steel deck are constructed and tested with simple span conditions, however, the ratings also apply to continuous span conditions.

4. Electrical Boxes for Concrete Floors

Outlet Boxes and Fittings Certified for Fire Resistance (CEYY) covers pre-set and post-set inserts for use in concrete floors for electrical and communication connections. These devices have demonstrated an ability to be used in specific assemblies without reducing their fire-resistive ratings. In those floor-ceiling designs where the inserts are not specifically shown, penetrations to the concrete topping with electrical inserts may jeopardize the rating unless proper compensating protection is provided. In the absence of specific information for inserts in the individual designs, inserts that do not penetrate through the entire floor and bear the UL Certification Mark for Outlet Boxes and Fittings Certified for Fire Resistance may be used in floor-ceiling designs which include fire-resistive coating materials on both fluted and cellular floor units for the entire floor span between supports. The cellular units should be protected in one of the following ways:

1. For inserts that penetrate into the top of the cell and where concrete is not removed from the valleys of the steel floor units, the thickness of fireproofing material specified below standard trench headers (with bottom pan) is applicable.
2. For inserts that penetrate into the sides of the cells with no concrete in the valley between the cells under the inserts, the thickness of the fire-resistive coating specified below the bottomless trench header (without bottom pan) is applicable.

The above recommended protection is intended only for structural concrete floors that contain welded wire fabric or fiber reinforcement when permitted and consist of a blend of one or more fluted to one cellular unit. The entire underside of the cellular units should be protected with the same material and thickness as required below the trench headers with a gradual reduction in thickness to that specified for fluted units in the individual designs. The spacing between inserts should be sufficient for structural integrity. The diameter of any holes in the insert cover for the passage of wire should be no more than 1/8 in. larger than the diameter of the wire.

5. Nonmetallic Outlet Boxes for Ceilings

Certified nonmetallic outlet boxes investigated for installation in floor-ceiling or roof-ceiling assemblies are covered under Outlet Boxes and Fittings Certified for Fire Resistance (CEYY).

6. Metallic Electrical Outlet Boxes

Metallic outlet boxes with metallic or nonmetallic cover plates may be used in floor-ceiling and roof-ceiling assemblies with ratings not exceeding 2 hours. These assemblies should have gypsum board membranes. The metallic outlet boxes should be securely fastened to the joists and the opening in the gypsum board facing should be cut so that the clearance between the box and the gypsum board does not exceed 1/8 in. The surface area of individual boxes should not exceed 16 sq. in. The aggregate surface area of the boxes should not exceed 100 sq. in. per 100 sq. ft of ceiling surface.

The specified minimum-size joist in floor- or roof-ceiling designs is the joist that meets the requirements for both the minimum depth and the minimum weight per foot. Joists that exceed the specified minimum size may be used, provided the accessories are compatible. The dimension from the bottom chord of joists to the ceiling, whether given or calculated, is a minimum.

Spacing between joists may be increased from that specified to a maximum of 4 ft on centers if the floor slab meets structural requirements and the spacing of the hanger wires supporting the ceiling is not increased. Where it is necessary to provide support for the ceiling hanger wires between the joists, this may be accomplished by using 1-1/2 in., 16 gauge or larger cold-rolled steel channels. Each channel with its web oriented vertically should be placed on top of and perpendicular to the joist's bottom chord and tied thereto with a double strand of 18 SWG galvanized steel wire.

The area of bridging bars or angles specified in the individual designs is a minimum. Larger bridging may be necessary in order to meet the structural and/or code requirements.

For designs requiring application of coating materials to steel joists, the bridging bars or angles should be protected with the coating material thickness required on the joist for a minimum distance of 12 in. beyond the joist.

When the joists are coated with a fire-resistive material, the cavities, if any, between the upper flange of the joist and the steel floor or roof units, should be filled with the fire-resistive coating material applied to the joist, unless specified otherwise in the individual designs.

For designs that require the bottom chords of the joists to consist of round bars, the substitution of angles of an equivalent area is not recommended.

K-Series joists, LH-Series joists and joist girders specified in floor- or roof-ceiling assemblies should be designed and fabricated in accordance with the Steel Joist Institute's Specifications adopted November 4, 1985, and revised May 1, 2000.

K-Series joists may be substituted for other joists specified in floor- or roof-ceiling designs as follows:

Floor-Ceiling Assemblies

K-Series joists of equal or greater depth and weight per foot may be substituted for any S-, J-, H-, LH- and/or DLH-Series joists in any floor-ceiling design, which employs a structural concrete floor and a suspended membrane ceiling.

Roof-Ceiling Assemblies

K-Series joists of equal or greater depth and weight per foot may be substituted for any S-, J-, H-, LH- and/or DLH-Series joists in any roof-ceiling design, with the following restrictions:

a) Minimum nominal depth = 10 in.
b) Maximum tensile stress = 26,000 psi

Any stress limitation specified in floor or roof designs containing S-, J-, H-, LH- and/or DLH-Series joists should remain applicable when a K-Series joist is substituted.

When a K-Series joist is substituted, any restriction regarding minimum allowable joist member sizes, areas of steel, and/or bridging material sizes remain applicable. Refer to section "Fire-Resistance Ratings with Steel Joists" in the "Standard Specifications Load Tables & Weight Tables for Steel Joists and Joist Girders," 41st edition, published by the Steel Joist Institute, for guidance.

8. Precast Concrete Units

For restrained assembly ratings, some designs require end clearances and lateral expansion joints with the use of noncombustible compressible materials along the sides of the precast concrete units. This requirement may be waived and the clearance spaces filled with sand-cement grout if the stiffness of the building floor and supporting column system surrounding the precast concrete units does not exceed 80% of the stiffness of the test frame in which the assemblies are tested and rated.

The relative stiffness of the frame work surrounding a building floor assembly may be calculated using an approximate test frame size of 14 ft by 17 ft and an approximate stiffness of frame of 700,000 kip-in. and 850,000 kip-in., expressed by EI/L, along the 17 ft and 14 ft dimensions, respectively.

For unrestrained assembly ratings, clearances should be provided around the ends and sides of the precast concrete units so that they may expand freely during fire exposure.

In most floor-ceiling designs, sand-cement grout is required to be poured between adjacent precast units. This grout may be omitted if a minimum 1 in. thick concrete topping is placed over the precast concrete units.

9. Ceiling Control Joints

For G500, L500 and M500-Series floor-ceiling designs having a maximum 1 hr Unrestrained Assembly Rating and having a ceiling membrane consisting of a single layer of nominal 5/8 in. thick gypsum board, max 1/2 in. wide control joints may be incorporated in the ceiling using one of the following methods:

Ceiling Suspended Below Floor Assembly

1. Floor Assembly — (Not Shown) — The floor assembly should be constructed of the materials and in the manner described in the individual G-500, L500 or M500-Series Floor-Ceiling design.
2. Cold-rolled Steel Channel — Nom 1-1/2 in. deep, min 16 gauge cold-rolled steel channels installed perpendicular to control joint direction. Channels suspended from floor joists with 12 SWG galv steel hanger wires. Hanger wires spaced max 48 in. OC. Channels spaced max 24 in. OC. Channels installed to extend approx 6 in. past control joint location with channels on opposite sides of control joint offset from each other. Hanger wire at end of each channel to be located in span between furring channels over control joint location.
3. Furring Channels — Nom 7/8 in. deep, min 25 gauge painted or galv steel rigid furring channels installed perpendicular to cold-rolled steel channels and spaced max 16 in. OC. Furring channel along each side of ceiling control joint to be located with its centerline 3 in. from the center of the control joint. Furring channels secured to cold-rolled steel channels with a double strand of 18 SWG galv steel wire.
4. Gypsum Board — Installed with long dimension perpendicular to furring channels. Gypsum board type, fastener type and fastener spacings to be as specified in the individual L500-Series Floor-Ceiling design. Max width of control joint centered between furring channels is 1/2 in. Strip of gypsum board over control joint to be nom 5/8 in. thick by 3-1/2 in. wide and to be secured to ceiling along only one side of control joint with 1-1/2 in. long Type G gypsum board screws spaced max 24 in. OC.
5. Control Joint — Vinyl or zinc control joint conforming to ASTM C1047, "Standard Specification for Accessories for Gypsum Wallboard and Gypsum Veneer Base." Control joint stapled to gypsum board on each side of joint opening prior to finishing of ceiling.

Control Joint Parallel With Wood Joists

1. Flooring — Lumber or plywood subfloor with finish floor of lumber, plywood or floor-topping mixture as specified in the individual L500 or M500-Series Floor-Ceiling design.
2. Wood Joists — 2 by 10 in., spaced 4 in. apart at the control joint location and max 16 in. OC away from control joint as specified in the individual L500 or M500-Series Floor-Ceiling design.
3. Gypsum Board — Installed with long dimension perpendicular to wood joists. Gypsum board type, fastener type and fastener spacings to be as specified in the individual L500-Series Floor-Ceiling design. Max width of control joint centered between wood joists is 1/2 in. Strip of gypsum board over control joint to be nom 5/8 in. thick by 3-1/2 in. wide and to be secured to ceiling along only one side of control joint with 1-1/2 in. long Type G gypsum board screws spaced max 24 in. OC.
4. Control Joint — Vinyl or zinc control joint conforming to ASTM C1047. Control joint stapled to gypsum board on each side of joint opening prior to finishing of ceiling.

Control Joint Perpendicular to Wood Joists

1. Flooring — Lumber or plywood subfloor with finish floor of lumber, plywood or floor-topping mixture as specified in the individual L500 or M500-Series Floor-Ceiling design.
2. Wood Joists — 2 by 10 in., spaced max 24 in. OC as specified in the individual L500 or M500-Series Floor-Ceiling design.
3. Furring Channels — Nom 7/8 in. deep, min 25 gauge painted or galv steel rigid furring channels installed perpendicular to wood joists and spaced max 16 in. OC. Furring channel along each side of ceiling control joint to be located with its centerline 3 in. from the center of the control joint. Furring channels secured to wood joists as specified in the individual L500-Series Floor-Ceiling design.
4. Gypsum Board — Installed with long dimension perpendicular to furring channels. Gypsum board type, fastener type and fastener spacings to be as specified in the individual L500-Series Floor-Ceiling design. Max width of control joint centered between furring channels is 1/2 in. Strip of gypsum board over control joint to be nom 5/8 in. thick by 3-1/2 in. wide and to be secured to ceiling along only one side of control joint with 1-1/2 in. long Type G gypsum board screws spaced max 24 in. OC.
5. Control Joint — Vinyl or zinc control joint conforming to ASTM C1047. Control joint stapled to gypsum board on each side of joint opening prior to finishing of ceiling.

Control Joint Parallel with Wood Joists

1. Flooring — Lumber or plywood subfloor with finish floor of lumber, plywood or floor-topping mixture as specified in the individual L500 or M500-Series Floor-Ceiling design.
2. Wood Joists — 2 by 10 in., spaced max 24 in. OC as specified in the individual L500 or M500-Series Floor-Ceiling design.
3. Furring Channels — Nom 7/8 in. deep, min 25 gauge painted or galv steel rigid furring channels installed perpendicular to wood joists and spaced max 16 in. OC. Furring channels to cantilever approx 1/4 in. beyond wood joist in 4 in. wide joist cavity containing control joint. Furring channels secured to wood joists as specified in the individual L500-Series Floor-Ceiling design.
4. Gypsum Board — Installed with long dimension perpendicular to furring channels. Gypsum board type, fastener type and fastener spacing to be as specified in the individual L500-Series Floor-Ceiling design. Max width of control joint centered in 4 in. wide joist cavity is 1/2 in. Strip of gypsum board over control joint to be nom 5/8 in. thick by 3 in. wide and to be secured to ceiling along only one side of control joint with 1-1/2 in. long Type G gypsum board screws spaced max 24 in. OC.
5. Control Joint — Vinyl or zinc control joint conforming to ASTM C1047. Control joint stapled to gypsum board on each side of joint opening prior to finishing of ceiling.

10. Acoustical Materials

The type and size is specified in the individual designs. Where a range of panel sizes is indicated, compatible sizes of suspension members must be used. Designs incorporating lay-in acoustical ceiling panels specify the use of hold-down clips. Hold-down clips are required for assemblies incorporating ceiling panels weighing less than 1 lb per square foot.

11. Suspension Systems

The type and size of the suspension system are specified in the individual designs. Support of the system is an important feature in its performance. Spacing of the supports should not exceed but may be less than specified. When the length of the cross tee between the main runner and the wall molding is 30 in. or longer, each such cross tee should be supported by a hanger wire at midpoint of the tee or at a location nearer the wall unless specified differently in the design.

As an alternate to the wall molding specified in the individual designs, the molding may be an angle fabricated from minimum 0.017 in. thick steel. Each leg of the angle should be at least 7/8 in. long with a 0.115 in. hemmed edge. The wall molding should be reliably secured to the wall with steel fasteners on maximum 16 in. centers unless specified otherwise in a design.

Cross tees which are parallel and adjacent to walls and are spaced 12 in. or less from the wall should each be supported by a hanger wire at midpoint. These hanger wires are intended to minimize their rotation under fire conditions due to the unbalanced weight of panels on their flanges.

Where a ceiling is supported directly from structural members, it may be lowered. If necessary, intermediate supports may be used to support the ceiling, provided they produce an in place stiffness equivalent to that of the originally tested elements. A suggested method for providing an equivalent in place stiffness is by use of 1-1/2 in. cold-rolled channels made of 16 gauge or heavier painted or galvanized steel, with the web oriented vertically and suspended from the structural members by 12 SWG or heavier galvanized steel wire at a maximum spacing of 48 in. OC. The channels may be oriented parallel or perpendicular to the structural members but should be spaced not more than the spacing of the members.

Where it is necessary to cut away the expansion mechanism of suspension members to fit room dimensions or corridor widths, the member should be installed with a gap of approximately 1/10 in. per ft of length to permit free thermal expansion.

Hanger wires should be installed vertically unless permitted otherwise in a design.

Some floor-ceiling designs with structural concrete topping on steel floor units specify the use of steel hanger clips as an attachment provision for hanger wires. As an alternate to hanger clips, low-velocity, powder-actuated, steel-eye pin fasteners may be used for hanger wire attachment in the floor-ceiling designs. The fasteners should have a minimum 5/32 in. diameter by minimum 7/8 in. long pointed shank with a washer and nominal 7/8 in. long by 7/16 in. wide head containing a rounded slot opening. The fasteners are intended to be secured to concrete in valleys of fluted steel floor units with powder charges sufficient to fully embed the shank portion without shattering the concrete.

12. Fluorescent Recessed Luminaires (Troffers)

Luminaires may be installed individually or end to end (in rows). Side-by-side installation has not been investigated.

The spacing of luminaires specified in the individual designs refers to the maximum aggregate area of the luminaires to be used in each 100 sq ft of ceiling. Unless specified otherwise, the luminaires are of the fluorescent-lamp type with steel housing and hardware. UL-certified LED luminaire retrofit kits (see Light-emitting-diode Luminaire Retrofit Kits, IFAR) may be used to replace or upgrade the fluorescent fixtures to energy-efficient LED fixtures, provided the conversion does not require the existing steel housing to be removed and/or modified, and the fixture protection (enclosure) above the steel housing is as described in the individual design.

Where air-handling-type luminaires were tested, the design may describe the luminaire as air-handling or as provided with slots in the housing. However, since no air movement was employed during the test, the ratings require that air movement be effectively stopped at the start of a fire. Air-handling luminaires may be used in any design that specifies luminaires, provided it is not necessary to alter the enclosure surrounding the luminaire and that provisions are made for effectively stopping the movement of air at the start of a fire.

In ceilings employing an exposed-grid suspension system, when hanger wire is required at midpoint of the cross tee on each side of luminaires, the wire should be installed with approximately 1/8 in. of slack such that it will not be pulling on the cross tee at room-temperature conditions.

13. Enclosures for Fluorescent Recessed Luminaires (Troffers)

Enclosures for luminaires should be spaced away from the top of the luminaire housing as shown in the individual designs. When luminaires are installed end to end, one end piece of the protection material that is part of the enclosure should be placed on top of the adjoining top protection pieces to cover the gap at the junction of the luminaires. Spacers placed on top of the luminaire housing to provide clearance for the protection material should not be located directly over or adjacent to luminaire ballasts. Installation is intended to be in conformance with ANSI/NFPA 70, "National Electrical Code." For lay-in panel ceilings, as an alternate to the spacers cut from ceiling material or mineral wool batts, pieces of ceiling-suspension-system tees may be used to maintain the clearance between the protection material and the top of the luminaire.

14. Luminaires Certified for Fire Resistance

In addition to the luminaires described above, luminaires specifically investigated for installation in floor-ceiling and roof-ceiling designs are covered under Luminaires, Luminaire Assemblies and Luminaire Enclosures Certified for Fire Resistance (CDHW). Refer to the individual CDHW certifications for details on the designs in which the luminaires have been investigated and found acceptable.

15. Restrained and Unrestrained Assemblies

Floor-ceiling and roof-ceiling assemblies include fire-resistance ratings for use in both restrained or unrestrained conditions. It is up to the designer and code authority to determine if an assembly is being used in a restrained or unrestrained application, as required by the building code being enforced. Unrestrained Assembly ratings may be used for floor-ceilings and roof-ceilings designed for either restrained or unrestrained conditions.

The conditions of acceptance in ANSI/UL 263 provide criteria for Restrained Assembly Ratings, Unrestrained Assembly Ratings, Restrained Beam Ratings and Unrestrained Beam Ratings. Because of their more onerous criteria, Unrestrained Assembly Ratings may be used for floors and roofs designed for either restrained or unrestrained conditions.

Certifications resulting from a tested assembly containing a full representation of a floor or roof construction may include: (1) Restrained Assembly Ratings and (2) Unrestrained Assembly Ratings. Results from the testing of these assemblies are identified as Design Nos. A ____, D ____, G ____, J ____ or P ____. Tested assemblies supported by beams may also include an Unrestrained Beam Rating, but do not include a Restrained Beam Rating. A Restrained Beam Rating is determined only from a test on an assembly with a restrained beam and a partial representation of a floor or roof. Results from tests on this type of assembly are identified as Design Nos. N ____ or S ____.

D900 Series Dual Unrestrained Assembly Ratings

Two unrestrained assembly ratings are indicated for some D900 Series floor-ceiling designs that include unprotected steel floor units. These unrestrained assembly ratings are influenced by the span of the steel floor units. For the longer rating, the maximum span is the span with which the assembly was tested. This rating is determined by the assembly's structural performance during the fire test. The shorter rating is determined by the steel temperatures measured during the test and the span is limited only by the manufacturer's loading tables.

Restraint Conditions

Certifications of floor-ceiling and roof-ceiling assemblies and individual beams include restrained and unrestrained ratings. ANSI/UL 263 and, specifically, Appendix C, provides general nonmandatory information with respect to the concept of these classifications.

Appendix C of ANSI/UL 263 defines restraint in buildings as: "Floor-ceiling and roof-ceiling assemblies and individual beams in buildings should be considered restrained when the surrounding or supporting structure is capable of resisting substantial thermal expansion throughout the range of anticipated elevated temperatures. Constructions not complying with this definition are assumed to be free to rotate and expand and should be therefore considered as unrestrained."

The restrained condition in fire tests is defined in Appendix C of ANSI/UL 263 as: "one in which expansion at the supports of a load carrying element resulting from the effects of the fire is resisted by forces external to the element." This definition may not be appropriate for conditions of restraint in actual structures. The Standard recognizes that the exercise of engineering judgment is required to determine what constitutes "substantial thermal expansion" when determining the conditions under which the restrained or unrestrained ratings should be used.

Table C1.1 of ANSI/UL 263, shown below, provides considerations of restraint for common construction techniques.

Table C1.1

Considerations of Restraint for Common Construction

I. Wall Bearing:
A. Single span and simply supported end spans of multiple baysa
1. Open-web steel joists or steel beams supporting concrete slab, precast units, or metal decking Unrestrained
2. Concrete slabs, precast units, or metal decking Unrestrained
B. Interior spans of multiple bays
1. Open-web steel joists, steel beams, or metal decking supporting continuous concrete slab Restrained
2. Open-web steel joists or steel beams, supporting precast units or metal decking Unrestrained
3. Cast-in-place concrete slab systems Restrained
4. Precast concrete where the potential thermal expansion is resisted by adjacent constructionb Restrained
II. Steel Framing:
A. Steel beams welded, riveted, or bolted to the framing Restrained
B. All types of cast-in-place floor and roof systems (such as beam-and-slabs, flat slabs, pan joists, and waffle slabs) where the floor or roof system is secured to the framing members Restrained
C. All types of prefabricated floor or roof systems where the structural members are secured to the framing members and the potential thermal expansion of the floor or roof system is resisted by the framing system or the adjoining floor or roof constructionb Restrained
III. Concrete Framing:
A. Beams securely fastened to the framing members Restrained
B. All types of cast-in-place floor or roof systems, such as beam-and-slabs, flat slabs, pan joists, and waffle slabs, where the floor system is cast with the framing members Restrained
C. Interior and exterior spans of precast systems with cast-in-place joints resulting in restraint equivalent to that which would exist in Condition III, item A Restrained
D. All types of prefabricated floor or roof systems where the structural members are secured to such systems and the potential thermal expansion of the floor or roof system is resisted by the framing system or the adjoining floor or roof constructionb Restrained
IV. Wood Construction:
A. All types Unrestrained
a Floor and roof systems can be considered restrained if they are tied into walls with or without tie beams, and the walls are designed and detailed to resist thermal thrust from the floor or roof system.
b For example, resistance to potential thermal expansion is considered to be achieved if:
1. Continuous structural concrete topping is used.
2. The space between the ends of precast units or between the ends of units and the vertical face of supports is filled with concrete or mortar.
3. The space between the ends of precast units and the vertical faces of supports or between the ends of solid or hollow core slab units does not exceed 0.25 percent of the length for normal-weight concrete members or 0.1 percent of the length for structural light-weight concrete members.

Restrained conditions for the fire-test assemblies are provided by constructing floor-, beam- and roof-test assemblies within nominal 14 ft by 17 ft frames of composite steel/concrete cross sections having an approximate stiffness (EI/L) of 850,000 kip-in. and 700,000 kip-in. along the 14 ft and 17 ft sides, respectively. The frame stiffness remains constant throughout the fire test because the test frame is insulated from the fire environment.

When applying the published restrained ratings, it is recognized that the individual responsible for the design of the fire-rated construction may ascertain that a different degree of restraint may be provided to the building assembly during a fire condition than was provided to the test sample during the fire test. Under these conditions, the designer may review the Conditions of Acceptance for restrained and unrestrained assemblies and beams in ANSI/UL 263 for additional guidance when determining whether restrained or unrestrained ratings should be specified.

16. Air Ducts and Protection Systems

Unless otherwise specified by the design, the ratings were developed based on fire tests employing no air movement. The ratings, therefore, require that air movement be effectively stopped at the start of a fire.

Unless specified otherwise, the minimum distance between the bottom of the duct and the top of ceiling membrane should not be less than 4 in.; where a greater minimum distance is specified, it may be reduced to 4 in. minimum. For ducts equipped with hinged sheet-steel dampers over duct outlets, unless specified otherwise, the maximum distance between the bottom of the duct and the top of the ceiling should not exceed 8 in. When certified ceiling dampers are used, no limit is required for the maximum distance between the bottom of the duct and the top of the ceiling since fire dampers are installed close to the top of ceiling membrane per installation instructions. Where hinged sheet-steel dampers are specified, they should be equipped with spring catches and corrosion-resistant hinges. Dampers designed to close by gravity should be installed to close in the direction of the air flow. Air diffusers should be of steel and attached to the duct outlet with steel sheet-metal screws. Spacing of screws should be at least three equally spaced for round diffusers and 8 in. OC max per side for square diffusers, with no less than one on each side.

Except where noted in the individual designs, the air diffusers used in the test assemblies were of the surface-mounted type which also supported the surrounding acoustical material by a flange at least 1 in. wide. The opening in the ceiling membrane for attachment of the diffuser to the duct outlet should not be more than 1 in. greater than the size of the duct outlet. Lay-in-type diffusers may be used when they are described in the individual designs or in the certification information of Ceiling Air Diffusers (BZZU) for individual companies.

Certified Ceiling Dampers (CABS) may be used in lieu of the hinged-door-type dampers in those designs that employ air ducts with the duct outlet protected with a hinged-door-type damper. The maximum area for individual duct outlets and the total aggregate area of duct outlets per each 100 sq ft of the ceiling area are specified in the individual designs and are applicable when the hinged-door-type damper is used. If the certified ceiling damper is also eligible for use in the design, then the maximum size of the duct outlets for the certified ceiling damper would apply. The size of the duct outlets should be no larger than the maximum size of the certified ceiling damper.

Some designs specify a smaller aggregate duct outlet area for each 100 sq ft of ceiling area than the maximum size of an individual outlet. In this case, when a certified ceiling damper is used, the allowable outlet area per 100 sq ft of ceiling area should be established on the basis of half the area of the individual maximum size.

When a design requires the use of a covering material around the duct outlet and/or the hinged-door damper, ceramic paper or a material having equivalent thermal properties of the ceramic paper should be used.

Duct outlets should be located in the field of an acoustical panel; however, where it is necessary to cut a main runner or cross tee, each cut end should be supported by a vertical 12 SWG hanger wire. A 1/2 in. clearance should be maintained between the duct outlet and each cut end of the main runner or cross tee. The duct outlet should be located so that no more than one main runner or cross tee is cut when penetrating the ceiling membrane.

Flexible air ducts may be used with certified air-terminal units designated for use in designs. The flexible air duct should be 6 to 8 in. diameter, Class 0 or Class 1 air connector or air duct, bearing the UL Certification Mark. For assemblies with wood joists ("L" and "M" Series designs), air ducts only should be used. The flexible duct should be supported 4 to 6 ft OC with steel straps and/or 12 SWG steel hanger wire so that no portion of the flexible duct is within 4 in. of the top of the ceiling membrane, except where connected to the air-terminal unit.

The following duct outlet protection may be used as alternate systems. System A may only be used when it is specified in the individual designs. System B may be used in any design that contains a steel duct with the duct outlet protected by a hinged-door damper, for equal or smaller outlet size. The systems have been investigated for their effectiveness in retarding the transfer of heat into the ceiling space, but their ability to retard smoke and other combustion products has not been investigated.

Duct Outlet Protection System A

1. Steel Air Duct — Construction and support provisions are specified by the individual fire-resistance design. Duct outlet to be provided with a louvered, surface-mounted, steel air diffuser, secured with steel fasteners. Duct supported by 1-1/2 in., min 0.053 in. thick (16 gauge) cold-rolled steel channels hung at each end from structural members of floor or roof with 12 SWG galv steel wire. When duct outlets are 144 sq in. or smaller, cold-rolled channels should be located adjacent to one or both sides of the duct outlet and spaced a max of 48 in. OC. When duct outlets are larger than 144 sq in., cold-rolled channels should be located adjacent to each side of the duct outlet and spaced a max of 48 in. OC.
2. Glass Fiber Duct Lining — Min 1 in. thick, 3.0 to 5.0 pcf density, unfaced or faced with paper, foil, plastic film or asphalt emulsion. Lining affixed to inside of duct with adhesive or steel fasteners or both. Lining and adhesive should have a flame-spread rating of 25 or less and a smoke-developed index of 50 or less, as determined by ANSI/UL 723 and should comply with all other specifications in ANSI/NFPA 90A, "Installation of Air-Conditioning and Ventilating Systems." Lining should cover the full inside perimeter of the duct, extending at least 12 in. beyond the edges of the duct outlet. Lining on bottom of duct to be cut flush with the edges of the duct outlet.
3. Acoustical Lay-in Panel — Any nom 5/8 in. acoustical lay-in panel certified by UL for use in fire-resistance designs. Panels should be laid on top of duct, extending at least 6 in. beyond sides of duct outlet along width of duct, and extending at least 18 in. beyond sides of duct outlet along length of duct. More than one panel may be butted together to form a panel of the required dimensions. Panels should have a flame-spread index of 25 or less and a smoke-developed index of 50 or less as determined by ANSI/UL 723 and should comply with all other specifications in ANSI/NFPA 90A.
4. Ceramic Paper — Where specified by the individual fire-resistance design, ceramic paper should be affixed to the duct outlet.

Duct Outlet Protection System B

1. Steel Air Duct — Construction and support provisions as specified in the individual designs. Outlet to be provided with a louvered, surface-mounted, steel diffuser, fastened securely with steel fasteners. Duct supported by 1-1/2 in., min 0.053 in. thick (16 gauge) cold-rolled steel channel hung at each end from structural members of floor or roof with 12 SWG galv steel wire. When duct outlets are 144 sq in. or smaller, cold-rolled channels should be located adjacent to one or both sides of the duct outlet and spaced a max of 48 in. OC. When duct outlets are larger than 144 sq in., cold-rolled channels should be located adjacent to each side of the duct outlet and spaced a max of 48 in. OC.
2. Mineral Wool Batts — 1-1/4 in. thick mineral wool batts, 3.5 to 8.0 pcf density. Top piece of batt should extend at least 3 in. beyond the sides of the duct and 6 in. beyond the edges of the duct outlet. Side pieces should extend from the lower face of the top piece to the upper face of the ceiling membrane along the entire length of the top piece. Side pieces tied to top piece with 18 SWG galv steel wire, 18 in. OC. Material should have a flame-spread index of 25 or less, a smoke-developed index of 50 or less as determined by ANSI/UL 723, and should comply with all other specifications in ANSI/NFPA 90A.
3. Ceramic Paper — Where specified in the design, ceramic paper should be affixed to the duct outlet.

17. Blanket Insulation

Unless specifically described in the individual designs, the addition of insulation in the concealed space between the ceiling membrane and the floor or roof structure may reduce the hourly rating of an assembly by causing premature disruption of the ceiling membrane and/or higher temperatures on structural components under fire-exposure conditions.

Insulation in G500, L500, M500 and P500 Series Designs — For 1-hour-rated G500, L500, M500 and P500 Series assemblies, fiberglass insulation, either loose-fill, or faced or unfaced batts or blankets may be added to the plenum or joist space above the gypsum board, provided an additional layer of gypsum board is added to the assembly. The gypsum board should be of the same type as shown in the individual designs. The base layer of gypsum board should be attached with the fastener type and spacing as described in the design. It is not necessary to tape the joints of the base layer. The finish layer of gypsum board should also be attached with the fastener type and spacing as described in the individual design. The length of the fasteners should be increased by a minimum of the gypsum board thickness of the additional layer. The joints in the finish layer should be finished as described in the design.

Other methods of adding insulation in the plenum or joist cavity are not permitted unless indicated in the individual designs.

18. Wood Frame Construction

The size of wood joists is a minimum unless otherwise stated in the individual designs.

The spacing of wood joists is a maximum unless otherwise stated in the individual designs.

Spaces between joists or trusses and spaces between the ceiling and the floor above should be provided with fireblocking or draft stopping as specified in the provisions of building codes.

When a non-fire-rated wood stud wall assembly abuts the bottom of a wood joist floor-ceiling assembly employing a membrane ceiling, the membrane should be continuous above the top plate of the wall assembly, or the wall should be constructed with double wood top plates, the ceiling membrane should be tightly butted to the top plates, and the wall should be sheathed with 5/8 in. Type X gypsum board. When the second option is employed, it is not necessary to protect penetrations, door and window opening, or ducts and air-transfer openings into or through the non-fire-rated wood stud wall assembly. However, all penetrations through the double top plates and floor-ceiling assembly should be protected as required in the building code.

19. Roof Coverings

Most roof assemblies are tested with Class C roof covering. The fire-resistance ratings for these assemblies are also applicable when the roof covering is a Class A, B or C system consisting of hot-mopped or cold-applied bituminous materials. The Class A, B and C ratings are determined by ANSI/UL 790 (ASTM E108), "Standard Test Methods for Fire Tests of Roof Coverings."

20. Roof Insulation

The type and thickness of roof insulation should be as specified in the individual designs. Less than the specified thickness could result in higher temperatures on the roof covering, while a greater thickness of insulation could cause earlier structural failure.

Certified polystyrene insulation, with a density of 5 pcf or less, may be placed on concrete floors or structural concrete roofs without reducing the assembly rating.

When certified mineral and fiber boards, polystyrene insulation exceeding 5 pcf or polyisocyanurate insulation are used over the concrete in D900 Series designs, the unrestrained beam rating is increased by a minimum of 1/2 hr.

21. Uplift Resistance

The resistance of the roof assemblies to uplift by pressures on the roof surface or other damage that may result from high-velocity wind has not been investigated. See Roof Deck Constructions (TGKX) for a list of roof constructions that have been investigated for uplift resistance.

22. Steel Roof Deck Fasteners

Steel roof deck fasteners that have been investigated as part of a roof deck construction may be used to fasten the roof deck to steel joists or beams in lieu of welding or screws in fire-resistive assemblies. See Roof Deck Fasteners (TLSX) for a list of manufacturers. See Roof Deck Constructions (TGKX) for a list of roof constructions that have been investigated for uplift resistance. The steel fasteners must be compatible with the construction shown in the individual fire-resistive designs.

Screw tips penetrating the steel roof deck in all P700 and P800 Series designs require spray-applied fire-resistive material. The spray-applied fire-resistive material specified in the design should be applied to cover the tips at a minimum thickness of 1/2 in.

23. Steel Floor Unit Fasteners

The connection of the steel floor or roof units to the supporting steel structure is specified in the individual design. For A___, D___ and G___ Series designs requiring puddle welds of the steel floor units to the supporting steel structure, powder-driven fasteners or self-drilling structural screws may be used as an alternate to the puddle welds, provided equivalent strength capacity is maintained in the connection.

Minimum 3/4-in. long #10 self-drilling screws may be used as an alternate to button-punching the side laps of adjacent steel floor and form units in A ____, D ____, G ____ and P ____ Series designs. The spacing of the screws should be the same as indicated for the button punches.

24. Use of Floor-Ceilings as Roof-Ceilings

Class A, B or C roof coverings consisting of hot-mopped or cold-applied bituminous materials or a roof-covering material certified under Roofing Membranes (CHCI) may be applied directly to the concrete or wood surface of floor designs being used as roofs without a reduction of fire-resistance ratings.

Class A, B or C prepared roof coverings may be used on wood floor designs without a reduction of the fire-resistance rating, provided a nailer of equal thickness to the length of the mechanical fasteners is added to the flooring.

IV. BEAMS

Beam designs, described under the N and S series designs, are used for two purposes. First, when the building code only requires a fire-resistance rating on the structural elements, a beam design can be used to show compliance with the code. Second, where the building code requires a fire-resistance rating of the floor-ceiling or roof-ceiling assembly, a beam design can be used to replace a similar beam or joist specified in the floor-ceiling or roof-ceiling assembly as described in item 4, Beam Substitution, below.

This section applies to W-, M- or S-shaped hot-rolled structural steel sections as defined by the American Institute of Steel Construction. Unless otherwise noted in the individual certification or design, castellated beams have not been investigated.

The conditions of acceptance in ANSI/UL 263 provide criteria for Restrained Beam Ratings and Unrestrained Beam Ratings. A greater thickness of protection material is typically required for the Unrestrained Beam Rating as compared to the protection material thickness required for the Restrained Beam Rating based on the differences in the rating criteria. Accordingly, Unrestrained Beam Ratings may be used for beams designed for either restrained or unrestrained conditions. Restrained Beam Ratings may be used for beams designed for restrained conditions.

ANSI/UL 263 provides for beams to be included in two types of test assemblies. One type of test assembly contains a full representation of the floor or roof construction being supported by the beam. Certifications resulting from this type of tested assembly may include: (1) Restrained Assembly Ratings, (2) Unrestrained Assembly Ratings, and (3) Unrestrained Beam Ratings. Restrained Beam Ratings are not determined from this type of test assembly. Results from these tests are identified as Design Series Nos. A00, D00, G00, J00 or P00. The other type of test assembly contains a partial representation of the floor or roof construction. Certifications resulting from this type of tested assembly may include: (1) Restrained Beam Ratings and (2) Unrestrained Beam Ratings. Ratings for floor or roof assemblies are not determined from this type of test assembly. Results from these tests are identified as Design Series Nos. N00 or S00.

1. Beam Size

For fire-resistance purposes, the minimum beam size is expressed in terms of a W/D ratio, where W is the weight of the beam per lineal foot and D is the perimeter of protection material at the interface between the steel section and the protection material. Accordingly, beams of the same configuration and having a greater W/D ratio than the beam size specified in the fire-resistive design are considered larger than the specified minimum-size beam and may be used in that design.

2. Composite and Noncomposite Beams

For assemblies that specify both Restrained and Unrestrained Assembly ratings, noncomposite beams may be substituted when composite beams are specified in a design because composite beams deflect more under fire conditions when loaded to their design load than noncomposite beams. Composite beams may only be substituted into designs which specify composite beams.

3. Cavities

Cavities, if any, between the upper-beam flange and the steel floor or roof units should be filled with the fire-resistive coating material applied to the beam, unless specified otherwise in the individual design. As an alternate to filling fire-resistive coating material between the upper beam flange (wide flange beams only) and the steel floor or roof units, sections of min 6 pcf (96 kg/m3) density mineral wool batt insulation is permitted to be firmly packed into the open flutes. When the width of the beam flange is 8 in. or less, the flute is to be filled for the entire width of the flange. For beam flanges wider than 8 in., the flutes are to be filled to a minimum depth of 4 in. on each side. The mineral wool installed in the flutes is to be flush with each outer surface of the upper beam flange. The beams are to be protected with the fire-resistive coating material thickness from the design being utilized. The exposed ends of the mineral wool are to be sprayed with the same thickness and density of the fire-resistive coating material applied to the steel beam as specified in the individual design.

1. Wide-flange Beam — Specific to the individual design.
2. Fire-resistive Coating Material — Protects the beam with thicknesses from the design being utilized. Covers the exposed ends of the mineral wool with the same thickness and density of the fire-resistive coating material applied to the steel beam as specified in the individual design.
3. Batts and Blankets — Mineral wool batt sections of min 6 pcf (96 kg/m3) density, firmly packed into the open flute. The mineral wool is to be installed flush with the surface of the upper beam flange.
4. Steel Floor and Form Units — Specific to the individual design. Flutes are permitted to be filled for the entire width of the flange with mineral wool when the width of the beam flange is 8 in. or less. Flutes are permitted to be filled to a minimum of 4 in. on each side of the structural member for beams flanges wider than 8 in.

4. Beam Substitution

Beam ratings depend upon the type of floor or roof the beam is supporting and the protection on the floor or roof units, as well as the type and thickness of protection material applied to the beam. The substitution of beams into a floor assembly (A--, D--, G-- or J-- Design) or roof assembly (P-- Design) should be limited to assemblies that have a similar or greater capacity for heat dissipation from the beam as compared to the capacity for heat dissipation of the floor or roof construction specified in the design from which the beam is being transferred.

For concrete floors, an equal or greater capacity for heat dissipation exists when the concrete has an equal or greater density range and volume per unit floor area.

Spray-applied Fire-resistive Materials

Application of N Series Designs

When it is the intent to only maintain the existing Assembly Rating, the beams, steel joists and steel trusses from N Series designs may be substituted for the tested structural member, provided the hourly Unrestrained Beam Rating of the structural member being transferred is at least equal to the Unrestrained Beam Rating of the structural member being replaced. Additionally, for steel joists and steel trusses the Restrained Beam Rating of the joist or truss being transferred should be equal to or greater than the Restrained Assembly Rating of the floor-ceiling assembly into which the joist or truss is being transferred.

When it is the intent to comply with requirements that the structural member's hourly rating be equal to or greater than the assembly's hourly rating, the structural member from the N Series design may be substituted for the tested structural member, provided also that the hourly Beam Rating of the structural member being transferred is at least equal to the hourly rating of the requirement. Additionally, the Restrained Beam Rating of the structural member being transferred should be equal to or greater than the Restrained Assembly Rating of the floor assembly into which the structural member is being transferred.

For applications where the assembly's hourly rating differs from the structural member rating, particular attention should be made to the thickness of fire-protection materials applied to the underside of the floor adjacent to the structural member. The thickness of the fire-protection material required within 12 in. beyond the edges of the structural member should be the lesser of the beam protection thickness or the deck protection thickness as required by the N Series design but not less than the thickness of the fire-protection material required by the assembly.

Application of S Series Designs

When it is the intent to only maintain the existing Assembly Rating, the beams, steel joists and steel trusses from the S Series designs may be substituted for the tested structural member, provided the hourly Unrestrained Beam Rating of the structural member being transferred is at least equal to the Unrestrained Beam Rating of the structural member being replaced. Additionally, the Restrained Beam Rating of the structural member being transferred should be equal to or greater than the Restrained Assembly Rating of the roof assembly into which the structural member is being transferred.

When it is the intent to comply with requirements that the structural member's hourly rating be equal to or greater than the assembly's hourly rating, the structural member from the S Series design may be substituted for the tested beam, provided also that the hourly Beam Rating of the structural member being transferred is at least equal to the hourly rating of the requirement. Additionally, the Restrained Beam Rating of the structural member being transferred should be equal to or greater than the Restrained Assembly Rating of the roof assembly into which the structural member is being transferred.

For applications where the assembly's hourly rating differs from the structural member rating, particular attention should be made to the thickness of the fire-protection materials applied to the underside of the roof deck adjacent to the structural member. The thickness of the fire-protection material required within 12 in. beyond the edges of the structural member should be the lesser of the beam protection thickness or the deck protection thickness as required by the S Series design but not less than the thickness of the fire-protection material required by the assembly.

Application of A, D, G, J and P Series Designs

When it is the intent to only maintain the existing Assembly Rating, the beams from A, D, G, J and P Series designs may be substituted for the tested beam, provided that: (1) the Unrestrained Beam Rating of the beam being transferred is equal to or greater than the Unrestrained Beam Rating of the beam being replaced; and (2) the Restrained Assembly Rating of the assembly from which the beam is being transferred is equal to or greater than the Restrained Assembly Rating of the assembly into which the beam is being transferred.

When it is the intent to comply with requirements that the beam's hourly rating be equal to or greater than the assembly's hourly rating, the beams from A, D, G, J and P Series designs may be substituted for the tested beam, provided also that the hourly Unrestrained Rating of the beam being transferred is at least equal to the hourly rating of the requirement.

Mastic and Intumescent Coatings

Application of N Series and S Series Designs

The beams, steel joists and steel trusses from N Series designs may be substituted for the tested structural member, provided the hourly Unrestrained Beam Rating of the structural member being transferred is at least equal to the Unrestrained Beam Rating of the structural member being replaced, and the Restrained Beam Rating of the structural member being transferred is equal to or greater than the Restrained Assembly Rating of the floor-ceiling assembly into which the structural member is being transferred.

5. Unprotected Floors and Roofs

The Unrestrained Beam Ratings in the N400, N600, N700 and N800 Series designs with spray-applied fire-protection material on the steel floor decks may be used with unprotected steel floor deck assembly designs (D900 Series) or unprotected precast concrete floors, provided that the beam fire-protection material is oversprayed to the underside of the floor on both sides of the beam for a minimum width of 12 in. beyond the edges of the beam flange. The thickness of the fire-protection material oversprayed to the underside of the floor should be the same as required for the beam. Overspraying is not required when the N Series designs with unprotected steel floor decks are substituted in the D900 Series designs or to support unprotected precast concrete units.

The Unrestrained Beam Ratings in the S400, S600, S700 and S800 Series designs with spray-applied fire-protection material on the steel roof decks may be used with unprotected steel roof deck assembly designs (P9-- designs), provided the beam protection material is oversprayed to the underside of the roof on both sides of the beam for a minimum distance of 12 in. beyond the edges of the beam flange. The thickness of fire-protection material oversprayed to the underside of the roof should be the same as required for the beam. Overspraying is not required when the S-- designs with unprotected steel roof decks are substituted in the P9-- roof designs.

6. Adjustment of Thickness of Spray-applied Fire-resistive Materials for Restrained and Unrestrained Beams

Alternate-sized steel beams may be substituted for the given beam in the A700, A800, A900, D700, D800, D900, G700, G800, J700, J800, J900, N700, N800, P700, P800, P900, S700 and S800 Series designs, provided the beams are of the same shape, and the thickness of spray-applied fire-resistive material for 1, 1-1/2, 2, 3 and 4 h Restrained and Unrestrained Beam ratings is adjusted in accordance with the following equation:

Where:

T = Thickness (in.) of spray-applied material
W = Weight of beam (lb/ft)
D = Perimeter of protection, at the interface of the fire-protection material and the steel through which heat is transferred to steel (in.)
Subscript 1 = Refers to alternate beam size and required material thickness
Subscript 2 = Refers to given beam size and material thickness shown in the individual designs

1) W/D values are not less than 0.37,

2) T1 values are not less than 3/8 in., and

3) the Unrestrained and Restrained Beam Rating is not less than 1 h.

The use of this procedure is applicable to the adjustment of spray-applied fire-resistive material thickness on restrained and unrestrained beams having solid web members. It is not applicable to the adjustment of mastic and intumescent coatings on restrained and unrestrained beams.

When used to adjust the material thickness for a restrained beam, the use of this procedure is limited to steel sections classified as compact in accordance with the "Specification for the Design of Structural Steel Buildings," by the American Institute of Steel Construction, Load and Resistance Factor Design (Third Ed.).

7. Restrained and Unrestrained Conditions

Certifications of floor-ceiling and roof-ceiling assemblies and individual beams include restrained and unrestrained ratings. See Section III. FLOOR-CEILINGS AND ROOF-CEILINGS, Item 15, Restrained and Unrestrained Assemblies for additional information.

V. COLUMNS

The minimum column size and configuration of the steel member is specified in the X and Y Series designs. The same hourly rating applies when a steel section with an equal or greater W/D ratio is substituted for the specified column size of the same configuration.

The thickness of the coating materials in the X700, X800 and Y700 Series designs required on wide flange steel sections smaller than specified in a design may be calculated as follows:

Where:

X2 = Thickness of coating for smaller wide flange section
X1 = Thickness of coating used on the rated steel section
W1 = Weight per foot of the rated steel section
W2 = Weight per foot of smaller wide flange section
D1 = Perimeter of the rated steel section at interface with coating
D2 = Perimeter of smaller steel section at interface with coating

Guidance addressing the application of spray-applied fire-resistive materials to primed or similarly painted wide flange steel shapes is provided under Coating Materials.

The fire-resistive materials applied to the steel sections should be protected from damage.

The ratings for walls and partitions apply when either face of the assembly is exposed to the fire unless indicated otherwise in a specific design. Flashing and corner details may vary from those described in a design provided structural equivalency is maintained and similar materials to those specified in the design are used for supports, fasteners and flashings. Where dynamic movement is specified in Joint Systems (XHBN) that utilizes either U400, V400 or W400 Series fire-resistance-rated wall and partition assemblies, the special features of the walls to accommodate dynamic movement are intended to be as specified in the individual joint systems under XHBN.

As stated in ANSI/UL 263, the test specimen is to be representative of the construction for which classification is desired as to materials, workmanship, and details such as dimensions of parts, and is to be built under conditions representative of those practically applied in building construction and operation. Accordingly, wall and partition hourly ratings are applicable when walls are constructed in a true vertical position. Unless otherwise noted in an individual design, the performance of angled walls or walls constructed in the horizontal position has not been investigated.

The hourly rating of a load-bearing assembly also applies to the same assembly when it is used as a non-load-bearing assembly.

The size of studs is a minimum unless otherwise stated in the individual designs.

The spacing of studs is a maximum unless otherwise stated in the individual designs.

Spacing between parallel rows of studs are minimums unless otherwise stated in the individual designs.

1. Gypsum Board

Gypsum board thicknesses specified in specific designs are minimums. Greater thicknesses of gypsum board are permitted as long as the fastener length is increased to provide penetration into framing that is equal to or greater than that achieved with the specified gypsum board thickness and fasteners.

Additional layers of gypsum board are permitted to be added to any design.

Gypsum board used on walls and partitions should be oriented, either vertical or horizontal, as specified in the individual designs.

Except when gypsum board is allowed to be applied horizontally in the individual wall design, horizontal butt joints of vertically applied gypsum board should be backed by the same type studs as specified in the design. Alternatively, minimum 25 gauge steel framing with a minimum attachment face of 1-1/4 in. may be used for the backing. Both edges of the gypsum board forming the horizontal joint should be attached to the backing with the same screws and spacing as specified in the design for the attachment of the gypsum board edges. The horizontal joints should be finished as specified for the vertical joints.

2. Mineral Fiber Insulation

The addition of mineral fiber insulation in any thickness and with and without facers is permitted in the stud cavities of any wood stud or steel stud wall assemblies described under the U300, V300, W300, U400, V400 and W 400 series of wall designs.

Horizontal butt joints on opposite sides of the studs in single-layer applications should be staggered a minimum of 12 in. unless otherwise stated in the individual designs. Horizontal butt joints in adjacent layers on the same face of the assembly in multiple-layer applications should be staggered a minimum of 12 in. unless otherwise stated in the individual designs.

Walls of combustible construction should be fireblocked as required by the building code to prevent the free passage of flames and hot gases.

The hourly fire ratings for load-bearing wood stud walls tested before January 1, 2009, were derived with a superimposed load applied to the wall assembly intended to theoretically develop maximum working stresses not exceeding the design values published in the Supplement to the 1991 Edition of the "National Design Specification" for wood when horizontally braced at mid-height. When horizontal bracing is referenced in the design it is mandatory, unless otherwise stated.

For fire-resistive designs based upon data generated after December 31, 2008, the superimposed load applied to the wall assembly was derived from ASTM D6513, "Standard Practice for Calculating the Superimposed Load on Wood-frame Walls for Standard Fire-Resistance Tests," and includes a reference to the edition of the "National Design Specification" used to calculate the design load, the design method, the limiting design factor, and the percentage of the design load applied to the test sample.

Wood stud walls may contain fire-retardant-treated studs as well as untreated wood studs. The use of fire-retardant-treated plywood (wood structural panels) may be used in designs that contain use of untreated plywood when all other specified attributes are equivalent to the wood structural panel in the design.

The dimensions and gauge of steel studs are minimums. The hourly ratings apply when the steel studs are of a heavier gauge and/or larger dimensions than specified in a design. The superimposed load of bearings walls utilizing steel studs should be based on the capacity of the studs as determined by the "North American Specification and Commentary for the Design of Cold-Formed Steel Structural Members."

Where lateral support of studs (by means of straps, channels or similar steel members) is required in the design, the loads applied to steel studs should be based on the steel-braced design. The loads based on sheathing bracing should not be assumed, unless otherwise stated in the design.

The loads applied to steel studs having a yield stress higher than the stated minimum should be based upon the specified minimum yield stress stated in the design.

Non-load-bearing steel studs should comply with ASTM C645, "Standard Specification for Nonstructural Steel Framing Members." The minimum flange width should be 1-1/4 in. and the minimum return lip should be 3/16 in. Studs should also be constructed with steel having a minimum yield strength of 33 ksi.

5. Metal Thickness

Unless otherwise indicated in the individual designs, the following minimum metal thickness tables apply where a metal gauge designation is stated. Metal gauges are no longer referenced in ASTM Standards. It is still an industry practice to specify steel components by gauge. Because many of the designs contained herein refer to metal gauge, the following information should be used as a guide where field questions occur. The tables shown herein should be used as a reference and the code authority should be consulted if discrepancies exist between these tables and a local code requirement. Due to structural considerations and fire-performance considerations, the minimum thickness tables are different for steel deck (floor or roof), load-bearing studs and non-load-bearing studs.

The minimum thickness for load-bearing steel studs is based upon ASTM C955, "Load-Bearing (Transverse and Axial) Steel Studs, Runners (Tracks) and Bracing or Bridging for Screw Application of Gypsum Panel Products and Metal Plaster Bases." The color code denoted by the ASTM Standard is also shown below. For load-bearing steel studs, the minimum bare-metal thickness should be as follows:


Gauge

Color Code
Min Thickness
Bare Metal, in.
20 White 0.0329
18 Yellow 0.0428
16 Green 0.0538
14 Orange 0.0677

For non-load-bearing studs, the minimum thickness is based upon ASTM C645. The color code denoted by the ASTM Standard is also shown below. For non-load-bearing steel studs, the minimum bare-metal thickness should be as follows.


Gauge

Color Code
Min Thickness
Bare Metal, in.
25 None 0.0179
22 Black 0.0269
20 White 0.0329
18 None 0.0428
16 None 0.0538

6. Wood Structural Panels

The addition of wood structural panels in fire-rated gypsum board wall assemblies is permitted as described in this section. Wood structural panels that are 4 ft wide, minimum 7/16 in. thick oriented strand board (OSB) or 15/32 in. thick structural sheathing (plywood) complying with DOC PS1 or PS2, or APA Standard PRP-108, manufactured with exterior glue, may be applied horizontally or vertically to the framing members. Vertical joints should be centered on studs, and staggered one stud space from the gypsum board joints. The wood structural panels are permitted to be applied either as (1) a base layer (directly to the wall framing and under the gypsum board), (2) in between gypsum board layers, or (3) over the top of the completed gypsum board layers. When wood structural panels are used on top of the gypsum board layers of exterior wall assemblies, the wood structural panel should be protected from the exterior environment either as specified in the design or as specified under item 10, Exterior Walls, below. When wood structural panels are added to wall assemblies that include furring channels, there should be no more than two layers (either gypsum board or wood structural panel or combination thereof) attached to the furring channel. When wood structural panels are added to the wall assembly, the length of the fastener used for the outermost layer (either gypsum board or wood structural panel) should be sized appropriately to accommodate the additional thickness of the wall panel.

7. Gypsum Board Joint Treatment (Taping)

The joints in gypsum board applied to wood or steel studs may be left unfinished for that portion of the joint above a suspended ceiling which is part of a fire-resistive floor-ceiling or roof-ceiling assembly.

8. Nonmetallic Electrical Outlet Boxes

Outlet Boxes and Fittings Certified for Fire Resistance (CEYY) includes certifications for nonmetallic outlet and switch boxes for use in wall or partition assemblies. The information provided for each certification includes the model numbers for the certified products, a description of the rated assemblies, the spacing limitations for the boxes and the installation details. Nonmetallic boxes should not be installed on opposite sides of walls or partitions of staggered stud construction unless certified for use in such constructions.

9. Metallic Electrical Outlet Boxes

Certified single- and double-gang metallic outlet and switch boxes with metallic or nonmetallic cover plates may be used in bearing and nonbearing wood stud and steel stud walls with ratings not exceeding 2 h. The metallic outlet or switch boxes should be securely fastened to the studs and the opening in the gypsum board facing should be cut so that the clearance between the box and the wallboard does not exceed 1/8 in. The surface area of individual metallic outlet or switch boxes should not exceed 16 sq in. The aggregate surface area of the boxes should not exceed 100 sq in. per 100 sq ft of wall surface. The aggregate surface area of the boxes may be exceeded when Wall-opening Protective Materials (CLIV) are installed according to the requirements of their certification.

Metallic boxes located on opposite sides of walls or partitions should be separated by a minimum horizontal distance of 24 in. This minimum separation distance between metallic boxes may be reduced when Wall-opening Protective Materials (CLIV) are installed according to the requirements of their certification.

Metallic boxes should not be installed on opposite side of walls or partitions of staggered stud construction unless wall-opening protective materials are installed with the metallic boxes in accordance with certification requirements for the protective materials.

10. Exterior Walls

The fire-resistive designs and UL-certified materials for walls and partitions are investigated to ANSI/UL 263, which addresses fire-resistive requirements only with the understanding that their use is intended for interior applications. Where an exterior application of a UL-certified wall or partition design is desired, the local building code and Authority Having Jurisdiction should be consulted to ensure compliance with other code requirements applicable to exterior walls.

The fire-resistive designs and UL-certified materials for walls and partitions are investigated with the understanding that their use is limited to interior applications unless otherwise specified in the individual designs or certification information (e.g., "Investigated for Exterior Use"). Where an exterior application of a UL-certified wall or partition design is desired, the code authority should be consulted to ensure compliance with the code requirements applicable to exterior walls.

11. Concrete Masonry Units

Unless otherwise indicated in the individual designs, the allowable compressive stress for the concrete masonry units have been determined from the empirical design method for masonry found in the model codes. For assemblies that have been tested at less than 100% of the allowable compressive stress, the design states the maximum allowable compressive stress for the assembly.

ADDITIONAL INFORMATION

For additional information, see Fire-resistance Ratings (BXRH).

* * * * * * * * * * * * * * * * * * * * * * * * *

UL, in performing its functions in accordance with its objectives, does not assume or undertake to discharge any responsibility of the manufacturer or any other party. UL shall not incur any obligation or liability for any loss, expense or damages, including incidental or consequential damages, arising out of or in connection with the use, interpretation of, or reliance upon this Guide Information.

Acoustical MaterialsAir Ducts and Protection SystemsBeamsBlanket InsulationCable, Radiant HeatingCeiling Control JointsCeiling DampersCeiling Suspension SystemsCeilingsCoating MaterialsColumnsConcreteControl Joints, CeilingCurtain Wall/Floor Protection SystemsDampersDesign Numbering SystemsElectrical Outlet Boxes, Floor InsertsElectrical Outlet Boxes, MetallicElectrical Outlet Boxes, NonmetallicExterior ApplicationsExterior Wall SystemsFasteners, Steel, Floor UnitFasteners, Steel, Roof DeckFiber ReinforcementFinish RatingsFire Door FramesFire Door HardwareFire DoorsFire-resistant Joint SystemsFloors and RoofsFloor InsertsFloor Unit Fasteners, SteelFloorsGlass BlocksGlazingGypsum Board Joint TreatmentsInterior ApplicationsJoint Systems, Fire ResistantJoint TreatmentsJoists, SteelLuminairesMetallic Electrical Outlet BoxesMetric DimensionsMineral Fiber InsulationNailsNonmetallic Electrical Outlet BoxesNumbering SystemsOutlet Boxes, Floor InsertsOutlet Boxes, MetallicOutlet Boxes, NonmetallicPartitionsPenetrationsPlasterPrecast Concrete UnitsRadiant Heating Cable and PanelsRestrained AssembliesRoof CoveringsRoof Deck Fasteners, SteelRoof InsulationRoof Uplift ResistanceRoofsScrewsSteel Floor and Form UnitsSteel Floor Unit FastenersSteel JoistsSteel Roof Deck FastenersSteel Stud Wall AssembliesSteel StudsStuds, SteelStuds, WoodSuspended Ceiling DampersSuspension SystemsSystem A and B Ceiling DampersUnrestrained AssembliesUplift ResistanceWall and Partition AssembliesWall AssembliesWall Systems, ExteriorWired GlassWood Frame ConstructionWood Structural PanelsWood Stud WallsWood Studs
Last Updated on 2016-11-03
BXUV.GuideInfo BXUV Active 20161103 20161227

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