Perimeter-fire-containment Systems, XHDG

Guide Information for Fire-resistance Ratings



This category covers perimeter-fire-containment systems, which are specific constructions consisting of a floor with an hourly fire-endurance rating, an exterior curtain wall with no hourly fire-endurance rating, and material installed to fill gaps between the floor and the curtain wall to prevent the vertical spread of fire in a building. The hourly ratings apply only to the complete systems. The individual components are not assigned ratings and are not intended to be interchanged between systems.

The specifications for materials in a perimeter-fire-containment system and the assembly of the materials are details that directly relate to the established ratings. Information concerning these details is described in the individual systems. Materials used in these perimeter-fire-containment systems are intended to be installed in accordance with the manufacturer's instructions provided with the material. The substitution or elimination of components required in a system should not be made unless specifically permitted in the individual system or in these general guidelines.

When the joint system specifies the insulation material is to be compressed prior to installation into the joint, the uncompressed thickness necessary can be calculated as follows:

Tuncomp = (Wnom x 100) / (100 - Icomp)


Tuncomp = Uncompressed Thickness Necessary, in.
Icomp = Insulation Compression Percentage Specified in System, percent
Wnom = Nominal (Installed) Joint Width, in.

All perimeter-fire-containment systems have been tested with the curtain wall at the maximum clearance distance from the floor.

Curtain wall spandrel panel dead-load anchors located below the concrete floor should be protected from direct fire exposure. When lateral anchors or braces are required to be used with the curtain wall spandrel panels, the lateral anchors or braces located beneath the concrete floor should also be protected from direct fire exposure. The protection for the anchors and braces may consist of a fire-resistive ceiling membrane, spray-applied fire-resistive material, or other protective material with known hourly fire-resistive properties.

Perimeter-fire-containment systems that specify installation in concrete floors may include installation in floors consisting of fluted or corrugated steel deck topped with structural concrete, provided that (1) the concrete topping thickness measured above the top plane of the steel deck is equal to or greater than the minimum concrete thickness specified in the perimeter-fire-containment system, and (2) the perimeter-fire-containment system does not require any portion of the forming material or fill material to extend below the bottom plane of the floor.

The certification of perimeter-fire-containment systems contemplate installation in heated and air-conditioned environments unless stated otherwise in the description of the system.

Authorities Having Jurisdiction should be consulted as to the particular requirements covering the installation and use of these certified systems.


Ratings for some perimeter-fire-containment systems may also include an Integrity Rating, an Insulation Rating and a Leakage Rating. These perimeter-fire-containment systems were tested in compliance with ANSI/ASTM E2307, "Standard Test Method for Determining Fire Resistance of Perimeter Fire Barriers Using Intermediate-Scale, Multi-story Test Apparatus," but the required minimum pressure of 0.01 in. of water was maintained 12 in. below the floor, as compared to the lowest point of the perimeter joint as specified in ANSI/ASTM E2307. This practice ensures a higher level of positive pressure beneath the lowest point of the perimeter joint and this exceeds the minimum requirement specified in ANSI/ASTM E2307.

The criteria for the Integrity Rating complies with the requirements for the "F Rating" of ANSI/ASTM E2307, but also limits the passage of flame through openings in the curtain wall above the perimeter-fire-barrier system.

The criteria for the Insulation Rating complies with the "T Rating" of ANSI/ASTM E2307, but also limits the temperature rise to 325°F above the starting temperature on the interior surface of the curtain wall.

The criteria for the Leakage Rating ("L Rating") is a measure of the amount of air leakage, in cubic feet per minute per linear foot, through the perimeter-fire-containment system at ambient and/or 400°F air temperature at an air pressure differential of 0.30 in. of water. The "L Rating" is intended to assist Authorities Having Jurisdiction and others in determining the suitability of perimeter-fire-containment systems for restricting the movement of smoke in accordance with ANSI/NFPA 101, "Life Safety Code."


The systems are identified in this category by an alpha-alphanumeric identification system. The first two alpha characters, CW, identify the perimeter-fire-containment system as being for use at the interface of a fire-rated floor and a nonfire-rated exterior curtain wall. The third alpha character is either S or D. The S signifies perimeter-fire-containment systems that do not have movement capabilities (i.e., Static). The D signifies fire-containment systems that do have movement capabilities (i.e., Dynamic). The numeric component uses sequential numbers to identify the maximum clearance distance between the curtain wall and the perimeter of the floor. The significance of the number used is:

No. Range
Max Clearance Distance
Between Curtain Wall &
Perimeter of Floor
0000-0999 Less than or equal to 2 in.
1000-1999 Greater than 2 in. and less than or equal to 6 in.
2000-2999 Greater than 6 in. and less than or equal to 12 in.


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


The basic standard used to investigate the systems in this category is ANSI/ASTM E2307 (2010), "Standard Test Method for Determining Fire Resistance of Perimeter Fire Barriers Using Intermediate-Scale, Multi-story Test Apparatus."

Two hourly ratings are defined for each perimeter-fire-containment system: the "T Rating" and the "F Rating." The "T Rating" is a measure of the ability of the perimeter-fire-containment system to limit the temperature rise on the unexposed surface of the perimeter-fire-containment system and the adjacent supporting construction as defined in ANSI/ASTM E2307. The "F Rating" is a measure of the perimeter-fire-containment system to limit flame penetration through the system or around its boundaries and the passage of flames and hot gases sufficient to ignite cotton waste as defined in ANSI/ASTM E2307.

The test method requires joint systems with movement capabilities to be cycled through the intended range of movement prior to the fire test. The movement cycling is intended to demonstrate the compatibility between the individual components of the joint system and the supporting construction. Joint systems are required to be cycled through the intended movement range 500 or 100 complete movement cycles at a minimum rate of 1, 10 or 30 cycles per minute prior to the fire test. Perimeter-fire-containment systems with movement capabilities are noted through the appearance of a Class I, II and/or III designation included as part of the heading information. The definitions of the movement class designations are as follows:

Min No.
of Cycles
Min Cycling Rate
(cycles per min)
Class I 500 1
Class II 500 10
Class III 100 30

Each perimeter-fire-containment system with movement capabilities specifies a nominal opening width and the movement capabilities, expressed in either a numerical value or as a percent of the nominal opening width. When the shear movement capabilities are expressed as a percent, the shear movement capabilities in inches which the joint system can accommodate can be calculated as follows:

Shear = Wnom(% Shear / 100)


Shear = Shear Movement, In.
Wnom = Nominal Opening Width, In.
% Shear = Shear Movement, Percent


Those materials identified by an (*) in the system description text are eligible to be produced under UL's Follow-Up Service Program.

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Curtain Wall/Floor Protection Systems
Last Updated on 2015-04-17
XHDG.GuideInfo XHDG Active 20150417 20150421

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