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What is Perimeter Fire Containment (PFC)?

​Architects and curtain wall designers have long recognized that the void created between the floor slab and exterior wall, if left unprotected, would allow fire and smoke to propagate to the floor above. The logical fix seemed to be to fill the void with fire resistant material. However, if the void is simply filled with mineral wool and a portion of the spandrel area is left unprotected, the curtain wall will fail, causing the mineral wool to fall out of the void. Once the mineral wool at the joint is lost, fire will propagate through the opening, allowing fire to engage combustibles in the floor above.

What does it do?

​Perimeter Fire Containment is designed to prevent Flame and Hot Gasses from entering the room above via the void created at the intersection of the floor slab and the interior of the exterior wall assembly. WHY is this necessary? THE ANSWER: The unprotected void at the edge of slab becomes a chimney or flue for fire to rage up the inside of the building, transmitting fire from floor to floor in the building. Often overlooked is how much exposure is actually created by the void at the edge of the building. A small building with a perimeter of 200' x 200' and a typical void of 3" creates 200 square feet of open area that will allow smoke and hot gasses to flow freely to the floor above. Multiply this open area times the number of floors and the risk to life safety of the occupants and first responders becomes a magnitude unthinkable to a building owner or community.

Section 705.8.5 Vertical Separation of Openings

​Openings in exterior walls in adjacent stories shall be separated vertically to protect against fire spread on the exterior of the buildings where the openings are within 5 feet (1524 mm) of each other horizontally and the opening in the lower story is not a protected opening with a fire protection rating of not less than ¾ hour.  Such openings shall be separated vertically not less than 3 feet (914 mm) by spandrel girders, exterior walls or other similar assemblies that have a fire-resistance rating of not less than 1 hour rated for exposure to fire from both sides, or by flame barriers that extend horizontally not less than 1 hour. The unexposed surface temperature limitations specified in ASTM E 119 or UL 263 shall not apply to the flame barriers unless otherwise required by the provisions of this code. 

Exceptions:

1. ​This section shall not apply to buildings that are three stories or less above grade plane.
2. This section shall not apply to buildings equipped throughout with an automatic sprinkler system in accordance with section 903.3.1.1 or 903.3.1.2.
3. This section shall not apply to open parking garages.

Section 715.4 Exterior Curtain Wall/Floor Intersection

Where fire resistance-rated floor or floor/ceiling assemblies are required, voids created at the intersection of the exterior curtain wall assemblies and such floor assemblies shall be sealed with an approved system to prevent the interior spread of fire. Such systems shall be securely installed and tested in accordance with ASTM E2307 to provide an F rating for a time period not less than the fire- resistance rating of the floor assembly. Height and fire-resistance requirements for curtain wall spandrels shall comply with Section 705.8.5.

Exception:

• Voids created at the intersection of the exterior curtain wall assemblies and such floor assemblies where the vision glass extends to the finished floor level shall be permitted to be sealed with an approved material to prevent the interior spread of fire. Such material shall be securely installed and capable of preventing the passage of flame and hot gases sufficient to ignite cotton waste where subjected to ASTM E 119 time-temperature fire conditions under a minimum positive pressure differential of 0.01 inch (0.254 mm) of water column (2.5 Pa) for the time period not less* than the fire-resistance rating of the floor assembly.
  

        * Indicates change in language from 2015 IBC Code. 2015 states "equal to".

Section 715.4.1 Exterior curtain wall/nonfire-resistance-rated floor assembly intersections.

Voids created at the intersection of exterior curtain wall assemblies and nonfire-resistance-rated floor or floor/ceiling assemblies shall be sealed with an approved material or system to retard the interior spread of fire and hot gases between stories.

Section 715.4.2 Exterior curtain wall/vertical fire barrier intersections.

Voids created at the intersection of nonfire-resistance-rated exterior curtain wall assemblies and fire barriers shall be filled. An approved material or system shall be used to fill the void and shall be securely installed in or on the intersection for its entire length so as not to dislodge, loosen or otherwise impair its ability to accommodate expected building movements and to retard the passage of fire and hot gases. 

Section 715.5 Spandrel Wall

Height and fire-resistance requirements for curtain wall spandrels shall comply with Section 705.8.5. Where Section 705.8.5 does not require a fire-resistance-rated spandrel wall, the requirements of Section 715.4 shall still apply to the intersection between the spandrel wall and the floor.

​Section 705.8.5 Vertical Separation of Openings

Openings in exterior walls in adjacent stories shall be separated vertically to protect against fire spread on the exterior of the buildings where the openings are within 5 feet (1524 mm) of each other horizontally and the opening in the lower story is not a protected opening with a fire protection rating of not less than ¾ hour.  Such openings shall be separated vertically not less than 3 feet (914 mm) by spandrel girders, exterior walls or other similar assemblies that have a fire-resistance rating of not less than 1 hour, rated for exposure to fire from both sides, or by flame barriers that extend horizontally not less than 30 inches (762 mm) beyond the exterior wall. Flame barriers shall have a fire resistance rating of not less than 1 hours. The  unexposed surface temperature limitations specified in ASTM E119 or UL 263 shall not apply to the flame barriers or vertical separation unless otherwise required by the provisions of this code.

Exceptions:

1. This section shall not apply to buildings that are three stories or less above grade plane.
2. This section shall not apply to buildings equipped throughout with an automatic sprinkler system in accordance with section 903.3.1.1 or 903.3.1.2.
3. Open parking garages.

Section 715.4 Exterior Curtain Wall/Floor Intersection

Where fire resistance-rated floor or floor/ceiling assemblies are required, voids created at the intersection of the exterior curtain wall assemblies and such floor assemblies shall be sealed with an approved system to prevent the interior spread of fire. Such systems shall be securely installed and tested in accordance with ASTM E2307 to provide an F rating for a time period not less than the fire-resistance rating of the floor assembly. Height and fire-resistance requirements for curtain wall spandrels shall comply with Section 705.8.5.

Exception:

• Voids created at the intersection of the exterior curtain wall assemblies and such floor assemblies where the vision glass extends to the finished floor level shall be permitted to be sealed with an approved material to prevent the interior spread of fire. Such material shall be securely installed and capable of preventing the passage of flame and hot gases sufficient to ignite cotton waste where subjected to ASTM E 119 time-temperature fire conditions under a minimum positive pressure differential of 0.01 inch (0.254 mm) of water column (2.5 Pa) for the time period equal to the fire-resistance rating of the floor assembly.

Section 715.4.1 Exterior curtain wall/nonfire-resistance-rated floor assembly intersections.

Voids created at the intersection of exterior curtain wall assemblies and nonfire-resistance-rated floor or floor/ceiling assemblies shall be sealed with an approved material or system to retard the interior spread of fire and hot gases between stories.

Section 715.4.2 Exterior curtain wall/vertical fire barrier intersections.

Voids created at the intersection of nonfire-resistance-rated exterior curtain wall assemblies and fire barriers shall be filled. An approved material or system shall be used to fill the void and shall be securely installed in or on the intersection for its entire length so as not to dislodge, loosen or otherwise impair its ability to accommodate expected building movements and to retard the passage of fire and hot gases. 

Section 715.5 Spandrel Wall

Height and fire-resistance requirements for curtain wall spandrels shall comply with Section 705.8.5. Where Section 705.8.5 does not require a fire-resistance-rated spandrel wall, the requirements of Section 715.4 shall still apply to the intersection between the spandrel wall and the floor.

​Section 715.4.1

Voids created at the intersection of exterior curtain wall assemblies and nonfire-resistance-rated floor or floor/ceiling assemblies shall be sealed with an approved material or system to retard the interior spread of fire and hot gases between stories.

3.1.8.3. Continuity of Fire Separations

4) The continuity of a fire separation shall be maintained where it abuts another fire separation, a floor, a ceiling, a roof, or an exterior wall assembly. (See Note A-3.8.3.(4).)

A-3.1.8.3.(4) Fire Separation Continuity.
The continuity of a fire separation where it abuts against another fire separation, a floor, a ceiling or an exterior wall assembly
 is maintained by filling all openings at the juncture of the assemblies with a material that will ensure the integrity of the fire
separation at that location.

Canadian Firestop Systems tested to:

• CAN/ULC-S115 “Standard Method of Fire Tests for Firestop Systems”

​Canadian PFC Industry Practice

​Canadian curtain wall manufacturers use metal backpans

CAN/ULC-S115-R2016 does not recognize, and is not intended to test, perimeter joint systems between a fire rated floor and a non-fire rated exterior wall

CAN/ULC-S115-18 now includes direct reference to ASTM E2307.

Image Source: G. Chen & F. Victor, Curtain Wall Firestop: Review of Code Requirement and Design Issues, October 2012, http://ghl.ca/wp-content/uploads/shared/2012F_-_Curtain%20Wall%20Firestop.pdf

NRCC - 49677

Best Practice Guide on Fire Stops and Fire Blocks and their Impact on Sound Transmission (Link)

June 2007

“ In the U.S.A., perimeter fire stops with non-fire-rated exterior curtain walls are tested and listed using the Intermediate Scale Multi-Storey Apparatus (ASTM E 2307) [12-2]. A number of designs have been evaluated and listed for this application. While this test method has not yet been adopted in Canada, users may wish to specify a listed design the U.S.A. as evidence of having met the intent of the NBCC requirement for building perimeter fire stops. ”

GHL Consultants LTD | Building Codes & Fire Science

Curtain Wall Firestop: Review of Code Requirement and Design Issues (Link)

October 2012

“ In our opinion, any firestop system proposed for use with curtain wall systems should be reviewed by a qualified professional engineer with expertise in compartment fire dynamics and behavior of curtain wall construction in fires. The engineer should review the floor-to-curtain wall joint detail and possibly make adjustments to the design to reduce the risk of premature curtain wall failure. While such proposed designs may not be ‘equivalent’ to an ASTM E 2307 compliant design, the engineer’s review and any subsequent adjustments would be a significant improvement over the minimum requirement of the Building Code. ”

​NBCC 2020 Cycle

Perimeter Fire Barrier ASTM E 2307 Proposal

• Carried over from previous cycle​​​

[4] 4) Except as provided in Sentence (5)-2020, T the continuity of a fire separation shall be maintained where it that abuts another fire separation, a floor, a ceiling, or a roof, or an exterior wall assembly, shall be maintained by a fire stop conforming to Sentence (3)-2020. (See Note A-3.1.8.3.(4).)

[6] --) Joints located in a horizontal plane between the floor and exterior wall shall be sealed by a fire stop that, when subjected to the fire test method in ASTM E 2307 "Determining Fire Resistance of Perimeter Fire Barrier System Using Intermediate Scale, Multi-Storey Test Apparatus," has an F rating not less than the fire-resistance rating of the horizontal fire separation. (See Note A-3.1.8.3.(4).)

• Approved by SC & CCBFC
  
• Public Review completed Fall 2018
  
• To be reviewed at April 2019 SC Fire Protection meeting
  

CCR = Code Change Request
SC = Standing Committee
PR = Public Review
CCBFC = Canadian Commission on Buildings and Fire Codes

​New edition of CAN/ULC-S115 published June 1, 2018

​9. PERIMETER JOINT FIRESTOP SYSTEMS
9.1 GENERAL
9.1.1 Perimeter Joint Firestop Systems shall be tested in accordance with the requirements in ASTM E2307, Standard Test Method for Determining Fire Resistance of Perimeter Fire Barriers Using Intermediate-Scale, Multi-Storey Apparatus.
……
9.4.4.1 The placement and measurement of unexposed surface temperatures shall be in accordance with the requirements in the standard ASTM E2307, Standard Test Method for Determining Fire Resistance of Perimeter Fire Barriers Using Intermediate-Scale, Multi-story Test Apparatus.

• New edition to be added to NBCC 2020 prior to publication
• After 2020, next code cycle NBCC 2025
• CAN/ULC-S115-18 now published

​Canada PFC Review

Still 2 years away from ASTM E 2307 tested systems recognized in NBCC 2020

• Must pass Public Review
• S115-2018 will not be recognized in code until 2025

Fire Consultants currently have final say

• ASTM E 2037 systems is the best reference for tested systems
• Engineering judgments could be used to support ASTM E 2307 systems adopted into Canada

Canadian Curtain Wall industry uses Backpans

• Identifying and testing “Canadian” systems will be necessary

​What are the 5 basic design criteria? 

Training

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• PFC One Day Seminar Training Resources
  
• Discuss one day inspector program
  
• Link to PPT
  

Testing and Certifications

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• ASTM E2307
  
• Labs
  
• Where to find listings
  
• EJ Guidelines