perimeter curtain wall fire protection · •perimeter joint curtain wall test is performed in...

Saving Lives and Property

Through Fire and Smoke Containment ©2004 IFC

Perimeter Curtain

Wall Fire Protection



• Brief history

• Dynamics of fire

• What do the codes say?

• How are they tested?

• How testing is affecting design

Topics for Discussion



Curtain Walls

&

the Perimeter Joint



A Brief History of Fires -Where Curtain Wall or

Safing Issues Have Been Cited…



• Summerland, Isle of Man, British Isles. Fire spread

through safing slot. 50 people killed.

• Hilton Hotel, Las Vegas, NV. Fire spread from 8th to 13th

floor in 25 minutes. 8 fatalities.

• First Interstate Bank, Los Angeles, CA. Flames spread

from 13th to 16th floor via perimeter joint. One death.

• One Meridian Plaza, Philadelphia, PA. Fire spread from

22nd to 30th floor through unprotected openings including

slab edge.

Unsealed or Improperly sealed

perimeter joints cost lives and huge

liability losses…



What are the dynamics of

vertical spread in a high-rise building?



Rated Floor Assembly and

non-rated Curtain Wall SystemVision Glass

Fire begins on a lower floor,

products of combustion

accumulate at ceiling level,

and positive pressure builds



The fire follows the flow of

air currents…

Vision Glass Rated Floor Assembly and

non-rated Curtain Wall System

If the void between

the floor and curtain

wall is not properly

sealed, flames will

spread vertically…

and

compartmentation

is breached!



Vision Glass



Elevated temp. and pressure

breaks lower vision glassFlames may erupt through

the windows. Oxygen fuels

the fire.

Fire attacks the curtain wall

structure from both sides

causing a premature failure of

the wall structure and potentially

the vision glass above!



Firestop Coating or Sealant

over mineral wool safing



A properly designed & tested

Perimeter Fire Barrier System

not only protects the perimeter

joint but critical wall framing and

support elements as well!

Properly installed &

supported mineral wool

spandrel insulation



How do the codes address the

protection at the perimeter?



• All Model Codes call for the rating of the floor to

extend to the exterior wall

• All Model Codes require minimum spandrel height

• All Model Codes allow spandrel height exceptions

in certain sprinklered conditions

What do the codes say?



Extending the Rated Floor to

the Wall...

In rated construction,

all floors are rated

The perimeter joint must be sealed with an

approved material or system that extends

this rating to the exterior wall surface

MANDATORY!



Code Compliance

Firestopping the perimeter joint is mandatory.

Meeting the Letter of the Law...

1. Designing the wall to keep the firestop

system in place for the rated period of

the floor is an obvious necessity.

PROTECTING THE PERIMETER JOINT:

2. Designing and installing the firestop

correctly is the final step!



The Leap Frog Effect…



Fire may break out of a

window and leap back to

the floor above!

That being the case…

Why bother to protect the

perimeter???

The Leap Frog effect…



Sprinklers are an exception

to window separation

requirements…

But not to requirements for

protection of safing slot!




Sprinkler advocates are

lobbying to reduce these

requirements…

After all… The fire may

jump around the protection!




The Leap Frog affect…

The fact is, depending on

window spacing and other

factors, the fire may jump!

So what exactly does a

Perimeter Fire Barrier

System do?



Slows the process down. Of course it

depends on window spacing and

other construction factors…

As well as the nature and severity of

the fire…

The Perimeter Fire Barrier

System…



Along with sealing the slot area, a

well engineered system provides

structural protection and maximizes

the integrity of the wall system…

Keeping the wall and window system

above intact longer!


System…



• Extends the rating of the floor to the wall.

• Forces the fire to exit the building in order to

propagate to upper floors.

• Protects structural elements and helps prevent

catastrophic failure of the spandrel system.

• Maximizes fire protection afforded by the

non-rated wall.


System…



• Prevents the migration of flame, hot gases

and smoke through to floors above.

• Buys time for occupants to escape.

• Buys time for first responders to secure the

building

• Provides additional protection in the event of

a sprinkler or detection failure.


System…




System…

Provides energy savings through

increased thermal efficiencies

throughout the life of the building…

When considered this way, the

life safety benefits are free!



How Are Perimeter Fire

Barrier Systems Tested?



ASTM E2307

Standard Test Method for

Determining Fire

Resistance of Perimeter

Fire Barriers Using

Intermediate-Scale,

Multi-Story Test

Apparatus



How Are Perimeter Fire Barrier

Systems Tested?

Only two labs presently perform testing in

accordance with newly developed test methods:

• Underwriters Laboratories Inc. – Northbrook, IL

• Omega Point Laboratories – Elmendorf, Texas



UL & OPL Testing

• Perimeter joint curtain wall test is

performed in accordance with ASTM E2307

• Other labs, testing per UL 2079 alone, do

not adequately capture the dynamics

between a rated floor and a non-rated

curtain wall assembly, the structural nature

of curtain walls, and fire attacking at two planes

• Intermediate-Scale, Multi-Story Test Apparatus

(ISMA) was developed for this application



• Two ratings are provided per the ASTM E2307 test:

- “F”-rating, in hours (resistance to fire spread)

- “T”-rating, in hours (temperature on non-fire side)

• UL provide two additional ratings using same test apparatus

- “integrity rating” & “insulation rating”

Question: What Test is used to Evaluate

Perimeter Fire Barrier Systems?

Testing Questions…

Answer: ASTM E2307 using the Intermediate-

Scale, Multi-Story Test Apparatus (ISMA)

is used to determine…



Question: How can this be representative of real life?

Answer: It can’t! The test method indicates whether…

1. The safing method can last as long

as the floor.

2. The protection scheme can adequately

protect wall framing and attachments.




Question: Then how representative is this test?

Answer: It should be considered broadly representative.

Spandrel width, height, and window spacing

are limited because the test is not full scale.

Story height is approximately 7 feet.

Wall framing methods, support, and the safing

slot itself are well represented and provide

excellent engineering data.




Curtain

Wall Test

Assembly

Pre-Burn

Transom above floor

Transom below floor

Mechanical attachments

supporting insulation

Mineral wool insulation at

spandrel area

Mullions



Assembly

Interior

View

Pre-Burn

Thermocouples measuring

temperature rise



Interior Burner Lit - Time: 0:00



Exterior Burner Lit - Time: 0:05



Flames

Climbing

Exterior

Time: 0:15



Melting of

Mullions

&

Transoms

Time: 0:45



Vision

Glass

Breaks

Time:

2:00



Burner Off at 2 hours



Post Test:

Close up Detail of

Mullion and Transom

Damage



Post Test – Interior View



ASTM E2307 Testing has Improved

Perimeter Joint Evaluation…



Vertical Mullions

Transoms

Mechanical

Attachment

Mullion Covers

Firestop Coating

Vision

Glass

Spandrel

Panel

Mineral Wool Safing

Stiffback

Angle

Spandrel

Insulation



Perimeter Fire Containment - Basic Design Criteria

1. Mechanically Attached Curtain Wall Insulation



1

Mechanically

Attached




2. Protect Aluminum Mullions




2Protect

Mullions

1

Mechanically

Attached





3. Compression-Fit Safing Insulation -as required per tested assembly

Install Safing Impaling Clips -as required per tested assembly

Horizontal fiber

orientationVertical fiber

orientation




2Protect

Mullions

1

Mechanically

Attached

3

Compression Fit

Safing (Direction of Safing

as required per tested assembly)

Safing Clips (as required per tested assembly)



Compression Fit Safing (Direction of

Safing as required per tested assembly)






3. Compression-fit Safing Insulation -as required per tested assembly


4. Provide Backing/Reinforcement Member at

Safing Line




2Protect

Mullions

1

Mechanically

Attached

3

Compression Fit




4 Reinforcement

Member



75% of fire related

deaths are caused by

smoke inhalation

What about smoke?





3. Compression-fit Safing Insulation -as required per tested assembly


4. Provide Backing/Reinforcement Member at

Safing Line

5. For “Smoke Containment,” Add Firestop Coating




5 Firestop

Coating

4 Reinforcement

Member

2Protect

Mullions

1

Mechanically

Attached

3

Compression Fit






5Firestop

Coating



Question: Why aren’t floor-to-wall (FW) systems acceptable for

curtain walls?

Answer: Floor-to-wall systems test fire resistance between a

rated floor and rated wall tested per ASTM E1966.

CW systems are specific perimeter tests between a

rated floor and non-rated curtain wall using the

Intermediate Scale Multi-story Apparatus (ISMA) per

ASTM E2307.

Additional Design

Questions…



Question: Why are windows spaced so far apart?

My windows are closer together…

Answer: ASTM E2307 evaluates the interior

passage of fire and hot gases

through the perimeter joint only.

Increasing the spandrel height

reduces the likelihood of the leap

frog effect.

Additional Design Questions…



Question: What is the function of the firestop

coating in these systems?

Answer: The firestop coating performs

several important functions.

Additional Design

Questions…



Additional Design

Questions…

1. The most obvious role is as a smoke seal.

2. Seals off the path of hot gasses. Makes

the safing more effective.

3. “Glues” everything together.

The Role of the Firestop Coating:



Additional Design

Questions…

Question: Are curtain wall joints static or dynamic?

Answer: This area is referred to as a slot. The word joint

suggests movement. Experts tend to agree that a

small amount of movement occurs within the slot

area. It is up to the design professional to

determine the level of movement required for the

project.

Some wall designs are subject to a small amount

of vertical shear or horizontal sway and some

systems incorporate these values.



Additional Design

Questions…

Question: What if our design isn’t a perfect match

for a system?

Answer: We strongly suggest specifying tested

systems. However, real world designs are

seldom a perfect match!

Find a listing that is reasonably close and

contact the manufacturer for an Engineering

Judgment to match the design.



Benefits of Specifying A Listed

Perimeter Joint System

• Completes the curtain wall package

• Applies pedigreed testing and competent

engineering

• Assists the local AHJ

• Standardizes design and cost

• Limits liability

• Provides energy conservation from insulation value

perimeter curtain wall fire protection · •perimeter joint curtain wall test is performed in...

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