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Evaluating Fire Performance of Facade Assemblies Using ANSI/FM 4880

Yi Wang FM Global

5th International Tall Building Fire Safety Conference, June 2018

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ACM fire catastrophes– Accelerated vertical spread

International efforts– Scrutinize codes and fire testing methods

Recent Façade Fires

Korea 2010Electrical fire

Grenfell (UK) – 2017Source: Interior

71 causalities, No Sprinklers

Dubai 2015Electrical short-circuit

Atlantic City (US) – 2007Hot-work sparks in cavity wall

France 2012Exterior/Balcony

Turkey 2018Source: Unknown

Australia 2014Exterior/Balcony

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ACM – Aluminum Composite Material 3-6 mm panel with aluminum facers and plastic core External wall finish, cladding, rain screen Alternatives: HPL, FRP

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External Façade Assembly Cladding panel (ACM, HPL, FRP, etc) Cavity wall Insulation, water resistive barrier

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High Rise Building Fire Safety All protection strategies based on the

premise of no vertical flame spread

Goal: no vertical flame spread under the worst case scenario

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Façade Fire Scenarios1. Post-flashover interior fire Spill plume through windows

2. Exterior fire Dumpster fire, storage … Re-entrant corner

3. Cavity wall fire

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Façade Fire – Post-flashover Oleszkiewicz 1990: Realistic Heat Flux ~ 100 kW/m2

Oleszkiewicz, “Fire Exposure to Exterior Walls and Flame Spread on Combustible Cladding”, Fire Technology, 1990

Single-wall Re-entrant Corner

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Façade Fire – Exterior fires Alpert & Davis 2002: Wood crib fire in corner – dumpster fire Realistic Heat Flux ~ 100 kW/m2

Alpert & Davis, “Evaluation of Exterior Insulation and Finish System Fire Hazard for Commercial Applications”, J. Fire Protection Eng., 2002

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Standard Tests for Facade Fire

Sweden France

BS-8414 (UK)

Draft GermanyGermany

Canada (UL)NFPA 285 (US) ISO-13785

Russia Hungary

25 ft corner 50 ft corner 16 ft-PPT

ANSI/FM 4880

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NFPA 285NFPA-285 heat flux

Peak heat flux: ~40 kW/m2

Two propane burners: 1300 kW Pass criteria

– Max 10 ft vertical propagation above window – Max 5 ft horizontal propagation from centerline – Max temperature in

• insulation (750 F), in cavity/exterior (1000 F)

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BS-8414 Peak heat flux: ~75 kW/m2

1.5 m3 wood crib 8 m x 2.6 m x 1.5 m Pass criteria

– Max temperature in exterior/cavity/insulation at 16.4 ft above window is 1110 F (600 ⁰C) above ambient

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ANSI/FM 4880 Peak heat flux: > 100 kW/m2

25-ft and 50-ft corner tests 16-ft PPT

25 ft corner testSince 1970s

50 ft corner testSince 1990s

16 ft PPTSince 2000s

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Correlation between PPT and Corner Test

16 ft x 3.5 ft panels, similar view factor 360 kW gas burner Same heat flux: >100 kW/m2

HRR as criteria

Nam and Bill, “A New Intermediate-scale Fire Test for Evaluating Building Material Flammability”, J. Fire Protection Eng., 2009

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Comparison of Fire Tests – Heat fluxNFPA-285 BS-8414 ANSI/FM 4880 - 16 ft PPT

Scenario Single-wall(flashover)

Re-entrant corner(flashover)

Re-entrant corner(Exterior/flashover)

Peak Heat flux 40 kW/m2 75 kW/m2 100 kW/m2

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Fire Tests Comparison – Failure CriteriaTest Peak Heat Flux Criteria for Fail

16 ft. PPT ~ 100 kW/m2 Peak HRR > 1100 kW

BS-8414 ~ 75 kW/m2 Temperature at 16 ft height > 1110 °F

NFPA-285 40 kW/m2 Temperature at 10 ft height > 1000 °F

*HRR – Heat Release RateRate of energy release in fires

Global measurement of fire performance.

Objective and Repeatable.

Correlated to peak fire propagation height in PPT.

Approval Installation Height ↓ Test Criteria ↓

Unlimited height Peak HRR ≤ 830 kW

50 ft 830 kW< Peak HRR ≤ 1100 kW

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Test # Exterior Sheathing WRB Insulation Air Cavity ACM

4 Gypsum -- -- 2.0 inch FR-core

5 Gypsum Yes -- 2.0 inch FR-core

6 Gypsum Yes PIR1 (2 inch) 2.0 inch FR-core

7 Gypsum Yes PIR2 (2 inch) 2.0 inch FR-core

Tested AssembliesTest # Exterior Sheathing WRB Insulation Air Cavity ACM

1 Gypsum Yes -- 0.2 inch PP-core

2 Gypsum Yes PIR1 (2 inch) 1.2 inch PP-core

3 Gypsum -- -- 2.0 inch PE-core

Test # Exterior Sheathing WRB Insulation Air Cavity ACM

4 Gypsum -- -- 2.0 inch FR-core

5 Gypsum Yes -- 2.0 inch FR-core

Wide representation of practiced installations

PP – Polypropylene FR – Fire Retardant

PE – Polyethylene WRB – Water Resistive BarrierPIR– Polyisocyanurate

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Test # Exterior Sheathing WRB Insulation Air Cavity ACM

4 Gypsum -- -- 2.0 inch FR-core Passed, test

5 Gypsum Yes -- 2.0 inch FR-core Passed, test

6 Gypsum Yes PIR1 (2 inch) 2.0 inch FR-core Passed, Desktop Ass.

7 Gypsum Yes PIR2 (2 inch) 2.0 inch FR-core Passed, Desktop Ass.

Test # Exterior Sheathing WRB Insulation Air Cavity ACM NFPA 285 Compliance

1 Gypsum Yes -- 0.2 inch PP-core Passed, test

2 Gypsum Yes PIR1 (2 inch) 1.2 inch PP-core Passed, Desktop Ass.

3 Gypsum -- -- 2.0 inch PE-core Failed

Tested Assemblies

PP – Polypropylene FR – Fire Retardant

PE – Polyethylene WRB – Water Resistive BarrierPIR– Polyisocyanurate

NFPA 285 Compliance

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Assembly Prep ExampleGypsum and WRB Insulation Joint system & ACMs with air cavity

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Assembly Prep ExampleCentral Vertical/Horizontal Joints 16-ft PPT

– 16 ft x 3.5 ft panels– 360 kW fire source– Heat flux: 100 kW/m2

– Placed under 5 MW calorimeter

– Approval Criteria:

Approval Height Test Criteria 50 ft 830 < HRR ≤ 1100 kW

Unlimited height HRR ≤ 830 kW

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Categorize fire performance:• Unlimited Height• Up to 50 ft (15.2 m)• Very bad performers

Test # Assembly

1 PP-Core → WRB → Gypsum

2 PP-Core → PIR1 → WRB→ Gypsum

3 PE-Core → Gypsum

Test # Assembly

4 FR-Core → Gypsum

5 FR-Core → WRB → Gypsum

6 FR-Core → PIR1 → WRB → Gypsum

7 FR-Core → PIR2 → WRB → Gypsum

Unlimited Height

Up to 50 ft Only

Failed

Fire terminated

Results: HRR

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Unlimited ht. vs. 50-ft vs. Failed Assemblies

Unlimited HeightHRR ≤ 830 kW

Burnt height < 8 ft

50-ft limited height830 < HRR ≤ 1100 kW

8 ft < Burnt height < 16 ft

FailedHRR > 1100 kW

Burnt height > 16 ftTest #4 FR-Core ACM with Non-comb. Test #6 FR-Core ACM with PIR Comb. Test #3 PE-Core (Grenfell-like ACM )

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Post-test pictures

Unlimited HeightHRR ≤ 830 kW

Burnt height < 8 ft

50-ft limited height830 < HRR ≤ 1100 kW

8 ft < Burnt height < 16 ft

FailedHRR > 1100 kW

Burnt height > 16 ftTest #4 FR-Core ACM with Non-comb. Test #6 FR-Core ACM with PIR Comb. Test #3 PE-Core ACM

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Comparison with NFPA-285 and BS-8414Test # Exterior Sheathing ANSI/FM 4880 BS-8414 NFPA-285

1 PP-Core → WRB → Gypsum Fail Not tested Pass (tested)

2 PP-Core → PIR1 → WRB→ Gypsum Fail Not tested Pass (desk top)

3 PE-Core → Gypsum Fail Fail Fail

4 FR-Core → Gypsum PassUnlimited Height Pass Pass (tested)

5 FR-Core → WRB → Gypsum PassUnlimited Height Not tested Pass (tested)

6 FR-Core → PIR1 → WRB → Gypsum Fail Unlimited ht.Pass 50 ft ht. Fail (6 inch PIR) Pass (desk top)

7 FR-Core → PIR2 → WRB → Gypsum Fail Unlimited ht.Pass 50 ft ht. Fail (6 inch PIR) Pass (desk top)

BS-8414 tests performed by BRE in 2017, with different insulation thickness

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Compare PP and PE-ACM Video

Heat flux difference → Different Evaluations.

FM 16-ft Test #1Passed NFPA-285

FM 16-ft Test #3 (Similar to Grenfell)Failed NFPA-285

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Test #1: NFPA-285 Passed Assembly

FM 4880Test # Exterior Sheathing WRB CI Air Cavity ACM

1 Gypsum Henry paint -- 0.2 inch PP-Core

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Summary 7 ACM wall assemblies evaluated using 16’ PPT

– Covers typical materials and configurations– Can differentiate safe and dangerous materials with objective

global measurement

Comparison with other tests– 16-ft PPT and BS-8414 provide generally consistent evaluation for

the tested ACM assemblies, more test data are needed– NFPA-285 passed assembly demonstrated high fire hazard for

realistic fire scenario

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FM Global Technical Report 16’ PP tests are cost effective and robust for evaluating

façade assemblies– Representative to realistic and severe hazard condition– Smaller overall size, but similar evaluation height, correlate with

larger scale severe fire tests

FM external technical report– http://www.fmglobal.com/research-and-resources/research-

and-testing/research-technical-reports

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Next Step FM Approvals Standard 4411

updated– “Approval standard for cavity walls

and rainscreens”– Revision allows cladding systems

to be evaluated

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Acknowledgement Dr. Gaurav Agarwal Mr. Kevin Mullins Mr. Thomas Roche Dr. Sergey Dorofeev Dr. Louis Gritzo