Assessing the Effect of 

Backcoatings and Fire Barrier 

Technologies on Upholstered 

Furniture Flammability

Mauro Zammarano

Project Leader,

Reduced Flammability of Residential Upholstered Furniture,

Flammability Reduction Group, Engineering Laboratory,

National Institute of Standards and Technology, USA.

Recent Advances in Flame Retardancy of Polymeric Materials

BCC Meeting on Flame Retardancy

May 20-23, 2018

Stamford, CT

Disclaimer

Some of the data in this presentation hasn’t been through NIST review 

process and should be considered experimental / draft results. However, 

the data has been analyzed by subject matter experts within the research 

team and is believed to be scientifically sound and consistent with the 

integrity expected of NIST research 
FLAME 

RETARDANT

• Residential-Upholstered-Furniture (RUF):

moving away from Flame Retardants 

(FRs)

• Fire safe RUF without Flame Retardants

- NIST Silicone Backcoating

- Fire Barriers

• Testing (CUBE TEST)

composite cone-based-test for

assessing Fire Barriers and 

Backcoatings

2

Outline
Residential Upholstered Furniture (RUF)

RUF fires are the largest cause of civilian deaths in US home fires* 

*J.R. Hall Jr, Estimating Fires When a Product is the Primary Fuel But Not the First Fuel, With an Application to Uphol.Furn., NFPA, 2014.

**Ahrens, Home Fires that Began with Upholstered Furniture, NFPA, 2017

Smoldering Flaming Flash-over

How can we reduce RUF fire deaths?

1. Fire Prevention (ignition suppression)

 Reduce smoldering ignitions (most frequent ignition source - 1

st item) 

2. Fire Mitigation (heat release rate reduction)

 >90 % of casualties from fires spreading beyond the initial burning object 

 >70 % from fires spreading outside the initial fire room** 
NFPA 277:

Sudden Death of a Draft Standard Flaming test for RUF

• 2014: started development of NFPA 277

• April 2018: NFPA Standard Council voted to cease NFPA 277

4

[1] https://www.nfpa.org/News-and-Research/News-and-media/Press-Room/News-releases/2018/NFPA-Standards-Council-votes-to-cease-standards-development-of-NFPA-277

• NFPA stated that [1]:

- The concerns about the toxicity of flame 

retardant chemicals raised by participants, 

including first responders, need to be 

answered.
Other Positions

• Fire Fighters: It would appear that any proposed new fire test 

designed to resists ignition from a second item and/or designed to 

limit growth of Heat Release Rate will require much higher levels 

of FR than those required to pass TB117. Probably at similar 

levels or exceeding TB133 (15-30%)”

5

• CPSC recommends to refrain from intentionally adding nonpolymeric, 

organohalogen FRs

[CPSC Docket No. CPSC–2015–0022, Sept’17]

• State of Maine first State banning all flame retardants in RUF

Effective on Jan 1 2018 - https://www.mainelegislature.org/legis/bills/bills_128th/billtexts/HP013801.asp

Why Do Fire Fighters Support the Banning of Flame Retardants?

Joseph Fleming PFFM (Professional Fire Fighters of Massachusetts)

http://greensciencepolicy.org/wp-content/uploads/2018/02/6-Fleming_FRDPresentation_2518.pdf
Other Positions

• Fire Fighters: It would appear that any proposed new fire test 

designed to resists ignition from a second item and/or designed to 

limit growth of Heat Release Rate will require much higher levels 

of FR than those required to pass TB117. Probably at similar 

levels or exceeding TB133 (15-30%)”

6

• CPSC recommends to refrain from intentionally adding nonpolymeric, 

organohalogen FRs

[CPSC Docket No. CPSC–2015–0022, Sept’17]

• State of Maine first State banning all flame retardants in RUF

Effective on Jan 1 2018 - https://www.mainelegislature.org/legis/bills/bills_128th/billtexts/HP013801.asp

Why Do Fire Fighters Support the Banning of Flame Retardants?

Joseph Fleming PFFM (Professional Fire Fighters of Massachusetts)

http://greensciencepolicy.org/wp-content/uploads/2018/02/6-Fleming_FRDPresentation_2518.pdf

Why Do Fire Fighters Support the Banning of Flame Retardants?

Joseph Fleming PFFM (Professional Fire Fighters of Massachusetts)

http://greensciencepolicy.org/wp-content/uploads/2018/02/6-

Fleming_FRDPresentation_2518.pdf

FLAME 

RETARDANT

moving away from 

Flame Retardants in 

RUF
What is NIST doing?

7

• NIST SP1220 Workshop Report: Research Roadmap for Reducing 

the Fire Hazard of Materials in the Future (2018): 

https://www.nist.gov/publications/workshop-report-research-roadmap-reducing-fire-hazard-materials-future

identified RUF as the top priority application for fire safety research in 

terms of overall impact on the fire problem

• NIST project - Low Heat Release Upholstered Furniture

Project Objectives:

- low heat release rate RUF without the need for fire FR.

- bench-scale methodology for predicting the RUF flaming hazard.

- robust standard reference cigarettes for smoldering ignition testing

- bench-scale methodology for predicting the RUF smoldering hazard.
Fire Barriers

Reduce flammability without the use of chemical FRs by 

reducing

(1) Heat Transfer and (2) Mass Transfer (of pyrolyzates

produced by foam decomposition)

8

Simplified Model of a 

burning cushion

mሶfoam

mሶ bottom (gaseous & liquid pyrolyzates) 

mሶ top (gaseous pyrolyzates) 

Fire 

Barrier/Back 

coating

qሶtop

qሶbottom
NIST Silicone Backcoating

Before Cone Test After Cone Test

Atom%

O 61

Si 32

C 5

Atom %

O 16

Si 0

C 84

FORMULATION (Flexible Pre-ceramic):

 Vinyl terminated PDMS crosslinked by Pt-catalyzed hydrosilation. 

 Vinyl-modified aluminum-hydroxide (65 % by mass)

 vinyl-modified nanosilica (13 % by mass) 

 Ethyl acetate (solvent)

Zammarano et al., Smoldering and Flame 

Resistant Textiles via Conformal Barrier 

Formation, Adv. Mat. Interf., Nov 2016

Top Exposed Surface Top Exposed Surface
• Four cushion mock-ups:

• California TB 133 burner

(18 kW square burner) – 80 s

• Cover Fabric (Cotton velvet):

Uncoated (UC) vs. Backcoated (BC)

10

Silicone Backcoating – Large Scale

Sample

Area 

density

[g m-2]

Thickness

[mm]

Uncoated 447±3 1.3 ±0.2

Backcoated 813±16 1.5 ±0.3

46 cm
Uncoated Mock-up

11
12

Backcoated Mock-up
Seams are Critical

13

• Backcoated fabric: no sign of failure

• Kevlar thread failure
14

HRR 

Triplicate tests with high repeatability
Data Summary 

15

Backcoated sample after test Backcoated sample without cover fabric

Peak HRR Total Heat 

Release Mass Loss EHC

[kW] [MJ] [%] [kJ/g]

Uncoated 179±2 59.2 ±0.7 95.5 ±0.8 22.6 ±0.1

Backcoated 24±1 1.3 ±0.1 3.8 ±0.1 8.3 ±0.5

Uncoated sample after test
Smoldering Ignition Resistance

16

Backcoated Uncoated

NIST Docket number:

15-026US1 

U.S. PATENT

filed on April 21, 2016
Fire Barriers

Reduce flammability without the use of chemical FRs by 

reducing

(1) Heat Transfer and (2) Mass Transfer (of pyrolyzates

produced by foam decomposition)

17

Simplified Model of a 

burning cushion

mሶfoam

mሶ bottom (gaseous & liquid pyrolyzates) 

mሶ top (gaseous pyrolyzates) 

Fire 

Barrier/Back 

coating

qሶtop

qሶbottom

Challenge - Design a bench-scale test capable of capturing the effect 

of Heat Transfer and Mass Transfer on HRR of RUF after ignition
Cone Calorimetry for RUF

• CBUF Test (de-facto standard)

Foam Size:  4  4  2

 (102  102  51) mm3

• NIST Cube Test 

Foam Size:  41/4  41/4  41/4

 (108  108  108) mm3

18

Foam

Fire Barrier

Al Foil

Substrate

Insulation

Foam

Fire Barrier

Custom Frame
16x

Cube test: capturing mass transfer effects

POOL FIRE! 4x

Combustion Efficiency 
Areafabric/Volumefoam

(m-1)

RUF Cushion* 19.1

Cube 19.0

CBUF 58.8

For foam=29 kg/m3 and fabric= 0.4 kg/m2

*(610×737×152)cm3 (24×29×6)in.3

Massfoam/Massfabric

RUF Cushion* 3.8

Cube 3.8

CBUF 1.2

Fabric to Foam ratios

20

Foam

Substrate

Foam

CBUF Test

CUBE Test
CBUF Test: Sample Preparation (30 min+24h)
Cube Test: Sample Preparation

22
Which Heat Flux?

23

Heat Flux measured in full-scale mock-ups

CUBE:

50 kW/m2

CBUF:

35 kW/m2

Incident Heat Flux can reach values up to 70 kW/m2

 50 kW/m2 adopted in the Cube test 25 mm

Back cushion

Seat cushion

TB 133 

Burner

457 mm

356 mm

Armrest Armrest

Heat Flux Gauge 1

Heat Flux Gauge 2

102 mm 102 mm
Correlation between CUBE and CBUF tests

• 11 Commercial Barriers were tested in triplicate tests in the 

CUBE and CBUF test

- Type barrier: woven, non-woven, knitted, backcoated

- Thickness range: 0.5 mm to 10 mm

- FRs: X, Sb, P, N, Si

• 1 Foam:

- No-FR, TB117-2013 foam

24
Edge Effects

25

CBUF Cube Test

Playback Speed: 32x

BF19 - External Heat Flux: 50 kW/m2
Edge effects

26

0

5 0

100

150

200

250

300

350

400

450

500

0 200 400 600 800 1000 1200 1400 1600

HRR, kW/m2

Time, s

PUF-B F-19

THR, MJ/m2

CBUF 50 kW/m2 = 32.2

Frame 5 0 kW/m2 = 2.3

Cube Test 5 0 kW/m2 = 3.5

0

50

100

0 100 20

HRR, kW/m2

Time, s 
Failure Induced by Barrier Shrinkage

27

CBUF:

Barrier is not 

constrained

No visibl

Certain fire barriers tend to shrink (e.g., cellulosics)

Cube Test:

Barrier is 

constrained by 

edge seal

Shrinkage 

induces stress

and possible 

failure

No stress 

induced failure
Cube Test: Effect of Bottom Upholstery Fabrics

28

0

50

100

150

200

250

300

350

400

450

500

0 500 1000 1500 2000 2500 3000

HRR, kW/m2

Time, s

Same Top Barrier

Different Bottom Barrier

The cube test captures the effect of bottom fire barrier

Foam

Top Fire Barrier

Bottom Fire Barrier

Bottom Barrier 1

Bottom Barrier 2

50 kW/m2
FR-free barriers: Glass Fabrics

29

Density 

(g/m2)

Glass 

(%)

Permeability 

(L/s)

K1 46 ±2 100 158 ±35

K2 102 ±1 100 53 ±11

K3 102 ±2 100 81 ±26

3 fabrics (K1, K2, K3), 100% Glass, no sizing

K1: Plain weave, nominally 48.5 g/m2(1.43 oz/yd2)

K2: Plain weave, nominally 107.1 g/m2(3.16 oz/yd2)

K3: Satin weave, nominally 107.1 g/m2(3.16 oz/yd2)

Pictures of the 3 glass fabrics (25 mm by 25 mm)

K1 K2 K3
30

Glass Fabrics as Fire Barriers – Cube Performance

Glass fabrics appear to be very effective even at a very low areal densities of 46 g/m2

In a typical cushion the glass would account for less than 3 % of the mass of the cushion

High Permeability

Low Permeability

Medium Permeability
31

ti

(s)

PHRR

(kW)

AHR 

(kW)

THR

(KJ)

EHC

(MJ/kg)

Foam ML

(%)

Foam 2 ±1 10.2 ±0.3 4.6 ±0.2 938 ±15 27.0 ±0.3 97 ±2

K1+Foam 3 ±1 1.8 ±0.1 0.35 ±0.14 461 ±24 21.2 ±0.2 58 ±4

K2+Foam 5 ±1 1.4 ±0.1 0.17 ±0.03 238 ±71 13.9 ±0.7 47 ±11

K3+Foam 5 ±1 1.7 ±0.1 0.16 ±0.02 237 ±17 16.8 ±0.9 39 ±2

Glass Fabrics as Fire Barriers – Summary

The use of glass fabrics as fire 

barriers induces:

• 6- to 7-fold reduction in PHRR

• 1.3- to 2-fold reduction in EHC Combustion Efficiency 
32

Glass Fabrics + Silicone Coating

SILICONE COATING FORMULATION:

 Vinyl terminated PDMS crosslinked by Pt-catalyzed hydrosilation. 

 Vinyl-modified aluminum-hydroxide (65 % by mass)

 vinyl-modified nanosilica (13 % by mass) 

 Ethyl acetate (solvent)

Sample size shown (25 mm by 25 mm)

K1c K1 K2c K2 K3c Density 

(g/m2)

Glass 

(%)

K1c 244 ±18 30 ±2

K2c 390 ±37 41 ±4

K3c 429 ±34 36 ±5

Case Western Reserve University:

Kimberly DeGracia, PhD Candidate,

Prof. David A Schiraldi 
33

Glass Fabrics + Silicone Coating – Cube
34

Ignition time

(s)

Peak HRR

(kW)

AHR 

(kW)

THR

(KJ)

EHC

(MJ/kg)

Mass Loss

(%)

Foam 2 ±1 10.2 ±0.3 4.6 ±0.2 938 ±15 27.0 ±0.3 97 ±2

K1+Foam 3 ±1 1.8 ±0.1 0.35 ±0.14 461 ±24 21.2 ±0.2 55.4 ±3.7

K2+Foam 5 ±1 1.4 ±0.1 0.17 ±0.03 238 ±71 13.9 ±0.7 42.6 ±10.3

K3+Foam 5 ±1 1.7 ±0.1 0.16 ±0.02 237 ±17 16.8 ±0.9 35.1 ±1.5

K1c+Foam 25 ±4 0.3 ±0.02 0.051 ±0.003 55 ±7 - 5.9 ±0.25

K2c+Foam 35 0.58 0.05 54 - 2.33

K3c+Foam 31 0.62 0.04 51 - 2.9

Glass Fabrics + Silicone Coating – Cube

The addition of the coating to the glass fabrics induces:

• 7-fold increase in ignition time

• 2- to 8-fold reduction in Peak HRR

• 9- to 18-fold reduction in Mass Loss of the foam
• NIST developed silicone backcoatings have proven to be 

an effective all-in-one solution for fire-safe RUF

• A bench-scale test for fire barriers has been developed at 

NIST

• Glass Fabrics appear to be effective Fire Barriers

Ongoing NIST research (Real-scale tests):

• Feasibility of Low Heat Release Furniture without FRs

• Full-scale performance prediction by Cube test

35

Conclusions
THANK YOU!

Acknowledgements:

Contact Information:

Mauro Zammarano

Phone: 301-975-5244

e-mail: mauro.zammarano@nist.gov

Flammability Reduction Group, NIST:

Shonali Nazaré, Randy Shields, Ickchan Kim, Andre Thompson, 

William M. Pitts, Sung Chan Kim, Isaac Leventon, Anthony 

Hamins, Dick Gann, Rick Davis 

Case Western Reserve University:

Kimberly DeGracia, PhD Candidate,

Prof. David A Schiraldi