Understanding and Reducing the Fire Risk of 

Residential Upholstered Furniture Fires

Mauro Zammarano

Fire Research Division

Some of the data in this presentation hasn’t been through the NIST review process and should be considered experimental / draft results.

SFPE Member Webinar Series

May 24, 2021

www.nist.gov/el/fire-research-division-73300/flammability-reduction-73304/low-heat-release-upholstered-furniture
What do we do?

• Maintain and develop standard reference cigarettes 

required for smoldering ignition resistance 

classification

• Develop bench-scale tests to predict full-scale 

performance in smoldering and flaming scenarios

• Provide a methodology and guidance on 

non-fire-retardant mitigation strategies

“Low Heat Release Upholstered Furniture” Project

Project Goal: to conduct research aimed at helping U.S. industries’ efforts to 

reduce the fire losses associated with residential upholstered furniture fires.

2
Outline

• Introduction: Background Information and Objectives

• PART 1

Smoldering Hazard

• PART 2

Flaming Hazard

• Conclusions

Barrier Fabrics Why BF?

Action mechanism?

Failure mechanism?

Full scale-performance?

Performance Prediction? 

Cigarette Ignition Tests

SRM Cigarettes

3
Residential Upholstered Furniture (RUF):

Fire Losses

• 74 % of U.S. fire deaths and injuries occur in home fires [1]

• RUF persists as the leading cause of residential fire deaths* in U.S [1,2]

• RUF fires are about fourteen times (14 x) more likely to result in fire deaths than other home fires [2] 

[1] Home Structure Fires, National Fire Protection Association, 2019

[2] Ahrens, M. "Soft furnishing fires: They're still a problem" Fire and Materials 2021;45:8–16

[3] Hall JR. Estimating Fires When a Product is the Primary Fuel But Not the First Fuel, With an Application to Upholstered Furniture. Fire Technology. 2015;51(2):381-391

[4] Pitts W., NIST TN1757r1 - Summary and Conclusions of a Workshop on “Quantifying the Contribution of Flaming Residential Upholstered Furniture to Fire Losses in the U.S.” NIST; August 2013, 

https://nvlpubs.nist.gov/nistpubs/TechnicalNotes/NIST.TN.1757r1.pdf

[5] M Ahrens, Home Fires That Began With Upholstered Furniture February, 2017, www.nfpa.org/-/media/Files/News-and-Research/Fire-statistics-and-reports/US-Fire-Problem/Fire-causes/osupholstered.pdf

• Deadly RUF fires are more likely to start with a smoldering source (about 55 %) rather than a

flaming source [3]

• Independent of ignition source, most RUF fire deaths occur as a result of flaming, often after

transition from smoldering to flaming [4]

• About 70% of RUF fire deaths occurs in fires that reach flashover [5]

4

- 570 civilian deaths (about 22 % of civilian deaths in home fires)

- 900 civilian injuries

- $357 million in direct property damage

*followed by cooking (21 % fire deaths), heating (19%) electrical (19%) and mattress/bedding (14%)

yearly averages 

2013-2017
1. Fire Prevention

increasing resistance to flaming and smoldering ignition sources

(safest approach, not always feasible especially without FRs)

2. Fire Mitigation

decreasing heat release rate

(less effective than fire prevention, feasible without FRs)

How can we reduce RUF fire losses?

Smoldering Flaming Flashover

5
PART 1: SMOLDERING RISK REDUCTION

6

Fire Testing for 

Upholstered Furniture

Fire Prevention: 

Increase in 

Ignition Resistance

Fire Mitigation: 

Burning Rate Reduction

Smoldering Ignition Resistance Test

Heat-Release-Rate Test

Fire Testing Classification for Upholstered Furniture

Flaming Ignition Resistance Test
1. Maintain/develop SRMs (cigarettes)

• SRM 1196a

(high ignition propensity cigarette - certified on 2/18/2020)

required for 16 CFR Part 1632, NFPA 260/261 and ASTM 

1353/1352

• SRM 1082 

(reduced ignition propensity, RIP, cigarette, required to 

verify compliance of commercial cigarettes with RIP criteria)

2. Develop bench-scale tests:

• Cigarette ignition strength (ASTM E2187-20a)

• Bench-scale tests for the classification of upholstery 

materials smoldering propensity

PART 1: SMOLDERING RISK

7
Cal TB117-2013 to be adopted as Federal Standard

NIST research aims to improve the correlation between 

smoldering bench-scale tests (TB117-2013, UFAC, ASTM 

E1353, NFPA 260) and full-scale performance. 

[1] J.J. Loftus, Test Method for Classifying Cigarette Ignition Characteristics of Upholstered Furniture, NBS report to CPSC, March 6, 1975

[2] Jiuling Yang, Guillermo Rein, Haixiang Chen, Mauro Zammarano, J. Applied Thermal Engineering, 181 (2020) 115873

8

Two major proposals based on NIST research were submitted to NFPA 

Committee on Fire Tests: 

- “Concealed smoldering” (accepted and moved to the next stage)

- Modification of testing apparatus (deferred)

TB117 underestimates smoldering propensity of RUF:

not able to predict smoldering ignitions observed at fullscale (Cal TB116) in (37 to 40)% of the cases [2].

Based on NIST research [1]
“Concealed” Smoldering in Bench-Scale testing

No obvious ignition (smoke or glowing generation) 

at the end of the 45 min test duration

Obvious glowing and smoke generation inside the crevice when 

the two panels are separated at the end of the test.

9

The two foams panels shall be separated at the end of the test to exclude the presence of concealed smoldering
Effect of “Concealed” Smoldering in Full-Scale Tests

10

Top-left view Top-right view

Bottom view IR camera

Transition from smoldering to flaming with 

no visible smoke or heat after 45 min testing
Modification of testing apparatus

Dynamic mass loss (average and 1 standard Deviation) (3 tests)

Foam: Cal117-2013

Fabric: Cotton Fabric 

450 g/m2

MODIFIED MOCKUP

(MM)

STANDARD MOCKUP

(SM)

FOAM THICKNESS: either 51 mm or 76 mm

SM2: standard mock-up, 51 mm thick foam

SM3: standard mock-up, 76 mm thick foam

MM2: modified mock-up, 51 mm thick foam

MM3: modified mock-up, 76 mm thick foam

 5-fold increase in Mass Loss at 35 min [1]

11

[1] Jiuling Yang, Guillermo Rein, Haixiang Chen, Mauro Zammarano, J. Applied Thermal Engineering, 181 (2020) 115873
PART 2: FLAMING RISK REDUCTION

12

Fire Testing for 

Upholstered Furniture

Fire Prevention: 

increase in 

Ignition Resistance

Fire Mitigation: 

Burning Rate Reduction

Smoldering Ignition Resistance Test

Heat-Release-Rate Test

Fire Testing Classification in Upholstered Furniture

Flaming Ignition Resistance Test
16 CFR Part 1633, CPSC:

• flaming regulation for mattresses, introduced in 2007,

Heat Release Rate (HRR) < 200 kW

• based on NIST test method and analysis showing the HRR range that would 

lead to measurable and significant life savings

• allowed a reduction of ≈ 70 % in fire deaths from bed fires with about 

50 % to 80 % of the mattresses replaced so far [1]

• unquestionably demonstrated the effectiveness of fire mitigation strategies

Fire Mitigation: A Success Story 

From www.flammabilitytestingequipment.com/

27 kW Burners

Comparable reduction in fire deaths expected in RUF with the 

implementation of Fire Mitigation Technologies →

[1] SW Gilbert, DT Butry RD Davis RG Gann, April 2020, Estimating the impact of the mattress fire safety Standard 16 CFR Part 1633 on bed 

fire outcomes, Fire and Materials. 2021;45:17–27, https://doi.org/10.1002/fam.2932

13
• California State [Assembly Bill 2998, 2018 https://leginfo.legislature.ca.gov/faces/billTextClient.xhtml?bill_id=201720180AB2998]

bans the use of FR based on halogenated, organo-phosphorous, organo-nitrogen, nanoscale 

chemical, chemicals of high concern in children’s products, mattresses, or upholstered furniture

Severe Restrictions on FRs in USA

CPSC recommends refraining from intentionally adding 

nonpolymeric, organo-halogen FRs in:

• children’s products

• upholstered furniture (UF) sold for use in residences

• mattresses (and mattress pads)

• plastic casings surrounding electronics.

14

• State of Maine [HP013801 https://www.mainelegislature.org/legis/bills/bills_128th/billtexts/HP013801.asp]

first State to ban all flame retardants in RUF

STATE LEVEL:

FEDERAL LEVEL

[CPSC Docket No. CPSC–2015–0022, ’17 https://s3.amazonaws.com/public-inspection.federalregister.gov/2017-20733.pdf]

?

FIRE 

RETARDANT
Technologies 

Silicone 

Backcoating

Atom %

O 16

Si 0

C 84

Flaming (18 kw square burner) Smoldering

Pristine fabric Backcoated fabric Pristine fabric Backcoated fabric

[1] Zammarano et al., Adv. Mater. Interfaces 2016, 1600617

[2] www.nist.gov/el/fire-research-division-73300/flammability-reduction-73304/upholstered-furniture-fire-videos

Backcoating for Cover Fabrics

All-in-one solution for Smoldering and Flaming Hazard Reduction 

Backcoating Formulation: aluminum hydroxide and silicone - compliant with CA AB2998

15

[2] www.nap.edu/catalog/9841/toxicological-risks-of-selected-flame-retardant-chemicals
Barrier Fabrics:

protective layers designed to decrease the HRR 

generated by the padding material (main contributor 

to fire growth in upholstered furniture).

Padding

Barrier

Cover

16
FOAM

Heat / Mass Transfer Reduction (Physical Mechanisms) 

Two-fold mechanism of action:

(1) Limiting generation rate of flammable pyrolyzate (Heat Transfer)

(2) Limiting or controlling the rate and location at which pyrolyzates 

are released and able to burn (Mass Transfer)

17

Schematic Combustion Process

mሶ bottom

mሶ top

Fire Barrier

qሶtop

qሶbottom

POLYMER → Gaseous products + Liquid products 

POLYMER PYROLYSIS

(gaseous pyrolyzates) 

(gaseous & liquid pyrolyzates) 

Idealized cross-section 

of a RUF Cushion [1]

[1] M. Zammarano, JR Shields, I Leventon, I Kim, S Nazare, AL Thompson, RD Davis, A Chernovsky, M Bundy, Reduced‐scale test to assess the effect of fire barriers on the flaming combustion of cored composites: 

An upholstery‐material case study doi.org/10.1002/fam.2910

Heat 
Case Study: Chair Mock-ups

1000

25

1000 150

FRONT VIEW Back cushion (polyester fibers)

Armrest padding (TB117-2013 foam)

Seat cushion (TB117-2013 foam)

Armrest support (5 mm plywood)

950 

300

SIDE VIEW

7 chair types:

Chair C0: cover fabric (C0) only

Chair B1 to B6: cover (C0) +1 barrier (B1 to B6)

7 chair types in triplicate tests: tot. of 21 chairs

All chair components protected by FB

Seams (Metal Staples) 

Dimensions in mm

B1 to B6 are expected to be compliant with 

California Bill AB 2998

18
• C0: PP cover fabric (Figure A)

• B1: bi-layer nonwoven fabric using polyester fibers as binder where the outer

layer was made of regenerated cellulose/polysilicic acid fibers, and the inner

layer was made of cotton fibers (Figure B)

• B2: woven (plain weave) fabric made of E-glass fibers without sizing, developed

for fiber-reinforced composites (Figure C)

• B3: nonwoven fabric made of oxidized polyacrylonitrile fibers and using

regenerated cellulose (5 % by mass) as binder (Figure D)

• B4: identical to B2 but with a lower density (Figure E)

• B5: woven fabric with a core spun yarn where para-aramid fibers were twisted

around a fiberglass core (Figure F)

• B6: bilayer fabric with outer layer made of needle-punched hybrid yarn (regener.

cellulose/polysilicic acid), inner layer made of woven glass (Figure G)

Barrier and Cover Fabric Composition

19
Elemental concentrations by XRF, IC, Kjeldahl, ICP-AES and ICP-OES, and targeted FRs content by GC-MS. 

XRF data are semi – quantitative.

Ion chromatography (IC); inductively coupled plasma atomic emission spectroscopy (ICP-AES); X-ray fluorescence (XRF) spectroscopy

Screening for Fire Retardants in Barriers 

GC-MS excluded the presence of tributyl phosphate (TBP), tri(2-chloroethyl) phosphate (TCEP), tris(2-chloroisopropyl) phosphate 

(TCPP), tris(1,3-dichloroisopropyl) phosphate (TDCPP), triphenyl phosphate (TPP), and 1,2,5,6,9,10-hexabromocyclododecane (HBCD)

→ Insufficient presence of common fire retardants to significantly affect the performance of the barriers

[1] AL Thompson, I Kim, A Hamins, M Bundy, and M Zammarano, Performance and Failure Mechanism of Fire Barriers in Full-Scale Chair Mock-ups, submitted to FAM

20
Tear strength of barriers

Paper B1 B2 B3 B4 B5 B6

0

20

40

60

80

100

120

140 Tear Strength (N)

B3 (non-woven oxidized PAN) has a Tear 

Strength comparable to a letter size paper sheet

The padding material encased within the barrier was slid inside the cover-fabric cushions through the open zipper. 

Shear between the barrier and the cover fabric caused tearing of B3. Torn areas were patched by removing the 

cover fabric and applying an extra layer of barrier, which was stapled over the original barrier layer. The padding 

material encased within the patched barrier was then slid again inside the cover-fabric cushions with extra care, but 

the formation of additional tears could not be excluded. 

→ Performance of B3 in full–scale chair mock-ups could be significantly affected by tearing

21

ASTM D2261-13 (2017) 
Ignition Source

• Square Burner (18 kW for 80s) 

Flux Gauge

22
Effect of Barriers

• increase time to peak HRR from 3 min (C0) to 22 min (B1 and B6)

• decrease peak HRR from about 3 MW (C0) to about 1 MW (B1 and B6)

C0 B4 B1

Playback speed: 73x

23

Credit to:

Matt Bundy for 

composite video 

and data overlay 
Barrier Performance

24
Barrier Failure

25

A, “wetting” of the barrier due to the percolation of liquid products; B, ignition of liquid products (“bottom ignition”); 

C, pool fire formation, and; D, feed-back between the flame on the pool fire and the remaining fuel in the chair mock-up 

at the time of PHRR2. (Snapshots from Chair B6)
Burning of Upholstered Furniture

tBI and AHRRBI are used to characterize “Plateau Phase” burning stage

26

0

200

400

600

800

1000

1200

0 5 10 15 20 25 30 35 40

HRR (kW)

Time (min)

Bottom Ignition AHRRBI

tBI  Plateau Duration

tBI : time to bottom ignition

AHRRBI : average HRR between 0 < t < tBI
Bottom Ignition (BI)

C0: PP cover fabric

B1: cellulose/polysilicic acid and cotton

B2: E-glass (high density)

B3: oxidized polyacrylonitrile

B4: E-glass (low density)

B5: para-aramid fibers with fiberglass core

B6: cellulose/polysilicic acid, woven glass

27
y = 1.0578x + 1.208

R2 = 0.9994

0

5

10

15

20

25

30

0 5 10 15 20 25

tPHRR

- Time to PHRR (min)

tBI - Time to Bottom Ignition (min)

Bottom Ignition (BI) and PHRR

Bottom Ignition leads to PHRR within (2 ± 1) min

28
Bench-scale to Full-scale Correlation

• 1 Polyurethane Foam (TB117-2013)

• 1 Cover Fabric (Polypropylene)

• 6 Fire Barriers compliant with 

California Assembly Bill No 2998

Reduced Scale Test 

(Cube Test)

Full-scale Test

(Chair Mock-ups)

C

o

r

r

e

l

a

t

i

o

n

Materials

29
NIST Cube Test 

qሶ mሶ

One-Dimensional 

Heat/Mass Transfer

The sample is intended 

to be a representative 

cross-section of an item 

(e.g., seat cushion)

Foam dimensions 

(uncompressed) :

(108 × 108 × 108) mm3

30

TOP VIEW

BOTTOM 

VIEW

WIDE 

VIEW

Core

(e.g., Foam)

Insulation

Fire Barrier

Fire Barrier

Metal 

Frame

Substrate

Cone Heater

• New bench-scale test, developed at NIST based on the Cone Calorimeter

• It allows to characterize mass and heat transfer phenomena in multi-component products 

containing a flammable core and superficial layers that may act as fire barriers

(ASTM WK65005) 
Schematic Drawing

FF

31
Sample Holder Design

v2

Fire Barrier 

Fire Barrier 

Core Flammable Material

Core Flammable Material

Fire Barrier 

Fire Barrier 

ASTM E05-21 WK65005

v3

32
Cube Test (Barrier B6)

“Wetting”: appearance of visible liquid pyrolyzates on the bottom barrier 

Playback speed: 30x

33

Credit to:

Matt Bundy for 

composite video 

and data overlay 
Example of HRR Curve in the Cube Test

0

1

2

3

4

5

6

0

200400600800

10001200

Time (s)

HRR (kW)

Wetting Point

HRR

w

tW

tW= time to foam liquefaction + time for liquid percolation

[1] M. Zammarano et al., Reduced‐scale test to assess the effect of fire barriers on the flaming combustion of cored composites: An upholstery‐material case study doi.org/10.1002/fam.2910

t = tW

34
Cube to Full-Scale Correlation?

35
5/24/2021

Fire Safety Evaluation of Barrier Fabric in a Furnished Room

NIST conducted 3 full-scale tests on furnished living rooms, where the sofa was the main 

fuel load [1,2]

All tests used the same room configuration and furniture, except for a different 

combination of cover fabrics/barrier in the sofa:

• Test 1: Sofa with cellulosic cover fabric

• Test 2: Sofa with cellulosic cover fabric and passive barrier fabric (B6)

• Test 3: Sofa with thermoplastic cover fabric

Purpose and Scope:

Measure the effect of passive fire barriers on the fire hazard of RUF in a realistic livingroom-like scenario

[1] Mauro Zammarano, Matthew S. Hoehler, John Randy Shields, Andre L. Thompson, Ickchan Kim, Isaac Leventon, Matthew F. Bundy. NIST TN2129 - Full-Scale Experiments to 

Demonstrate Flammability Risk of Residential Upholstered Furniture and Mitigation Using Barrier Fabric, December 11, 2020, https://doi.org/10.6028/NIST.TN.2129 

[2] www.nist.gov/el/fire-research-division-73300/flammability-reduction-73304/low-heat-release-upholstered-furniture

36
5/24/2021

Sofa

Schematic drawing of the couch (dimensions are in cm)

sectional RUF with a chaise section (on the left) and a loveseat section (on the right)

In Test 2, all padding components in the 

cushions and the frame were wrapped by a 

Barrier; metal staples were used to build the 

seams and fasten the barrier to the frame.

Test 1 Test 2 Test 3

FPUF* (kg) 16.4 15.9 16.3

Fiber fill (kg) 7.1 7.1 7.2

Cover fabric (kg) 6.7 6.3 6.3

Barrier fabric (kg) 0 4.1 0

Frame (kg) 74.4 74.4 74.4

Total (kg) 121.0 123.6 120.5

.

Mass of the main 

components used 

for the construction 

of the Sofas
5/24/2021

Room Layout

Picture of the furnished compartment

Water cooled

360° camera 

(BOB)

Air cooled cameras

Layout of the compartment 
5/24/2021

Ignition

• the throw pillow on the right arm of the couch was ignited by a  3 cm long propane diffusion flame 

applied under the pillow for about 25 s to 30 s (see Fig. 1)

Figure 1

Figure 1

Figure 2 Figure 3: HRR generated by: (1) TB 133 burner and (2) throw pillows 

PHRR

(kW)

THR

(MJ)

TB133 18 1.44

Throw 

pillows 35 to 45 4.0 to 4.2

• the HRR generated by a single throw pillow was measured (Fig.2)
Flashover time vs. first responder's response time

40

Time to smoke alarm 

triggering

(s)

Time to 

flashover

(min)

Time to peak heat 

release rate

(min)

Peak heat release rate, 

PHRR

(kW)

Total heat release rate, 

THR

(MJ)

tceiling 200 C 

(min)

Available safe egress time, 

ASET*

(min)

Test 1 42 ± 2 7.0 ± 0.2 8.1 ± 0.2 9180 ± 550 2550 ± 160 3.92 2.63

Test 2 47 ± 2 21.0 ± 0.2 21.7 ± 0.2 8420 ± 500 2250 ± 140 16.03 15.25

Test 3 45 ± 2 6.0 ± 0.2 6.7 ± 0.2 9640 ± 580 2640 ± 160 3.05 2.30

The addition of the barrier fabric 

delayed flashover by about 15 min. 

Considering fire service response 

times, this delay allows first 

responders to likely intervene before 

flashover
Video/audio editing: Matt Hoehler
• Fire mitigation strategies have been proved to drastically decrease fire losses

• As demonstrated by backcoatings/passive barriers, technologies promoting fire safety and 

health/environment safety in residential upholstered furniture not only exist but are commercially 

available

• Passive barriers mitigate the flaming hazard of RUF by slowing down the fire growth and generating 

an initial low HRR plateau

• At the end of the HRR plateau, percolation and ignition of liquid pyrolizates underneath the RUF 

item can lead to a rapid increase in HRR (i.e., barrier failure)

• The Cube test has been developed to predict this barrier failure mechanism; this is accomplished by 

measuring the time required for liquid polyols percolation in a specimen mimicking a cross-section 

of the seat cushion

• The full-scale performance of the barrier (HRR at plateau, plateau duration, PHRR, time to PHRR) 

shows a strong correlation with the time to wetting in the Cube test (within the limited data set 

available)

• In a realistic living room scenario, barrier fabrics delay fire growth to most likely allow first 

responders to intervene before flashover

Conclusions

42
43

THANK YOU!

Acknowledgements:

Contact Information:

Mauro Zammarano

Phone: 301-975-5244

e-mail: mauro.zammarano@nist.gov

“Low Heat Release Upholstered Furniture” Project page:

www.nist.gov/el/fire-research-division-73300/flammability-reduction-73304/low-heat-release-upholstered-furniture

Fire Research Division:

J. Randy Shields, Ickchan Kim, Isaac Leventon, Andre Thompson, 

Anthony Hamins, Matthew Hoehler, Matt Bundy, Arthur Chernovsky,

Jiuling Yang, Bill Pitts, Dick Gann, Rick Davis

Mat. and Struct. Systems Division: Ronald Lankone

This presentation is dedicated to the memory of our 

friend and colleague John Randy Shields, whose 

contributions to the project were essential