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February 20, 2009
7.1 Smoke Detector Performance
Paul E. Patty, P.E.Senior Research EngineerNorthbrookX [email protected]
February 20, 2009p/2
Smoke Detector Performance
• Smoke Characterization Project– Quality of smoke– Material characteristics– Smoke movement– Photo/Ion response
• STP Activities– Improving response– Nuisance issues
• NFPA 72 Chapter 11 Task Group Activities– Tenability issues
• Media Coverage Photoelectric/Ionization Alarms– Is there a hazard?
• Recommendations
February 20, 2009p/3
Smoke Detector Performance Smoke Characterization Project
• Quality of smoke– Color
• black, grey, yellow, white– Particle size
• .01-10 microns– Velocity
• > 32ft/min.– Temperature
• <150 degrees F– Build-up rate
• obscuration %/ft/min.– Gases of combustion
February 20, 2009p/4
Smoke Characterization Project
• Material characteristics– Develop smoke characterization analytical test protocol using flaming and
non-flaming modes of combustion.– Develop smoke particle size distribution data and smoke profiles in the UL
smoke detector room for materials found in residential settings for both flaming and non-flaming modes of combustion.
• Survey Materials – Survey materials and products in contemporary residential settings– Selection of materials for the research investigation based on:
• Presence in residential settings
• Chemistry
• UL 217 specifications
February 20, 2009p/5
Smoke Characterization Project Sampling Method
N2dilution
FTIREvery 15 s
Calorimeter
Smoke ParticleEvery 67 s
February 20, 2009p/6
Smoke Characterization Project Smoke Particle Analyzer Data
PET Carpet
11 17 26 40 6310
216
929
736
044
5
575
900 0
48115
182249
316383
450517
584
0.0E+00
2.6E+05
5.1E+05
7.7E+05
1.0E+06
1.3E+06
Particle density (1/cc)
Particle Size (nm)
Time (s)
February 20, 2009p/7
Smoke Characterization Project Key Findings - Gas Analysis
• Smoke Gas Effluent Composition - Gas effluent analysis showed the dominant gas components were water vapor, carbon dioxide and carbon monoxide.
Water CO2 COSO2 NO2 MethaneAmmonia Phenol SiF4Formaldehyde HCN PropaneHCl HF EthyleneAcrylonitrile Styrene
February 20, 2009p/8
Smoke Characterization Project Key Findings - Influence of Material Chemistry
0
100
200
300
400
500
600
700
800
Cookin
g oil
Heptan
e
Heptan
e/ Tolu
ene m
ixDou
glas f
irNew
spap
erPon
d. pin
eHDPEBrea
d
Mattres
s com
posit
e
Mattres
s PU fo
amCott
on ba
tting
Polyes
ter pi
llow st
uffing
Cotton
/Poly
ester
blen
d fab
ricRay
on fa
bric
Nylon c
arpet
PET carpe
t
Polyiso
cyan
urate
foam
PVC wire
Pea
k H
RR
(kW
/m²)
UL 217 materials
Flaming Mode
February 20, 2009p/9
Smoke Characterization Project Key Findings - Mode of Combustion
0.00
0.05
0.10
0.15
0.20
0.25
0.30
Cookin
g oil
Bread
Newsp
aper
Dougla
s fir
Ponde
rosa p
ineCott
on ba
tting
Cotton
/Poly
ester
blen
d (fab
ric)
Rayon
(fabri
c)
HDPENylo
n carp
etPoly
ester
carpe
tPoly
ester
fillin
g
PU foam
Polyiso
cyan
uarat
e foa
m
PVC M
ean
Par
ticle
Dia
met
er (m
icro
n)
FlamingNon-Flaming
UL 217 materials
February 20, 2009p/10
Smoke Characterization Project Key Findings - Mode of Combustion
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Cookin
g oil
Bread
Newsp
aper
Dougla
s fir
Ponde
rosa p
ineCott
on ba
tting
Cotton
/Poly
ester
blen
d (fab
ric)
Rayon
(fabri
c)
HDPENylo
n carp
etPoly
ester
carpe
tPoly
ester
fillin
g
PU foam
Polyiso
cyan
uarat
e foa
m
PVC S
peci
fic E
xtin
ctio
n A
rea
(m²/g
)
FlamingNon-Flaming
UL 217 materials
February 20, 2009p/11
Smoke Characterization Project Key Findings – Particle size
Mean Diameter at:Flaming Tests0.5 %/ft 10 %/ft
Douglas fir 0.13 0.17Newspaper 0.17 0.18Heptane/Toluene 0.19 0.30Coffee maker 0.17 0.18PU foam 0.08 NAPU foam in Cotton/Poly 0.09 NANylon carpet 0.10 NA
February 20, 2009p/12
Smoke Detector Performance Smoke movement
• Smoke Stratification - Non-flaming fires result in changes in the smoke build up over time, such that stratification of smoke below the ceiling occurs. This time-dependent phenomenon results in less obscuration at the ceiling than below the ceiling. This caused both detection technologies to drift out of alarm.
February 20, 2009p/14
Smoke movement
0
2
4
6
8
10
12
0 1000 2000 3000 4000 5000 6000 7000
Time (sec)
OB
S (%
/ft)
4 in below ceiling
24 in. below ceiling
36 in. below ceiling
60 in below ceiling
PU foam in Poly
February 20, 2009p/15
Smoke movement
0
2
4
6
8
10
12
0 1000 2000 3000 4000 5000 6000 7000
Time (sec)
OB
S (%
/ft)
4 in below ceiling
24 in. below ceiling
36 in. below ceiling
60 in. below ceiling
PU foam in Cotton
February 20, 2009p/16
Smoke Detector Performance (Photo/Ion Response Fire Test Room MIC 1)
0
10
20
30
40
50
60
70
80
90
100
0.0E+00 2.0E+05 4.0E+05 6.0E+05 8.0E+05 1.0E+06
Σ(n idi)
MIC
Sig
nal C
han
ge (
pA)
Bread
Bread
Bread
Nylon Carpet
PolyisocyanurateFoamPolystyrene
Ponderosa Pine
Ponderosa Pine
Ponderosa Pine
Ponderosa Pine
Ponderosa Pine
PU Foam
PU Foam
PU Foam
PU + cotton
PU + cotton
PU + poly
PU + Poly
Non-Flaming Tests
February 20, 2009p/17
Photo/Ion Response Fire Test Room MIC 2
0
10
20
30
40
50
60
70
80
90
100
0.0E+00 2.0E+05 4.0E+05 6.0E+05 8.0E+05 1.0E+06
Σ(nid i)
MIC
Sig
nal C
han
ge (
pA) Coffee Maker
Coffee Maker
Nylon carpet
Nylon carpet
Nylon carpet
PU Foam
PU Foam + cotton/poly
PU Foam + cotton/poly
PU Foam + cotton/poly
PU Foam + cotton/poly
Flaming Tests
February 20, 2009p/18
Photo/Ion Response Fire Test Room Analog Ion 1
0
10
20
30
40
50
60
70
0.0E+00 2.0E+05 4.0E+05 6.0E+05 8.0E+05 1.0E+06
Σ(nidi)
An
alo
g Io
n S
igna
l Ch
ange
Bread
Bread
Bread
Nylon Carpet
Isocyanuarate Foam
Polystyrene
Ponderosa Pine
Ponderosa Pine
Ponderosa Pine
Ponderosa Pine
PU Foam
PU Foam
PU Foam
PU Foam
PU Foam + cotton
PU Foam + poly
PU Foam + polyNon-Flaming Tests
February 20, 2009p/19
Photo/Ion Response Fire Test Room Analog Ion 2
0
10
20
30
40
50
60
70
0.0E+00 2.0E+05 4.0E+05 6.0E+05 8.0E+05
Σ (nidi)
Ana
log
Ion
Sig
nal C
han
ge
Coffee Maker
Coffee Maker
Douglas Fir
Douglas Fir
Douglas Fir
Heptane/Toluene
Heptane/Toluene
Heptane/Toluene
Heptane/Toluene
Newspaper
Newspaper
Newspaper
Nylon Carpet
Nylon Carpet
Nylon Carpet
PU Foam
PU Foam + cotton/poly
PU Foam + cotton/poly
PU Foam + cotton/poly
PU Foam + cotton/poly
Flaming Tests
February 20, 2009p/20
Photo/Ion Response Fire Test Room Beam 1
0
5
10
15
20
25
30
35
40
0.0E+00 2.0E+04 4.0E+04 6.0E+04 8.0E+04 1.0E+05 1.2E+05
Σ (n idi3)
OB
S (
%/ft
)
Bread
Bread
Bread
Nylon Carpet
PolyisocyanurateFoamPolystyrene
Ponderosa Pine
Ponderosa Pine
Ponderosa Pine
Ponderosa Pine
Ponderosa Pine
PU Foam
PU Foam
PU Foam
PU Foam + cotton
PU Foam + cotton
PU Foam + Poly
PU Foam + Poly
Non-Flaming Tests
Alarm Trigger Range
February 20, 2009p/21
Photo/Ion Response Fire Test Room Beam 2
0
5
10
15
20
25
30
35
40
0.0E+00 2.0E+04 4.0E+04 6.0E+04 8.0E+04 1.0E+05 1.2E+05
Σ (n idi3)
OB
S (
%/ft
)
Coffee Maker
Coffee Maker
Douglas Fir
Douglas Fir
Douglas Fir
Douglas Fir
Heptane/Toluene
Heptane/Toulene
Heptane/Toluene
Newspaper
Newspaper
Nylon Carpet
Nylon Carpet
Nylon Carpet
PU Foam
PU foam + cotton/poly
PU Foam + cotton/poly
PU Foam + cotton/poly
Flaming Tests
February 20, 2009p/22
Photo/Ion Response Fire Test Room Analog Beam 1
0
10
20
30
40
50
60
0.0E+00 5.0E+04 1.0E+05 1.5E+05 2.0E+05 2.5E+05
Σ(nidi2)
An
alo
g P
hoto
Sig
nal C
han
ge
Bread
Bread
Bread
Nylon Carpet
Isocyanurate Foam
Polystyrene Foam
Ponderosa Pine
Ponderosa Pine
Ponderosa Pine
PU Foam
PU Foam
PU Foam
PU Foam + cotton
PU Foam + poly
PU foam + poly
Non-Flaming Tests
February 20, 2009p/23
Photo/Ion Response Fire Test Room Analog Beam 2
0
10
20
30
40
50
60
0.0E+00 5.0E+04 1.0E+05 1.5E +05 2.0E+05 2.5E+05
Σ (n idi2)
Ana
log
Pho
to S
igna
l Cha
nge
Coffee MakerCoffee MakerDouglas FirDouglas FirDouglas FirHeptane/TolueneHeptane/TouleneHeptane/TolueneNewspaperNewspaperNewspaperNylon CarpetNylon CarpetNylon CarpetPU FoamPU Foam + cotton/polyPU Foam + cotton/polyPU Foam + cotton/poly
Flaming Tests
February 20, 2009p/24
Particle Size Influence on Sensing Technology
d, Particle Size
Rel
ativ
e Si
gnal
Sen
sitiv
ity
Obscuration ~ d3
Scattering ~ d2
Ion ~ d
⇒ Physics of ionization technology is linearly responsive to particle size.
⇒ Physics of light-based technologies are more responsive to larger particles than smaller particles.
February 20, 2009p/25
STP Activities
• Improve alarm/detector response‐ New polyurethane smoldering, and flaming tests‐ Adjust obscuration base‐ Adjust time base
• Nuisance alarm issues‐ Spike values‐ Spike duration‐ Gases of combustion‐ Marking
February 20, 2009p/26
Development: Flaming & smoldering polyurethane tests
• Develop new flaming and smoldering polyurethane (PU) foamfire tests to compliment existing UL 217 and 268 tests.
⇒ Increase available egress time for non-specific fires by expanding alarm responsiveness to other smoke signatures.
• Rationale– Flaming PU foam generates smaller smoke particles than the
current fire tests.– Synthetic materials generate greater heat and smoke release rates
than natural materials.– Prevalence of PU foam in residential settings (mattresses,
upholstered furniture, etc.).
February 20, 2009p/27
“Standard” Foams Currently Used
Product Test MethodFoam Test Material Description
Smoke detectors
EN 54-7,ISO 12239
“Soft polyurethane foam”- No fire retardant- Density: c. 20 kg/m3
ASTM E 1353,CPSC 1634
SPUF: Polyurethane foam- No inorganic fillers or FR- Density: 28.8 ±1.6 kg/m3 (1.8 ±0.1 lb/ft3)
CA TB117+,CPSC 1634
SFRPUF: Flame-retardant polyurethane foam- Density: 22.4 ±1.6 kg/m3 (1.4 ±0.1 lb/ft3)
UFACPolyurethane foam- No inorganic fillers or FR- Density: 24.0 ± 1.6 kg/m³ (1.5 ± 0.1 lb/ft³)
Residential sprinklers UL 1626
Polypropylene oxide polyol, polyether foam- Density: 27.2 - 30.4 kg/m3 (1.70 - 1.90 lb/ft3)- PHRR at 30 kW/m2: 230 ±50 kW/m2
- HOC at 30 kW/m2: 22 ±3 kJ/g
Upholstered furniture
February 20, 2009p/28
Scenario Development
• Task Objectives:– Investigate influence of scenario variables on combustion
products.– Develop smoke particle size and gas effluent data on the
scenarios.
Test Parameters:Variables Output
Foam densitySample size & shape Smoke build-up rate
Heating method
February 20, 2009p/29
Flaming Fire Scenarios
• Goal:– Flaming foam test that achieves obscuration levels similar to the
UL 217 flaming tests in a comparable time frame.
• Potential Scenarios:– EN 54-7 TF 4 flaming foam test– Variations in foam density, sample size & shape, ignition point
February 20, 2009p/30
Smoldering Fire Scenarios
• Goal:– Smoldering foam test that:
• Achieves 10 %/ft obscuration at 45 min.• Achieves 12-15 %/ft obscuration by 60 min.• Avoids settling/stratification (test < 75 min.).
• Potential Scenarios:– Radiant panel: Heat from sample top surface– Hot plate: Heat from sample bottom surface– Cigarette ignition: Heat from sample top surface but
covered– Hot wire: Heat from sample center
February 20, 2009p/31
Flaming Fire Scenarios
2 step burning process:• Flame front• Molten sample
Variables:• Foam density• Sample size & shape• Ignition point
Completed:• 26 Calorimeter tests• 22 Fire Room tests
⇒ Flame-out ranged from260 to 2129 s
⇒ 10 %/ft Obs reached in85 to 1540s & never
February 20, 2009p/33
NFPA 72 Chapter 11 Task Group Activities
• Test method variability– Tenability issues
• 3 foot visibility• 20 foot visibility
February 20, 2009p/34
Media Coverage
• Photoelectric/Ionization Alarms– Test demonstrations in question– Is there a hazard?– Earliest possible warning– New vs. existing construction
• No scientific study shows superiority of one technology over another when installed per NFPA 72.
• Not measuring the quality of smoke can lead to misleading conclusions.
• The movement of smoke in a building is a complex issue
February 20, 2009p/35
Recommendations
• The responsiveness of smoke alarms depend upon a number of factors including the type of fire (smoldering, flaming), the chemistry of materials involved in the fire, and the color of the resulting smoke. Both ionization and photoelectric type smoke alarms provide adequate response to these factors but their sensitivity to them varies. Therefore, several fire safety organizations recommend a consumer utilize both ionization and photoelectric technology, or another technology with similar performance characteristics, in their home smoke alarm systems to permit the longest potential escape times for nonspecific fire situations.
February 20, 2009p/36
Recommendations
• Installing Listing products as follows:1. as described by the manufactures instructions2. as required by the minimum requirements of NFPA 72
• Reduces ones risk to lose of life, or injury resulting from a nonspecific fire.
• Deviating from these two simple steps can cause you to lose the benefit of early warning from your fire alarm system.