performance of current smoke alarms to the additional test requirements of ansi ul 217 ......
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Performance of Current Smoke
Alarms to the Additional Test
Requirements of ANSI UL 217-
2015
Thomas Cleary
National Institute of Standards and Technology
Gaithersburg, MD
Consumer Product Safety Commission
Bethesda, MD
February 15, 2017
Acknowledgement
This work is a collaborative research project
with funding support from the U.S. Consumer
Product Safety Commission.
Arthur Lee is the technical point of contact.
Acknowledging Michael Selepak, Laurean
DeLauter, Anthony Chakalis, Mariusz
Zarzecki, Amy Mensch, and Maylin Odenthal
for smoke box and test room fabrication, and
assisting with the data collection.
Objectives
The objectives of this research were to assess:
1. whether the new performance tests in ANSI/UL
217-2015 Standard for Safety of Smoke Alarms
will foster a demonstrable enhancement in
smoke alarm performance compared to a wide
range of currently available smoke alarms
2. whether the single nuisance source test in the
Standard is representative of a range of
cooking nuisance scenarios
Background
• The issuance of ANSI/UL 217-2015 Standard for Smoke Alarms (8th Ed.) has introduced requirements in the form of new flaming and smoldering polyurethane foam tests, and a new cooking nuisance test.
• During the extensive development of the new test requirements, limited information was gathered on the performance of existing smoke alarms to the new proposed tests.
• The timeframe between now and the roll out of new smoke alarms meeting this Standard (after the Standard’s effective date) provides an opportunity to examine performance of currently available smoke alarms.
Research Leading to the Addition of
Tests to ANSI/UL 217-2105• NIST- Dunes II smoke alarm research (2001-2002)
• FPRF/UL - Smoke Characterization Project (2007)
• UL – STP task groups and research at UL on new tests (2008-2015)
• NFPA - 72 task group reports
– Minimum Performance Requirements for Smoke Alarm Detection
Technology (2008)
– Task Group on Smoke Detection Follow-up Report (2009)
• CPSC - Pilot Study of Nuisance Alarms Associated with Cooking (2010)
• NIST/CPSC - Smoke Alarm Performance in Kitchen Fires and Nuisance
Alarm Scenarios (2013)
• NIST - Improving Smoke Alarm Performance – Justification for New
Smoldering and Flaming Test Performance Criteria (2014)
• FPRF - Smoke Alarm Nuisance Source Characterization: Experimental
Results conducted by Jensen Hughes (2015)
NIST Smoke Alarm Sensitivity Study
(2008)The fire tests were conducted in a building mock-up designed to
represent a portion of an apartment or small home
Fire Fire
BedroomLiving
Room
Kitchen
15.8 m
4.9 m
x x
xx c
cc
S5S6
S4 S3
S2 S1
hf
DoorLaser
ExtinctionLaser
Extinction
Laser
Extinction
X - thermocouple tree location
hf - total heat flux gage (1.5 m above the floor and pointing toward the fire)
S1…S6 - alarm set location
c - gas sampling location (1.5 m above the floor)
dashed line - beam path for extinction measurements (1.5 m above the floor)
Smoke alarms were mounted four across on
panel boards in random order
P1 photoelectric
I1 Ionization
D1 dual alarm
D2 dual alarm
Analyzing the Data
ASET/RSET Concepts
• Available Safe Egress Time - ASET is the time to reach a threshold
tenability limit on either combustion gas exposure, thermal
exposure, or smoke concentration
• Required Safe Egress Time – RSET is the time it takes for
occupants to egress. It depends on pre-movement activities, travel
distance and speed
Installed smoke alarms should provide early
enough warning such that ASET > RSET
Master
Bedroom
(MBR)Living Room
(LR)
Kitchen
Bedroom
(BR)
Door(closed)
Door(open or closed)
Exit
3.7 m
8.9 m
3.0 m
4.0 m
ChairMock-up
ChairMock-up
4.0 m
Analysis of Full-scale Experiments to
Aid Selection of New Fire Test Criteria
• Estimate proposed alarm activation times and
corresponding ceiling smoke obscurations for
flaming and smoldering fire scenarios subject to
ASET and RSET assumptions for a desired
performance metric.
• Relate the ceiling smoke obscurations for
flaming and smoldering scenarios to the
performance criteria for the flaming and
smoldering polyurethane foam test fires.
Matched pairs of flaming and smoldering fire performance criteria
where the average success rate is nominally equal for smoke
obscuration target values on the same row
Flaming fire test alarm criterion
Smoldering fire test alarm criterion
Smoke Obscuration(%/ft obsc.)
Averaged success rate and standard deviation (%/%)
Smoke Obscuration(%/ft obsc.)
Averaged success rate and standard deviation (%/%)
2* 94.3/5.7 12* 93.0/4.4
4 86.0/11.4 14 86.0/11.6
5 79.0/14.1 16 80.8/16.5
6 71.8/17.0 20 69.0/19.7
8 59.8/19.1 22 58.8/20.0
10** 49.0/19.1 24** 45.3/21.7
*Matched performance achievable with combination photoelectric/Ionization alarm
**Current standalone photoelectric and ionization alarms would most likely pass with these criteria
NIST/CPSC Cooking Nuisance Tests
• Cooking scenarios consisted of: – broiling a hamburger
– broiling frozen pizza
– frying a hamburger
– making a grilled-cheese sandwich in a no-stick frying pan
– stir-frying vegetables in a wok on the electric burner
– frying bacon
– toasting bread
• Light, medium, and dark toast
– toasting frozen bagels
Alarm activation frequency for equal fractions
of range top, oven and toasting activities
0
0.2
0.4
0.6
0.8
1
0 1 2 3 4 5 6 7
P1 I1 D1 D2 M1 M2
Ala
rm A
cti
va
tio
n F
req
uen
cy
Distance from Cooking Source (m)
New Test Descriptions
• Smoldering Flexible Polyurethane Foam
– Heated foam block to induce smoldering
– Passing criterion – must alarm before 12 %/ft obscuration
• Flaming Flexible Polyurethane Foam
– Flaming ignition of a foam block
– Passing criterion – must alarm before 5 %/ft obscuration
• Broiled Hamburgers
– Electric range oven, frozen hamburgers 75/25 blend
– Passing criterion – No alarm before 1.5 %/ft obscuration
Experimental Details
• Experimental sources
– Flaming foam
– Smoldering foam
– Broiled hamburgers
– Lightly toasting bread
– Frying a hamburger
– Stir-frying vegetables
• The cooking experiments produce mean particle
sizes from ~ 0.1mm to over 1 mm
Experimental Details
• 45 Alarm Models from 8 Manufacturers
– 14 Ionization
– 14 Photoelectric
– 7 Ionization/Carbon Monoxide
– 4 Photoelectric/Carbon Monoxide
– 4 Combination Ionization/Photoelectric
– 2 Photoelectric/Thermal
• Six units for every model, each smoke alarm
checked in the smoke box with cotton wick
smoke
Experimental Details
NIST constructed a smoke box per ANSI-UL
217 specifications. All smoke alarms tested
in the smoke box before room experiments.
Experimental Details
80
85
90
95
100
30405060708090100
Be
am
Lig
ht
Tra
ns
mis
sio
n (
%)
Measuring Ionization Chamber (MIC) Current (pA)
Typical smoke box smoke profiles
Beam light transmission
versus time
Beam light transmission versus MIC
reference chamber
Thick solid lines are bounding curves from the Standard
Experimental DetailsNIST constructed a test room per ANSI-UL 217specifications
for the new test experiments and additional cooking sources
Experimental LayoutUL 217 test room in the NIST National Fire Research Laboratory
36 ft.
22 ft.
17.7 ft.
MIC
Obsc.
Fire
36 ft.
22 ft.
10 ft.
MIC
Obsc.
Electric
Range
Wall
Fire Tests Cooking Tests
Experimental Details
• The 45 smoke alarm models distributed to 15
test boards with three different alarms on each
board
• Each fire and cooking experiment conducted
three times for each set of nine alarms
• Nine smoke alarms (three test boards) per
experiment, 15 (5x3) experiments per source
• The three test boards changed position for each
repeated experiment
Smoke Sources
Smoldering Source:
Radiant heating of foam slab
Smoldering Source:
Cigarette ignition w/ or w/o radiant
heating
Smoke Sources
Radiant heating Cigarette ignition Radiant heating
w/ cigarette ignition
Sequence chosen
for testing
Cooking Nuisance Source
75 % lean beef and 25 % suet by
weight, 10 cm diameter
Two frozen patties on broiler
pan
Pan placed on top rack close to
broiling element
Broiler on high, door open
Other Cooking Experiments
Two-slice toaster placed on
range top
Toasted bread after experiment
Stir-fried vegetables
Fried hamburger
Measurements
• Time to Alarm
• Light Obscuration
• MIC (reference ionization chamber)
• Temperature, Relative Humidity
• CO, CO2, HCN
• Particle Size Distribution
• Light Scattering
Smoke Box Results
Ionization alarm I09
0
1
2
3
4
30
40
50
60
70
80
90
100
1 2 3 4 5 6
Be
am
Ob
sc
ura
tio
n (
%/f
t)
MIC
(p
A)
Alarm Unit Number
Average MIC Results
Ionization alarm models
40
50
60
70
80
90
100
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Av
era
ge
MIC
Cu
rren
t (p
A)
Ionization Alarm Model
Smoke Box Results
Photoelectric alarm P01
0
1
2
3
4
30
40
50
60
70
80
90
100
1 2 3 4 5 6
Be
am
Ob
sc
ura
tio
n (
%/f
t)
MIC
(p
A)
Alarm Unit Number
Average Beam Obsc. Results
Photoelectric alarm models
0
0.5
1
1.5
2
2.5
3
3.5
4
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Ave
rag
e B
ea
m O
bs
cu
rati
on
(%
/ft)
Photoelectric Alarm Model
Range of Smoke Box Results for
All Alarm Types
Allowable range for alarm
response
• MIC reference chamber
– 93 pA to 37.5 pA
• Smoke Obscuration
– 0.5 %/ft to 4.0 %/ft
Range of average results
for various alarm types
• Ionization
– 87 pA to 53 pA
• Ionization/CO and /photolectric
– 74 pA to 64 pA
• Photoelectric
– 1.8 %/ft to 3.3 %/ft
• Photoelectric/CO and /thermal
– 1.1 %/ft to 3.9 %/ft
Flaming Foam Results
Beam light transmission
versus MIC current
Beam light transmission
versus time
40
50
60
70
80
90
100
0 100 200 300 400 500 600
Be
am
Lig
ht
Tra
ns
mis
sio
n (
%)
Time (s)
40
50
60
70
80
90
100
0102030405060708090100B
ea
m L
igh
t T
ran
sm
iss
ion
(%
)
Measuring Ionization Chamber (MIC) current (pA)
Thick solid lines are bounding curves from the Standard
Smoldering Foam ResultsThree trial smoldering initiation sequences
40
50
60
70
80
90
100
2000 2500 3000 3500 4000
Radiant HeaterCigarette Radiant Heater and Cigarette
Be
am
Lig
ht
Tra
ns
mis
sio
n (
%)
Time (s)
Beam light transmission
versus MIC current0
20
40
60
80
100
0102030405060708090100
Radiant HeaterCigaretteRadiant Heater and Cigarette
Be
am
Lig
ht
Tra
ns
mis
sio
n (
%)
Measuring Ionization Chamber (MIC) current (pA)
Beam light transmission
versus time
Thick solid lines are bounding curves from the Standard
Smoldering Foam Results
40
50
60
70
80
90
100
2000 2200 2400 2600 2800 3000
Be
am
Lig
ht
Tra
ns
mis
sio
n (
%)
Time (s)
0
20
40
60
80
100
0102030405060708090100B
ea
m L
igh
t T
ran
sm
iss
ion
(%
)
Measuring Ionization Chamber (MIC) Current (pA)
Beam light transmission
versus time
Beam light transmission
versus MIC current
Thick solid lines are bounding curves from the Standard
Radiant heater and cigarette initiation sequence
Broiling Hamburgers Results
0
0.5
1
1.5
2
2.5
3
0 500 1000 1500
Ob
sc
ura
tio
n (
%/f
t)
Time (s)
0
0.5
1
1.5
2
2.5
3
3.5
4
30405060708090100O
bs
cu
rati
on
(%
/ft)
MIC Current (pA)
Beam light transmission
versus time
Beam light transmission
versus MIC current
Thick solid lines are bounding curves from the Standard
Frying Hamburger Results
0
0.5
1
1.5
2
2.5
3
0 500 1000 1500
Ob
sc
ura
tio
n (
%/f
t)
Time (s)
0
0.5
1
1.5
2
2.5
3
3.5
4
30405060708090100
Ob
sc
ura
tio
n (
%/f
t)
MIC Current (pA)
Beam light transmission
versus MIC currentBeam light transmission
versus time
Thick solid lines are bounding curves for broiling
hamburgers from the Standard
Stir-frying Vegetables Results
0
0.5
1
1.5
2
2.5
3
0 500 1000 1500
Ob
sc
ura
tio
n (
%/f
t)
Time (s)
0
0.5
1
1.5
2
2.5
3
3.5
4
30405060708090100O
bs
cu
rati
on
(%
/ft)
MIC Current (pA)
Beam light transmission
versus MIC current
Thick solid lines are bounding curves for broiling
hamburgers from the Standard
Toasting Bread Results
0
10
20
30
40
50
60
70
80
90
100
0 300 600 900 1200 1500
MIC
Cu
rre
nt
(pA
)
Time (s)
Beam light transmission versus time
Thick solid lines are bounding curves for broiling
hamburgers from the Standard
Flaming and Smoldering Source
Ionization Alarm Results
Flaming Source Tests
0
2
4
6
8
10
12
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Bea
m O
bs
cu
rati
on
at
Ala
rm (
%/f
t)
Ionization Alarm Model
Pass
0
5
10
15
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Bea
m O
bs
cu
rati
on
at
Ala
rm (
%/f
t)
Ionization Alarm Model
Estimated Pass
Smoldering Source Tests
Open symbol - Alarm
Closed symbol - Test maximum, no alarm
0
0.5
1
1.5
2
2.5
3
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Bea
m O
bs
cu
rati
on
at
Ala
rm (
%/f
t)
Ionization Alarm Model
Pass
Broiling and Frying Hamburgers
Source Ionization Alarm Results
0
0.5
1
1.5
2
2.5
3
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Bea
m O
bs
cu
rati
on
at
Ala
rm (
%/f
t)
Ionization Alarm Model
Broiling Source Tests Frying Source Tests
Open symbol - Alarm
Closed symbol - Test maximum, no alarm
Stir-frying and Toasting Source
Ionization Alarm Results
0.5
1
1.5
2
2.5
3
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Beam
Ob
scu
rati
on
at
Ala
rm (
%/f
t)
Ionization Alarm Model
60
70
80
90
1 2 3 4 5 6 7 8 9 10 11 12 13 14
MIC
Cu
rren
t a
t A
larm
(p
A)
Ionization Alarm ModelOpen symbol - Alarm
Closed symbol - Test maximum, no alarm
Stir-frying Source Tests Toasting Source Tests
Flaming and Smoldering Source
Photoelectric Alarm Results
Flaming Source Tests
0
2
4
6
8
10
12
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Bea
m O
bs
cu
rati
on
at
Ala
rm (
%/f
t)
Photoelectric Alarm Model
Pass
0
5
10
15
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Bea
m O
bs
cu
rati
on
at
Ala
rm (
%/f
t)
Photoelectric Alarm Model
Pass
Smoldering Source Tests
Open symbol - Alarm
Closed symbol - Test maximum, no alarm
0.5
1
1.5
2
2.5
3
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Bea
m O
bs
cu
rati
on
at
Ala
rm (
%/f
t)
Photoelectric Alarm Model
Pass
Broiling and Frying Hamburgers
Source Photoelectric Alarm Results
0.5
1
1.5
2
2.5
3
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Beam
Ob
scru
ati
on
(%
/ft)
Photoelectric Alarm Model
Broiling Source Tests Frying Source Tests
Open symbol - Alarm
Closed symbol - Test maximum, no alarm
Stir-frying Source Photoelectric
Alarm Results
0
0.5
1
1.5
2
2.5
3
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Beam
Ob
scu
rati
on
at
Ala
rm (
%/f
t)
Photoelectric Alarm Model
Stir-frying Source Tests
Open symbol - Alarm
Closed symbol - Test maximum, no alarm
Performance Ranking Scheme
• Specify threshold limits that correspond to the Standard (M),
somewhat less (L) and more (H) restrictive threshold limits.
– Flaming foam limits: L=7 %/ft, M=5%/ft and H=3%/ft
– Smoldering foam limits*: L=16%/ft, M=12%/ft and H=8%ft
– Cooking nuisance limits: L=1%/ft, M=1.5%/ft and H=2%/ft
• Tabulate how many times out of the three repeated tests an alarm
responsed within the specified limit
• Tabulate the number of three out of three successes for flaming,
smoldering and cooking tests to give a particular alarm model’s
ranking.
• A rank of 3 at the threshold limits corresponding to the Standard (M)
suggests the particular alarm model would pass the new Standard.
* Corresponding limits for ionization alarms: L=68 pA, M=75 pA and H=81 pA
Performance Ranking of
Photoelectric Alarms
Model Smoldering fire
tests meeting limit
Flaming fire
tests meeting limit
Broiling hamburgers
tests meeting limit
Performance rank
L M H L M H L M H L M H
P01 3 3 3 0 0 0 3 3 0 2 2 1
P02 3 3 3 3 1 0 0 0 0 2 1 1
P03 3 3 3 3 0 0 0 0 0 2 1 1
P04 3 3 3 2 0 0 0 0 0 1 1 1
P05 3 3 3 3 0 0 3 0 0 3 1 1
P06 3 3 3 3 1 0 0 0 0 2 1 1
P07 3 3 3 1 0 0 3 3 3 2 2 2
P08 3 3 3 3 0 0 2 1 1 3 1 1
P09 3 3 3 3 1 0 3 0 0 3 1 1
P10 3 3 3 3 1 1 0 0 0 2 1 1
P11 3 3 3 2 0 0 3 0 0 2 1 1
P12 3 3 3 3 0 0 0 0 0 2 1 1
P13 0 0 0 0 0 0 0 0 0 0 0 0
P14 3 3 3 1 0 0 3 3 0 2 2 1
Performance Ranking of
Photoelectric/CO and /thermal Alarms
Model Smoldering fire
tests meeting limit
Flaming fire
tests meeting limit
Broiling hamburgers
tests meeting limit
Performance rank
L M H L M H L M H L M H
PCO01 3 3 3 1 1 1 2 0 0 1 1 1
PCO02 3 3 3 0 0 0 0 0 0 1 1 1
PCO03 3 3 2 0 0 0 0 0 0 1 1 0
PCO04 3 3 3 1 1 1 2 0 0 1 1 1
PCO05 3 3 3 3 2 0 1 0 0 2 1 1
PCO06 3 3 3 3 1 0 0 0 0 2 1 1
PCO07 3 3 3 0 0 0 3 3 0 2 2 1
PT01 3 3 3 0 0 0 3 1 0 2 1 1
PT02 3 3 3 2 0 0 1 1 0 2 1 1
Performance Ranking of
Ionization Alarms
Model Smoldering fire
tests meeting limit
Flaming fire
tests meeting limit
Broiling hamburgers
tests meeting limit
Performance rank
L M H L M H L M H L M H
I01 0 0 0 3 3 3 3 0 0 2 1 1
I02 2 0 0 3 3 3 0 0 0 1 1 1
I03 3 3 0 3 3 3 0 0 0 2 2 1
I04 3 3 3 3 3 3 0 0 0 2 2 2
I05 3 3 1 3 3 3 0 0 0 2 2 1
I06 3 1 1 3 3 3 0 0 0 2 1 1
I07 2 0 0 3 3 3 0 0 0 1 1 1
I08 3 1 0 3 3 3 0 0 0 2 1 1
I09 3 0 0 3 3 3 0 0 0 2 1 1
I10 3 0 0 3 3 3 0 0 0 2 1 1
I11 0 0 0 3 3 3 0 0 0 1 1 1
I12 0 0 0 3 3 2 0 0 0 1 1 0
I13 0 0 0 3 3 1 3 1 0 2 1 0
I14 0 0 0 3 3 2 3 1 0 2 1 0
Performance Ranking of Ionization/CO
and Photoelectric Alarms
Model Smoldering fire
tests meeting limit
Flaming fire
tests meeting limit
Broiling hamburgers
tests meeting limit
Performance rank
L M H L M H L M H L M H
ICO01 1 0 0 3 3 3 0 0 0 1 1 1
ICO02 2 0 0 3 3 0 3 3 1 2 2 0
ICO03 3 0 0 3 3 3 0 0 0 2 1 1
ICO04 2 0 0 3 3 3 0 0 0 1 1 1
IP01 3 3 3 3 3 3 0 0 0 2 2 2
IP02 3 3 3 3 2 2 0 0 0 2 1 1
IP03 3 3 3 3 3 3 0 0 0 2 2 2
IP04 3 3 3 3 3 3 0 0 0 2 2 2
Average Performance RankingThe average ranks of alarms containing a photoelectric sensor but
not an ionization sensor (and not considering P13) are 1.9, 1.1 and
0.9 for sensitivity levels of L, M and H respectively.
For alarms containing an ionization sensor but not a photoelectric
sensor the average ranks are 1.7, 1.2 and 0.8 for sensitivity levels of
L, M and H respectively.
A rank of 3 is required at the performance level M to meet the
performance level in ANSI/UL 217-2015. Thus, it is concluded that
smoke alarms meeting the performance criteria in ANSI/UL 217-2015
would demonstrate significantly improved overall performance by
expanding range of fire scenarios alarms must respond to while
requiring greater resistance to nuisance alarms than a wide range of
currently available models.
Comparison of Smoke Development
for Cooking Nuisance Sources
0
0.5
1
1.5
2
2.5
3
0 300 600 900 1200 1500 1800
Broiling hamburger
Frying hamburger
Stir frying vegetables
Ce
ilin
g S
mo
ke O
bsc
ura
tio
n (
%/f
t)
Time (s)
60
65
70
75
80
85
90
95
100
0 300 600 900 1200 1500 1800
Broiling hamburger
Frying hamburger
Stir frying vegetables
Toasting bread
MIC
Cu
rre
nt
(pA
)
Time (s)
Cooking Nuisance Source Analysis
The broiling hamburgers test produces an aerosol that
causes majority of alarm models studied to respond at low
enough levels that could be characterized as a nuisance,
and it appears to be a conservative test in that respect.
However, the observed differences in the cooking aerosol
production rates and aerosol properties appear to affect the
alarm response for photoelectric and ionization alarms for
the cooking activities examined.
Conclusions
• 1. Analysis of the results show that no current smoke
alarm model would meet the performance level required
in ANSI/UL 217-2015. Of the smoke alarms tested, three
models, all photoelectric sensor alarms, came closest to
meeting the new requirements.
• 2. An across the board increase in the level of
performance to that specified in ANSI/UL 217-2015
would significantly improve the overall performance of
smoke alarms by expanding range of fire scenarios
alarms must respond to while requiring resistance to
nuisance alarms.
Conclusions
• 3. The changes in ANSI/UL 217-2015, which include
the new performance fire tests and the new nuisance
resistance test, may make it challenging for
manufacturers to meet the requirements by simply using
a combination of photoelectric and ionization sensors, or
designing alarms that perform as well against the new
fire tests as the combination ionization / photoelectric
models examined.
• 4. The cooking aerosol production rates and beam /
MIC relationship between the sources varied significantly
and appeared to have an impact on the alarm response.
Conclusions
• 5. Toasting bread produced essentially no measurable
obscuration, carbon monoxide nor significant heat, thus
alarms that use sensors to detect these characteristics
will most likely not alarm during normal toasting
scenarios. The toasting bread aerosols produced
particles that caused the ionization alarms to responded,
which was similar to the measuring ionization chamber
(MIC) current levels in the broiling hamburgers
experiments.
Conclusions
• 6. The broiling hamburgers nuisance test challenged
the majority of smoke alarms included in this study, and
therefore may be considered a conservative test.
Ultimately, cooking nuisance experiments on a range of
smoke alarms that pass ANSI/UL 217-2015 will confirm
the appropriateness of the broiling hamburgers cooking
nuisance scenario as the model test.