March 4, 2015 - NFPA

National Aeronautics and Space Administration

www.nasa.gov49th AIAA Aerospace Sciences Meeting, January 2011 1

Smoke Detection in Low Gravity – Results from the Smoke Aerosol

Measurement Experiments (SAME) Conducted on the International Space

Station

March 4, 2015


www.nasa.gov 2

Smoke Detection in Low Gravity – Results from the

Smoke Aerosol Measurement Experiments (SAME)

Conducted on the International Space Station

NASA Glenn Research Center

David Urban, Gary Ruff, Marit Meyer,

Paul Greenberg, David Fischer

University of Maryland

George Mulholland

National Center for Space Exploration Research

Zeng-guang Yuan, Victoria Bryg

National Institute of Standards and Technology

Thomas Cleary, Jiann Yang


www.nasa.gov 3

Smoke Detection Background:

Destiny Smoke Detection Simulation-25% Sooteffect of gravity

Low-gravity

Normal-gravity


www.nasa.gov 4

Background: Spacecraft Fire Detection

STS Detector: sensitive < 1 micron•Dual-chamber ionization with inertial separator which rejects particles larger than 1-2 microns

•Developed in the late 70’s when Ionization detectors were prevalent

ISS detector: sensitive > 0.5 micron

•2-pass IR laser-diode forward-scattering detector (30

degrees) minimum reported sensitivity is 0.3 μm

•Developed in the 90’s and took advantage of the

availability of stable diode light sources


www.nasa.gov

Smoke Detector Obscuration and Scatter -

Current

Crew

Sleep

Crew

Work

USL

Detectors

Node 3

Detectors

Spikes represent dust

passing through SD


www.nasa.gov

ISS Background Conditions

50th AIAA Aerospace Sciences Meeting, Nashville, TN 6

Inter-module ventilation filter

screen Smoke detector with dust

deposits


www.nasa.gov 7

Objective

Determine whether typical conditions on spacecraft will change the particle size distribution of target smokes

•Soot particle size increases seen in low-gravity

(work of Megaridis and Dobbins; Ku and Greenberg; and Faeth et al.)

•Increased residence time in high concentration zone

•Potential for trapped smoke in avionics enclosures


www.nasa.gov 8

Approach

Preflaming pyrolysis smoke

Vary pyrolysis rate, air flow rate

Measure statistics of particle size distribution and

capture samples for TEM analysis


www.nasa.gov 9

Log-Normal Distribution

Log-normal distribution

σg = 1.6, Dg= 1

g

g

g

tN

DD

D

NDf

2

2

2/1 ln2

lnlnexp

ln)2()(

Number is dominated by the smaller particles

Mass is dominated by the larger particles (tail)


www.nasa.gov 10

Zeroth Moment: TSI

PTrak™

First Moment:

First Alert™

Smoke Detector

Third Moment:

TSI Dust Trak™

SAME Experimental Diagnostic Measurements

All measure moments of the particle size distribution

dDDfDM N

i

i )(

Arithmetic Mean Diameter (M1 / M0)

Diameter of Average Mass (M3 / M0)1/3

Geometric Mean can be calculated with the assumption of a log-normal distribution


www.nasa.gov 11

SAME Sample Carousel

Sample Materials:

SiliconeTeflon

Kapton

LampWick

Pyrell

DBP


www.nasa.gov 12

Aging

Chamber

Commercial

Diagnostics

Sample

Diluter

P-Trak

EnclosureThermal

Precipitator

Fluids

Control

Unit

Data

Acquisition and

Control Unit

Sample

Carousel

Experiment

Support

Plate

Hose

Bundle

SAME in MSG (mockup)


www.nasa.gov 13

SAME Hardware on orbit


www.nasa.gov 14

SAME Particle Capture

Handle for quick

installation and

removal

X-valve

solenoid bank

Vacuum

Connection

Cover

Electrical

Connection

Hot-wire

Leads

Stereolithography

manifold


www.nasa.gov 15

Thermal Precipitator

Overview image showing deposition boundary


www.nasa.gov 16

TEM Results

Kapton

(Run

62)

Length scale

2 μm

Pyrell

(Run 63)

Lampwick

(Run 54)

Teflon

(Run 56)


www.nasa.gov 17

TEM Results - Pyrell Aging

2 microns 2 micronsPre aging Post aging

High Temperature Pyrell: 480 second aging run (Run 84)


www.nasa.gov 18

TEM Results – Pyrell- effect of flow

Pyrell with and without flow

5 microns 5 microns

No air flow8 cm/s air flow


www.nasa.gov 19

SAME Raw Data

Silicone Run 24 GMT 267

0

1

2

3

4

5

6

7

75 125 175 225 275 325 375

0

10

20

30

40

50

60

70

80

ISSDetectorScatterMeasurement(Volts)

STSDetectorMeasurement(Volts)

IonDetectorBMeasurement(Volts)

PTrakMeasurement(PtPerCC)/1000 (right)

DustTrakAMeasurement(MgPerM3) (right)

DustTrakBMeasurement(MgPerM3) (right)

Teflon Test 25 GMT 268

0

1

2

3

4

5

6

7

73975 74025 74075 74125 74175 74225 74275

Time (Seconds)

-10

0

10

20

30

40

50

60

70

80




PTrakMeasurement(PtPerCC/1000) (right)



Silicone Rubber:

Note difference in Dust Traks

indicating large particles

Teflon:

Note similarity in Dust Traks

indicating smaller particles

Two Dust Traks were used one with a 10

micron cut off and one with a 1 micron cutoff.

The difference between the two gives an

indication of the particle size distribution.


www.nasa.gov 20

SAME Raw Data

Silicone Run 24 GMT 267

0

1

2

3

4

5

6

7

75 125 175 225 275 325 375

0

10

20

30

40

50

60

70

80




PTrakMeasurement(PtPerCC)/1000 (right)



Teflon Test 25 GMT 268

0

1

2

3

4

5

6

7

73975 74025 74075 74125 74175 74225 74275

Time (Seconds)

-10

0

10

20

30

40

50

60

70

80




PTrakMeasurement(PtPerCC/1000) (right)



Silicone Rubber:

Note strong signal on both smoke

detectors

Teflon:

Note weak scattering (ISS) detector

signal but ionization (STS) is still

strong


www.nasa.gov

10 Micron versus 1 micron Mass ratios

21

10 micron versus 1 micron mass ratios for different flow rates and sample

temperatures

0.0

0.5

1.0

1.5

2.0

2.5

0.0000 0.2000 0.4000 0.6000 0.8000

Du

stT

rak

Ra

tio

(1

0 m

icro

n m

as

s/ 1

mic

orn

ma

ss

)

Diameter of average mass (µm)

Dust Track 10 micron/ 1 micron impactor mass ratio

Kapton unaged

LampwickunagedTeflon unaged

Silicone unaged

Kapton Aged

Lampwick Aged

Teflon aged

Silicone Aged


www.nasa.gov

0.0

0.5

1.0

1.5

2.0

2.5

0.0000 0.2000 0.4000 0.6000 0.8000

Du

stT

rak

Ra

tio

(1

0 m

icro

n m

as

s/ 1

mic

orn

ma

ss

)

Diameter of average mass (µm)

Dust Track 10 micron/ 1 micron impactor mass ratio

Kapton unaged

LampwickunagedTeflon unaged

Silicone unaged

Kapton Aged

Lampwick Aged

Teflon aged

Silicone Aged

10 Micron versus 1 micron Mass ratios

22

10 micron versus 1 micron mass ratios for different flow rates and sample

temperatures


www.nasa.gov

SAME Flight Size Results for fresh and aged

smoke

23

Geometric Mean Diameter (Dg)

(µm)

Count Mean Diameter (M1/M0)

(µm)

Diameter of Average Mass

(M3/M0) (µm)

σg

Kapton Unaged 0.042 0.056 0.101 2.154

Aged 720 s 0.089 0.109 0.161 1.872

Lampwick Unaged 0.090 0.128 0.258 2.312

Aged 720 s 0.229 0.276 0.398 1.834

Silicone Unaged 0.128 0.196 0.465 2.530

Aged 720 s 0.269 0.355 0.619 2.108

Teflon Unaged 0.081 0.101 0.170 2.198

Aged 720 s 0.070 0.105 0.232 2.442

Pyrell Unaged 0.149 0.204 0.384 2.211

Aged 720 s 0.293 0.359 0.539 1.892


www.nasa.gov

Effect of Air Flow on Diameter of Average

Mass

24

Constant temperature for each material with no aging.

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

0 2 4 6 8 10

Dia

mte

r o

f A

vera

ge M

ass (

µm

)

Air Flow (cm/s)

Diameter of Average Mass versus Air Speed

Teflon

Kapton

LampWick

Pyrell

Silicone


www.nasa.gov

Effect of Aging on Diameter of Average Mass

25

8 cm/s airflow

Constant temperature for each sample.

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0 500 1000 1500 2000

Dia

mte

r o

f A

vera

ge M

an

ss (

µm

)

Aging Duration (s)

Diameter of Average Mass versus Aging (v=8cm/s Baseline T)

Teflon

Kapton

LampWick

Pyrell

Silicone


www.nasa.gov

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

Dia

me

ter

of

Ave

rag

e M

as

s,

low

-gra

vit

y r

es

ult

s (

µm

)

Diameter of Average Mass, normal-gravity results (µm)

Diameter of Average Mass: low-gravity versus normal gravity

Teflon, Baseline Temperature

Teflon,High Temperature

Teflon, Baseline Temperature, Aged

Kapton, Baseline Temperature

Kapton, High Temperature

Kapton, Baseline Temperature, Aged

Kapton, High Temperature, Aged

Lampwick, Baseline Temperature

Lampwick, High Temperature

Lampwick, Baseline Temperature, Aged

Lampwick, High Temperature, Aged

Silicone, Baseline Temperature

Silicone, High Temperature

Silicone, Baseline Temperature, Aged

Pyrell, Baseline Temperature

Pyrell, High Temperature

Pyrell, Baseline Temperature, Aged

Pyrell, High Temperature, Aged

Slope = 1

Effect of Gravity on Diameter of Average Mass

26

8 cm/s flow

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

Dia

mete

r o

f A

vera

ge M

ass,

low

-gra

vit

y r

esu

lts (

µm

)

Diameter of Average Mass, normal-gravity results (µm)

Diameter of Average Mass: low-gravity versus normal gravity

Teflon, Baseline Temperature

Teflon,High Temperature

Teflon, Baseline Temperature, Aged

Kapton, Baseline Temperature

Kapton, High Temperature

Kapton, Baseline Temperature, Aged

Kapton, High Temperature, Aged

Lampwick, Baseline Temperature

Lampwick, High Temperature

Lampwick, Baseline Temperature, Aged

Lampwick, High Temperature, Aged

Silicone, Baseline Temperature

Silicone, High Temperature

Silicone, Baseline Temperature, Aged

Pyrell, Baseline Temperature

Pyrell, High Temperature

Pyrell, Baseline Temperature, Aged

Pyrell, High Temperature, Aged

Slope = 1


www.nasa.gov

Conclusions

27

• Particle sizes ranged from 100 to 600 nm

• Consistent with a log-normal distribution

• Particle sizes increase substantially with aging

• Particle dimensions increase substantially as air flow

was decreased

• TEM showed a significant range of distinct particle

morphologies

• For lampwick and silicone approximately 40% of the

aerosol mass had aerodynamic diameters greater

than 1 μm

• Ground based testing at 8 cm/s showed particle

dimensions very close to the flight results


www.nasa.gov

Conclusions

28

Spacecraft fire conditions include an even

wider array of materials and conditions.

Spacecraft background aerosols can be quite

large.

Detection methods that can measure more than

one moment of the size distribution may show

more successful detection and false alarm

rejection than single moment detectors.

Documents

March 4, 2015 - NFPA