THE MOST TRUSTED NAME IN WEATHERING
Accelerated
Weatherability Testing –
The Right Choice
Presented by: Stephen Novak
CRRC Membership Meeting
February 13, 2006
THE MOST TRUSTED NAME IN WEATHERING
Topics
– Weathering Testers: Simulating the Forces of Destruction
– Developing Accelerated Test Protocols
– Discussion
THE MOST TRUSTED NAME IN WEATHERING
Q-Lab Corporation (Formerly Q-Panel Lab Products)
– Founded in 1956
– Specialize in light stability and material durability testing
products and services
Cleveland, Ohio
World Headquarters
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A Global Company with
Representatives in
over 60 Countries
Shanghai, China
Q-Lab China
Bolton, England
European Headquarters
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Q-Lab Products
Q-Sun
QUV
Q-Panels
MTG
Outdoor
Weathering
Q-Fog
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Q-Lab Test Service Division
Miami, Florida
Phoenix, AZ
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Forces of
Weathering
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Forces of Weathering
Know Your Enemy!!!
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Sunlight
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Temperature
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Moisture
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Other Factors
THE MOST TRUSTED NAME IN WEATHERING
Sunlight
THE MOST TRUSTED NAME IN WEATHERING
International Society for Illumination
– CIE Publication #85 Table 4
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Peak Natural Daylight Standard
2
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0.68 W/m @ 340 nm
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Noon Summer Sunlight
2.0
Visible Light
UV-A
UV-B
1.5
UV-C
Irradiance W/m2/nm
UV Region
1.0
0.5
0.68 W/m2 @ 340nm
0.0
250
350
450
Wavelength (nanometers)
550
650
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Spectrum
Modified
•
•
•
•
Time of Day
Time of Year
Latitude
Altitude
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Seasonal Variation
Intensity changes 8:1 @ 320 nm
Cut-off shifts from 295 to 310 nm
Summer
Winter
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Temperature
THE MOST TRUSTED NAME IN WEATHERING
Heat Aging Causes Deterioration
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“Rule of Thumb”
10°C Increase in Temperature Doubles Rate of
Chemical Reaction
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Solar Radiation +
High Temperature =
Increased Rate of Degradation
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Moisture
THE MOST TRUSTED NAME IN WEATHERING
Rain
Dew
Humidity
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Q-Panel’s TOW Research
Things Are Wet Outdoors Longer Than
You Think
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TOW vs Rainfall
Miami, FL
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Synergistic Effect
– Light
– Temperature
– Moisture
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These are the Forces
of Weathering
THE MOST TRUSTED NAME IN WEATHERING
Topics
–Weathering Testers: Simulating the Forces of
Destruction
– Developing Accelerated Test Protocols
– Discussion
THE MOST TRUSTED NAME IN WEATHERING
The Right Choice?
QUV Weathering Tester
Q-Sun Xenon Tester
Q-Trac Sunlight Concentrator
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Fluorescent UV Tester
QUV Accelerated
Weathering
Tester
model QUV/se
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Fluorescent UV Lamp
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Specimen Holders
•Standard Holders
•Specialty Holders
•3 dimensional
products
•Unique sizes
•Over 100 types
THE MOST TRUSTED NAME IN WEATHERING
UV-B Lamps
1.2
Sunlight
Irradiance W/m²/nm
1.0
0.8
0.6
UVB-313 Lamps
FS-40 Lamps
0.4
0.2
0.0
270
290
310
330
350
Wavelength (nm)
370
390
THE MOST TRUSTED NAME IN WEATHERING
UVA-340 Lamps
1.2
Sunlight
Irradiance (W/m²/nm)
1.0
0.8
QUV with UVA-340 lamps
0.6
0.4
0.2
0.0
260
280
300
320
340
Wavelength (nm)
360
380
400
THE MOST TRUSTED NAME IN WEATHERING
Automatic
Irradiance
Control
Solar Eye™
Irradiance
Control
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Lamp Aging – Automatic Control
0.6
5,000 + hours
0.4
2-hours
0.2
0.0
260
280
300
320
340
Wavelength (nm
360
380
400
THE MOST TRUSTED NAME IN WEATHERING
Automatic
Irradiance Control Preferred
–
–
–
–
More Precise
Much Longer Lamp Life
Allows Higher Irradiance for Faster Tests
ISO 9000 Compliant
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traceability
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calibration
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Effect of Intensity Control
1.5
Sunlight
Irradiance (W/m²/nm)
Intensified 75%
1.0
Typical Intensity
0.5
0.0
270
290
310
330
350
Wavelength (nm)
370
390
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Calibration with AutoCal Radiometer
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QUV
Moisture
– Condensing
Humidity
– Water Spray
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Condensation Advantages
– Identical to natural wetness (dew)
– Elevated temperature = acceleration
– Pure water: Condensation process creates distilled
water
– Easy to use
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Erosion &
thermal shock
ensure parts get
wet
Water Spray
THE MOST TRUSTED NAME IN WEATHERING
State of the Art Fluorescent UV Tester:
QUV
– Irradiance Control
– Calibration with AutoCal
Radiometer
– Self-diagnostic
– Ethernet Capabilities
THE MOST TRUSTED NAME IN WEATHERING
The Right Choice?
QUV Weathering Tester
Q-Sun Xenon Tester
Q-Trac Sunlight Concentrator
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Types of Xenon Testers:
Rotating Drum
Schematic
of
Ci Series
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Types of Xenon Testers:
Flat Array
Schematic
of
Q-Sun Xe-3
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Filter Selection Considerations
–Simulate Service Environment
–Material Spectral Sensitivity
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Filters Types
–Daylight Filters
(exterior exposures)
–Extended UV
(auto specs., fast results)
–Window Glass
(indoor exposures, textiles, inks, etc.)
THE MOST TRUSTED NAME IN WEATHERING
Example of Q-Sun Filters
Window Glass
Daylight
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Q-Sun With Daylight Filters
3.0
Irradiance (W/m²/nm)
2.5
Q-Sun with
Daylight-Q Filter
2.0
1.5
1.0
0.5
Sunlight
0.0
250
300
350
400
450
500
550
600
Wavelength (nm)
650
700
750
800
THE MOST TRUSTED NAME IN WEATHERING
Q-Sun with Daylight Filters
Irradiance (W/m²/nm)
1.2
1.0
Q-Sun with
Daylight Q Filter
0.8
0.6
Sunlight
0.4
0.2
0.0
260
280
300
320
340
Wavelength (nm)
360
380
400
THE MOST TRUSTED NAME IN WEATHERING
Irradiance Control
–
–
Control Intensity
Select Control Points
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@ 340 nm
@ 420 nm
285-400 nm (TUV)
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Irradiance Control
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Feedback Loop
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Light sensor
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Control module
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Xenon arc lamp
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Water Spray
Spray System for Xenon
Requires Extremely Pure
Water Input
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Q-Sun Spray System
– Single Water Spray
– Dual Spray
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Acid Etch Simulation
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Specialty Solutions
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Q-Sun Xe-3 Dual Spray
– Allows user to introduce solutions in addition to
purified water for simulation of unique
environments
– Dual spray system already adopted by BASF to
study automotive coatings systems for acid-etch
defect
– Solutions may include
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Acid Rain
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Organic Solutions
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Q-Sun Xe-3
Dual Spray
THE MOST TRUSTED NAME IN WEATHERING
Temperature Control with Black Panel
Temperature Sensor
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Chamber Air
Temperature Control
– Required by certain Test Methods
– Necessary to control RH
– Requires advanced Technology to achieve
simultaneous control of Black Panel Temp and
Chamber Air Temp
THE MOST TRUSTED NAME IN WEATHERING
Simultaneous Control of
3 Inter-dependent Variables
• Chamber Air Temperature
• Relative Humidity
• Black Panel Temperature
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Relative Humidity Control
100
90
TEMP (C) & RH (%)
80
Black Panel Temperature (70C)
70
60
Chamber RH (50%)
50
40
Chamber Air Temperature (47C)
30
20
10
0
0
5
10
15
20
Test Time (min)
25
30
35
THE MOST TRUSTED NAME IN WEATHERING
State of the Art Xenon Arc Tester: Q-Sun
– Irradiance Control
– Choice of Filters
– Calibration with AutoCal
Radiometer
– Simultaneous Control of
Black Panel Temp,
Chamber Air Temp, and
Relative Humidity
THE MOST TRUSTED NAME IN WEATHERING
QUV
– UVA-340 best simulation
of shortwave UV
– UVB-313 might be too severe
– No visible light
Q-Sun
– Full spectrum
– Best simulation of long
wave UV & visible light
– Stable spectrum
– Spectrum changes over
time
– Irradiance control
– Irradiance control
– No RH control
– Relative humidity control
– More aggressive moisture
attack
– Water spray options
THE MOST TRUSTED NAME IN WEATHERING
QUV, Xenon, Sunlight...
3.0
Irradiance (W /m²/nm)
2.5
2.0
Q-Sun with
Daylight Filter
1.5
1.0
0.5
Sunlight
QUV with
UVA-340 Lamps
0.0
250 300 350
400 450 500 550 600 650
Wavelength (nm)
700 750 800
THE MOST TRUSTED NAME IN WEATHERING
The Right Choice?
QUV Weathering Tester
Q-Sun Xenon Tester
Q-Trac Sunlight Concentrator
THE MOST TRUSTED NAME IN WEATHERING
q
THE MOST TRUSTED NAME IN WEATHERING
Natural Sunlight Concentrator
Q-Trac
Fresnel Concentrator
Solar Concentrator
THE MOST TRUSTED NAME IN WEATHERING
THE MOST TRUSTED NAME IN WEATHERING
THE MOST TRUSTED NAME IN WEATHERING
Mirrors Reflect Sunlight
onto Specimens
Mirrors only reflect 80%
of solar UV radiation
THE MOST TRUSTED NAME IN WEATHERING
Summer Sunlight vs Q-Trac
12
Irradiance (W/m²/nm)
10
8
Q-Trac
6
4
Summer Sunlight
2
0
250
350
450
550
Wavelength (nm)
650
750
THE MOST TRUSTED NAME IN WEATHERING
Morning
Following the Sun...
Noon
Afternoon
THE MOST TRUSTED NAME IN WEATHERING
Acceleration
–
–
–
–
5 times more UV
5 years Florida sunlight in 1 year
1420 MJ/m2 TUV annually
Light intensity is only one
stressor
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Q-Trac Target Board
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Specimens Under Exposure
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Specimen Cooling
Typical Maximum Temperature is 10ºC
Above Conventional Exposures
Cooling Blower
Air Flow Vector
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Q-Trac
Water
Spray
Cycle
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THE MOST TRUSTED NAME IN WEATHERING
Q-Trac Natural Sunlight Concentrator
–
–
–
–
–
Fast Results
Full Spectrum Natural Sunlight
High Temperature
May Be Moisture Deficient
Seasonal Variability
THE MOST TRUSTED NAME IN WEATHERING
Topics
– Weathering Testers: Simulating the Forces of Destruction
–Developing Accelerated Test Protocols
– Discussion
THE MOST TRUSTED NAME IN WEATHERING
Points to Consider for Accelerated Testing
Evaluations
Water Spray
Lamp Type
RH%
Filter
Defined Test Method
Temperature
Test Duration
Irradiance
Dual Spray
THE MOST TRUSTED NAME IN WEATHERING
Current Test Methods For Roofing:
– Q-Sun (ASTM D4798)
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Filter: Daylight
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Irradiance: 0.35 W/m2 @ 340 nm
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Cycle A:
51 min light, 9 min light + water spray,
Black Panel Temperature: 60ºC
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Cycle B:
60 min water spray,
90 min light exposure
120 min water spray
990 min light exposure
180 min cold exposure, -18ºC
Black Panel Temperature, 60ºC
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THE MOST TRUSTED NAME IN WEATHERING
Current Test Methods For Roofing:
– QUV (ASTM D4799)
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Lamp Type: UVB-313
Irradiance: Not Specified
Three Cycles Specified:
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4 h UV Light @ 60ºC, 4 h Condensation @ 50ºC
20 h UV Light @ 60ºC, 4 h Condensation @ 50ºC
20 h UV Light @ 80ºC, 4 h Condensation @ 50ºC
THE MOST TRUSTED NAME IN WEATHERING
Cool Roof Requirements
Requirements
• Energy Department
recommends roofs with initial
solar reflectance of >65% and
>50% after 3 wears
weathering
• California Title 24 sets
minimum requirements of
reflectivity >70% and
emissivity >75%
• CRRC Ratings
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Current Materials:
–Coil Coatings
–Liquid Coatings
–Single-Ply
–Shingles
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Cool Roof Factors Influencing Performance
Factors
• Sunlight
• Temperature
•
Thermal Shock
• Moisture
•
Water Ponding
• Mildew Growth
• Dirt Pickup
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Pick Light Source/Spectrum That Causes
Degradation
–UV
–Visible
–Infrared
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Temperature
To maximize acceleration
use maximum service temperature
To minimize error
DO NOT exceed maximum service temperature
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Moisture/Dirt/Mildew
Select instrumentation that best simulates service
environment
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Types of Xenon Testers:
Flat Array
Schematic
of
Q-Sun Xe-3
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Q-Sun Xe-3
Dual Spray
For Mildew and
Dirt Pickup
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QUV
Moisture
– Condensing
Humidity
– Water Spray
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Perfect
Correlation
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How Many Hours in a QUV Equals a
Year in Florida?
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Realistic Expectations
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No Universal Acceleration Factor
(no magic number)
Different materials have
different acceleration factors
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Practical Methods
of
Addressing Correlation
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– Accumulated
Radiant Dosage
– Compare Test
Material to a Control
– Rank Order
Correlation
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Correlating Exposures
by
Accumulated Radiant Dosage
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Accumulated Radiant Dosage:
Timing exposure duration by the amount of
light energy received by the test specimen
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Timing Exposures by
Accumulated Radiant Dosage
Most useful when:
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primary mode of degradation is light
comparing exposures performed
under identical conditions
THE MOST TRUSTED NAME IN WEATHERING
Comparison to a Control
– Use Control Material of Known
Durability
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Outdoor performance
Lab performance
– Similar Composition to Test Material
– Similar Degradation Mode to Test
Material
THE MOST TRUSTED NAME IN WEATHERING
Benefits of a Control
– Compare performance of
control to a known material
– Allows confidence in lab exposure
– Assure that lab tester is operating
properly
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Does my lab test give me the same
results as my outdoor exposure?
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Use Rank Order
to
Correlate Exposures
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Rank Order Correlation
Quantitative measure of how well the lab test
matches outdoors
Process:
– Rank materials from best to worst
i.e. outdoors vs laboratory
– Calculate correlation coefficient using Spearman
Rank Correlation Coefficient
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Five-year
Florida Ranking
vs.
QUV Ranking
S ample ID
F
K
T
S
L
U
A
M
P
Q
V
N
W
J
H
O
G
I
E
R
D
C
B
Ranking
Florida
1
2
3.5
3.5
5
6
7
8
9
11.5
11.5
11.5
11.5
14
15
16
17
18
19
20
21
22
23
Ranking
(QUV-B-313)
3
5
9.5
4
6
8
13
9.5
11
7
14
12
2
16.5
1
20
15
16.5
21
23
18.5
18.5
22
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Spearman Rank Formula
rho = 1 −
6 • ∑ (rank A − rank B ) 2
N ( N 2 − 1)
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Significance of Spearman rho
– Spearman rho = 1.00 when you have perfect
correlation
– Spearman rho < 1.00 means less-than-perfect
correlation
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Roadmap For Accelerated Protocol
– Develop outdoor protocol (Complete)
– Collect data from outdoor protocol, sanitize and share
(Complete?)
– Agree on failure criteria/endpoints (Complete?)
– Determine goals for accelerated test method
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% False Failures Acceptable?
% False Positives Acceptable?
Minimum Acceptable Rank Order Correlation Coefficient
– Try everything!
– Oh yes, get statistician!!!!!