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System Reliability for Outdoor SSL
Luminaire System Life
There’s more to Life than L70.
System Reliability for Outdoor SSL
Luminaire System LifeWhat about Mechanical Design?
System Reliability for Outdoor SSL
Luminaire System Life
What about Product Durability?
System Reliability for Outdoor SSL
What Could Go Wrong?System Reliability for Outdoor SSL
Non-Illumination Related Reliability Concerns
• MechanicalVibration
• ElectricalDriver Life and ReliabilitySurge Protection
• FinishCorrosion Protection
System Reliability for Outdoor SSL
Vibration
System Reliability for Outdoor SSL
City of Greensburg, KS – Greensburg, KSSystem Reliability for Outdoor SSL
I35W, St Anthony Falls Bridge – Minneapolis, MNSystem Reliability for Outdoor SSL
Maxwell Street Bridge – Napa, CASystem Reliability for Outdoor SSL
Vibration
Types of Roadway Vibration• Wind Induced (ground mounted)• Traffic Induced (bridge / overpass mounted)
Relevant Testing and Standards• ANSI C136.31-2001 Normal Applications Vibration Standards• ANSI C136.31-2001 Bridge & Overpass Vibration Standards• CALTrans 611 Vibration Testing
System Reliability for Outdoor SSL
VibrationANSI C136.31-2001 CALTrans 611 Vibration Testing
These standards were designed tosimulate what could be encounteredIn normal installations and are notintended to cover natural / catastrophicdisasters
System Reliability for Outdoor SSL
Vibration - ANSI C136.31-2001
Some of the Details• Special vibration tables are required• Mount accelerometer @ luminaire center of
gravity• Test to the levels per Tables 1 and 2 (next two slides) in the x, y and z planes• Luminaire shall be capable of withstanding the described vibration for 100,000
cycles in each plane• A major change in frequency or displacement indicates failure• And, there should be no damage to, loosening of any part of the luminaire or
any changes that could result in a safety problem
System Reliability for Outdoor SSL
VibrationANSI C136.31-2001 Normal Applications
System Reliability for Outdoor SSL
VibrationANSI C136.31-2001 Bridge & Overpass Applications
System Reliability for Outdoor SSL
Vibration - CALTrans 611 Vibration Testing
Other test guidelines may be negotiated by the specifierCALTrans 611 Vibration Testing RequirementsHorizontal Cyclic Loading Test (critical in ground-mounted luminaires)• Adjust frequency and displacement until 1.5 G peak to peak (0.75 G peak)
acceleration is obtained. Driver is installed for this test• Cycle until 2 million cycles or until failure occurs
Vertical Cyclic Loading Test (critical for bridge-mounted luminaires)• Adjust frequency and displacement until 3 G peak to peak (1.5 G peak)
acceleration is obtained. Driver is removed for this test. Frequency must be kept under resonant frequency for this test
• Cycle until 2 million cycles or until failure occurs
System Reliability for Outdoor SSL
Driver Life and Reliability
System Reliability for Outdoor SSL
Driver Life and Reliability
• MTBF Test Data
• Reputable Manufacturers
• Warranty
System Reliability for Outdoor SSL
Surge Protection
System Reliability for Outdoor SSL
Surge Protection
Relevant Testing and Standards - IEEE/ANSI C62.41.2
How much protection is needed?Does everyone require the same level of protection?
System Reliability for Outdoor SSL
Surge Protection - IEEE/ANSI C62.41.2
• No performance requirements are specified in this recommended practice
• A rational, deliberate approach to recognizing many of the variables in this complex subject area is recommended
• The considerations listed below are necessary to reach the goal of practical surge immunity. They are: Protection level desired Worst case or typical case scenarios No system damage No upset Specific equipment sensitivities
System Reliability for Outdoor SSL
Surge Protection - IEEE/ANSI C62.41.2
• Considerations (continued): Power system characteristics Interactions with communication and other systems No system damage No system upset Specific equipment sensitivities
System Reliability for Outdoor SSL
Surge Protection - IEEE/ANSI C62.41.2Two Major Types of Surges for equipment connected to low voltage
AC power circuits• Voltage Surges• Current Surges
Two Major Sources• Lightning • Switching Surges (power system)
System Reliability for Outdoor SSL
Surge Protection - IEEE/ANSI C62.41.2
Lightning Surges: The standard points toward two cases / scenarios:• Senario 1: Indirect Lightning Flash – the most common type• Scenario 2: Direct Lightning Flash – the least common
• It further defines Location Categories within Scenario 1• Categories A, B and C
System Reliability for Outdoor SSL
Finish
System Reliability for Outdoor SSL
Finish
• Aesthetic Concerns
• Mechanical Concerns
System Reliability for Outdoor SSL
Finish – Salt Spray (Fog) TestRelevant Testing and Standard – ASTM B117
• This practice provides a controlled corrosive environment which has been used to produce relative corrosion resistance information for specimens of metals and coated metals in a given test chamber
• Special Salt Solutions, Air Supply, Salt Fog Chamber, Specimen Cleaning etc.
• Test specimens: A scratch or scribed line is made through the coating with a sharp instrument (per ASTM D 1654) so as to expose the underlying metal
• Results reported based upon creepage from scribe in millimeters (per ASTM D 1654)
System Reliability for Outdoor SSL
Finish – Salt Spray (Fog) TestResults Per ASTM D 1654
System Reliability for Outdoor SSL
Finish
Corrosion and UV Resistance
Relevant Testing and StandardASTM B117 Elevated Ambient Salt Fog(Pass at 2,000, 3,000, 4,000, 5,000 hours?)
System Reliability for Outdoor SSL
LED Mechanical Life
System Reliability for Outdoor SSL
LED Mechanical Failure RatesSystem Reliability for Outdoor SSL
LEDs are Extremely Reliable
What are the odds of 3 or more LED failing in a 50 LED luminaire?
Probability at 10,000 Hours = 1 in 1.25E-10Probability at 25,000 Hours = 1 in 1.95E-9Probability at 50,000 Hours = 1 in 1.56E-8 (1 in 156 Million)Probability at 100,000 Hours = 1 in 1.25E-7
There are other reasons that an LED may stop working (loose wire, failed driver, etc), but the LED itself is very mechanically reliable
How to Predict Reliability?
Look to standards
System Reliability for Outdoor SSL
How to Specify Reliability?
Look to standards
System Reliability for Outdoor SSL
Thank You
System Reliability for Outdoor SSL