system reliability for outdoor ssl - energy.gov · • luminaire shall be capable of withstanding...

System Reliability for Outdoor SSL

Luminaire System Life

There’s more to Life than L70.


Luminaire System LifeWhat about Mechanical Design?


Luminaire System Life

What about Product Durability?


What Could Go Wrong?System Reliability for Outdoor SSL

Non-Illumination Related Reliability Concerns

• MechanicalVibration

• ElectricalDriver Life and ReliabilitySurge Protection

• FinishCorrosion Protection


Vibration


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


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


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


VibrationANSI C136.31-2001 Normal Applications


VibrationANSI C136.31-2001 Bridge & Overpass Applications


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


Driver Life and Reliability


Driver Life and Reliability

• MTBF Test Data

• Reputable Manufacturers

• Warranty


Surge Protection


Surge Protection

Relevant Testing and Standards - IEEE/ANSI C62.41.2

How much protection is needed?Does everyone require the same level of protection?


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



• Considerations (continued): Power system characteristics Interactions with communication and other systems No system damage No system upset Specific equipment sensitivities


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)



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


Finish


Finish

• Aesthetic Concerns

• Mechanical Concerns


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)


Finish – Salt Spray (Fog) TestResults Per ASTM D 1654


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?)


LED Mechanical Life


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


How to Specify Reliability?

Look to standards


Thank You


system reliability for outdoor ssl - energy.gov · • luminaire shall be capable of withstanding...

Documents