By Stan Walerczyk
A very good example of reduced maintenance being more important than energy savings is the I-35W Bridge project. The bridge had to be rebuilt and they compared new HPS with LED fixtures. Since it is in Minneapolis there is a lot of traffic. Having to put up and remove signs and safety cones, bucket trucks and labor, it is quite expensive to repair lights. 100,000+ hour rated LEDs were considered much better than 24,000 – 30,000 hour rated HPS lamps. Here is the DOE study on this.
Pulley systems in high mast pole fixtures often do not work well when they age, and since these fixtures are often on 100′ poles, various lifts and labor can be expensive. So 100,000+ hour rated LED fixtures can reduce a lot of maintenance costs.
Although pole fixtures in most high school, college and even professional sports stadiums may only be on 1000 or fewer hours per year, these poles are often quite tall and it is expensive to get to the fixtures. The typical 1000 – 1500W MH lamps are only rated for about 10,000 hours, but with the wind and vibration may last much less. There are now several 300 – 400W 100,000+ hour rated LED floods, which may cost $1000 – $1200 and replace MH one for one.
Here is information on the LED retrofit that was done in August at Lewis and Clark College’s Griswold Stadium in Portland Oregon. There were 118 1500W MH floods on 85′ poles. They were replaced with 90 PlanLED 400W Maha LED floods. There will be substantial maintenance savings, because the college had to rent a boom truck to replace short lamps and ballasts. In addition to that, energy savings and rebates, lighting quantity and quality are much better. A control system is planned for dimming and scheduling.
In general with 100,000+ hour LED fixtures, photocontrols should last that long. Standard photocontrols typically last about 50,000 hours and are often replaced with HPS lamps are replaced. Some companies provide extra long life photocontrols, which should last as long as the LED fixtures. Some LED fixture manufacturers offer these as an option.
Motion sensors probably will not last as long as 100,000+ LED fixtures, so it would probably be good budget lift and labor costs to replace them before the LED fixtures need to be replaced.
Another issue with motion sensors on pole and other fixtures in new parking lots, etc. is that trees and bushes are often planted, but as they get tall and bushy, they can block motion sensor coverage.
Maintenance can also be an issue inside, including hibays, especially ones mounted 40 feet or higher. At Moffett Field in California, where they store blimps, I went up on a lift up to the 90′ to the 1000W MH high hibays. I sure had white knuckles and told the other person on the lift not to move at all. 400W 100,000+ hour rated LED hibays would help a lot.
Explosion proof fixtures usually take a lot of time replacing lamps and ballasts and LED would be very good.
As mentioned before it is good to consider electronically ballasted ceramic metal halide (CMH). For example Global Energy & Power’s CMH lamps are rated for 50,000 hours and have up to a 5 year warranty, and their electronic ballasts are rated for 100,000 hours and have up to a 10 year warranty. It can often be more cost effective to retrofit existing fixtures with electronically ballasted CMH than to replace them with new LED fixtures.
I always ask end-customers how they do maintenance in hard to reach fixtures. Do they do it in-house with their own lift, scaffold or bucket truck? Do they rent a lift, scaffold or bucket truck? Do they hire a maintenance company to do it? I also ask them about what does it cost them.
Distributors and contractors, who discuss and include maintenance savings in their proposals, probably have a much better chance to get end-customers to approve projects than if they just use energy savings and rebates. Often the maintenance savings can be at least twice the energy savings.
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