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Whether you're interested in new constructon, retrofitting, or a completely custom solution, we can help. We'll give you advice, help you navigate your options and even show you how much you can save. All you have to do is ask...
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Thursday, March 11, 2010 |
It's time for the 3rd installment in our Best Of Ask An Engineer series, where we take some of our most insightful "Ask An Engineer" questions and post their answers where anyone can find them.
Customer names have been changed to protect the innocent.
"The Effectiveness Of Lowering Lights"
The Question
"I have 400 watt high bay light fixtures in my warehouse. I have a 40 ft high ceiling, with the fixtures mounted 5ft from the ceiling. My racking is at 24 ft.
How do I measure the effectiveness of moving the lights to a lower level. Is there a formula to calculate? What if I change to T8 fixtures? Would I need the same or fewer fixtures? Please advise"
The Answer
Thanks for the question and the opportunity to be of service.
Short answer is yes and yes. Yes, we can help with measuring the effectiveness of existing systems. Yes, changing to a fluorescent high bay fixture should be strongly considered.
A new fluorescent hi-bay layout tailored to your space would result in dramatically reduced energy use and dramatically improved lighting. As your question recognizes, there are many variables that produce a sound lighting application for high piled storage applications.
The circumstance you describe is common; fixtures are often mounted in a High-bay/Open-bay configuration in a building shell at the time of construction. Subsequently the building is occupied, internal structures put in place and high piled storage racks are installed. The original generic lighting layout remains in place, and because it is not designed for configured space, it is less than optimal.
Lowering the fixtures to approx 27-28’ elevation, centered on your 24’ high piled storage aisles, is a logical step. However, there are things that work for you and against you when you do this.
Lowering the fixtures has the positive effect of eliminating the light lost on top of the racks. A negative consequence can be that when lowered, the reduced mounting height may not allow sufficient lateral spread of the light down the length of the aisle, resulting in “pooling” and poor uniformity.
The best way to predict the effectiveness of a new configuration is through a photometric analysis, which we are happy to perform for both your baseline system, and for the iterations you would consider. This analysis will give you the data you need; horizontal and vertical foot-candles, uniformity ratios which are equally important to good lighting, and analysis of energy savings resultant from an upgrade to fluorescent Hi-bays.
That is a long answer to a short question but that is typical in energy efficient lighting. We’d be happy to support you with product information.
We’d also like to introduce you to one of our Valued Added Resellers: Energy Efficiency Specialists who can design and implement a turnkey solution for you, secure rebates, and deliver an outstanding result.
Attached please see a generic example of a professional approach to energy efficient relighting. Such an approach will help you realize the potential for significant energy savings and a dramatically improved illuminated environment.
Relighting your plant can produce an outstanding return on investment. I’ll call you to follow up or feel free to call me.
Sincerely,
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Joe Martin
Vice President of Engineering
Precision-Paragon [P2]
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MORE RESOURCESFAQ >>We've put together a list of answers to some of the questions our engineers are most often asked. Glossary >>This is where you can translate lighting engineer talk into something more comprehensible. Technical Info >>Here we've gathered technical information with the potential to help any lighting professional with a project.
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