The vast majority of existing warehouse space in the US is lit with inefficient high intensity discharge or magnetically ballasted T12 fluorescent light fixtures. Unfortunately, lighting is one of the few areas that is often overlooked when investigating cost reduction opportunities. Owners and managers blindly budget tens to hundreds of thousands of dollars for utility bills without realizing that switching to more
energy efficient warehouse lighting can provide a tremendous opportunity to reduce energy demand and therefore cut utility costs. Many believe that the only option to lowering the electric bill is to shut off all the lights in the facility which results in an unsafe work environment. We have had major advances in lighting technology that allow for warehouses lighting systems to be optimized for bulk storage and rack aisle applications.
This application guide outlines warehouse lighting requirements and best practices and gives practical examples you can use as a basis for your warehouse lighting retrofit project. As with our
gymnasium lighting application guide, we will use examples to illustrate these guidelines that are based on typical warehouse layouts. If you have any questions or need any clarifications, don't hesitate to
contact us.
Overview of Benefits
We have talked about
what T5 and T5HO high bays are and described the
benefits of T5 high output fluorescent lighting in other articles. We have even provided a great summary
table that compares T5HO high bays to 400W metal halide fixtures. An overview of the key advantages is provided below:
- Energy Efficiency: A T5HO lamp uses less energy to create a given amount of light output than an HID lamp.
- Lumen Maintenance: Light levels from a T5 HO lamp don't degrade as much as traditional HID lamps.
- Instant On: There is no delay when turning on a T5 fixture. This allows for the use of occupancy sensors.
- More Usable Light: Since the T5 lamp is very narrow, special reflectors can direct more light down to the work surface.
- Better Quality Light: T5HO fixtures have a color rendition index closer to natural light.
Warehouse Lighting Requirements
There are just a few design considerations to keep in mind when planning a lighting retrofit. These are ensuring sufficient light is available to maintain a safe and productive work environment and meeting the requirements of local, state and federal incentives.
Warehouse Light Levels
In the US, light levels are measured in foot-candles (fc). The Illuminating Engineers Society publishes recommended light levels for all types of facilities. For warehouse applications, the IES recommends the light levels to be in the range of 5 fc to 30 fc. These levels ensure a safe working environment with ample lighting to perform the required tasks. The table below provides a more detailed summary of the recommended light levels for various areas commonly found within a warehouse.
| Application |
Foot-Candle Level |
| Warehouse - Inactive |
5 fc |
| Warehouse - Active: bulky items; large labels |
10 fc |
| Warehouse - Active: small items; small labels |
30 fc |
| Shipping and Receiving |
30 fc |
| Assembly/Packaging – Medium |
50-70 |
| Assembly/Packaging – Fine |
75-100 |
Lighting Power Density
In addition to light level requirements, care should be taken to ensure the new lighting system can qualify for any local and state rebates as well as the $0.60 per square foot tax deduction made available by the Energy Policy Act of 2005. The Energy Policy Act of 2005 requires that warehouses reduce their lighting power density from the 1.2 Watts per square foot allotted in the ASHRAE 90.1-2001 standard down to 0.6 Watts per square foot. The Energy Policy Act also requires that there be some form of bi-level switching in place to allow for two levels of lighting within the warehouse. This can be accomplished by having multiple contactors to turn on alternating lighting circuits, or providing occupancy sensors that dim or turn off light fixtures when there is no activity in the area.
Bulk Storage Warehouse Lighting
We recommend lighting bulk storage facilities to an average of 15-20 fc. This is slightly higher than the 10 fc requirement, but it allows for some future flexibility. The vast majority of bulk storage facilities we see have the lighting laid out in a standard grid layout. If the facility is lit with 400W metal halide fixtures, this grid can be between 25' to 30' on center.
As an example, a typical 100,000 sq. ft. warehouse facility measuring 200' x 500' with 30' ceilings would have approximately 119 fixtures in a 30' x 30' grid mounted at 28'. This system can be retrofitted to
4-lamp T5HO high bay fixture and get an average of 19 fc. The following table provides a summary of the cost savings for this example:
| Fixture Type |
400W MH |
4-Lamp T5 |
6-Lamp T5 |
| Fixture Wattage |
454 W |
228 W |
342 W |
| Fixture Quantity |
119 |
119 |
119 |
| System Power Consumption/Hour (demand) |
54.0 kW |
27.1 kW |
40.7 kW |
| Lighting Cost/Year |
$28,304 |
$14,204 |
$21,333 |
| Savings/Year |
- |
$14,100 |
$6,971 |
Related Resources
Relight Depot can provide customized lighting layouts for your warehouse with the same level of detail shown in these diagrams. Don't hesitate to
contact us if you would like to see what results you can achieve in your warehouse.
March 5, 2010 by Ray De Varona.
