Primary audience: Contractors
Use the high bay lighting calculator to estimate fixture count, approximate spacing and watts from published Allmax output.
Measure from the fixture to the work
A building’s ceiling height is only one measurement. A suspended fixture sits below the ceiling, and the visual task may sit above the floor. Record the fixture’s luminous opening and the actual surface where people need light. Those elevations establish the working distance used in the layout.
For floor movement, the relevant horizontal plane may be near floor level. A packing bench uses its working surface. Rack labels need a vertical calculation plane. Do not use one default plane for every task merely because the fixtures share a circuit.
The IES Illuminance Selector FAQ explains that the task surface follows the actual visual task. Have the designer establish the appropriate target and plane. This guide does not prescribe a universal light level for every warehouse or manufacturing operation.
Record suspension length, ceiling slope, beam depth and existing mounting points. If a proposed pendant lowers a fixture, update the working height in the calculation. A drawing based on ceiling height alone can misrepresent both distribution and clearance.
Use height to inform optics, not a fixed wattage rule
As the fixture-to-task distance changes, the light pattern on the surface also changes. Distribution controls where intensity is concentrated. A narrow optic and a broad optic at the same wattage can produce different useful illumination and different gaps between fixtures.
| Input | Why it matters | Evidence needed |
|---|---|---|
| Task distance | Changes the pattern at the work surface | Measured elevations |
| Optic | Directs output toward aisles or open areas | Configuration-matched IES file |
| Obstructions | Block light from reaching the task | Rack and equipment plan |
| Surface conditions | Change reflected contribution | Documented room assumptions |
A height-to-wattage table omits these variables. It can encourage a contractor to reuse an unsuitable grid or overlight the center while leaving racks dark. Compare candidate configurations in the actual room geometry instead.
Use the warehouse lumen method for a preliminary estimate, then calculate the layout. That initial arithmetic does not establish spacing, minimum illumination or the final order quantity.
Compare the published high-bay configurations
The UHB26 UFO high bay publishes a 90° beam angle and model-specific selectable power settings. Its lumen column gives maximum output. Request output for the actual selected setting before using a lower-power configuration in a calculation.
The MLH06 130–210 W and MLH06 300 W pages publish prismatic, aisle and narrow optic choices. Their tables separate output by power setting and color temperature. Preserve that pairing when the fixture schedule moves from design to quotation.
The FLS21 linear high bay publishes a 110° beam angle and maximum lumen values by model. A larger maximum output does not automatically make it the right choice for a taller room. Compare the actual intensity distribution and the sight lines from occupied areas.
Housing dimensions matter too. Check equipment clearance, attachment space and the available service route. An alternate that fits electrically may still require a different suspension detail. Keep the mounting assembly on the same schedule row as the selected fixture.
Review shadows, sensors and maintenance before ordering
Model the room as it will operate. Empty-floor calculations can hide shadows from racks, tall machines and suspended services. Check light at the aisle ends and the rack faces where labels are read. For manufacturing, distinguish general movement from inspection and machine-specific work.
Review sensor coverage at the proposed fixture height. A sensor’s detection pattern has its own limits; fixture output does not establish whether the sensor sees a worker below. Confirm the accessory, coverage drawing, timeout and response to small movements at the task.
Separate the dimming signal from the device that switches the connected load. A 0–10 V interface does not establish that a proposed wall control can switch every fixture in a zone. Request the controller and driver documents for the complete arrangement.
Plan service access while fixing the suspension height. Record lift routes, machine shutdown requirements and access to driver compartments. Check how the selected fixture and mounting can be maintained without conflicting with permanent equipment. These decisions affect the installation scope before the first unit is ordered.
Send a height and submittal checklist
- Floor plan with room dimensions, ceiling slopes and proposed fixture tags.
- Fixture elevation, suspension length and each task-plane elevation.
- Rack heights, aisle widths, equipment and overhead obstructions.
- Required maintained light levels and uniformity criteria from the designer.
- Exact model, optic, power setting, color setting and driver input.
- Mounting documents, sensor coverage and control-zone schedule.
- Matching photometry, calculation assumptions and service-access plan.
Mark which dimensions were measured and which remain estimates. A later change to rack height or pendant length should trigger a review of the affected calculation. Keep revision dates on the plan and fixture schedule so the installer does not use an obsolete layout.
Send the plan and high-bay configuration schedule through RFQ to request the matching product documents. Ask the project designer to approve the layout before treating the estimate as a purchase quantity. At commissioning, record installed elevations and final settings against the approved schedule.
Before the lift arrives, compare the delivered labels and mounting accessories with the approved schedule. Identify any different optic, driver or suspension component while it can still be resolved on the ground. After installation, verify representative task locations under the agreed operating conditions. Record the measurement plane and whether adjacent zones were operating, so later checks compare the same condition rather than an unexplained light-meter reading.
Related guides
- Warehouse Lighting: Lumens, Foot-Candles and Fixture Count
- Linear High Bay vs UFO: Choosing Warehouse Fixtures
- Gymnasium Lighting: Glare, Court Layout and Controls
Prepare the contractor fixture schedule.
Browse all buyer guides or send your fixture schedule for a quote.
Follow NEC/local code and use a licensed electrician.