Lighting Level Reference Chart

Use this worksheet after the calculator result to document target level, room or task type, average and minimum illuminance notes, uniformity, glare, fixture photometrics, CU/LLF, controls, and owner criteria.

Open calculator

Quick reference table

A lighting level reference chart is a calculator-led planning record for matching illuminance to the actual visual task. It keeps the foot-candle or lux result beside task difficulty, owner criterion, uniformity, glare, fixture photometrics, and field verification needs before fixture selection.

Lighting level planning bands

Lighting level planning bands
Planning band	Typical use in screening	Follow-up note
Low level	Circulation, orientation, low-detail areas	Confirm visibility and egress needs separately
General level	Office, classroom, retail, or general room screening	Check task plane, uniformity, and glare
Task level	Detailed work, inspection, counters, benches	Review task location and supplemental lighting
High-detail or critical task	Quality control, color review, inspection, safety-sensitive work	Use project criteria and photometric data
Special condition	Emergency, exterior, industrial, or owner-specific criteria	Use project standards and AHJ review where applicable

Average-result context checks

Average-result context checks
Context item	Record on worksheet	Why it changes the target
Task plane	Desk, floor, counter, shelf, equipment face	The same room can have different useful planes
Uniformity	Average-to-minimum or low-point concern	Average illuminance can hide dark spots
Glare and contrast	Fixture type, lens, mounting height, finish color	More light is not always more usable visibility
Controls	Occupancy, dimming, daylight, schedules	Measured level can change under automatic control states
Owner criterion	Project target or facility standard	Project requirements can override generic planning bands

Formula basis

Average illuminance = adjusted lumens / area. Adjusted lumens may include utilization and light-loss factors when those inputs are known.

Adjusted lumens are total fixture lumens after documented utilization or light-loss factors.
Area is the task, room, or zone area used in the calculator.
Target level is a project planning value, not a universal code requirement by itself.
Uniformity, glare, mounting height, and fixture photometrics control whether the average result is practical.

Worked examples

Office target reviewRecord the calculated average foot-candles, selected office target, task plane, luminaire output, CU/LLF assumptions, glare note, and whether a photometric plan is required.

Bench inspection areaFor a workbench, keep the task location, required detail level, supplemental fixture plan, shadow concern, and owner criterion beside the calculator result.

Assumptions. Balanced load and line-to-line voltage assumptions behind this chart.

This chart uses planning bands rather than reproducing proprietary lighting tables or project-specific criteria.
Final lighting criteria may depend on owner standards, task visibility, age of occupants, energy limits, fixture data, and field measurements.
Average illuminance does not show the lowest point, veiling reflections, glare, shadows, or user comfort by itself.

Code and standard notes. Planning limits that should be checked before final equipment selection.

Use this chart as a reference table; verify adopted energy, workplace, life-safety, owner, fixture manufacturer, and AHJ requirements before treating a lighting level as final.

How to use this chart

1Name the taskWrite the room, zone, task, and task plane before comparing the calculated illuminance with any planning band.

2Keep average and minimum separateAverage illuminance does not show the darkest point, uniformity, glare, veiling reflection, or shadowing.

3Route the decisionUse the chart to decide whether to revise lumens, select fixtures, check branch-circuit load, or request a photometric layout.

Worksheet checklist. Record source basis, review gaps, and assumptions before using the chart result.

Capture the calculator valueRecord foot-candles, lux, area, fixture count, lumen output, CU, LLF, and average-result basis if used.
Capture the project basisDocument the room use, visual task, owner criterion, fixture family, mounting height, glare concern, and control strategy.
Capture verificationList whether photometric files, energy checks, commissioning measurements, field readings, or AHJ review are still needed.

Common mistakes to avoid. Review these before turning chart current into an equipment decision.

Using a generic room label without checking the actual task performed in that area.
Treating an average illuminance result as proof of uniformity, glare control, or energy-code compliance.
Ignoring owner criterion, fixture photometrics, mounting height, and surface reflectance after the calculator target looks acceptable.

Frequently asked questions

These answers explain how to use the chart without turning a quick reference into a final design decision.

Why not list one mandatory level for each room?

Lighting targets depend on task, occupant needs, surface reflectance, controls, fixture distribution, and project criteria. The worksheet preserves the context instead of turning a planning value into a universal rule.

How should the calculator result be used?

Use it as the first average-illuminance screen, then document fixture data, task-plane assumptions, uniformity needs, and any required photometric or field verification.