| Unified Glare Rating (UGR) | UGR < 19 | Calculate or verify using the intended room geometry, luminaire spacing, mounting height, surface reflectances, and viewing direction. EN 12464-1 commonly uses UGR ≤ 19 for offices and screen-based workplaces. | Reduces discomfort glare, reflections, squinting, and visual fatigue in workspaces. |
| Flicker modulation depth | Keep percent flicker below the IEEE 1789 low-risk recommendation at the operating frequency | For frequencies from 8 to 90 Hz, IEEE 1789-2015 gives a low-risk reference of approximately 0.0333 × frequency in percent. At 90 Hz, this is about 3%. The specific driver waveform and dimming level must be tested. | Limits visible and invisible light modulation that may contribute to discomfort, headaches, or photosensitive risk. |
| Flicker frequency | Avoid low-frequency modulation; verify performance across the full dimming range | Measure at 100%, 75%, 50%, 25%, and minimum rated output. A high carrier frequency alone does not prove low flicker because dimming can change the waveform. | Flicker behavior can worsen at partial load or with incompatible controls. |
| Stroboscopic visibility | Verify low-risk operation using SVM or an equivalent flicker metric | Use a calibrated flicker meter and report SVM together with percent flicker and frequency. SVM is addressed in IEC TR 61547-1 and complements, rather than replaces, IEEE 1789 evaluation. | Helps reduce the risk of visible motion artifacts and stroboscopic effects around moving machinery. |
| Luminous efficacy | Typically 100–150 lm/W for modern commercial LED panels | Compare delivered lumens divided by input watts, measured at the rated input voltage and operating temperature. | Higher efficacy can reduce energy use, but it should not be prioritized over glare, flicker, optical distribution, and lifetime. |
| Color rendering | CRI (Ra) ≥ 80 for general offices; ≥ 90 where color accuracy is important | Check the complete spectral test report, including R9 when strong red rendering is required. | Supports accurate appearance of documents, skin tones, equipment, and interior finishes. |
| Correlated color temperature | 3,000–4,000 K for many offices; select according to the project brief | Use the same CCT throughout visually connected spaces unless a deliberate zoning strategy is specified. | A consistent color appearance improves visual comfort and interior coherence. |
| Illuminance at the task plane | Use the applicable lighting standard; office desk tasks commonly require about 500 lux | Verify average and uniformity on the actual workplane after installation. Requirements vary by task and jurisdiction. | A panel with low glare can still perform poorly if spacing or output does not provide adequate uniform light. |
| Optical distribution | Use a wide, controlled distribution suited to the ceiling height and layout | Review the photometric file and confirm spacing criteria, shielding, and luminance distribution—not only the beam angle. | Proper distribution supports uniformity while reducing bright-source reflections on screens. |
| Power quality | Power factor ≥ 0.90; low input-current distortion preferred | Check values at rated voltage and load. Project or local requirements may specify stricter limits for total harmonic distortion. | Good power quality can reduce electrical losses and improve compatibility in larger installations. |
| Dimming and control compatibility | Confirm stable dimming without visible flicker from 100% to the required minimum level | Test the complete combination of driver, control protocol, sensors, emergency equipment, and wiring. | The control system can alter flicker, audible noise, minimum output, and startup behavior. |
| Thermal performance and lifetime | Prefer a documented L70 rating of at least 50,000 hours for commercial applications | Review LM-80/TM-21 or equivalent lifetime evidence, ambient-temperature limits, driver lifetime, and warranty conditions. | Lower operating temperature generally helps preserve light output and color stability over time. |