Lighting Glossary

The terms buyers and designers use when they compare industrial lighting specifications.

Efficacy (lm/W)

Luminous flux divided by power. It is not the same as the lumen output; a high-efficacy fixture can still be the wrong choice if the beam or the delivered lux is wrong.

L70

The hours until lumen output falls to 70% of its initial value. L70 is a projection, not a warranty period; the basis (LM-80 data and TM-21 method) matters.

LM-80 and TM-21

LM-80 measures lumen maintenance of the LED source over time. TM-21 projects longer-term behaviour from that data. A fixture-level L70 claim should say which data and method it uses.

CCT and SDCM

CCT is the colour temperature in kelvin (for example 4000K). SDCM describes how far a batch can drift from the target colour; a lower number is tighter. “<5 SDCM” is a common project requirement.

IP and IK

IP is ingress protection against dust and water (for example IP66). IK is impact resistance (for example IK08/IK10). They are separate ratings; one does not imply the other.

UGR

Unified Glare Rating. Lower values mean less glare; the acceptable value depends on the task and the standard applied to the space.

DALI and 0-10V

DALI is a digital control protocol with addressing and feedback. 0-10V is an analogue dimming signal. They are not interchangeable, and the driver, sensor and control system must be tested together.

DLC

DesignLights Consortium qualification, used by some US utilities for rebates. It is not a safety certificate. We do not currently claim DLC; confirm before specifying it.

ATEX / IECEx

Hazardous-area certification schemes. They are not the same as IP or a general CE marking. We do not list them as confirmed; check the exact model and zone before a hazardous-area project.

Incoterms

FOB, CIF and DDP define who arranges freight, insurance, import clearance and delivery. The Incoterm changes the landed cost, not the fixture specification.