Linear luminaire distribution and layout

Key parameters

Power	20–60 W
Luminous flux	2,600–7,800 lm
Mounting height	2.8–4 m
Beam angle	90° × 30°
Distribution type	Asymmetric wide

Product family: Linear Lights

The distribution decides where the light goes

Two fixtures with the same wattage and the same flux can put a twofold different illuminance on the floor, purely because of distribution. This page is Asymmetric wide. Distribution decides three things: the shape of the pool of light, how much of the flux reaches the floor, and whether the spacing can be opened up.

A common misjudgement is comparing distributions by centre illuminance. A narrow beam usually wins at the centre point and loses badly at the edges, giving a lower average. Compare average illuminance plus uniformity (minimum over average) — those two numbers match what people actually see.

Angle and height come as a pair

This page is 90° × 30° at 2.8–4 m. The direction is unambiguous: the higher the ceiling, the narrower the optic, or the light lands on the walls; the lower the ceiling, the wider the optic, or the floor gets discrete bright spots and hard shadows under each fixture.

Rule of thumb: pool diameter ≈ 2 × height × tan(half angle). At 10 m, 90° gives about 20 m and 60° about 11.5 m. Sketch the layout with that first and ask for a photometric calculation second — the other order usually costs a revision.

Four things to verify before ordering

① Whether flux and efficacy are quoted for the complete fixture or the light source — a 10–15% difference that changes the fixture count. ② Whether colour temperature and CRI are measured or nominal values; mixed CCT within one batch is the most common arrival dispute. ③ Driver brand and model, plus its derating curve at high temperature — it is the only part that really sets life. ④ The mounting kit list: chain, bracket and anchors in the box, or the site stops for a day.