A warehouse operator in the UK bought 180 units of 6ft LED linear batten because the listing said 6ft covers more area per fixture. He mounted them on a 3 metre beam grid, spaced them 3 metres apart along the beam, and walked the aisles on handover. The middle of each aisle was bright enough, but the shadow band between two 6ft units ran the full length of the rack. His consultant walked the site with a light meter and found 80 lux in the middle and 32 lux between fixtures. The job was rejected, and he paid for a second install. The mistake was not the fixture. It was the way he picked length.
The 3 Metre Aisle Mistake
Most buyers choose a LED linear batten the way they would choose a fluorescent tube: by length. The longer the tube, the more fixture they get for the money. This logic worked when every tube was 4ft and output 1800 lumens. It does not work in 2026, when a 5ft LED linear batten can put out 4500 lumens and a 6ft unit can put out 6500.
A 3 metre beam grid is the standard for warehouses built in the 1990s. When you mount a 6ft LED linear batten (1.8 metre) on that grid, you leave 1.2 metres of beam with no light directly under it. When you mount a 4ft unit (1.2 metre), you leave 1.8 metres. The dark band is the gap, and the human eye catches it instantly even if the average lux number on the spec sheet looks fine.
The fix is to work out the spacing, then pick the length. If your beam grid is 3 metres, a 1.5 metre LED linear batten (5ft) sits closest to the sweet spot. If your grid is 4 metres, a 6ft unit starts to make sense.
Lumen per Metre Beats Total Watts
The second mistake is comparing fixtures by watts. A 6ft 60W unit and a 5ft 45W unit do not deliver the same light per metre. The 60W fixture is putting 60W into 1.8 metres, about 33W per metre. The 45W fixture is putting 45W into 1.5 metres, about 30W per metre. The gap is small, but the lumen difference is what your customers see.
Ask the factory for lumens per metre, not just total lumens. A 5ft LED linear batten that delivers 3000 lumens per metre is a different product from one that delivers 2200 lumens per metre, even if both list 4500 lumens total. The first one will light a 3 metre aisle. The second one will not.
The number that matters for a warehouse target is lux on the floor. For a UK storage aisle, BS EN 12464 asks for 150 lux in the main aisle and 75 lux in racking. A spec sheet that lists only "5000 lumens" does not tell you what floor lux you will get. Ask for the photometric file.
4ft, 5ft, 6ft: When Each Length Wins
The 4ft (1.2m) LED linear batten is the right pick for corridors, stairwells, small offices and retail back rooms. It fits between standard ceiling joists, and two of them cover a typical corridor without overlap. Buyers in the UK keep ordering 4ft because it matches the old T8 grid.
The 5ft (1.5m) unit is the most versatile. It covers a 3 metre beam grid with the smallest gap, it fits in most UK warehouse bays, and it is the length most often quoted for a mixed office and warehouse space. This is the length we spec first.
The 6ft (1.8m) unit wins in high-bay warehouses with 4 metre or wider beam spacing, in production lines that need continuous light, and in retail aisles where shoppers walk the full length. It loses in a 3 metre grid.
Do not mix lengths on the same ceiling. A 4ft next to a 6ft makes the dark band obvious.
Surface Mount vs Suspended
A LED linear batten is usually surface mounted. It clips to the ceiling, hangs by two cables, or snaps onto a trunking rail. Each method changes the light angle.
Surface mount sits flush with the ceiling. This is fine for offices and corridors, but the light is trapped between the ceiling and the diffuser. Suspended by cables, the fixture emits light both up and down, which softens the shadows in a tall warehouse. Trunking rail mounting lets you join end to end, which is how supermarkets build continuous aisles.
If you are quoting a warehouse, ask the installer which mounting they will use before you choose the diffuser. A prismatic diffuser surface-mounted looks harsh; the same diffuser suspended 600mm below the ceiling looks fine.
Quick Answers
Can I replace T8 tubes with a LED linear batten? Yes, if the fixing holes line up. Most batten models come with end brackets that match the old T8 grid.
Is 6ft always brighter than 5ft? Per metre, not necessarily. Check lumens per metre, not total output.
Do I need a triproof rating for a dry warehouse? No. A standard IP20 batten is cheaper and lasts longer, because sealed covers trap heat.
What about cold storage? Use a sealed IP65 LED linear batten with a heater module, or the lens will fog.
Before You Order
Write these five numbers on your next RFQ, not just "5ft batten":
- Beam or grid spacing in metres
- Mounting height above the floor
- Target floor lux, 150 for aisle, 300 for packing, 500 for inspection
- Lumens per metre for the proposed length
- Mounting method, surface, suspended or trunking
You can compare warehouse coverage in our high bay buying guide, and check the office layout trade-off in our rectangular linear guide. Send the beam grid and target lux through our inquiry page, and we will match a 4ft, 5ft or 6ft LED linear batten to the actual aisle. When in doubt, contact our engineers; picking length by listing price is how a 180-unit order ends in a second install.
