Project: Detrez – LED light lines with tri-proof lights in a storage hall

In its 900 m² storage hall and workshop in Stokkem (Belgium), Detrez replaced 38 old twin fluorescent fittings with 38 LED tri-proof lights mounted in lines along the roof beams. The result works like a light-line system without the cost of a trunking rail: the light level rose from 300 to 480 lux, while the power dropped by 65%.

Project facts

Client	Detrez
Location	Stokkem, Belgium
Building	Storage hall with workshop area and mezzanine, approx. 900 m²
Completed	2026
Old lighting	38 × twin fluorescent fitting, 130W
New lighting	38 × LED tri-proof light 150 cm, 45W, 4000K
Mounting	6 m, mounting brackets on the roof beams, in continuous lines
Control	On/off
Illuminance	300 → 480 lux
Planning	DIALux light study

The starting point

Detrez uses its hall in Stokkem for storing materials, parking machines and as a workshop, with a steel mezzanine for extra storage. The hall was lit by 38 twin fluorescent fittings of around 130W each, including ballast.

Too dark and failing tubes

With 300 lux on average and several tubes burnt out, the light was too weak and uneven for finding materials and for work at the benches. Under the mezzanine and between the high racks, dark zones were common.

High consumption for what it delivered

Together the 38 fittings drew 4,940W. Fluorescent tubes also lose light as they age and need regular replacement at 6 m height, which means a lift every time.

The solution

Light lines without a trunking system

For long rows of light, a trunking system with a continuous mounting rail is a common choice. In a hall of this size, that rail is an extra cost and extra work. Here the DIALux light study showed that linkable tri-proof lights, mounted in lines directly on the steel roof beams, give the same even light line. The existing light points and wiring could be reused, with one LED fitting in place of each fluorescent fitting. More on when to choose which system in our guide to LED light lines and trunking systems.

38 LED tri-proof lights 150 cm

Each LED tri-proof light 150 cm of 45W delivers 9,000 lumen at 200 lm/W in neutral white 4000K. The fittings are mounted with brackets on the roof beams at 6 m. The wide 120° beam spreads the light between the racks and under the mezzanine, and the IP65 polycarbonate housing keeps out dust from the workshop. Because the fittings can be linked, one supply feeds a whole row. See our tri-proof light guide or all tri-proof lights 150 cm.

LED luminaire used in this project

Energy savings in figures

Every fluorescent fitting was replaced by one LED tri-proof light. The table compares the old installation with the new one.

	Old	LED	Difference
Luminaires	38 × 130W twin fluorescent	38 × 45W LED tri-proof light	−85W per fitting
Connected load	4,940W	1,710W	−65%
Load per m²	5.5W/m²	1.9W/m²	−3.6W/m²
Illuminance	300 lux	480 lux	+60%
Consumption per year	9,880 kWh	3,420 kWh	−6,460 kWh
Electricity cost per year	€3,063	€1,060	−€2,003
CO2 per year	1.5 t	0.5 t	−1.0 t

How we calculated this

• Old: 38 × 130W = 4,940W × 2,000 h = 9,880 kWh per year.
• LED: 38 × 45W = 1,710W × 2,000 h = 3,420 kWh per year.
• Cost: 6,460 kWh × €0.31/kWh = €2,003 per year.
• CO2: 6,460 kWh × 0.15 kg/kWh = 1.0 t per year.

The saving comes with 60% more light on the floor. Replacing tubes at height is no longer needed either.

Investment and payback

At current webshop prices, the 38 LED tri-proof lights cost €1,628. Half of the investment was covered by a relighting subsidy, leaving €814. With €2,003 lower electricity costs per year, that amount is earned back in about five months. Installation is not included in that figure, and no trunking rail had to be bought.

Calculate the savings for your hall

The calculator below is pre-filled with the figures of this project. Change the values to see what LED tri-proof lights would save in your own storage hall or workshop.

The result

• 60% more light: 480 lux instead of 300 lux, also under the mezzanine and between the racks.
• 65% less power: 1,710W instead of 4,940W for the same 38 light points.
• Light lines without a rail: even rows of light without the cost of a trunking system.
• No more tube replacement: no more burnt-out fluorescent tubes at 6 m, and 5 years' warranty on the new fittings.
• Lower running costs: €2,003 less on electricity every year and 1.0 tonne less CO2.

Frequently asked questions

Do I need a trunking system for continuous light lines?

Not always. A trunking system with a mounting rail is useful for long, uninterrupted rows or when fittings must be easy to move. In a hall like this one, linkable LED tri-proof lights mounted in lines on the roof beams give an even light line at a lower cost, without buying and installing a rail.

Can an LED tri-proof light replace a twin fluorescent fitting?

Yes. A 45W LED tri-proof light of 150 cm with 9,000 lumen replaces a twin 58W fluorescent fitting of around 130W including ballast. At Detrez that is 85W less per fitting, with 60% more light in the hall.

Are tri-proof lights suitable at a mounting height of 6 m?

Yes, for many halls up to around 6 to 7 m. With 9,000 lumen and a wide 120° beam per fitting, rows of tri-proof lights give even light between racks and under mezzanines. For higher halls, LED high bays are usually the better choice.

How are the tri-proof lights mounted on steel beams?

The fittings are fixed with mounting brackets directly on the steel roof beams. That keeps them in a straight line, close to the existing light points, so the old wiring can be reused.

Is there a subsidy for replacing fluorescent lighting?

That depends on the country and region. On this project half of the luminaire investment was covered by a relighting subsidy. We tell you which schemes apply to your hall and supply the technical data needed for the application.

Can you make a free light plan for my hall?

Yes. Send us the floor plan with the ceiling height, or a few photos of the current lighting. We make a free DIALux light study, work out how many luminaires you need and send a non-binding quote at direct-import prices.