Fluorescent to LED: office, shop floor and retail

The T8 fluorescent luminaire with an electromagnetic ballast sits in offices, retail floors, car parks, warehouses and production halls with ceilings up to 6 m. It is cheap, familiar and replaced more often than it seems. Below is a replacement calculation for linear LED luminaires, with numbers you can check.

What is installed now: T8 with ballast

• 4 × 18 W louvred luminaire. An 18 W lamp on a class B2 electromagnetic ballast draws 27.4 W (ballast efficiency 65.8% under table 17 of EU Regulation (EC) No 245/2009); four lamps make 108 W per luminaire. Flux 4 × 1,350 lm = 5,400 lm by the OSRAM L 18W/840 catalogue.
• 2 × 36 W louvred luminaire. A 36 W lamp on the same ballast draws 45.3 W, the luminaire 90 W. Flux 2 × 3,350 lm = 6,700 lm (Philips TL-D Super 80 36W/840); the lower bound by OSRAM is 6,200 lm.
• Class B2 is the best of the electromagnetic ballasts that were still permitted in the EU. Louvred luminaires from the 2000s carry these or worse, so 90 W and 108 W are lower estimates. With an electronic ballast a 2 × 36 W would draw 72 to 76 W.
• Depreciation: by 8,000 hours a T8 lamp must retain 90% of its flux (table 11 of the same regulation); rated life by catalogue is 20,000 hours. The flux out of a louvred housing is noticeably below the lamp rating, and with every year of dust in the louvre the gap grows.

What we replace it with and what you get

The Line series is a linear luminaire for suspended or surface mounting, mounting height 2 to 8 m, joining into a continuous run. The flux of Line Ultra 40W by the 2018 IES file is 5,600 lm at 40 W. For 95 × 95 mm grilliato ceilings there is Grilliato 30W: it has no IES file, its flux is calculated, and the calculator labels it that way.

• 4 × 18 W to Line Ultra 40W one-for-one: 108 W against 40 W, 63% less power; flux 5,400 against 5,600 lm, 4% more. A clean replacement with no loss of light.
• 2 × 36 W to Line Ultra 40W one-for-one: 56% less power, but flux 6,700 against 5,600 lm, 16% less. The calculator shows a warning. The real difference is smaller, because the lamp rating ignores the louvre and depreciation, but the count has to come from the calculation: either a denser run (1:1.5 gives 25% more flux at 33% less power) or Line 50W.

On 100 luminaires 4 × 18 W at 12 hours a day and 300 days a year, replacement with Line Ultra 40W removes 24,480 kWh a year: 38,880 against 14,400. At a tariff of 1,100 UZS per kWh including VAT (Cabinet of Ministers Resolution No. 243 of 15 May 2026) that is 26.9 million UZS a year and 6.8 kW of freed capacity. Payback at the price from the model card is about 17 months. You can run it for your own hours and count in the savings calculator.

The norm by room type

Fluorescent luminaires sit in rooms where the Uzbek building code ShNK 2.01.05-24 sets the target directly:

• office: 300 lx on the working plane at 0.8 m (app. 9);
• supermarket sales floor: 500 lx; self-service food store: 400 lx; sales floors of other shops: 300 lx, with Ra 85 or higher (app. 9, table 1, items 78 to 81);
• car park, parking bays: 50 lx on the floor (app. 9, table 2, item 2b);
• production hall, medium-precision work of visual task class IV: 200 to 300 lx (app. 1, table 1).

The maintenance factor for offices and sales floors is 0.71 (app. 1, table 3). The calculation for the room plan with these numbers is done by an engineer in DIALux; it shows that fewer runs are usually needed than there were louvred luminaires, because a continuous run leaves no gaps between points.

Example: a car park on 200 luminaires 2 × 36 W

An underground car park in Tashkent, ≈ 3,000 m², 3 m high, round-the-clock operation. There were 200 louvred 2 × 36 W, ≈ 18 kW, ≈ 45 lx on the drive lanes. 180 Line Ultra 40W were installed in a run along the lanes: ≈ 7.2 kW, ≈ 90 lx. Lumens by lamp rating were even higher before (≈ 1,340,000 against ≈ 1,008,000 by IES), but light from a run without gaps and without a dusty louvre gave twice the lux on the floor. Over a year at 24 hours and 365 days the difference of ≈ 10.8 kW is ≈ 94,600 kWh. The figures are estimates; we have no measurement record.

The Minamata Convention: a fact, not a prohibition

Under the amendments to the Minamata Convention adopted in 2022 and 2023 (restrictions on lamp types listed in the convention), the parties phase out the manufacture, import and export of linear fluorescent lamps: halophosphate lamps from 2026, tri-band T8/T5 lamps from 2027. In the EU, T8 lamps have been withdrawn from the market since 1 September 2023. Uzbekistan has not joined the convention, and there is no prohibition on fluorescent lamps in the republic. But lamps are made for the world market, and the range and price of replacement lamps will change regardless of local legislation. That is a reason to plan the replacement, not to fear it.

For state organisations there is a document of their own: Presidential Resolution No. PP-4422 of 22 August 2019 (clause 8(b)) has required LED light sources in buildings on their balance sheet since 1 January 2020. What goes into the tender pack is set out on the page for state customers.

Frequently asked questions

Can we just fit LED T8 lamps into the old louvred luminaire?

You can, but that is not an upgrade: the louvre and housing keep their efficiency, the ballast is either bypassed or keeps heating, and the flux out of the housing stays below the rating. A calculation to the norm for such a scheme usually does not add up, and a lamp warranty is not a luminaire warranty.

How many linear luminaires are needed instead of one 4 × 18 W?

At equal flux, one Line Ultra 40W per 4 × 18 W. The final count comes from a DIALux calculation to the room norm: runs are placed along workstations or drive lanes, and there are usually fewer of them than louvred points.

What about flicker?

An electromagnetic ballast at 50 Hz produces flicker that is visible on a moving tool. For work of visual task classes I to III, ShNK 2.01.05-24 limits percent flicker to 10%. The flicker value of our luminaires will appear in the data sheet after the measurement report; until then we do not state it.

What do we confirm with documents?

Flux from the 2018 IES files, a 3-year warranty, production in Tashkent since 2014. Savings and payback are calculated under the stated assumptions and are not guaranteed until measured on site.