Lux Recommends: LED tubes

If you are considering replacing your existing T8 fluorescent lamps with LED tubes, you have two choices.

If all you have to do is replace the lamp and starter (and nothing else), make sure that the LED tube complies with BS EN 62776:2015.

If you need to rewire the luminaire, we recommend you don’t do it. I’ll explain why later.

There are thousands of T8 installations in the UK, some quite old and in need of refurbishment. There is also the increasing need to save energy. We tested LED tubes from six major suppliers. All the tubes were tested at the new LIA Laboratory in Telford.  We tested them for light output, wattage, power factor, colour rendering, CRI and colour temperature, CCT.

Note that most LED tubes are highly unlikely to be suitable for use in luminaires which are used for emergency lighting. Neither can most LED tubes be dimmed. The tube should carry some kind of symbol to this effect – see below.

Most of the tubes we tested had fixed end caps but some were rotatable. This means that the light emitted can be angled to direct it where you most want it. I.e. the LEDs do not simply point straight down.

Rotating them can be a bit fiddly since you have to adjust the end caps independently. It is much easier to do it at ground level than at height. End cap strength is part of safety testing to BS EN 62776:2015 so that is another reason to check that your tube conforms.

Retrofitting the lamp
The full title of BS EN 62776:2015 is ‘Double-capped LED lamps designed to retrofit linear fluorescent lamps. Safety specifications’. It runs to 34 pages of safety tests because there is a lot to consider.

By placing a CE label on the tube, the supplier is acknowledging that the product is safe and complies to the requirements of the Low Voltage Directive.

If your fluorescent lamp has an electronic ballast, you only need to swap the lamps. However, not all LED tubes are suitable for all HF ballasts. Some manufacturers, supply a ballast compatibility table.

If the fluorescent lamp has a magnetic or wire-wound ballast you will also need to replace the starter canister. No other rewiring should be required.

Note that this means that the wire-wound ballast remains in the circuit so it will still consume some energy. This may well affect the overall power factor depending on exactly how the existing luminaire is wired.
One of the tubes we tested has a flying lead that is fed straight from the mains and therefore bypasses the ballast.

We have only tested lamps suitable for magnetic or wire-wound ballast I.e. non-electronic ballasts.

There should also be symbols indicating suitability for HF or magnetic gear. The symbol for this should be clearly marked on the tube.

You should ensure that full, complete and unambiguous installation instructions are supplied with the LED tubes. After conversion, the luminaire should have a label stating that it is no longer suitable for fluorescent lamps. Most LED tube manufacturers supply a label with the instructions.

Rewiring the luminaire
If fitting the LED tube requires you to alter the wiring (other than changing the starter canister), then our recommendation is that you don’t do it. Instead, choose an LED tube that can be simply retrofitted, as above.

The main reason we advise against rewiring is that you then become responsible for the luminaire complying with the relevant safety standards such as BS EN 60598.
Hopefully it will never happen but if there were an accident of any kind, the original luminaire manufacturer and your insurance company would be absolved of any responsibility.
The LIA Laboratory advises us that this is still the case if swapping the starter and retrofitting an LED tube.

If something goes wrong with the magnetic ballast, even through no fault of the LED tube, the original luminaire manufacturer will deny any liability as they can claim the original product was not designed for LED tubes.

A final note about safety
When T8 LED tubes were first launched many years ago, there were serious concerns about the safety of some tubes where both pairs of lampholder pins became live once one pair was inserted in the luminaire. In this case, the free pins would also be live and could easily be touched by the installer before inserting them into the second end cap.
Most importers and suppliers of these tubes are aware of this and now only sell ‘single-end connection’ tubes. You must check that the tubes you are buying have a single end connection.

The LIA Laboratory can also provide a limited safety assessment if in doubt of safety risks.

What else should you check?

Has the space changed its use?
The first point to make is that the activities in a space and ways of working often change over a period of time. When changing the lighting, you should re-evaluate what the lighting needs are. Obviously, the new scheme should meet the requirements of EN 12464-1 for health and safety reasons, if nothing else. There is plenty of design guidance available from the SLL, ILP and other sources.

Don’t forget the walls
There is a tendency when energy saving just to consider the horizontal illumination but for many areas such as offices and corridors, the vertical illumination (how well you can see someone’s face or read a notice board) is as important. As a rule, most tubes emit light in a 120 degree downward cone. Some of the tubes we tested have wider angles and these will produce results more similar to fluorescent.

Glare
High power LEDs can be more glaring than a T8 lamp. If you think glare may be an issue, compare two luminaires side by side or run a glare calculation.

Colour rendering
It’s very easy to achieve high efficiency in terms of lumens per watt if you aren’t concerned about colour rendering.

Any CRI greater than 80 should be OK for most applications. It is worth pointing out that the Energy Related Products (ERP) regulations already state that indoor lamps and luminaires should have a minimum CRI of 80 so if it were less, the tube would not be CE compliant. All the tubes in this review have a CRI >80.

Life
As a general rule, an increase of 10C above the rated value of an LED tube (typically 25C) halves the life. If your tube is in a sealed luminaire, it may reach 30C or 35C, possibly more in the roof space of a high factory.

Symbols
The tube is likely to carry one, or more, of these symbols:

The tube should carry this symbol if it is not suitable for emergency lighting.

The tube should carry this symbol if it cannot be dimmed.
These symbols indicate whether the tube is suitable for a high frequency (HF) ballast or a magnetic ballast.

WEEE Compliance
Companies selling LED tubes onto the UK market must comply with the WEEE regulations.  These require producers to fund their share of the costs of recycling waste lamps.  Buying from WEEE compliant suppliers is vital, to ensure that these important environmental obligations are met.  Non-compliant producers risk enforcement and prosecution by the Environment Agency.

LIA Technical Statements
More details about all these aspects are in the LIA Technical Statement TS 14. For emergency lighting using LED tubes, the LIA will shortly be issuing a new Technical Statement ‘Guidance document on the re-engineering of fluorescent emergency luminaire with LED lamps’.

 

 

 

Kosnic

An advantage of this tube is that Kosnic claim it is flicker free. We tested the 4000K version and it is also available as Daylight 6500K. It has fixed end caps, non-rotatable, and the tube is glass rather than plastic such as pmma or polycarbonate.

It is good to see that the technical data and installation instructions are on the sleeve of each tube rather than a separate, easily lost, data sheet.

A good lamp for the price.

 

Mackwell LLL

This is a lot different from the other tubes in that each tube has its own 650mm long flying lead coming out at one end. You then feed the lead directly to the mains terminal block inside the luminaire. The lamp holder pins on the ends are made of plastic and so cannot transmit any voltage to the luminaire of ballast.  In effect, the tube is a luminaire within a luminaire. It has an aluminium spine and is double-insulated.

Another advantage of these tubes is that they use remote phosphor technology so the light is emitted over 260 degrees and the lit appearance inside the luminaire is much more similar to that of a fluorescent lamp.

Unfortunately, the lm/W is lower than the other tubes.

 

 

Osram from LEDvance

This Osram branded tube had the highest lumens/W of all the ones we tested. At 22W and 3,700 lm, it also had one of the highest light outputs. The glass tube has a PET coating which gives it splinter protection and Osram say this means it is suitable food industry applications.

The rated life at 60,000 hours is more than most and so is the maximum ambient temperature of 50C.

There is plenty of information on the datasheet about how many tubes can be supplied from a circuit breaker. The only thing that is missing is the beam angle.

 

 

Philips

At 25W and over 4,000 lm, this had the highest output of the tubes we tested. The rated life is 60,000 hours and the maximum ambient operating temperature is 45C.

The big advantage of this tube is that due to its unique (according to Philips) electronic design, it is suitable for magnetic, HF electronic and mains power connections. If you have a large estate or multiple buildings, you don’t need to purchase different types of tube.

Like some other tubes, the beam angle is missing from the data sheet.

 

 

 

Tungsram

Tungsram was formerly known as GE Lighting in the UK and Europe. We tested its Value Glass tube which is available in lengths from 600mm all the way up to 1.8m. This is a greater range of lengths than many other tubes on offer in the market.

An advantage of this tube is that the light is spread over 300 degrees so it has a very similar appearance and beam distribution as a fluorescent tube. The frosted glass also adds to the similarity.

 

 

Valtavalo

This had one of the highest light outputs and efficacies, lm/W, of the tubes we looked at.

It has an aluminium spine and due to the thermal design of the tube means that Valtavalo claim a life of 125,000 hours, L70B50 at 25C, and a seven-year warranty.

The other difference with this tube is that the tube is rotatable. You push the endcap outwards and you can click it to the angle you want. This is much more easily done at ground level.

The standard version will operate up to 50C and there is a high temperature version for up to 70C.

 

 

 

 

  • See the latest LED tubes at the LuxLive 2019 exhibition. The show takes place at ExCeL London on Wednesday 13 November and Thursday 14 November 2019. Entry is free if you pre-register. For more info, click HERE