This series of articles will look at the factors that influence the specification of lighting product, LED tapes and strips, in particular. We’ll be looking at reliability, cost and performance as being the three most important considerations for specifiers, installers and users. And we’ll also be investigating what each of those factors actually means when we talk about ‘reliability’, ‘cost’ and ‘performance’.
This is the second article, focusing on the Performance of a product. What does that mean?
We need to start by asking what we mean by ‘performance’. After all, everything that exists ‘performs’. Things do what they do, and if they don’t appear to be doing anything at all – well, that is still describes what they do. For good or ill, that becomes their ‘performance’.
In lighting terms, what we usually mean by ‘performance’ is the conclusion of a process that starts with a design intention and then following the development of that design until we end up with a product that meets those intentions. For us, performance isn’t something that happens by accident, it comes from knowing what we want to achieve.
So what do we want to achieve?
Like any shopping list, we tend to put the priority items at the top and for the lighting industry that has always been:
1 Energy efficacy
Energy efficacy by itself doesn’t deliver Good Light. For that, we need to go deeper.
The transfer of electrical energy into light has dominated lighting technology since the invention of the electric lamp. The current infatuation goes back to the energy crisis of the 1970s and has never gone away. The development of the ultra-efficient LED has fundamentally changed the way that light is created, yet we still focus on the single metric of luminous efficacy (lumens/Watt), to the detriment of other factors.
There is an inevitable trade-off between the quality of the light that is produced and the efficacy figure. The rule of thumb is that every +10 increment in CRI value will ‘cost’ 10% in efficacy values.
OSRAM considers and monitors the entire lighting value chain, providing high light quality for projects requiring that kind of delivery. To retain control over the light quantity v. light quality issue, OSRAM selects the appropriate LED chip for purpose, working within a double-test regime of both source and product that includes actual lifecycle analysis – not just relying on mathematical models.
2 Light Output
Any light source needs to be manipulated for it to deliver illumination as required by the product designer. LED chips are integrated into projector housings to create symmetrical beams of light; installed in rows to create linear light channels (a light pattern that is unique to the LED); or combined to create multi-toned light delivery (colour-changing or tunable white). Whatever LED arrangement, the light output will be affected by such integration. As we say above, this is not detrimental to light performance, but will always impact luminous efficacy.
Linear solutions bring their own issues. There is the issue of voltage control along the illuminated length to be considered. Without proper control, the LED chips will produce less light the further away from the electrical supply they are. This is a problem.
OSRAM ensures that the light delivery is consistent along the length of an LED strip. This is an essential feature of linear illumination. Consistent light can be achieved by using internal electronic IC* regulators that control the voltage along the entire length of an LED strip or by using external sensors, adjusting driver output to alter light output automatically over the product’s lifetime to ensure a Constant Light Output (CLO).
ICs = Integrated Circuit
OSRAM also understands the wide variety of application that LED tape can be used for, responding to market demand by offering a range of luminous flux of tape from 200lm/m to 4000lm/m.
And, at a more fundamental level, the quality of the materials used in the manufacture of the LED chips will also determine light consistency over time. OSRAM maintains a given quality of components to ensure product longevity.
3 Colour Output
Conversations around ‘light colour’ are very recent. For decades, we were limited to a small range of colours from fluorescent sources – and no options when it came to filament lamps. The LED has changed all of that. The process of adding phosphors to a (naturally) blue LED chip means that we can produce a far wider range of white tones (and colours). But the push for colour accuracy comes at a cost, as we discuss above. To achieve higher CRI/TM30 figures, there has to be a reduction in light efficacy from the LED chip. This is a consequence of building LEDs with Spectral Power Distribution (SPD) curves that mimic ‘natural light’; it takes more energy to create some of those wavelengths than others. It’s physics.
OSRAM is one of the few companies to control its phosphor process and produce light engines that range from 1800K to 6500K, as well as tunable-white products that offer dynamic colour selection.
Once we have a product that meets design requirements there is another question that needs to be answered; how long will it last?
This is not just a case of ‘how long will it work’. LEDs tend to deteriorate over time. They still continue to ‘work’ but the quality of their performance becomes seriously compromised. We may not be suffering the same problems with heat generation as we did previously, when up to 95% of the expended energy could be lost to heat, but localised heating takes place within the LED and that needs to be controlled and dissipated.
There are test standards that manufacturers should meet that will determine the operational life of a light source.
OSRAM designs good thermal management into its LED systems, having invested in many years of research into the best materials for achieving thermal transmission from LED chip to printed circuit board (PCB) or mounting surfaces.
The LINEARlight flex range provides L90B10 reliability at 60,000 hours usage, with guarantees of 5 years. Seven-year guarantees can also be provided.
5 Ease of installation
There is a space between design specification and handover to client that is often forgotten by the specifier. How easy is it for the contractor to install the product? What lengths has the manufacturer gone to, to ensure that the contractor can work efficiently with the product?
OSRAM has made sure that its LED tape can be cut effectively to length, as required. To provide the most practical product, LINEARlight flex tape has 50mm cut points and has designed unique ease-of-use connectors for the product.
But that’s not the end of the story. There are many ways that an installation can be destroyed during installation, all the way from a static charge ruining the LED to electrical connections being made the wrong way round. Damage can be catastrophic, causing a complete failure of the system, or can lead to ‘latent damage’ where the product appears to be OK, but which fails in a very short time. To avoid these potential problems, OSRAM builds SDT (Safe Dimming Technology) and ESD (ElectroStatic Discharge) protection into the circuitry to protect swapped terminations.
There is also a partner network that can supply LED strips already mounted into profiles, requiring only the cable tails to connect to drivers.
6 Ease of maintenance
There is a common assumption in lighting specification that amounts to a failing in due diligence. It’s not until the design is approved and the installation is complete that the real work of the product begins. The client wants to know that the installation is reliable and performs according to specification but, should something happen, how easy is the product to maintain? Regular maintenance may be limited to occasional cleaning, but has the product been designed to permit replacement in the event of a component failure?
OSRAM starts its work at the drawing board and continually monitors the quality of its product up to, and sometimes beyond, it arriving on site. Maintenance should not be an issue. If everything has been done according to plan, there’s no reason to expect a failure.
7 End of life repurposing.
Every product arrives at an end-point. It is here that good quality product stands out. An LED tape that offers 90% light output at 60,000 hours will last longer than many of its competitors. That works in favour of extending the useful life of a product, delaying ‘end of life’ for many more operating hours.
OSRAM provides a very reliable product, designed to last for many working hours. Nevertheless, appreciating that everything must come to an end, the company works with industry bodies to promote on-going improvements to legislation that will reduce materials entering the waste stream or lost to landfill. The aim is to secure a global system whereby lighting hardware can be re-purposed and renewed before there is any thought of materials being lost or recycled.
Osram LED products are at the premium end of what is available in the market. Their LINEARlight FLEX products contain many surface-mount components, such as constant current regulators, IC’s compatible with high frequency PWM dimming and other discrete diodes that will not be found on lesser quality flexible LED products.
To achieve the best performance it is essential to understand the importance of handling and installation of these products.
There are many benefits for assembling LED products in a clean workshop, rather than on a building site; it is a process that offers both immediate and long-term cost benefits to the client, across the entire lifetime of the installation.
This why Penn-Elcom joined with Osram as a value-added partner; to provide a pre-wiring, kitting, assembly and testing service for the linear LED product. Custom lengths of all types of LED flex are assembled in a purpose-built, fully equipped, ESD-safe, wiring facility in the Penn-Elcom factory at Hastings. With their many years of experience, the team is able to realise the specification for each project, delivering complete units, labelled and ready for installation.
In conjunction with the wiring shop, Penn-Elcom has an office-based team providing technical support for projects and Osram products, as well as a warehouse with a large UK stockholding of Osram LED products.
To contact Penn-Elcom: LED@penn-elcom.com
LINEARlight FLEX Uniformity
LED strip for high quality homogenous lighting
- Lifetime up to 60.000 hours (L90B10 at Tp, with SDT Technology acc to IES LM-80 and IES TM-21 standards, and also internal OSRAM LAB tests – we target ZERO failures even when if the LED strips operates dimmed for the whole lifetime.
- Dimming to 0.1%, using internal constant current regulators on each single cut unit, specifically designed for dimming with OPTOTRONIC® LED drivers.
- Light stability over time typically 1 SDCM, tested acc. to IEC 62717 @ 6,000 h.
High speed protection in case of accidental miswiring up to 25V, this 100% prevents latent damages of LEDs which might
shorten the lifespan.
- Testing: all performances measured and tested by an accredited Product Qualification Lab. ISO9001, ISO 17025, ACCREDIA, VDE; the photometric data are acc. to: LM-80 and TM-21, LM-79, EN13032-4, CIE S 025, IES TM-30-15.
- Standards: the products feature the certifications: CE, ENEC 10, EAC, VDE, CSA and UL-recognized.