Q：What is the difference between a luminaire and a light source?

A:  A luminaire normally consists of a light source, an electrical device and the fitting. Without the electrical device or fitting, the luminaire is incomplete and the light source alone does not work.

Q: What is Acuity Brands like while compared to those lighting giants such as Phillips, Osram and GE?

A: Phillips, Osram and GE are great manufacturers of light sources in the world, while Acuity Brands is a provider of luminaires and lighting solution. Acuity Brands purchases the light sources from those companies and uses them for complete luminaires. Acuity Brands has a market share of 20% in US and it is a leading provider of luminaires to end users.

Q: What are the most common light sources?

A: Since Thomas Edison invented the first light bulb, the electrical light source industry has evolved through several generations. At the moment, the most common light sources are those listed below:

Incandescent bulb: it is the first generation of the electrical light sources human beings ever have, and it might be the one most persons recall in mind referring to light source.

Halogen Tungsten lamp: The MR16 bulb applies for spot lighting is a typical one. It is the result of the improvement from incandescent, both in lifespan and power efficiency. 

Fluorescent lamp: According to the physical shape, it can be divided into two categories, fluorescent tubes (T5, T8, T10) and compact fluorescent lamps (2U, 3U etc.). There is another fluorescent not so widely used which is called Induction. It is a fluorescent lamp without electrodes, by which improves the lifespan. 

HID: High Intensity Discharge lamp, which is most applied in industry. The members of this family include high pressure sodium lamp, mercury lamp, and metal halide lamp, which is in fact an improved version of mercury lamp.

Solid lighting: LED, or lighting emitting diode, is the most popular light source nowadays. It gives off light while electricity goes through a certain solid material. It is obviously the trend of the lighting industry. However it still has long way ahead before it finally prevails.

Q: What are the light sources suitable for industry lighting?

A: Incandescent and Tungsten lamps are phased out because of the low power efficiency.

  High pressure sodium and mercury lamps had been widely adopted in industry lighting for decades because of the relatively high efficiency, until replaced by metal halide. The reason is sodium and mercury lamps are way too poor in color rendering. Metal halides with good color rendering, are still popular in local plants. Despite the medium efficiency, low lumen maintain rate and short lifespan, it is a choice for some industries such as power plant and heavy industry.

Fluorescent tube (T5, T8, T10) is the light source with very high efficiency, relatively long life and good performance in light quality. It is suitable not only for industry apply, but for almost every fields as well.

The CFL (compact Fluorescent lamp) has an advantage of small dimension. In turn, it sacrifices the efficiency and lifespan. In industry cases the space for installation is usually big enough that, there is no sense to choose CFL rather than T5 /T8.

Induction lamp has an expected long life, but it has no comprehensive advantage over other light sources considering efficiency, light performance and cost. Because the induction lamp are usually very big in dimension, the luminaire has to be produced very big, which brings high the cost of the complete luminaire. Think of the long life of LED, induction might have a strong competition.

LED, with relatively high efficiency, long life, and most importantly, the instant on/off and dimming ability, is very suitable for industry use.

As a conclusion, Fluorescent tube T5/T8 and LED are the most suitable light sources for industry use. Metal halide, not so attractive in some cases, is still finding its application in some certain industries.

Q: What kind of light source does Acuity Brands’ industrial luminaire usually adopt?

A: The industrial luminaires of Acuity Brands adopt the T5/T8 fluorescent tube, CFL, induction, high pressure sodium/mercury, metal halide and LED. However, among them three kinds of light sources account for most parts: T5/T8, metal halide (PS) and LED. The reason lies in the last Q&A.

Q: Does Acuity Brands produce light sources?

A: Acuity Brands is a professional provider of luminaires and it does not produce light sources. Instead, it purchases light sources from credible brands such as Philips, Osram and GE, and use the light sources for complete luminaires.

Q: If we choose a high lumen per wattage light source, does it mean we will have a high efficiency lighting system?

A: The efficiency of a lighting system is determined by both the light source and the luminaire. In industry cases, the luminaire usually contributes more to the final efficiency of the whole lighting system.

Take the metal halide high bay for example, while the efficiency difference between two light sources may vary from 10%-30%, the efficiency affected by the luminaire can take up to 50% or more.

In fact, the available light sources for industry lighting are most standard products which do not have much difference in efficiency between each other, as long as they are the same type and in same wattage.  But the difference in efficiency between two luminaires can be huge, which leads to the drastic difference in the final lighting systems.

Q: Why there is such big difference in efficiency among different luminaires?

A: The difference in designing, raw materials and producing technics can affect the efficiency of a luminaire a lot. Produced by lousy process on low cost materials, the luminaire without reasonable designing probably has the efficiency as low as 50% or even less. That means half of the light emitted by the light source is wasted within the luminaire. As a contrast, the high quality luminaires have the efficiency more than 90% on average. They can distribute as much as possible the light to the area it is required, and use as less as possible the electricity to fulfill the same lighting task. 

Q: Do the clients really take more advantage by choosing cheaper luminaires?

A: No. When a client is going to purchase the luminaires, he is indeed purchasing the “lighting” rather than mere luminaires. So it is more reasonable to evaluate different lighting solutions by their initial investment, the gross lighting provided, the yearly electricity expenses and the maintenance cost. The cheap cost of individual luminaire may not make sense in the long term.

Q: Does the payback by energy saving attractive enough for plants to implement lighting reform?

A: In most cases the payback is highly attractive. The reason lies in two facts. Firstly, the amount paid for lighting in most plants accounts for a considerably high part of the whole electricity expenses. Secondly, most local plants have been paying little attention to choosing the suitable lighting system. As a result, many plants have been working with those low efficient luminaires. The ratio of electricity saved by replacing those luminaires would be stunning.

Q: How long is the payback period if we replace our plant’s lighting system by Acuity Brands’ industry luminaires?

A: It depends on the efficiency of the incumbent luminaires, the frequency of lighting used, the electricity rates and the illumination level expected. On average, the payback of using Acuity Brands’ luminaires is within 1 year to 6 months, if the same illumination level is required.

Q: The LED luminaires are very popular. Are they excellent in energy saving?

A: The LED as a light source, has achieved 100-130lumen per watt or even higher. But take it in mind that this is just a lab data, which means the testing environment is favorable in all aspects. Once a luminaire is produced with LED, the thermal issue and the luminaire itself hinders the final efficiency. At the current stage, most of the LED luminaires (not the LED itself) on the market are working at 80-90lumen per watt at most. This is notably higher than that of a metal halide: 60-70luemn per watt (and if considering the efficiency loss of the metal halide fixture, it is 50lumen per watt around), but still similar to a luminaire with T5. That means if we only consider the power efficiency, LED luminaires, at least at this moment, are not so much superior.

However, LED luminaires are with longer lifespan. This can bring the use cost down, and the long term maintenance cost lower.

Furthermore, LED luminaires are suitable to integrate with digital controls, thanks to its instant on/off and dimming ability. Once and only after LED luminaires are integrated with intelligent controls, they turn distinct in energy saving without any doubt.

Q: As far as metal halide is concerned, isn’t it a low efficient light source? Why Acuity Brans is still using it for some of the luminaires?

A: Firstly, in some industry environment, such as high temperature and dust thick places, there is no other choice but only metal halide.

Secondly, the empression that metal halide low in efficiency most probably comes from the widely used low quality local ones. If working within a decent luminaire, which efficiently distributes the light and diligently disperse the heat, the metal halide high bay can perform better than expected. For instance, Acuity Brands’ PS metal halides are still popular in a lot of large scale plants.

Q: We have seen T5 fluorescents tubes being used in office, but never did we experience them use in high bay. Does your T5 high bay work properly in a workshop with high ceiling?

A: Three band T5 fluorescent tubes are great light sources. Even take LED into account, T5 is the light source with the highest efficiency (more than 100lumen per watt) and very good in lifespan and color rendering.

The T5 had not been used in high bay until a high output technology breakthrough took place. Before, T5 with 1.2 M length could not be produced more than 30W, which prevents it from being used in high bay. Now T5 high output is rated at 56W per 1.2M. With a specially designed luminaire to match, this power density can guarantee the excellent performance in high bay rang from 6M to 15M high.

Q: Does an industry luminaire have to be sealed up?

A: It depends on the environment the luminaire is applied. To prevent moisture and dust is the main purpose by which a luminaire is sealed. Most indoor industry luminaires do not have to be sealed up.

The sealed luminaires have negative impacts on cost, heat disperse ability and the efficiency. In cases where there is moderate dust, the benefit of sealed luminaires does not compensate the loss in efficiency. In general, the open luminaires have higher efficiency, better heat disperse and as a result, longer life.

Q: What is the difference between American standard and European standard metal halides? Which one is better for industry application?

A: Compared to European standard, the metal halides with American standard have the following advantages:

(1)    More safe to use in the open luminaires;

(2)    The starting current is smaller, and more adaptable to voltage fluctuation;

(3)    Longer lifespan.

In industry application, the robust and durable American is more suitable.

Q: What is the working temperature for luminaires? What is the potential effect if a luminaire works beyond the nominal temperature?

A: A luminaire works within the working temperature can perform excellently to the nominal specs, for example, the expected life.

A luminaire works out of the working temperature can shorten the life drastically. In practice, working under temperature 10 degree higher than nominal can shorten the life by half.

Q: Why a lot of luminaires do not indicate the working temperature range?

A: This by default means the luminaires are requested to work under room temperature: 25 C。