What Does Maintenance Factor Mean?

When it comes to buying LED lighting products for an industrial or commercial facility, there are various factors to consider. Among all of them, Lighting Maintenance is a significant factor. Warehouse owners not only want to save money, they want a light that’s reliable and requires little maintenance. That is why they would switch to high bays in their facility.

The Maintenance Factor, or MF, refers to the lighting design that results in the yield reduction of the luminaries employed within a lighting installation. This factor assists in accurately predicting and ensuring the right lighting level are being distributed at the lighting fixture’s end of life.

In order to calculate the Maintenance Factor, lamp depreciation is considered. It also considers the impact that the environment is going to have on the lighting installation. If you have heard about LEDs before, you may already understand that these lights have a lower lumen decline and a longer lifespan than other bulbs out there.

As Maintenance Factor standards were premeditated before LED lighting became prevalent, they need slightly diverse calculations as compared to other kinds of fixtures.

Maintenance Lighting Plan

Maintenance Factors (mf) for LED Lighting Solutions

The way elements that are included in the MF calculation are employed; an LED luminaire is quite different from the traditional source luminaires. This is because of the intended design of LED lighting options and the performance statistics for LED luminaires.

As with other bulb types, the MF for LED lighting solutions is a number. This number describes the lighting level or lumen reduction over time. Using this number, one can regulate how illuminated a place will be.

Also, one can plan an effective way of installing the lighting options. With the onset of LEDs, MFs have significantly increased over HID and fluorescent counterparts. This makes sense as LED lighting solutions were developed to be an effective option. These lighting options were so successful that they had to come up with a new method for measuring MFs.

Lighting must be developed for the needed light levels at its life’s end. The lumens significantly decrease over time of an average lighting fixture or light.

This is typical as no lighting options last forever, including LEDs. So, lighting standards like maintenance factors assist in selecting the perfect fixture for diverse places to maintain the right lighting levels.

How are LEDs Different?

As the MF standards were developed for conventional lighting solutions, they seemed outdated when assigned to LEDs. The main reason is that the baseline maintenance factor is 0.8. Lighting engineers use shorthand techniques for turning out specifications. However, there is a danger in comprehensively applying such abbreviated ways.

A 0.8 MF is a perfect example. It has become the standard. However, it does not reflect newer lighting technology. LED lights do not experience the same issues compared to other lights. Thus, LEDs shouldn’t be calculated with it.

Lighting MFs examine the concern that a lighting product’s output will gradually diminish over time because of dirt, lumen depreciation, failures, and other factors. The Maintenance Factor refers to a fraction of the entire light yield at the installation life’s beginning as the yield may fall eventually. This factor tells you how much lighting level you should increase at the beginning to stay ahead of the needed light over the installation’s lifetime.

Therefore, if the needed lighting level of a project over a lifetime is about 500 lumens, where the MF is set to 80 percent (or 0.8), then an initial 625 lumens need to be installed in that area. This is important for maintaining the required lighting level over the entire span of its lifetime.

Compared to other kinds of lamps, LEDs are not much affected by exterior factors. Also, the light produced by LEDs is of higher quality. Because of this, if you are employing LED lighting, then you can look for a lighting fixture that offers similar results with fewer lumens produced.

Scheduled Maintenance and Lighting Mf

As all facility managers know, planned maintenance is important for keeping the lighting options running efficiently.

A facility manager needs to determine how often they need to properly clean the luminaries and the room. Also, they should factor in daily equipment maintenance, such as lamp-changing requirements. Plus, it is important to strike a judicious balance between operating hours and maintenance.

Maintenance interferes with the daily activities of an organization. Not only that, but maintenance routines are even linked to expenses. More luminaries equal a long operation period without upkeep. A high frequency of upkeep cycles is equal to a high maintenance factor.

LED lifespan

Lighting Mfs are Pretty Crucial

When planning to install lighting solutions, the most significant consideration is the maintenance factor. The Society of Light & Lighting Code for Lighting remarks that a lighting plan needs to be developed with a global maintenance factor measured for the chosen lighting equipment, detailed maintenance schedule, and environment.

This means that if one takes into consideration all the factors carefully by planning an effective maintenance schedule, the lighting options will shine longer than on average.

A Maintenance Factor of Around 0.8 Isn’t Great for All Projects

Although 0.8 MF is a good factor, it is a rather arbitrary number, especially in the cases of LED lighting solutions. Having said this earlier, every lighting setting is different, and thus, each lighting project too.

It does not make sense if you are employing the same MF for a factory and an office space. This is because a factory has harsh lighting conditions with robust machinery, whereas offices are usually clean and calm.

For these reasons, it is believed that the MF needs to be changed to fit both the lighting technology and the circumstances. But how do you do that? The formula given below illustrates the measurements for the total MF of lighting indoors.

mf = (llmf X Lsf) X Lmf X Rmf

 

 

So, as you can see, the formula gets affected by various things. It doesn’t just depend on the lifespan of the lighting fixture that you are using. Later, we are going to discuss these points in detail. For now, the following are some details that can affect the MF measurements.

  • LLMF – lamp lumen maintenance factor
  • LSF – lamp survival factor
  • LMF – luminaire maintenance factor
  • RMF – room maintenance factor
  • SMF – surface maintenance factor

What Factors Have an Impact on the Maintenance Factor?

As stated above, LED lighting solutions feature the longest life. Also, they show less lumen reduction than other lighting types. However, the lighting level decreases with time, even with LED lighting options.

There are various things responsible for this, including fixture failure and dirty surfaces. However, the most significant thing to consider is that people can take relevant measures to reduce the effects of such external factors.

LED lifespan

Room Surface Maintenance Factor

This is a ratio of the surface reflectance after and before you clean. A room’s light level is reduced when it gets dirty. If its surfaces are not clean, light reflects less and gets lost more. So, this maintenance factor is lower when your room is dirtier.

Luminaire Maintenance Factor

This is a ratio of the luminous flux after and before you clean. It largely hinges on the design and construction of the luminaire as well as on ecological conditions. So, this maintenance factor is higher when your room is cleaner. While setting up your maintenance plan, take into consideration the luminaries’ accessibility.

Fixture Maintenance Factors

This is a ratio of the luminous flux or fluctuation at a particular time to a new bulb. It describes the light intensity’s reduction over time.

Fixture Survival Factor

This factor largely depends upon the lamp’s service lifetime. The lifetime of some lamps is reduced through frequent switching. If a bulb does not work, you need to decide about a group replacement or an immediate replacement.

The decision can be to replace lamps as a group. This is true in the case of very large galleries, where you require machines to reach the lights.

LEDs Should Outlive Your Expectations

This is a novel issue. However, it is not actually a problem as such. Having the wrong LLMF (Lamp Lumen Maintenance Factor) for finding the right maintenance factor features other benefits for an illumination project.

These benefits could be in the form of planning as per the client’s requirements. For instance, with such a long lifespan of LED lighting options, clients may want to consider them if they require a lifespan of 50,000 hours.

You may be wondering if it is a good thing when life is longer. However, if you are taking an office space on a lease for only seven years, then it is best to invest in a lighting solution that can last about 12-15 years.

So, in that case, we recommend you take a glance at the various other benefits that LED lighting solutions have to offer.

This is because even when you are spending your money on LED lighting options and vacating the area before these lights need replacement, you have already made your investment back many times over.

LED lighting solutions save a great deal of money on energy charges. Plus, they are often accompanied by rebates. Also, you are going to experience high-quality, bright illumination with a constant lumen output if you choose LEDs for your facility.

A Mf over 0.8 is Not Essentially Incorrect

If you are concerned about higher maintenance factor numbers, you should be. However, just because this number is over 0.8, it does not essentially mean that it is incorrect. This high figure can provide you with a more precise number.

It is unavoidable that in a project’s early stages, whether it is a refurbishment or a new build, engineers are frequently asked to work without all the details at hand.

So, it is unreasonable to always expect precise numbers. However, there are standardized methods to verify LSF (Lamp Survival Factor) and LLMF (Lamp Lumen Maintenance Factor).

Also, there is guidance available regarding how you can directly compare these two. There’s no solid reason why you should solely employ 0.8. It’s just that it has always been done that way.

On several occasions, illumination engineers that employ an exact MF of around 0.88, have their estimates turned back with a special request to employ 0.8.

This practice inspires everyone to use 0.8 MF as the industry standard. You should refrain from using this figure because it does not offer the complete picture. It can even lead to wrong predictions.

Warehouse LED

Poor Planning Wastes the Advantages of LEDs

So, as pointed out by the SLL Code of Lighting, the Maintenance Factor impacts energy efficiency greatly. If you specify excess light at the beginning of an illumination project due to inaccurate MFs, then the customer has to pay heavily for that through the electricity bills.

Also, light is referred to as low-hanging fruit in the universe of energy savings.

Examples of Lighting Maintenance Calculations

We understand why such detailed information could be very confusing. This is true especially when we discuss numbers. Below are some examples to show how you can calculate the Maintenance Factor or MF in diverse settings.

Also, this provides you with a nice depiction of how performing little things, like ensuring that you have a clean facility, can enhance lighting lifespan, and decrease maintenance requirements.

Open-plan Office (50 Employees)

Working hours: 5 days per week, 16 hours a day, 50 working weeks per year (4000 hours each year)
Office renewed after 10 years (40,000 hours total)
Lighting System: closed luminaries (IP40) LED lighting sources
Maintenance Factor MF:

MF =

Room Surface

Maintenance Factor (xm)

Luminaire

Maintenance Factor (xe)

Lamp Survival

Factor (x)

Lamp Lumen Maintenance Factor
  very clean room closed luminaire Good – no chance of damage LED luminous flux degradation over 50,000 hours
MF = 0.97 0.92 1 0.9

Total Calculated Maintenance Factor = 0.8

Factory Location (2000 Sq Ft) with LED Lighting

Working hours: 7 days per week, 18 hours a day, 54 working weeks per year (6,800 hours each year)
One renews the factory floor after 15 years (102,000 hours complete)
Lighting System: pendant closed luminaries (IP64) LED lighting sources

 

MF =

Room Surface

Maintenance Factor (xm)

Luminaire

Maintenance Factor (xe)

Lamp Survival

Factor (x)

Lamp Lumen Maintenance Factor
  dirty room closed luminaire (IP65) Good – no chance of damage LED luminous flux degradation over 100,000 hours
MF = 0.9 0.94 1 0.7

 

Total Calculated Maintenance Factor = 0.6

Same Factory Location (2000 Sq Ft) with HID Lighting

HID lighting sources
Lamp replacement every 2 years (13,600 hours) 

MF =

Room Surface

Maintenance Factor (xm)

Luminaire

Maintenance Factor (xe)

Lamp Survival

Factor (x)

Lamp Lumen Maintenance Factor
  dirty room closed luminaire (IP65) HID service lifetime HID luminous flux depreciation over 13,600h
MF = 0.9 0.94 0.84 0.65

 

Total Calculated Maintenance Factor = 0.46

LED Industrial and Commercial Lighting and Maintenance Factor

When we talk about lighting installations, the maintenance factor becomes a significant thing to consider. However, if you install LED lighting solutions, then this should not be your primary focus.

That’s because LED lights have a long lifespan with non-prevalent lumen reduction. So, these two factors are the most significant ones when you calculate the MF.

However, this does not mean that one should ignore the Maintenance Factor altogether. LEDs were designed specially to overcome and eliminate maintenance requirements.

Also, this is not the only factor that the Maintenance Factor considers. As stated above, the Maintenance Factor even considers the facility’s conditions, the housing of lighting fixtures, and the walls. So, all these factors affect the lifespan of a lighting option, including LEDs.

For these reasons, you should take some precautions while designing a maintenance plan for lighting installations. All the information should be accurate so that you can develop a precise assessment.

This begins when you select your lighting sources. As mentioned above, LED Lighting Modules are highly efficient and likely to not fail. Also, they provide long lifespans of about 50,000 hours to 100,000 hours. These lighting options go well with a variety of control features, such as photocells and dimmers.

All these factors can affect the Maintenance Factor rating. So, think carefully to make sure that you take everything into consideration. However, despite MF factors, LED lighting options are the perfect way for upgrading the lighting system in an industrial or commercial setting.

Dwayne Kula

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About the Author

Dwayne Kula is President of LED Lighting Supply. On any given day, Dwayne is writing content for the site and helps manage the marketing initiatives that are on-going. He has a Software Engineering degree and still dabbles in writing software for the company as needed. When not working, he enjoys spending time with his family, working out, playing the occasional game of golf and exploring New England.

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