For luminaires with integrated light sources, the luminous flux maintenance factor LLMF for the entire luminaire shall be determined. For lamps with non-integrated light sources, the luminous flux factor LLMF should be determined as the luminous flux maintenance factor of the light source (ie LED module). The luminous flux factor LLMF determined at the luminaire level will better reflect reality as it includes all components and operating conditions. Therefore, this is the default method for all types of fixtures. For LED luminaires, the luminous flux factor LLMF should be jointly confirmed according to the light source or luminaire replacement interval and the luminaire supplier’s IEC 62722-2-1.

Why is a maintenance factor required? Because in the process of use, due to the light decay of the light source, the decrease of the light transmittance of the reflector/refractor/light-emitting surface of the lamp, the pollution of the environment to the lamp and other factors, the light output of the lamp will definitely attenuate, and the lighting result will become worse. Br this we can know that the maintenance factor is in the range of 0-1, and when we design, we should appropriately increase the design value (increase the luminous flux of the lamp) to balance the overall light decay of the lamp in the future, so that the lighting result can meet the standard requirements. Because the standard stipulates the maintenance value instead of the initial value (design value), we need to determine the maintenance factor in advance according to the particularity of the lamp, the use environment, project time and daily maintenance, etc. The coefficient by which the design value is increased is the reciprocal of the maintenance factor. Therefore, the maintenance factor is an economic index, and the larger the value, the better, because under certain technical conditions, the efficiency of lamps (light sources) is generally close, and a certain increase in luminous flux also means a certain increase in investment costs. Reasonable determination of the maintenance factor is of practical help to the correct implementation of the project and project investment, so we must take the maintenance factor of LED products in the project seriously.

The actual maintenance factor of lamps in lighting simulation is affected by many factors, and its result is determined by lamp lumen maintenance factor, lamp survival factor, luminaire maintenance factor and room surface maintenance factor. The formula for calculating the maintenance factor for indoor lighting design is as follows. The calculation formula for outdoor lighting (except tunnels and underpasses) is similar, except that the room surface maintenance factor is not considered.

To ensure optimal adhesion in any process, you can choose between UV light curing adhesives and sealants with different characteristics designed to work with various substrates and processes. Both acrylic and silicone UV cure adhesives and sealants work effectively on a broad range of substrates, with each displaying properties to ensure manufacturers have flexibility in any application. In addition to acrylic and silicone UV adhesives, LED curing adhesives are also available, delivering a unique range of properties for manufacturers. This type of adhesive provides an alternative to conventional UV adhesives and sealants where substrates do not transmit in the UV wavelength. Additionally, outstanding optical clarity makes these adhesives an excellent choice within the optical industry.

UV adhesives and sealants are often found within both the medical and electronics industries, fulfilling a range of functions in manufacturing processes that require superior environmental resistance, wide operating temperature range, low shrinkage, and strong, tack-free finishes. However, they may also be used within industries such as:

This document is intended to help lighting designers apply reasonable MF values during the lighting design process to maximize the performance of LED luminaires. This will ensure that the provided solution will still provide the correct lighting level at the end of its useful life. At the same time, it will also be of great help to project parties and lighting designers, including implementing lighting projects in different places, better developing lighting, and better answering related questions, all of which will promote the vigorous development of the LED industry.

MF = LLMF (Lamp Lumen Maintenance Factor) x LSF (Lamp Survival Factor) x LMF (Luminaire Maintenance Factor) x RSMF (Room Surface Maintenance Factor)

Because maintenance factor is very important, we listed below the different street lamps and highbay lights with different MF in practical application, and how to optimally achieve the required lighting results with less energy consumption or fewer lamps.

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Since LEDs typically have no upward-facing surfaces and are typically enclosed, this reduces the surface area for dirt to deposit on LEDs. For example, IP Class: IP66, Pollution category: Low, Luminaire cleaning interval: 3 years, by consulting the corresponding table, we get that the maintenance factor of the lamp should be 0.9.

Lamp lumen maintenance factor (LLMF) represents the depreciation of luminous flux over time due to the aging of a light source or luminaire during normal operation (excluding external factors). This is defined as the ratio of the decayed luminous flux to the initial luminous flux.

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Example for checking luminous flux factor: When installation lifetime is 10 years with 4 000 burning hours per year, this results in a total of 40 000 burning hours for the full project. As the provide specifications only provide the depreciation for 50 000 h, the depreciation after 40 000 h can be estimated based on below formula. Using the reference specification of L80 = 50 000 h, the estimated luminous flux factor LLMF = 0.84

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Under the LOCTITE brand, Henkel offers a spectrum of high-performance, light curing medical device UV adhesives, specifically developed for use in the production of medical equipment and items such as syringes, catheters, and blood filters. These UV cure adhesives are tested with the same techniques used in the licensing of medical components and are certified in accordance with the generally accepted global ISO test standard 10993.

Used across a broad range of industries for their fast cure times and efficient application, on-demand curing delivers greater control during manufacturing processes. Additionally, with reliable adhesion and sealing in colorless to near-colorless curing, manufacturers can assemble consumer goods to meet high aesthetic standards as well as meeting various levels of compliance in the medical industry.

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Lamp Lumen Maintenance Factor LLMF, which describes the reduction in luminous flux of a light source over the duration of use.

The challenges faced by the medical industry are twofold. First, precision manufacturing processes require accuracy and speed when affixing substrates. Second, meeting high-level standards for compliance in medical facilities of all kinds is paramount. Medical grade UV cure adhesives rise to this challenge by ensuring fast curing and high resistance while also being manufactured to medical grade.

UV cure adhesives and sealants are flexible enough to be used across a wide range of industries. However, they are commonly found within components that use plastic and glass substrates. In particular, UV adhesives for glass, in both precision and decorative applications, allow manufacturers to easily bond materials with a high degree of control and in ultra-quick times through the application of the specified UV light range.

This article mainly describes the meaning of maintenance factor, its purpose, and the meaning of the four factors related to maintenance factor confirmation: Lamp lumen maintenance factor, lamp survival factor, luminaire maintenance factor and room surface maintenance factor, and how we should go to confirm these factors. From these aspects, we know that these are factors that affect the maintenance factor which cause the light decay of the lamp, as well as the IP level of the lamp structure, the degree of environmental pollution, the lifetime of the light source and the power supply. Generally speaking, lamps with high IP level and relatively clean environment which cause slower lamp pollution, good quality of LEDs and power supply. The higher maintenance coefficient, the less illuminance (brightness) that needs pre-compensation, and better economic benefits.

For more information on individual products and to discuss your specific requirements and application, contact us today and we will be happy to help.

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Room surface maintenance factor (RLSM) takes into account the depreciation of surface reflections. For indoor applications this refers to all relevant reflective surfaces such as walls and ceilings, while for outdoor applications this refers only to tunnel and underpass applications (this document does not cover, more information on tunnels and underpasses can be found in CIE 088:2004). For outdoor lighting (except tunnels and underpasses), the surface maintenance factor LSM is set to 1.00. Indoor surface maintenance factor LSF should be confirmed based on the principles described in CIE 097:2005. This factor is based on luminaire distribution, reflectivity of major surfaces (ceiling/wall/floor), environmental pollution category and surface cleaning interval. The confirmation of its maintenance factor can refer to the attached table CIE 097:2005, and we will not expand it here due to space limitations.

Survival factor (LSF), which represents the probability that a light source and/or luminaire will continue to function at a given time. This factor should be based on the type of replacement regime (spot replacement regime and group replacement regime). In practice, the point replacement system is the default system to ensure safety. However, point replacement needs to track each luminaire in the project, which is bound to be a huge waste of resources. If it is a group replacement, we need to share the life of each component of the lamp to determine the LSF. Due to the performance of LEDs, some projects will consider the chances of LED damage to be low, so will default this factor to 1.

Maintenance Factors (MF) are applied to lighting design to account for the reduction in output of luminaires used in any lighting fixture and to ensure that the correct light levels are provided at “end of life”. The MF calculation takes into account the depreciation of the luminaire and the impact of the environment on the installation, which is also applied to LED lighting. The method of calculating the maintenance factor is clearly specified in the lighting SLL specification. Since the structure and performance data of LED lamps are different from those of traditional lamps, the standard ISO_CIE 22012-2019 Light and lighting — Maintenance factor determination gives a detailed introduction to the calculation of the maintenance factor of LED lamps and the factors that affect the calculation of the maintenance factor.

A choice of photoinitiators allows you to tailor your UV cure adhesive to materials that only transmit visible light or only transmit UV light. This ensures you can easily bond all types of substrate in any application. It is simply a matter of choosing the right UV adhesive for your purposes.

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To choose the right UV adhesive, consider the photoinitiator system in the adhesive: UV-only or UV-plus visible. Then determine transmission characteristics of the substrate. If the substrate transmits visible light but not UV light (that is, is UV opaque), you cannot use a product that contains only a UV photoinitiator; a visible light photoinitiator must be present in the product. If the substrate transmits both UV and visible light, any source will cure a product, although the main concern is speed of cure, which is related to light intensity.

A maintenance factor shall be used in the lighting design to ensure that the luminaire will meet the corresponding lighting requirements throughout the agreed lifetime of the installation when the installation is maintained in accordance with the prescribed maintenance schedule. In the previous chapter, we introduced in detail the various factors that affect the maintenance factor. Here, we will give an example of the determination of the maintenance factor in practical applications, hoping to deepen the understanding of the calculation of the maintenance factor.

Luminaire maintenance factor LMF, which describes the effect of fouling of the luminaire optics between cleaning processes.

From this, we also know that when the same lamp is used in different installations, its input parameters are different, resulting in a large difference in the maintenance factor. Here maintenance factor and lumen maintenance factor are not the same concepts, we also need to consider other three factors, so that accurate maintenance factors can be obtained and implemented accordingly in the lighting design. If you want to know more, you can contact us at any time.

The continued miniaturization of modern electronics, alongside the predicted growth of automotive electronic systems such as ADAS, means that UV cure adhesives and sealants are perfectly suited to the industry. In particular, electronic displays that require stability and strength alongside excellent environmental resistance can benefit from the targeted application of UV cure adhesives and sealants during manufacturing. Additionally, smaller components such as speakers and microphones in handheld devices that require plastic bonding may also benefit from this type of adhesive, while printed circuit boards in other consumer electronics often rely on some type of light cure adhesion.

Offering an alternative to UV cure adhesives, LED curing adhesives do not require mixing and can be cured extremely quickly when exposed to an LED light source. In general, they are also more environmentally friendly and safer to use, while retaining many of the excellent properties of UV cure formulations. In some cases, they can also be used as gap fillers in thicker sections that standard UV cure.

UV cure adhesives and sealants are available in both epoxy and acrylate formulations, forming strong and reliable bonds when exposed to a light source after application. High transparency and exceptional stability, even in challenging environmental conditions, ensure that they are a reliable choice for manufacturers in applications using plastics, rubbers, ceramics, glass, and metal substrates. Additionally, they are optimally used wherever the precision assembly of components is required thanks to on-demand curing and setting.

For more information on individual products and to discuss your specific requirements and application, contact us today and we will be happy to help.

Light cure adhesives and sealants are selected over other methods of bonding and adhesion for a variety of reasons. Cure times are important in processes that require a high degree of accuracy, such as applications within the medical, optical, and electronics industries. Additionally, any component that requires high stability while retaining flexibility can benefit from the products within the Henkel catalogue.

Henkel works to balance the following features to ensure your specific application is covered regardless of your specific industry:

Luminaire maintenance factor (LMF) expresses the relative output of a luminaire due to the deposition of dirt on the light source, optics, or other components that affect the luminaire’s output. The luminaire maintenance factor(LMF) should be determined based on the three main factors of luminaire IP rating, environmental conditions and cleaning intervals as described in CIE 097:2005 (indoor luminaires) and CIE 154:2003 (outdoor luminaires). Here we mainly discuss how to confirm the maintenance factor of outdoor lamps (LED street lamps, floodlights) through the corresponding table. The structure and composition of LED lamps are different from standard lamps. The effect of dirt deposits is not as pronounced as with conventional light sources.

Single component formulations provide solvent-free adhesion while still curing in seconds when exposed to light. In general light cure acrylics are made of three components: the photoinitiator, monomer, and oligomer. Additionally, UV acrylic adhesives and sealants are selected for their highly flexible adhesion properties that maintain reliable adhesion to substrates such as ABS, Acrylic, HDPE (when treated), PP (when treated) and more.

My name is Taylor Gong, I’m the product manager of ZGSM Tech. I have been in the LED lights industry for more than 13 years. Good at lighting design, street light system configuration, and bidding technology support. Feel free to contact us. I’m happy to provide you with the best service and products.

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Solvent-free silicones that combine ultra-fast curing speeds with excellent temperature resistance, UV cure silicones are available in a range of viscosities to ensure flexibility across a broad range of applications. Additionally, being highly resistant to oxygen, ozone, UV light, aging, weather, and chemicals, it can be relied upon in a range of challenging conditions on a variety of substrates.

The maintenance factor in the lighting simulation is the product of the room surface maintenance factor and the lamp maintenance factor, the lamp lumen maintenance factor and the lamp survival factor, that is, MF = RSMF * LMF * LLMF * LSF. Approximate values over time can be, outdoors, the maintenance factor of lights is 0.9 (sports court), 0.8 (road) or 0.7; indoors, a very clean room, is 0.9, and a too dirty environment, is 0.8 or lower. If you need accurate values, you need to know the exact values of these 4 factors.

The room surface maintenance factor RSMF, which describes the deterioration of the utilization factor due to the reduction of the reflectance value of the room boundary surface.

For more information on Henkel’s UV adhesives download the respective PDFs for our catalogue of products here. Alternatively, contact us today for more TDS and SDS sheets or to learn more about our specific LOCTITE® products and how they can enhance your manufacturing processes.

Tables C.1, C.2, C.3 and C.4 of indoor Luminaire maintenance factor are shown below, and outdoors are shown in table 1. Indoor Surface maintenance factor, see CIE 097:2005 or contact ZGSM for more details.

Henkel’s UV cure adhesives and sealants are utilized in a number of industrial applications because of their excellent properties, including speed of cure and exceptional stability. These and other benefits have made LOCTITE® products the UV cure adhesive answer of choice for prominent manufacturers around the world.

Example for checking survival Factors: When a project uses group substitution, individual components need to be checked. During the service life of the luminaire, the failure rate of the light source is 1%, which corresponds to 0.8% within 40000 hours of installation life (probability of failure Pf = 0.8/100 = 0.008), which corresponds to a probability of survival Ps of 0.992 (Ps = 1.0 – Pf = 100 – 0.008). The LED driver has a failure rate of 1% every 5000 hours, which corresponds to an overall failure rate of 8% at 40000 hours (probability of failure Pf = 8/100 = 0.08). This corresponds to a survival probability Ps of 0.92 (Pa = 1.00 – 0.08) over the lifetime of the installation. Since the driver has the lowest probability of survival, the survival factor LSF = Ps = 0.92.

LLF is short for light loss factor, which is the loss of all light output after a certain time. Combined with the previous concept of maintenance factor, we can know that they are two identical concepts, which are now generally called maintenance factor. The cost of equipment maintenance and repair is greatly affected by this factor, so in order to reduce the overall equipment maintenance and repair costs, we need to pay attention to this factor.