Unified Glare Rating (UGR): Why Is It So Important?
In response to the technology-driven world, optimal lighting in educational and working environments cannot be overlooked. Glare can best be described as excessive brightness or discomfort caused by luminaires. Excessive glare holds the potential to disrupt concentration and strain the eyes, potentially amounting to welfare issues and an overall decline in productivity and well-being. To address the issue of glare, the concept of Unified Glare Rating (UGR) has emerged as a valuable metric in the field of commercial lighting design, and it is a crucial consideration when creating a lighting design for working environments. In this blog, we’ll delve into what Unified Glare Rating is, the UGR range, its importance, the types of glare and how it can be reduced in different environments. Please note, when selecting lighting solutions for educational and office environments, it’s essential to consider all factors beyond glare, including performance, lighting level, comfort, colour rendering, uniformity, direction, colour, shadow and ambience. What is Unified Glare Rating (UGR)? Unified Glare Rating, typically referred to as UGR, measures the intensity of glare produced from a luminaire within a given space. While there are recommended universal UGR guidelines from specialists, there are no legal requirements. The level of UGR ranges from 40 (high glare) to 5 (low glare). The lower the UGR, the better. A recommended UGR range typically falls between 16 and 19 for office and educational settings. However, this range should be approached as a guideline rather than an absolute rule. It’s important to recognise that the optimal UGR can vary depending on influencing factors specific to each environment, and therefore, UGR should be used intelligently with an understanding of the unique characteristics of each surrounding. Educational spaces may have distinct UGR requirements, considering the diverse activities carried out within classrooms and lecture theatres. But in comparison, specific environments, such as offices and retail spaces, may require unique UGR considerations to cater to particular tasks and user needs. UGR glare can be evaluated using two distinct avenues: glare tables or lighting design software. While glare tables provide an elementary grasp, lighting design software offers a more accurate calculation and meticulously calculates optimal luminaire placement based on the purpose and occupancy of the space in real life. At Mount Lighting, our professionals use advanced lighting design software to ensure accuracy across all our evaluations. Why is UGR important? There are several reasons why UGR is considered important and crucial to consider during the lighting design stage, including: Human Well-being and Comfort Suitable UGR helps ensure that an educational environment is comfortable and visually pleasing for students to learn in. Keeping glare to a minimum helps to prohibit discomfort, eyestrain, headaches and more, ensuring comfort for light recipients. Productivity and Performance Reducing glare and ensuring appropriate UGR levels can increase concentration levels, reduce fatigue, and increase overall productivity and performance. User Satisfaction Providing a working environment that is designed to meet fundamental needs helps to contribute to occupant satisfaction and well-being. What Types Of Glare Are There? There are two types of glare: directed and reflected. Each of these types of glare can impact the user differently. Direct glare is where the occupant looks directly into the light source, whereas Reflected glare occurs when light rays bounce off a glossy or reflective surface. This surface can be either vertical (screens, etc.), or horizontal (desk surfaces, for example). We also refer to glare in different levels of seriousness, “Disability”, and “Discomfort”. Discomfort glare may not impair vision but, instead, will cause discomfort through visual strain or irritation due to a noticeable difference in brightness levels. In comparison, disability glare is where the light source significantly reduces visibility and prevents the occupant from being able to see clearly. How Can Glare Be Reduced? There are, however, ways to reduce glare from luminaires, including: Beam Angle Lighting beams play a significant role in reducing glare. By carefully controlling the direction and intensity of a luminaire’s beam, you can direct light where it’s needed without causing discomfort to the user. Surface Reflectivity The interaction between light and surfaces can sometimes lead to unwanted reflected glare. This occurs when light bounces off surfaces. However, it’s possible to effectively minimise glare by ensuring surface uniformity and consistent luminance while maintaining the same lumen output. Visibility Luminaires that are visible to the eye can amount to glare and cause discomfort. Shading and shielding light sources prevent the harsh, blinding sensation that often accompanies glare. Output Putting systems in place like Casambi can assist with choosing appropriate output and contribute towards reducing the amount of glare. Intelligent lighting controls like Casambi are integral in enhancing the human-centric aspect of lighting, providing automatic control over lighting levels. Designed to interact with natural light that comes through windows harmoniously, Casambi delivers additional light where needed, all while skilfully maintaining suitable UGR levels. Luminaire Placement Placement of a luminaire is often an effective technique to minimise glare. Each space will have an appropriate height and angle for where luminaires should sit, which can help prevent light from directly hitting the line of sight. In particular environments, such as classroom reading areas and workspaces, this is especially important. Ambient Light Incorporating natural or diffused light sources with artificial lighting can reduce light and shadow contrast, lessening glare and supporting a more comfortable and harmonious atmosphere. Experience Enhanced Comfort With UGR Compliant Lighting Solutions Our specialists at Mount Lighting understand the implications glare can impose, especially on the educational sector. With our UGR19-supportive products, light the way to a glare-free school environment. Contact our lighting design specialists for a brighter, more comfortable learning space. Mount Lighting produce a wide range of low-glare lighting products including: Lens-Line – Surface or suspended Linear LED Blade – Suspended direct/indirect LED panel LEP32LG600– recessed LED panel Sonic – recessed downlight Enforce – surface or suspended downlight The Lens-Line linear LED range is incredibly energy efficient and holds the Made in Britain mark as it is manufactured in Britain by Mount Lighting. If you want to learn
Attracting Employees Back To Work Through Office Lighting Design
Where are you reading this post from now? Are you at home? At work? Perhaps you are in the office? Where once we could assume the majority of workers would be on-site for their jobs, our post-pandemic world has left us with a rather different working landscape. COVID-19 has forced us to adapt to many situations we could not have foreseen, and one of the lasting outcomes of this has been the massive shift in working patterns and environments. According to The Office of National Statistics, levels of flexible or hybrid working have greatly increased, with many now choosing to work both from home and their offices, with as much as 84% of workers now planning to carry out hybrid working. No doubt coming together in a working environment can offer benefits that working from home can not, such as improved work-home life balance, a more structured workday and the benefit of social interaction and in-person collaboration. But with this renewed sense of work autonomy, how can we ensure that people want to return to their offices? And how can we boost their productivity and well-being once back in the workplace? It may surprise you to know that efficient, effective lighting is a huge part of the answer. This blog will shed some light on how our bodies respond to lighting, and how we use efficient, human-centric lighting and wellness design to ensure those dark days are lit a little brighter, and that people benefit from coming back to the workplace. Download our workplace lighting guide What are Circadian Rhythms? There is a significant link between our internal body clock, or “circadian rhythm”, and lighting. Our energy, mood and well-being are driven by these rhythms, which in turn are impacted by not only how much light we are exposed to, but the quality of it. Our circadian rhythms are internal processes that regulate our bodies. They aid us with our sleep-wake cycle and coordinate our physical, mental and behavioural systems. The word circadian comes from the Latin meaning, “around a day”, as these processes work in 24-hour cycles. Not only do they remind us when to wake up and when to sleep, but they also impact our physical well-being and mental health. If these systems are thrown off, our body may not function as effectively as it should. Our rhythms are highly sensitive to many external factors, and everything from sun exposure, exercise and caffeine, to our phone screens, daytime naps and light-night TV can alter our circadian rhythms, impacting our quality of sleep, productivity, and day-to-day functioning. Modern life throws up constant challenges for our bodies, but healthy lighting can be aligned to natural human circadian rhythms to help aid healthy sleep and functioning, and improve alertness. We can certainly use lighting, automated lighting and wireless lighting controls to help attract employees back to work and offer them benefits they would not find at home. Lighting to Enhance Wellbeing in the Workplace Productivity and overall wellness in the workplace can be boosted by providing optimum working conditions for your workforce. Poor office lighting can send confusing signals to our brain, disrupting our internal body clock, and leaving us feeling sluggish, unfocused, and unable to sleep properly. A balance between natural light and artificial lighting can aid healthy functioning. However, sometimes natural lighting is not accessible, so then a solid lighting strategy is needed to restore balance. Differing levels of illumination in different environments all have an impact, and it isn’t as simple as adjusting light brightness. Colour temperatures, timing and the quality of the light all have effects. Some are subtle, and some are apparent, but all these elements work together to provide different effects. Unified Glare Rating (UGR) refers to how bright a luminaire is compared to the background illuminance, as well as the viewing angle for the user. The guidelines from The Society of Light and Lighting, state that office spaces should comply with UGR standard of 19 or below. This is especially important in office spaces, where employees spend many hours a day without natural lighting, often working from screens and needing to focus for long periods. Too high a UGR, or too much glare, can cause headaches and problems with eyesight, whereas too low can cause visibility problems and trouble focusing. Unfortunately, it is not as simple as simply choosing low glare/sub UGR19 lighting and installing it. While the UGR may be low, the actual quality and performance of the light are impacted by the dimensions of the space being lit, how the light is distributed, and properties such as how reflective the surfaces are. In fact, how the lighting interacts with the space is just as important as the strength of the luminaires. Our experts at Mount Lighting have the professional expertise needed to ensure you need not fret about these technical details and can rest easy in the knowledge that we have all the science covered. Our Products for UGR Applications Our products are always designed with your well-being in mind. Our versatile range of low-glare lights conforms to these guidelines and doesn’t compromise on style. Using a specialised microprismatic diffuser, the UGR levels are kept low, and our long-life LED solutions, from suspended lighting to recessed models, ensure that there is a solution to any space or need. As part of our suspended LED lighting range, our M-Line 54 is versatile and stylish, can be crafted to your preferred lengths, and have bespoke shape and colour options to suit any space. Perfect for office spaces, they have dimmable and emergency options or Casambi wireless controls give you more oversight over your lighting- you are totally in control. The Lens-Line range has a low carbon footprint and high energy efficiency, making it our most sustainable linear lighting option. It can be surface mounted or installed suspended and is super efficient at 195 Lumens per Watt. DISCOVER THE LENS-LINE Also available are recessed LED options, which can create an illusion of a larger space
Dimming Types Explained
DALI DALI stands for Digitally Addressable Lighting Interface. DALI is a recognised standard employed by all ballast manufacturers that offer DALI ballasts. This system assigns an individual address to each luminaire i.e. 001, 002, 003 and so on, allowing control of each individual luminaire. All luminaires can be controlled from a central desktop PC, and can be manually over-ridden at a wall switch, or can be used in conjunction with a daylight or occupancy sensor. DALI can offer two-way communication between the luminaire and the PC which provides valuable information and reports such as operating status of individual luminaires. DSI DSI is Digital Series Interface and is a more controllable version of digital dimming. This enables the user to group luminaires, operate daylight linked dimming and other controllable options. DSI is a Tridonic name and can be set up with a variety of control options and controllers, some offered by other manufacturers designed purely to work with the DSI ballast. DSI ensures that there are no issues with interference from the switching and the dimming of the luminaire which can affect switch on. DSI is wired using a dimming pair, run around to each luminaire in the circuit. ANALOGUE DIMMING Analogue dimming is known as 1-10v dimming. This is because the ballast produces a 1-10v DC supply that can be increased or decreased by a potentiometer, which can be either rotary or slider control. This DC supply can be increased or decreased by the switch to affect the resistance and hence the amount that the lamp is dimmed. Analogue dimming requires a ‘dimming pair’ of cables to be run around to each luminaire in the circuit. Switch Dim/Touch Dim This is the simplest option for digital dimming and is operated via a ‘push to make’ or retractive switch, which is then wired to each luminaire in the circuit via a 4 core cable consisting of switched live, neutral, earth and permanently live. The switch controls the switching on and off of the luminaire, and also the dimming. When the switch is pressed and held it will dim down. Another press and hold will dim back up. A momentary push will switch off and also bring back on. There are no issues with interference from the switching and the dimming of the luminaire which can affect switch on. DSI is wired using a dimming pair, run around to each luminaire in the circuit. Comparison Table of All Dimming Types GROUP SUB TYPE DESCRIPTION / HOW IT WORKS CABLING REQUIREMENTS CONTROLLER REQUIREMENTS NOTES Mains / Phase Dimming Leading Edge Consists of adjusting the leading edge of the mains power sine wave. Standard live neutral earth Dedicated phase dimming controller such as a rotary dimmer, or a Lutron-style system with phase dimming outputs. Mains / Phase Dimming Trailing Edge Consists of adjusting the trailing edge of the mains power sine wave. Commonly used for LED bulbs Standard live neutral earth Dedicated phase dimming controller such as a rotary dimmer, a Lutron-style system with phase dimming outputs, or a Casambi TED. Mains / Phase Dimming Adaptive Consists of adjusting the mains power sine wave Standard live neutral earth Dedicated system with autosensing of load type, and capability to provide either leading or trailing edge dimmed supply. Analogue 0-10v Consists of a DC voltage control signal between 0-10v, which corresponds to the desired brightness. Used in older drivers, not very common any more. Standard live, neutral and earth, with extra two core cable for positive and negative 0-10v signal, to each group of loads that require unique dimming. Dedicated system with 0-10v output for desired drivers. All drivers connected to that cable will get the same signal. Some systems also provide a relay to power down the driver at 0v to avoid it staying on at low brightness. Theoretically any number of drivers can run from one signal, but voltage drops in long lengths of control cable can lead to inaccurate dimming signals. Future proofing is difficult as cable can carry only one signal. Digital SwitchDim / TouchDim The simplest form of digital control, using an additional mains wiring core to dim up or down Standard live, neutral and earth, with additional live core to driver for dimming signal. Retractive switch to send mains signal to the driver. Digital DSI DSI stands for Digital Serial Interface was the precursor to DALI, developed by Tridonic in Austria, and consists of a digital signal to all connected drivers, with a dim level. This enables the user to group luminaires, operate daylight linked dimming and other controllable options. Not commonly used, as superseded by DALI. Standard live, neutral and earth, with additional two core cable to the driver for the dimming signal. Dedicated system with DSI output. Digital DALI DALI stands for Digitally Addressable Lighting Interface. DALI is a recognised standard employed by all driver manufacturers that offer DALI drivers. This system assigns an individual address to each luminaire i.e. 001, 002, 003 and so on, allowing unique control of each individual luminaire. DALI can offer two-way communication between the luminaire and the master controller which provides valuable information and reports such as operating status of individual luminaires, emergency lighting etc. DALI is an open protocol managed by the DALI Alliance, so any device manufacturer can certify their products to the standard. Standard live, neutral and earth, with additional two core cable to the driver for the dimming signal. Dedicated system with DALI output such as Tridonic SceneCOM or SceneCOM S. A DALI system is arranged in groups of DALI devices, called loops. Each loop can contain up to 64 devices, whether these are lights, switches or other types. Digital DMX-512 DMX stands for Digital Multiplex and is another protocol used for addressing devices and giving them unique control signals. The signal is unidirectional, meaning it only travels in one direction – from the controller or first light, all the way to the last. DMX is an open protocol also. Standard live,