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LIGHTING CONTROL GUIDE.
LIA Copyright © 2018. All information stated within this brochure is correct at time of publication – October 2018. www.thelia.org.uk
OBJECTIVES OF THE GUIDE
The aims of this guide are:
To provide an appreciation of the benefits of lighting controls
• To demonstrate that the benefits and abilities extend beyond electricity use reduction • To make the terminology of lighting controls more familiar • To inform those who are considering the use of lighting controls • To help match controls and light sources to ensure optimum results • To show where expert and reputable advice may be sought • To provide an introduction to a deeper understanding of the subject through training • To provide a decision tree to assist in the selection of the most suitable lighting controls
The creation of this guide would not have been possible without the valuable help provided by members of the LIA Controls Equipment Technical Committee (CETC).
Automatic lighting controls are often thought to be a dark art. In reality, they work in the background to manage the lighting without fuss.
You can rely on a number of reputable suppliers to sort out the details to suit your application. Just explain how, and when, your business works and they will design the best control strategy and system for your needs. www.thelia.org.uk
INTRODUCTION
This guide has been structured to give the reader a logical progression through the subject of lighting controls. The subject is divided into a number of sections, which are defined in the table below. Each section can be read independently, and links will guide the reader to any logical connections, both within this guide and to other relevant sources.
NAVIGATING THIS GUIDE Route to determine the control type for the application. EVOLUTION OF CONTROLS FOR LIGHTING This section provides the context for the guide and begins to familiarise the reader with the reasons for using lighting controls. It describes the origins of the solutions and products available today, while demonstrating that it is an established and reliable industry.
BENEFITS Lighting controls are not only provided to reduce electricity use; there are much wider benefits. They can be the means to deliver good lighting designs; to set moods and ambience. Controls ensure that the right light is provided in the right place, at the right time.
TECHNIQUES There are a number of ways to control lights; from simple wall switches to fully networked management systems. This section describes the various ways lights are controlled both manually and automatically; including daylight references and occupancy control.
APPLICATIONS Different building types and accommodation require different lighting control solutions. The most common applications are described and appropriate controls suggested. Sub- headings include offices, industry, schools, hospitality, museums, floodlighting and shops.
TECHNOLOGIES A brief technical description of generic lighting control products and systems is provided in this section. All the component parts of a lighting control system are introduced, including manual overrides, sensors, lighting control modules, software and interconnections.
STANDARDS AND REGULATIONS An overview of the standards, regulations and guides that are relevant to the specification, application and use of lighting controls. A number of links to Government and professional bodies are provided here.
GLOSSARY A dictionary of lighting and control terminology. www.thelia.org.uk
NAVIGATING THIS GUIDE www.thelia.org.uk
EVOLUTION OF CONTROLS FOR LIGHTING Lighting controls have existed for as long as we have had electric artificial lighting. However, today the term lighting controls is generally taken to refer to some form of electronic, or automatic solution, rather than the simple, mains ON/OFF switch. This section is intended to create a context for the understanding of lighting controls by explaining their origins, and how they have developed over time; both technically and functionally.
Lighting Controls - the two branches and how they came about
The first lighting controls can be traced to the theatre / entertainment world where there was a need to vary light output as well as to turn it ON and OFF. Initially largely manual in nature, theatrical controls evolved into highly complex systems and began to spread to wider - but related - applications. This branch has become known today as scene setting lighting controls. More recently - from the late 1960s onwards - automatic lighting controls entered the commercial built environment. The first systems were little more than an electronic switch that allowed the use of pushbuttons and extra low voltage wiring. The first energy crisis in the mid-1970s brought energy use in buildings into focus for the first time and gave purpose to this branch of the lighting control evolution - to reduce lighting electricity consumption. The two branches of lighting controls familiar to the built environment are, therefore: - Scene setting and Energy Saving
Dedicated theatrical control systems continued to evolve separately, but today they have returned to influence the main stream market.
In order to assist the designer to select the most suitable lighting controls solution for the application, a decision tree is provided for this purpose – follow this link.
Scene setting
The applications related to theatre lighting that led to scene setting lighting controls moving into the built environment were auditoria, lecture theatres and conference facilities. The term scene setting was derived from the fact that the systems generally allowed the user to select a specific lighting effect; normally by pushing one button. This action would set the various lighting circuits into a pre-set state - ON, OFF, or at a specific dimmed level.
These systems were usually manually operated and offered a wide range of static scenes - i.e. once selected the lighting remained fixed until another scene was chosen.
Scene setting systems also dictated the choice of lighting source because not all could be readily dimmed. Even today there are restrictions on certain light sources with respect to their control. These systems were seen to be an integral part of the lighting design and often specified by the lighting designer www.thelia.org.uk
Energy saving
The early systems developed to control the use of lighting electricity relied heavily on the use of localised switches overlaid with an automatic function that ensured lighting was turned OFF when the building was expected to be empty. These functions included day light levels and time of day.
Most of the early energy saving lighting control systems were retrofitted into existing installations and therefore had to be economical to install; they also only needed to be able to turn lights ON and OFF. Dimming had not yet become practical in the commercial building world. And, in stark contrast to the scene setting branch, energy saving lighting controls generally ignored the lighting design. Little or no notice was taken of the original design intent.
This was especially true when pull switches were fitted to individual fixtures, allowing staff to choose which lights were ON and which were OFF. The resulting ‘non-uniform’ lighting levels were the subject of much debate (back then) in the world of lighting designers.
The impact on the original lighting design was, however, somewhat relieved by the fact that most of these systems gave individual users far more control of their local lighting. This led to higher satisfaction being observed in affected staff, and avoidance of the design issue.
+25% +50% +60% +75%
No dimming Manual PIR + manual Daylight linked Daylight linked dimming dimming dimming dimming + PIR
Convergence
The two branches of lighting control began to converge when dimming became a practical element of the energy saving systems. The introduction of the dimmable high frequency electronic ballast for fluorescent lighting was the enabling technology.
As already mentioned, the past scene setting systems were all about dimming and levels and energy saving systems relied on ON and OFF commands. Now the dimming function was easily implemented in the building wide lighting controls; the basic functions of a light were no longer just ON and OFF but DIM or BRIGHT according to current need.
Convergence, DALI, DMX and LEDs
In the meantime pure theatrical lighting control had moved down its own evolutionary path and developed its own protocols; the most used of which is the DMX512. (See Sections 5 and 6.) This protocol was developed to allow theatres to buy stage lighting from multiple vendors and link it all to the ever more complex show control desks that delivered the lighting (and other) effects on cue. As a result the DMX512 protocol is a highly robust and dynamic control method. In a way two branches had become three; i.e. energy saving, scene setting and show control.
The arrival of LEDs onto the commercial lighting market has now brought the third way into the convergence of lighting control systems. LEDs came first to the theatre and early luminaires were all developed with DMX interfaces. As a consequence many of the evolved products moving into the commercial market continued to support this technology. As LED fixtures have become viable as commercial lighting solutions, the protocols from building lighting control systems have been adopted. DALI and IP (internet protocol) interfaces are to be found in both LED luminaires and drivers. www.thelia.org.uk
Integration and networks
The evolution of lighting control systems has involved many proprietary as well as open protocols in creating networks. With these diverse communication methods the question of integration to wider building management systems has been considered over the years.
The subject of integration is discussed in the technology section alongside the various network protocols and interfacing options.
Conclusion
Lighting controls today are now developing along a more flexible, but integrated path, with the idea that all the control needs of any lighting application can be met by a single system. From simple stand-alone movement sensors and time delay switches, through to full networked lighting management systems, controls can now meet the challenges of all types of lighting including LEDs. Functionally controls can now:
• turn lights ON and OFF • alter the intensity from dim to bright (where the light source is dimmable) • set scenes statically or dynamically • and with coloured light sources, change their hue and intensity
Add the fact energy saving lighting controls are practically required in order to meet compliance with the Building Regulations, and the importance of this technology to lighting design cannot be understated. www.thelia.org.uk
BENEFITS Lighting control systems of all types have been shown to deliver a number of real benefits, including:
• Energy saving • Safety and convenience • Installation cost reduction • Comfort, health and well-being • Flexibility of building use • Compliance with standards and regulations • Maintenance improvements
This section explains and quantifies these benefits with reference to case study material and other sources.
Energy saving
Energy saving lighting can be responsible for up to 40% of a building’s electricity use.
Lighting electricity use in commercial buildings can be successfully reduced if a control system can take account of available day light and ensure that no unnecessary lighting is kept ON. In early demonstration projects a number of case studies reported savings of 60% and more. This was achieved without such devices as movement sensors.
Most of these successes involved the addition of individual switches for most of the light fittings.
The savings realised by lighting controls can vary according to the application. Deeper floor plans, the extent of glazing, even the lighting layout can affect the end result. These variations will be explained by your supplier.
The use of such local switching arrangements meant that both occupancy levels and daylight factors were taken into account. In effect, staff had to make their lighting choice locally; and if they were not there, or there was enough daylight, then lights were not switched ON.
The later introduction of movement (or occupancy) sensors automated the local switching to a greater degree. Dimming technology has also brought new opportunities to reduce electricity use by adjusting levels to local needs, and preferences, as well as optimising levels for different tasks.
Energy -cons.(%) of Dimmings versus Fixed Output 110 100% with Fixed Output 100 90 80 70 60 51% Average with Dimming 50 40 30 20 10 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec www.thelia.org.uk
Installation cost reductions
In the mid-1980s some commercial lighting controls were integrated into the lighting installation in such a way that much site based, labour intensive, work was moved into the factory. This element of a lighting control system is not well understood, even today, and is often ignored when the construction project is priced.
Control systems have also dispensed with the power cable from every ON/OFF switch to the lights it controls. Instead separate power and switching control cables are used; a single control cable provides independent control of multiple luminaires fed from a common power cable. This reduces both the quantity of cabling required and the cost of installing it.
Flexibility of building use
The separation of switching from the mains supply offered by most lighting control systems provides a very cost effective route to making any changes as buildings are altered.
Devices like ceiling mounted movement sensors, extra low voltage local switches and/or remote control devices have all facilitated changes to lighting to match new partition layouts or changes in use.
Maintenance improvements
Some lighting control systems offer maintenance benefits through additional facilities and functionality. By ensuring lights are not ON when they are not needed the life of a lamp in situ may be extended. Some systems include monitoring features such as logging lamp hours run and control events.
Emergency lighting
There are legal obligations attached to the testing and monitoring of emergency lighting; lighting controls can, and do, help building managers to meet these obligations. (Ref: BS5266, BS EN50171, BS EN50172). www.thelia.org.uk
Safety and convenience
The ability of a networked lighting control system to relate the status of (e.g.) corridor lights to office lights means that safe exit routes can be maintained whenever staff are present. This facility is often referred to as the corridor hold function. In certain applications the automatic response of a movement sensor can aid convenience when entering a space with no natural light.
Comfort, health and well-being
Research into buildings equipped with full lighting control systems has demonstrated that those with most convenient and numerous user overrides contain the most content staff and use less lighting electricity. (Ref: Carter, Moore and Slater)
The comfort is derived from the fact that the staff feel they have more control over their environment.
A new interest in developing lighting to promote greater alertness, health and wellbeing in the work place may, in future, rely on controls to deliver the best solutions. New lighting concepts involving both illumination levels and diurnal variation of the colour temperature can only be delivered by using automatic lighting controls.
Compliance with standards, regulations and ratings
Compliance with standards, regulations and ratings.
Lighting controls are able to help the designer to meet obligations found in both standards and regulations. The following list covers the most relevant:
Building Regulations: • Approved Documents L2A and L2B (England and Wales) • HSG 38 • BS EN 12464-1 Lighting of indoor workplaces • BS EN 12464-2 Lighting of outdoor workplaces • BS EN 5266 Code of practice for the emergency escape lighting of premises • BS EN50171 Central power supply systems • BS EN 50172 Emergency escape lighting systems • BS EN15193 Energy performance of buildings – requirements for lighting • Building Management Systems (BMS) systems • CIBSE Lighting Design Guide LG7 • ECAs • BREEAM or LEED Rating of lighting • RICS-SKA Rating for fitouts for both office and retail
Lighting is the most pervasive and visible of all the building services. As a result it is sometimes beneficial to use the lighting control sensors to inform the BMS about occupancy. This information can be used to generate additional energy savings in the mechanical plant systems. www.thelia.org.uk
TECHNIQUES
The control techniques are those approaches required to control the lighting in different applications. This section looks at control regimes that can be applied and why. It discusses operational functions but not how these are technically delivered. The subheadings are:
• Manual operation • Maintained luminance • Timed control • Corridor hold • Occupancy control • Load shedding • Daylight linked control • Links to other building systems
In each of these sub-sections the use of both switching and dimming will be covered as required.
Note: The term technique is used because this element will look at the objectives of the lighting controls but NOT the actual technologies used. It is intended that this element may be understood without a knowledge of electronics.
Manual operation
This is a vital component within a lighting control system. Manual operation recognises the importance of user accessibility to the lighting. There is a widely held belief that to be truly energy conscious a lighting control system must operate automatically, and it is the users that waste electricity. This is quite wrong and the reality is that fully automatic regimes will usually use considerably more energy than those relying on the staff to use local switches.
The most successful energy reduction control regime can be summed up as request ON, auto OFF. This relies on the fact that lighting should be switched ON by staff as, and when, they need it, while relying on the lighting control system to turn the lighting OFF. Empowerment and involvement of the staff improves their performance and feeling of wellbeing.
The value of local manual controls is recognised in the Building Regulations- e.g. Approved Documents L2A and L2B for new and refurbished non-domestic buildings in England and Wales - which requires a switch to be within 6 metres of any light if conventional (manual) ON/OFF control is used. Both Part L, and CIBSE guidance on manual switching, encourage zoning and proximity of the switching control to the occupier. In other words by zoning according to light conditions, function and occupier groupings etc., economies are enabled because the appropriate lighting can be turned ON and OFF as required.
The automatic element of lighting control ensures that the economies are delivered. If the automatic scheme is planned in a similar way to that outlined above, it has been identified that request ON, request OFF with auto OFF back up is the most successful energy reduction regime. The automatic systems provide users with a relatively high level of control while ensuring space / building wide parameters (including safety) are adhered to. Such a system can be further enhanced if the manual ON control is supplemented by variable light level control, which provides additional savings and improves comfort for the occupier - NB: the majority of individuals do not need, or like, the maximum level of artificial light provided in a space at all times of the day. www.thelia.org.uk
Time control
Managing lighting according to the time of day was one of the earliest control regimes, or strategies, applied to reduce lighting electricity use. In effect automatically operating the lighting during hours of occupation. This technique is still relevant today where applications like shopping malls can still benefit from this type of managed operation. Time control may use fixed times, such as the opening hours of a mall, or astronomical times, such as sunrise and sunset.
However, in the office and workplace the rigidity of a time schedule is no longer valid because of the need to accommodate flexible working hours. In many lighting control applications timed events have taken on a new role altering the mode of operation rather than actually affecting the lighting directly. Mode changes can be used to alter or restrict the function of a photocell or movement sensor. Time control can also be used to initiate a load shedding function, when the lighting levels are restricted for a specific period e.g. when cleaners are operating outside working hours.
Occupancy control
Time scheduled operation can be considered to be a form of occupancy control because it is used to predict the occupancy of a building. However, this is not accurate or optimal in most modern workplaces and today sensors are used to monitor occupancy.
Practical movement sensors have been available to lighting control systems since the 1980s; various technologies have been used (see Movement Sensors) and certain applications benefit from one type over another. A movement sensor will confirm occupation and maintain lighting while it believes someone to be there. Because they rely on movement, such sensors invariably have a built in time- out delay that takes into account the fact that people can be still for short periods. This delay to OFF is usually set at about 15 - 20 minutes for fluorescent lighting schemes, and it also avoids frequent switching that might be damaging to the lamps. Advances in sensor technology and the advent of LEDs will reduce time out periods in future in many applications.
Movement sensors are often combined with manual switches to enhance the potential for minimum use of the lighting; in effect a small, self-contained example of request ON/OFF, auto OFF. This mode is often referred to as absence control because the lights are turned ON by the user, the movement sensor is an assurance that the lights are turned OFF in the absence of the user. When the movement sensor is used in fully automatic mode it is called presence control; it is beneficial in stock rooms where the user may not have a hand free to operate a wall switch.
The technique of using movement sensors for occupancy control is a well proven and effective method of limiting the unnecessary use of lighting electricity.
Occupancy; switching lights on or off
12am 6am 9am 12pm 3pm 6pm www.thelia.org.uk
Daylight linked control
Managing artificial lighting with respect to the availability of natural light is arguably both the most obvious thing to do and the most difficult to deliver.
The simplest form of daylight linked operation is found in street lighting where individual photocells determine the switch ON and OFF points at dusk and dawn. This occurs at very low light levels - typically 50-70 lux - and requires only a modest hysteresis between the ON and OFF points.
Using daylight linked controls in a workplace is more challenging. The lighting levels involved are much higher; in an office they may be anywhere between 350 and 500 lux.
The higher lighting levels mean that much greater care needs to be taken with the system settings; nuisance switching can happen when the ON and OFF levels are too close. In addition light is additive so that when a space is lit by both natural and artificial light there is a proportion of each in the total measured value. This means that if the artificial component is removed the eye will immediately notice a significant drop in illumination and the person will react by restoring the electric light. This is true for any value for the artificial lighting exceeding 25%. In other words the daylight component should be at least three times the artificial element before attempting a switch OFF. If the daylight control can be used to dim rather than switch the lighting, then many of the problems are overcome. With dimming the changeover from mostly artificial to mostly natural light can be done smoothly and evenly without intruding on the user’s concentration.
In most indoor spaces, the daylight factor varies greatly across the room with areas nearest to the windows enjoying the highest levels. Lighting control systems ideally need to be able to accommodate graduated levels of daylight and adjust the lighting accordingly. In a roof lit area the energy savings delivered by lighting controls will justify the use of up to 20% glazing. www.thelia.org.uk
Maintained illuminance
Most artificial lighting sources lose some of their brightness over time, and this includes fluorescent lamps. Much progress has been made with regard to minimising this effect but the designer still has to take this into account. In addition luminaires get dirty over time and this adds to the loss of light through life. Design specifications, therefore, refer to the required lighting levels to be a maintained level, which can be as low as 60% of the “as new” capability of the installed lighting; effectively the scheme is 40% over-lit on day one.
Maintenance factors - the difference between the designed and required level and the actual as new performance - can vary between 20% and 40%. This means that, over the maintenance cycle of cleaning and re-lamping, a dimming control system can save between 10% and 20% of the lighting electricity. Lighting controls can deliver the designed illumination levels as soon as the system is commissioned. This can reduce electricity use by as much as 20%.
Lamp Maintenance Cycle
100
Light loss due to aging 90 80 70 60
50 Light loss due to aging + dirt accumulation 40 % of Lumen Maintained % of Lumen 3000 6000 9000 30 Operating Hours
Corridor hold (or Group Dependency)
A useful feature of many lighting control systems is an ability to relate the status of one group of lights to another. So, for example, a single private office light kept ON by the occupant may dictate that lighting remains on along the safe exit routes from this location. This feature was developed as a convenience or comfort factor; today it is often used to help a lighting design to meet the recommendations contained in BS EN12464-1 - the European Norm for lighting the indoor workplace. For special applications and increased comfort, alternative versions of this system can be used.
Load shedding
Buildings are often equipped with standby generator systems so that they can continue to function during a supply interruption, albeit with a reduced capacity. Traditionally this required dual wiring divided into essential and non-essential circuits. Today lighting control systems can facilitate this function by limiting the lighting in use when the generator is running, controlling essential and non-essential luminaires over common wiring. The limit may be either a wholesale capping of the level (if dimmable) or a selection of specific lights.
This technique can also be employed in other circumstances; in an office at night during the cleaning period, in a shop when shelves are being restocked. It can also be used to avoid a maximum demand overshoot. www.thelia.org.uk
Links to other building systems
Lighting is the most pervasive service in any building; as a result many lighting control systems have the most widespread network of sensors and components. For this reason there is often a requirement that the lighting controls share information with other systems. The most usual requirement is for the occupancy information from the movement sensors to be passed on to the HVAC controls.
Linking can be done in a number of ways from full system integration to something as simple as a volt free contact. Whatever technology is chosen it is important to understand the consequences of such a choice. It is also highly important to define this element clearly and unambiguously to avoid unnecessary difficulties later on. www.thelia.org.uk
APPLICATIONS
Lighting controls can be applied to a wide range of both indoor and outdoor installations. The priorities of the functions delivered by lighting controls in these applications will vary according to the needs of the installation. For this reason this section will try to expand on the use of certain control functions / techniques whilst also attempting to avoid repetition. This section considers the application of lighting controls to:
• Offices • Museums and galleries, and • Industrial buildings, including warehouses other public buildings • Schools, and other educational buildings • Hotels, restaurants and cafes • Shops and shopping malls, • Street lighting including retail parks • Architectural lighting • Hospitals • Floodlighting
Whichever application is being considered it is helpful to bear in mind the purpose of the lighting to be controlled and its ownership. In effect it is important to understand (a) why the lighting has been provided, (b) who is responsible for it and (c) there is safe and ready access for maintenance and optimisation.
The Building Research Establishment developed the first two columns of the following table, which can be almost universally used across the different applications listed above when developing the design.
By testing each application, and any sub-application, against these six types of space, the designer can develop a control strategy and hence identify the correct equipment to be applied.
Selecting controls to match the space
Type of space Examples Controls
Cell office, small workshop, Wall switch, remote, movement Owned consulting room sensor - possibly in combination
Open plan office, production Manual switching, movement Shared area, ward light sensors sensors, - localised and combined
Scene control plate or logical Meeting room, hot office, Temporarily owned manual switching with automatic classroom OFF
Movement sensors, possibly Occasionally visited Store room, book-stack, toilet combined with local manual switching
Automatic or remote manual Un-owned Corridor (open or closed), stairs operation, movement sensors in some applications
Hotel lounge, museum, foyer, Remote manual and/or automatic Managed terminal control www.thelia.org.uk
Offices
Arguably the largest and most important part of the lighting control market, it is now unusual for any significant office building to be designed without a control system.
Lighting controls in offices may be a series of independent movement sensors right through to a fully networked lighting management system. The installation approach may be fixed or based on highly flexible, plug-in lighting control modules. The scale of the project and its intended use will influence the design choices. The Building Regulations (e.g. Approved Documents L2A and L2B in England and Wales) will also need to be considered, in order to ensure compliance.
Most office buildings contain the following accommodation, each of which require a detailed variation of the basic design applied:
• Open plan • Cell, or private, offices • Meeting rooms • Circulation areas, including corridors and lobbies • Toilets and store rooms
Open plan offices are shared spaces that may accommodate a very large number of people. The lighting in such a space has to be designed to provide the correct illumination for the people and space whenever the space is occupied. However, occupation levels may vary during the day, when it would be wasteful to provide full lighting levels throughout the space. The lighting controls therefore need to adapt the lighting to the varying occupancy, and daylight, levels whilst maintaining a well-lit working environment.
Current lighting control practice in open plan areas is to use movement detectors across the space to determine occupancy levels and to adjust the lighting accordingly. The designer needs to select the correct type of movement sensor (see Section 5: Technologies), and then place them correctly. Because the space is shared it is important that all the occupants are satisfied with the lighting and no single person - either deliberately through their actions or inadvertently through their absence - can adversely affect the lighting design. This design approach is very clearly expressed in the SLL Code for Lighting Design and BS EN 12464- 1 Lighting of indoor work places. People need to be able to make their way safely through such a space as they occupy the space, especially if they are among the first to arrive, or last to leave. www.thelia.org.uk
Offices (continued)
Cellular, or private, offices are owned spaces when they have a single occupant. The lighting in a private office only needs to provide for its occupant and normally does not play any other role. Simply put, the lighting should be OFF when the office is empty, ON only when the occupant requires it. This is most effectively achieved by using a combination of movement sensor and manual override. The occupant therefore has to choose to have the lighting ON and the sensor will turn the lighting OFF when the space is empty.
For truly personal lighting a manual controller that allows the user to set the lighting level is to be encouraged. In some larger cell offices this control might extend to scene setting, particularly if there are multiple lighting technologies (e.g. senior management offices).
Some cellular offices have two, or more, occupants, in which case the space is classed as being shared. In these circumstances the controls for such offices need to be thought of as small open plan areas. Consideration must be given to the comfort of each occupant whilst respecting the need to minimise energy use.
Meeting rooms are temporarily owned spaces, which should allow the organisers/user group the freedom to adjust the lighting to their requirements. This must be easily controlled in order to adapt it to different uses; e.g. presentations, interviews, discussions and other functions. This is often called scene setting; but it does require the lighting to be either dimmable or have multiple switch circuits - or possibly both. Scene setting is usually done via a manual controller with a number of buttons to recall pre-programmed lighting levels and/or select only certain lights. Solutions range from simple four button, wall mounted, switch plates to touch screens integrated into sophisticated AV (audio visual) controllers or smart devices. These facilities provide the user with the ability to turn lighting ON and OFF as well, but it is also worthwhile to consider adding movement sensors to ensure that the lights turn OFF when the room is not occupied. The control strategy when movement sensors are added must be set to absence mode; the sensor must not be able to turn the lights ON automatically.
In these applications the manual controller is there for simple functional flexibility; the movement sensor is there to minimise energy wastage. Higher tier conference facilities would need liaison with AV specialists and integrators for smart input and output devices (e.g. mobile phones and partition switches).
Circulation spaces including lobbies and corridors
Here lighting generally needs to be maintained, or available, whenever the building is occupied. Circulation space in office buildings may be dedicated (i.e. a distinct, walled, corridor) or notional corridor within a larger space. The lighting in these applications should be treated differently from each other.
A dedicated corridor, or lobby area, may be controlled by suitable movement sensors so long as they are located to monitor all possible points of entry to the corridor. In addition, if there is useful daylight then harvesting this could save energy.
A notional corridor is often lit in the same way as the whole area, and is effectively part of the lighting design. Any controls must, therefore, be sympathetic to the surrounding office space. However, where possible, such lighting may be set back to a lower circulation level by dimming or turning OFF some of the luminaires.
As a general principle, circulation lighting should be there to provide safe access and egress and it may often also be managed on a regular time schedule that matches the occupied hours of the building. The provision of a centralised manual override is also beneficial to facilitate security walk rounds, or for an out of hours event. www.thelia.org.uk
Toilets and store rooms
Lighting in toilets and store rooms is best controlled by movement sensors. In these applications the sensor can usually be used in a fully automatic mode; i.e. lighting is brought ON when people enter and is turned OFF some minutes after the space is vacated. In a toilet application, care must be taken to ensure that cubicles are properly covered by the sensors. In a store room the movement sensor control is an added convenience to those entering the room with their hands full, when reaching for the wall switch might be difficult. If there is sufficient daylight consider using photocell control as well.
The risk of an unwell person locked within a small compartment should be considered when setting time delays; i.e. set back provision could be a solution.
Always select, and locate, movement sensors carefully, to suit each application.
Industry, incl. warehouses
The lighting in industrial premises is more variable in design than those found in offices. The use and dimensions of the building will often dictate the lighting solutions, which used to limit the choice of dimming controls. Industrial spaces may include hazardous, high risk areas and ingress/impact protected products. In addition the selection of the lighting and control products should be optimised for the application to avoid potentially dangerous stroboscopic or flicker effects.
Industrial spaces can have very high ceilings and may contain large or moving equipment such as production lines or manufacturing plant. These applications are generally referred to as high bay spaces and frequently the lighting is installed before the plant and machinery. In effect the whole space is lit before the tasks and activities below are defined. The height and structure of many industrial buildings have influenced the lighting design towards the use of powerful high bay luminaires. The rationale behind this thinking largely relates to reduced energy usage, flexibility, controllability, light on demand and reduction of operating costs.
The design of the lighting installation is also likely to be delivering the highest required lighting level throughout the whole of the space instead of discerning between the task and circulation areas, precisely because the final machinery/equipment layout is not known. This is an approach found in many work places, including offices, which often leads to excessive lighting energy use. It is now possible to refine the lighting controls to maximise flexibility and controllability of the lighting
Other spaces having obstructions or lower ceiling heights such as mezzanines can be more complicated. Some applications may be laboratories and/or clean rooms; these situations have a significant influence on both the lighting and the potential for control systems.
Warehouses are frequently high ceiling buildings but, in the main, the storage racking and layouts are determined before the lighting design is fixed. In these applications lighting follows the aisles and storage racking layout. www.thelia.org.uk
Industry, incl. Warehouses
In the installations using addressable dimming control, it is possible to tailor lighting levels throughout the industrial space to match the activities and space utilisation below the lighting. In industrial lighting installations where it is possible to address and set the output of each individual luminaire, the energy use can be significantly reduced. Lights illuminating circulation space can be set to the appropriate level and where there is (for example) a large amount of automated machinery installed, it may be possible to turn OFF the overhead lighting in that place altogether until maintenance requires people to be present.
In many production facilities there is additional lighting provided at lower levels to illuminate small inspection areas, or a local requirement for extra light. Providing high levels of overhead lighting in these places is often unnecessary. This localised lighting should also, if at all possible, be included in the control system.
Low bay industrial (including laboratories / clean rooms) These applications often have false ceilings which can be akin to an office scheme. The lower ceilings in these applications open up the possibility of using movement sensors, especially where the ceiling height may be as low as 3 metres. The application of controls should complement whether the luminaires are linear, continuous or point-source
High bay warehouse These have high racking systems that are accessed by fork lift trucks, or cherry pickers. Lighting tends to be aligned with the storage rack aisles. If useful daylight is available then it should be harvested. Very substantial energy savings can be made by using localised zones and movement sensors in large warehouses, especially in infrequently visited aisles. www.thelia.org.uk
Industry, incl. Warehouses
Low bay warehouse / storage These applications are where the storage racking is low level and designed for manual sorting. Two basic methods of controlling these aisles can be considered. Either movement sensors can be used to operate the lighting or very localised manual switches can be effective if they are regularly turned OFF or dimmed.
Movement sensors can be applied in two ways in these aisles; either using a downwards looking device at regular intervals or by using a sideways, long range, unit to monitor the aisle. The former solution might even extend to the sensor being mounted in each luminaire. The use of downwards looking sensors has the benefit of only activating those lights that are local to each sensor; this avoids whole aisles being brought ON when the visit is to a bin at one end. The decision to choose between the downward v. sideways looking solutions is usually one of balancing cost (number of sensors) against benefit (potential energy cost savings).
Manual switching can be used with movement sensors (Absence mode) so that someone entering an aisle can choose to turn the lights ON and the sensor will turn them OFF.
Manual switching can also be used in conjunction with a timed reset. In its simplest form this may be a pull-switch or push-button that starts a countdown timer that turns the lighting OFF after a pre- determined period. A variation on this approach is the use of a timed reset command that turns all the aisle lighting OFF at pre-determined times of day; typically at shift change or during specific work breaks. With both these control strategies there should be some background lighting provided because the lights are turning OFF without the reference to occupancy made by a movement sensor. www.thelia.org.uk
Schools, and other educational buildings
The lighting of most educational buildings is most closely related to office lighting; luminaires and many of the spaces are often very similar. As a result many of the potential lighting control strategies use similar techniques to those used in office applications. The SLL Lighting Guide LG5 is dedicated to the subject of lighting education buildings.
Education buildings present a number of variables when each establishment is considered. A primary school has comparatively limited hours of use in general. Secondary schools, however, may be classed as community schools and used outside normal school hours; often by people unfamiliar with the building. The range of classrooms now encountered in schools is also quite wide; some have open plan teaching spaces while more traditional classrooms can be likened to meeting rooms in office applications. Education buildings within the tertiary sector - colleges and universities - extend the applications into lecture theatres and some specialised, larger spaces. Other spaces to be considered are assembly halls and indoor sports facilities.
Manual controls in public areas should be well labelled and intuitive to use.
Other spaces in education buildings include administration offices, store rooms, and (normally) quite extensive circulation and common areas.
The primary applications in education buildings are:
• Classrooms • Lecture theatres • Sports halls • Circulation space www.thelia.org.uk
Schools, and other educational buildings (continued)
Classrooms A classroom can be classed as a temporarily owned space on the grounds that a teacher or tutor is normally responsible for its use but they may not be the only one to use said classroom.
Most classrooms are rectangular spaces with between 9 and 12 main luminaires. Many benefit from generous daylighting with either large windows or some form of rooflight. The lighting should be absence controlled by wall switches adjacent to the door, which should be used to bring the lighting ON when needed. The switch circuits should be aligned parallel to the windows (or other daylight source) to encourage users not to use lights near the window, ideally dimming and daylight harvesting is recommended. There should also be provision for the lighting to be turned OFF automatically, either through an occupancy sensor or a pre-programmed, scheduled timed OFF. The latter is only to be considered if the class change times are closely adhered to. The manual switches must also allow the user to turn the lighting OFF so that the lighting can be adjusted to match the current teaching activity.
If lighting is dimmable then the controls should also be able to manually regulate the installation; in these circumstances it would also be beneficial to add a daylight sensor. The important consideration for any control panel is ease of use and clear labelling as teachers/students may not be familiar with the switches and end up using the first lighting arrangement they manage to create that will do.
Lecture theatres A lecture theatre may be little more than a larger, tiered classroom, in which case similar controls to those recommended immediately above are appropriate. However, in larger, more complex lecture theatres a scene setting type controller that can be operated from the lectern and/or associated projection booth is more appropriate. There is no reason, though, why these controls might not be supplemented with movement sensors in order ensure lights are turned OFF when the room is empty. www.thelia.org.uk
Schools, and other educational buildings (continued)
Sports halls Should be provided with readily accessed manual switches and some means by which lights might be turned OFF if the last occupants of the day forget.
Control is best done using a combination of movement sensors and manual switches. Lighting is selected to suit the current use of the hall and the movement sensors are then relied upon to switch the lighting OFF once the hall has emptied. The manual switches will, though, also allow users to switch OFF the lighting.
Alternatively some form of timed OFF command might be scheduled for a time when it is known that the hall is empty.
Circulation space The corridors, staircases, and entrance halls of schools and universities are important in any lighting control application because they are often extensive but they must be lit safely at all times that a building is occupied. Where these spaces are day lit then photocell control should be used to inhibit the artificial lighting. Other suitable control strategies include timed operation and occupancy sensing.
Atria, hubs and multi-use spaces Many modern schools now include large open areas that are akin to Atria. These spaces are used variously for assemblies, receptions and displays. They also contain reception desks and other functional spaces. It is important to zone the lighting in these spaces so that it may be controlled according to both ambient and functional conditions. So, for example, where there is good daylight the artificial lighting should be circuited so that it may be turned down or OFF in bright conditions. www.thelia.org.uk
Shops and shopping malls, including retail parks
Most of the lighting loads in retail premises have the primary role of enhancing displays and encouraging sales. However, lighting is also provided in stock rooms, training rooms, and other back of house facilities. Lighting within shops must be split so that it is possible to turn OFF the display lighting outside trading hours. The control strategies for lighting in retail premises can be most easily described by detailing a typical trading day.
These are outlined below by application:
• Shopping malls • Shops • Supermarkets • Retail parks
Each of these categories has different needs but all have to balance the cost of high levels of display lighting with the benefit of increased visibility and hence sales.
Shopping Malls These are very large, and diverse, indoor spaces that rely on artificial lighting throughout. Many have large indoor car parks associated with them but these areas are excluded from this section.
Many shopping malls have very high levels of daylight in the main malls where their major lighting loads are located. Clearly maximum advantage should be taken of any natural light so photocell operation is one control function that should be provided. Malls also keep regular hours and a daily routine might typically follow this sequence:
08:00 Open mall for arrival of staff using a pre-trading level of lighting.
Open for business; lighting brought to full level but subject to 09:30 photocell control where practical. Manage lighting according to available daylight and Trading period also balance mall lighting with shop fronts. Closed to public; reduce lighting to basic ‘safe circulation’ 18:00 level for egress of remaining visitors and then shop staff. End of post-trading period; reduce lighting to basic security level. 20:00 Maintain this level until the complex opens for shop staff next morning.
During the overnight period allow the security staff to remotely Overnight manage any additional ‘walk-round’ lighting.
The above daily routine very much defines the scheduled management of the artificial lighting to match the current activity. In back of house admin offices, store rooms etc. both local manual switches and movement sensors should be used. Public toilets should also be equipped with movement sensors.
Shopping malls may also contain significant amounts of feature and/or seasonal lighting, and some (or all) of it may be operated dynamically, which infers that it is equipped with lighting controls. If that is the case then consider linking the feature controls to the main mall lighting control system. www.thelia.org.uk
Shops and shopping malls, including retail parks (continued)
Shops A shop will go through the same daily routine as a shopping mall, whether it is itself within a mall or part of a High Street. The display lighting should be separated from the basic pre/post-trading lighting so that it is only used during trading hours. If the shop has a display window it may be necessary to have reverse photocell control; i.e. the photocell turns ON additional lighting in the window when the daylight is very bright and causing veiling reflections in the glass. Otherwise the application advice for malls pertains, even though the scale (much smaller) may be very different.
Supermarkets The link to daily routine also applies to supermarkets; however, this control regime may be enhanced by taking some additional measures. The main, overhead lighting in a supermarket is usually provided by a regular array of luminaires providing high levels of lighting throughout the store. This often ignores the fact that many of the displays in the aisles are also provided with lighting - e.g. freezer cabinets. Providing overhead lighting that is equipped with dimming control gear will allow the store manager to set lower levels where aisles contain cabinet display lighting. This feature can also be used for pre/post trading lighting levels throughout the store.
If possible any lighting control system provided to manage the main store lighting should also be linked to local display and cabinet lighting, as well as any illuminated posters. Where lighting have been used in freezer cabinets it is possible to include them in the display cabinet controls.
Supermarkets also contain significant back of house areas and these should be integrated into the main control system. Local manual switches, movement sensors and photocells should be deployed in these spaces to suit their use and environment. Application advice for these areas can be found under offices, and industrial.
Retail parks The buildings in retail parks are often more akin to warehouses in their construction. They are usually large, with only a single storey; many are constructed with a minimum of 10% roof lighting. The standard application advice to manage the lighting to match the daily routine applies, and where there are roof lights a daylight harvesting should also be used. Pre/post- trading lighting levels can easily be achieved by bringing ON an even pattern of lights to give just 50% (or possibly less) of the artificial lighting. If possible, schedule different lights to be part of the reduced lighting level so that usage is evened out over time.. www.thelia.org.uk
Hospitals
Wards - including nurse stations Most wards are, in reality, a number of rooms and spaces. There may be several 4 bed modules as well as a number of single bed side wards; there will also be bathrooms, toilets and a nurse station within each ward. There are both cost and operational reasons for installing lighting controls. The lighting in the patient areas has always been required to provide both day and night lighting levels; in the past this was done with completely separate luminaires. Using lighting controls and dimming luminaires both lighting levels can be provided from the same fixtures. Patient rooms are also normally well day lit and so photocell control should also be incorporated in the system. The main patient room lighting needs to be manually controlled from the nurse station as well as locally. Such switching should be obvious, accessible and where necessary clearly labelled. This will permit lighting to be increased in any patient room in the case of an emergency.
Local patient bed head lights are normally under the direct control of the individual patient.
Lighting in bathrooms is best controlled by local wall or ceiling switches but there is no reason why such lights should not be included in the overall control system. The general control strategy for these areas is one of inclusion in the system with scheduled events to manage day and night lighting, whilst largely relying on manual operation for the comfort and convenience of both staff and patients.
In some patient rooms novel wake-up lighting is used where the background lighting starts at a low level and high colour temperature gradually increasing in brightness and warming in colour temperature to simulate dawn. This facility obviously uses a scheduling control system. www.thelia.org.uk
Hospitals (continued)
Light and well being There is increasing evidence that lighting plays a part in the speed of recovery and wellbeing of patients. Setting the correct levels and colour of lighting, particularly at night, can help patients’ sleep patterns through maintenance of their circadian rhythm. SLL LG2 gives further information on hospitals and health care buildings.
Clinics A clinic within a hospital is also a multi-room complex, usually comprising of a reception area, waiting room and consulting rooms. Lighting for the general public areas should be controlled from the reception point; if the waiting area is large then consideration should be given to zoning it so that only a part is lit when the clinic is not busy. Consulting rooms should be equipped with both local manual switches and movement sensors. Operating the lighting with scheduled events that match the clinic opening times may also be practical.
Administration offices These areas should be treated in the same way as the recommendations for office buildings.
Corridors and circulation spaces Hospitals contain extensive corridors and circulation spaces, most of which benefit from high levels of glazing and hence good daylighting; photocells should be used in such applications. Where there is no daylight available, movement sensors can be effective so long as measures are taken to ensure sufficient light is available for safety purposes.
Operating Theatres Normally automatic lighting controls should not be considered when lighting the actual operating theatre. However, lighting in support areas and washrooms may be locally switched and movement sensors used to ensure lights go OFF when these areas are unoccupied. Any controls employed in these areas must be equipped with obvious local switches so that the lights can be put ON at any time the theatre might be required.
Lobbies and waiting areas In general, these can be treated as for similar areas in office buildings.
Other health buildings Doctors surgeries, health centres and care homes all contain spaces that are either similar to those found in hospitals, offices or hotels. The lighting controls can, therefore, be applied in a manner already described. www.thelia.org.uk
Museums, galleries, exhibition halls and other public buildings
This lighting sector has much common ground with retail applications but with additional, and interesting aspects concerning modelling and conservation of exhibits in some spaces. Lighting in museums and galleries is required to illuminate exhibits and display cases; however, where the artefacts being displayed are susceptible to degradation due to exposure to natural and artificial light it is clearly necessary to limit the amount and level. Many of these applications also use roof lighting so photocells are employed to turn OFF (or down) the artificial lighting and control blinds.
Most public buildings, museums and galleries are operated on regular hours and so scheduled ON and OFF commands are practical. These may be done in a progressive manner; lighting sufficient for the staff being brought ON initially and only during public attendance is the full display lighting added. In any associated offices, meeting rooms etc. the application advice for offices should be followed.
In an exhibition hall, the main lighting may be altered to suit the event as well as its different functional use at any time. Lighting may need to be at higher levels during the build-up and take-down periods. The lighting pattern may be different for each event. To meet both needs a lighting control system needs to applied to control small lighting groups or even individual fixtures to aid this control strategy.
Locational services may be of benefit in these applications.
Light management As mentioned above, it may be necessary to limit the quantity of light falling on certain exhibits; a quantity measured in lux hours. For a control system to manage such lighting it would be necessary to calibrate the light levels and then use a carefully chosen time schedule to operate the lighting. If daylight is also involved such a system might also require a feedback photocell to log the lux hours. Also movement sensors might be used to brighten lighting when a visitor approaches such exhibits.
Store rooms and associated warehousing Many museums and galleries have significant associated store rooms or warehouse areas; the lighting in these spaces may be controlled in the same way as described in previous similar applications. Guidance may be sought from SLL Lighting Guide No. 8. www.thelia.org.uk
Hospitality
This sector requires lighting design which is similar with other sectors but also has its own bespoke requirements. The common ground includes display / effect lighting as well as the need to light mundane office and other tasks. In considering the application of lighting controls in this sector it is practical to analyse the various areas within a hotel:
• Reception • Conference facilities • Bars and restaurants • Health spas / gymnasia • Guest rooms • Ancillary areas including toilets and store rooms
Using these headings means that restaurants and cafes are covered within the overall hotel sector.
Reception The lighting of the reception area of a hotel is important because of the impact that it will have on the guests on arrival. It should be both welcoming and practical ensuring the process of registration is performed in good lighting conditions. All signage and announcements being easily seen and read. However, the amount of lighting in use can vary during the day with, perhaps, lower levels being used late at night and during the normal night time hours. Reception lighting can be managed on a fully automatic, scheduled, control regime with the addition of an easily understood override facility to be used by reception staff should the occasion be necessary.
Conference facilities Many modern / larger hotels have extensive conferencing and business meeting facilities. Lighting in these areas needs to be controlled for both electricity conservation and operational purposes.
Most conference and meeting rooms are equipped with a scene control type lighting controls as a matter of course. These controls are intended to meet the operational / functional needs of these spaces but should be well labelled and/or intuitive to use. Many scene setting controllers offer multiple, unlabelled, pushbuttons, and the user has to guess which button to use to get a specific lighting effect. Although scene set controllers are generally the norm in these applications they do not always have automatic control functions; there is no reason why these features should not be added. These spaces often contain flexible partitioning, which requires control plates to adapt to the changing layouts. When a larger space is subdivided each must have its own detector and controller so that when the space becomes one they are correctly linked.
It is not unusual for conference and meeting rooms in these complexes to have generous windows or even rooflights. Having invested in the scene set controls the addition of photocells and automatic time scheduling is highly cost effective, as is the use of movement sensors in smaller rooms and support areas. This can be an attractive starting point to creating a hotel wide system. www.thelia.org.uk
Hospitality (continued)
Bars and restaurants Any bar or restaurant needs to be able to alter its ambience to suit the time of day and/or the occasion; this is most easily done by changing the lighting. These spaces, therefore, are usually provided with scene set controls that the staff use as each day progresses. Multiple light sources are used and the controls need to be compatible with the range of lamps and gear used. As per the conference facilities there is no reason why these controls should not be integrated into a building wide solution so that automatic commands can be used to set the appropriate lighting scenes throughout the day.
Note: For individual bars, cafes and restaurants (i.e. those not part of a hotel) it is probably sufficient to have a manually operated scene selection lighting controller.
If the bar is a night club the control system might be more dynamic and feature colour changing and responses to the music. These are specialised applications requiring expert advice. www.thelia.org.uk
Hospitality (continued)
Health spas and gymnasia Where these facilities are included in a hotel the lighting here should also be included in the control system. Scene control is most appropriate in a health spa and movement sensors would be effective in a gymnasium along with its associated changing rooms and toilets.
Guest rooms The first requirement for any form of lighting control within a hotel bedroom is that it should be obvious and accessible to the guest. In fact this requirement is often reflected in the way the lights are controlled from both the entrance and from the bedhead. The multiway wiring for this arrangement can often be simplified through the addition of electronics, which then opens the opportunity to manage the room lighting in accordance with current status - available or occupied.
Introducing automatic controls into a hotel room that is occupied is probably not practical; the guest must be in charge at all times whilst in the room. A good method to ensure that a guest does not use lighting when they are out, is the use of a room key operated enabling switch at the entrance. A time delay device should be used so that the guest can remove the key and leave the room without the lights going out suddenly.
However, there is no reason why the room lighting should not be linked to the reservations system, and consequently restricted to overhead lighting only for cleaning and maintenance.
Ancillary areas including toilets and store rooms Hotels contain many back of house spaces like offices, as well as public toilets and various store rooms. All of these areas can be included in a lighting control system so long as appropriate local switches are provided for staff areas, as well as movement sensors. The public toilet areas should be operated by movement sensors, local switches are not necessary in these areas. www.thelia.org.uk
Road, street and amenity lighting
The primary role of road lighting is to offer safety and security to the public, either as pedestrians, cyclists or motorists. This lighting covers public lighting in residential roads and footpaths all the way through to motorway lighting.
Most road lighting is currently controlled by individual dawn to dusk photocells but there is an increasing need to manage the hours of use more carefully. This can be done using individual controllers that work out the hours of darkness and then reduce lighting levels in the small hours of the morning, when there are far fewer people about. The alternative to the individual control per lighting column is to introduce some form of networked or smart control.
Controlling road lighting with a system There are three primary reasons for installing a road lighting management system; (a) to control the energy use, (b) to use as an asset management system and (c) for environmental impact or curfew/planning restraints. As a result such systems have been developed to cater for both needs. The majority of lighting management systems in this field use signalling methods that require no (or very little) new cabling. The reason for this approach is that the addition of some form of signal cable to existing lighting columns would be an almost prohibitive cost. In addition, it should be noted that most road lights are located in residential areas and share supply cabling with the surrounding houses.
There are two obvious technologies that can be used to control widespread electrical loads without new cabling; (1) use power line or mains borne signalling, or (2) employ an RF wireless solution. This application note does not consider the pros and cons of these methods but solely looks at the functionality that should be considered.
In its simplest form, a road lighting control system would turn the lights ON as the daylight fell below a specific threshold, allowing for any start-up time required by the lamp. If electricity use is not the principal concern, then the next event would be turning OFF the light as dawn broke. Where electricity use is a concern, then the OFF command might occur just after midnight and, depending on the time of year, another ON period delivered from (say) 0530 hours to dawn. HID lamps can now be partially dimmed and the use of this feature can also save energy. Thus a part night dimmed period could be used in the early hours of the morning, or when there is low traffic density. In these circumstances the road lighting is never entirely turned OFF after dark. However, the application of LED street lights will be more energy saving and even more controllable.
Controls can turn down road lighting - avoiding the need to turn OFF at all after dark. www.thelia.org.uk
Road, street and amenity lighting (continued)
Apart from the fact that a road lighting control system must have both photocell and time scheduled automatic functions there may be a need for some form of local area override. It may, for example, be necessary for the emergency services to request that street lighting be restored fully during an OFF or DIM period. With most of the solutions using a distributed hierarchical control with a web based supervisory software, it should not be difficult to introduce such measures via mobile telephony. Although such systems require every lighting column to contain an addressable control node, it is unlikely that the override would be placed on each column.
The other functionality of networked road lighting controls is their ability to monitor and report on the condition of the light source to assist in the maintenance cycle. Such systems may also be approved by UMSUG (unmetered supply users group) for reporting energy use to make billing more accurate.
Road lighting columns provide ideal positions for location of smart sensors which could give beneficial use to other equipment, systems or infrastructure.
Underpasses and tunnels Underpasses and tunnels on highways require lighting controls to manage their illumination. During the day the threshold areas need to be brighter to help driver’s eyes to adjust as they enter the tunnel. The controls must match these lighting levels to all daylight conditions and use photometers to do this accurately. At night the lighting must match the correct levels for the type of road involved. These lighting systems require expert designers, suppliers and installers. www.thelia.org.uk
Architectural lighting
Architectural applications, such as illuminating the exterior of a prominent building, are intended to enhance the viewer’s night time experience and improve the appearance and ambience of buildings and city spaces. As significant users of electricity it is logical that such schemes should only be lit when there are passers-by present to observe the effect. Architectural lighting may also be employed inside larger spaces like shopping malls and atria.
Lighting controls for architectural lighting schemes have, until recently, largely been designed to turn the scheme ON after dark and OFF at a time when the public have gone home. However, some schemes employ colour changing effects and have much in common with theatrical lighting. The introduction of LED lighting has brought colour changing within the reach of even quite modest schemes, and delivering these effects with much reduced connected loads. These schemes have altered significantly the requirements of the controls; they must now be capable of selecting specific elements or colours and adjusting their intensity as well as dictating the hours of use. Some colour changing, architectural lighting schemes will employ a control system that can operate the lighting loads dynamically - i.e. while the lighting is ON the control system varies the intensity and colour on a pre-programmed cycle to add interest and excitement. It is, therefore, not difficult to add overall time management to limit the hours of use as well as choose particular sequences or colours for specific occasions or anniversaries.
The likely system configuration involves a central controller that either includes a means of programming the system or just storing a programme loaded from an external source. The central controller then addresses the various light fixtures via a control bus (often using the DMX protocol used in the entertainment world) which tells each light what intensity, colour and rate of change it should follow. The fixture themselves often being supplied with the control node built in.
Floodlighting In the context of this guide floodlighting covers applications where the primary purpose is to illuminate a task (like a sports pitch) or to provide a specific functional benefit, like security. The latter might include area lighting in a town centre or other public place; floodlighting of buildings for artistic or ambient effect is considered separately as architectural.
Floodlighting is chiefly used to - in effect - turn night into day, so that sporting events can take place at night; either for the benefit of the public or for training purposes. Such lighting is, by definition, usually very powerful and covering a significant area. It may also be provided at different levels to suit different occasions; a base level for training, a normal level for attended matches and potentially a high level for broadcast TV. A lighting control system not only makes the multi-level operation easier to do, it also permits the economical addition of centralised control functions. Such systems usually comprise a number of distributed control panels (adjacent to the lighting gantries) all linked back to a central controller offering automatic time and photocell operations and a convenient means of overriding the system via (say) a key switch.
A floodlighting control system restricts the use of the lighting to the period when it is required and therefore limits the energy used. Many systems only need to have an ON/OFF capability because the different levels are achieved by the quantity of lights in use. This allows the use of simple and robust control technologies to give reliable operation; failure of a floodlighting system during an important sporting occasion is not desirable. The introduction of high power LED floodlights means that dimming controls may be required in preference to switching.
Area lighting Floodlighting includes the illumination of outdoor work areas and even public places like station platforms. These applications need to take account of times of use and daylight. Zoning should ensure that - for example - the need to illuminate a pedestrian underpass does not keep other lighting ON during the day. www.thelia.org.uk
Architectural lighting (continued)
Domestic Lighting Control The increasing use of wireless and smart devices in the home provide additional opportunities for users to adjust and integrate their own individual light sources directly with other IoT devices.
Historically lighting controls in domestic applications has involved the installation of wall switches. This normally has been a single way switch placed near to the doorway of a room controlling the main ceiling lamp and possibly a second switch controlling a set of wall lights where installed. Where switching a light source is required from more than one location such as in hallways and stair areas, two way switches and intermediate switches are used. In addition, users occasionally enhanced room lighting by retrospectively installing dimmer switches.
The rapid recent development of lighting controls for domestic use has been the result of the aspiration of users for greater levels of comfort, convenience and flexibility coupled to the trend for incorporation of greater number and types of light sources into lighting designs. In addition to switching and dimming, modern domestic lighting control systems provide two key additional functionalities. Firstly the ability to easily and flexibly group together several light sources to enable them to be controlled together. Secondly, through a series of predetermined settings, achieve different combination of light sources and lighting levels often known as scenes to match the task requirement of users from a single control operation. These two functions allow users to simply and precisely control their lighting requirements however complex their installed lighting design. Most systems will also provide users with the flexibility to alter the pre-determined groupings and scenes as their needs and requirements change over time.
There are a multitude of different alternative systems available to deliver lighting controls to a modern lighting installation. Key in deciding which option to adopt will be the level of adaption available for the installation especially in terms of providing new electrical and control circuits.
Where minimum change to an existing installation is required, systems based around wireless control will probably be the most appropriate. This involves the local installation of wireless receiver modules to control the selected light sources. Such systems are increasingly able to provide high level of controls especially in single room installations. Care has to be taken that there is not interference to the wireless transmission either from physical objects or other electrical equipment.
In new installations or where major refurbishment is taking place, a system based around circuits that provide separate power and control gives the greatest flexibility. In many cases the lighting control system forms part of wider home system. Often such installations centralise the controls (switching and dimming) in a control cabinet which aids maintenance, future alterations and upgrades. It is important in such installations to provide users with a method to plug in additional free standing lamp fixtures by provision for example of a lamp circuit with 5A plug integrated into the lighting system. A combination of control circuits and wireless devices is a common solution where the refurbishment does not impact the whole house but there is a requirement for the lighting system to be operable throughout the home. www.thelia.org.uk
TECHNOLOGIES
This section considers the how of lighting controls. The actual engineering - both electrically and electronically - of lighting control products is covered. The following subjects are introduced:
• Manual controls - override switches, scene • Central supervisors setting plates and remote controllers • Lighting management software • Sensors - presence detectors • Protocols (all types), photocells • Wiring and connectivity, including busbars and • Lighting control modules (load marshalling boxes controllers) - covering both switching • Compatibility with light sources and gear and dimming • Interfaces to other systems - AV, HVAC,, BMS • Network components
Lighting controls also vary in scale and structure from stand-alone devices that might operate an isolated room to building wide networks.
Manual controls
Override switches Lighting controls benefit from the addition of override switches that allow users to make some of the choices about lighting levels. Overrides may be very local or remote and come in several forms, which are listed and described below.
Their ability to place the onus on the user to choose to turn ON lights is the basis of the key control strategy of request ON, auto OFF. The range of manual control devices includes:
• Push buttons • ON/OFF switches • Scene setting controls • Touch screens • Wireless remotes (RF or IR) • Computer or smart device www.thelia.org.uk
Manual controls (continued)
Switches The simplest manual control, these are often connected using ELV wiring or mains voltage and provide a momentary closure to change the current state of the lighting. Some systems allow these controls to change the lighting level by pressing and holding until the desired level is reached.
Scene setting controls These generally use a number of buttons. However, some include additional electronics so that the controls are connected to the lighting control system network. Each button is assigned a specific scene so that it always recalls the same lighting choice whenever it is used.
A scene might be OFF, ON, 50% or some lights only; the choices are only limited by the systems abilities. It is important to select a control that is clearly labelled or intuitive to use.
Sometimes it is possible to reconfigure scenes using a Graphical User Interface, and external interface or some other means to reconfigure the system, depending on manufacturer.
Graphical User interface (GUI) Effectively these are evolved scene setting controls but using a computer, smart device or another touch enabled display screen. This allows the creation of clearly labelled virtual buttons as well as the inclusion of simple instructions. Some GUIs offer additional functionality over and above user override. Time scheduling, blind control, temperature control, room reconfiguration and interfaces to (e.g.) audio visual systems may be included. They may also be multi-purpose and provide access to other services.
Wireless remotes (RF or IR) Originally most wireless remote controls for lighting were point and shoot hand held devices to override the lighting. A receiver is mounted in the ceiling, which is connected to the lighting controller. Both radio frequency (RF) and infra-red (IR) versions are available; the latter requires line of sight to the receiver.
Fixed remotes using batteries or renewable energy sources are used to avoid additional cabling. These devices also allow installation directly to glazed partitions! Most use RF technology and some lighting controllers are now supplied RF enabled.
It is common for smart devices to be used as wireless remote controls. www.thelia.org.uk
Sensors
Presence detectors The ability of a lighting control system to manage the lighting according to space utilisation (presence, absence, heat maps, etc.). Often referred to as presence or occupancy detector the current sensors on the market typically rely on the following methods of detection:
• Passive Infra-Red (PIR) • Bluetooth • Ultrasonic • Wi-Fi • Microwave • CO2 • Cameras • Thermal
These sensor technologies have various pros and cons but all of them effectively depend on human activity to trigger an occupancy signal. In the lighting industry these can be used individually; however, two or more sensor types may be combined in one unit to give greater assurance of occupancy or presence. For example some sensors use both microwave and sound to make an alarm judgement or passive infrared and the presence of a Bluetooth device.
Passive Infra-Red (PIR) The most popular movement detector used for lighting control, the passive infra-red (PIR) sensor has been successfully applied in a wide range of applications for some 30 years. These units rely on a sensor that detects the movement of an infra-red emitting body as it crosses its zones of detection. The pyro-electric element of the sensor looks through a lens that creates the pattern of zones that suits the specific application. The complexity of the lens, or the more zones that are created, determines the sensitivity of the device.
Some sensors are designed to detect large movements, like a person walking through a corridor, and are not suitable for applications where a person is sitting at a desk typing on a keyboard. It is important to choose the right sensor for the specific application, as not all PIR sensors are the same.
PIR sensors are generally more versatile than other types simply because their detection patterns and sensitivities can be readily tailored by the choice of lens in front of the unit’s pyro electric element. Variants are available for longer range and higher mounted applications.
A PIR sensor does need to be positioned carefully, particularly with regard to its location with reference to the area it is intended to cover. The sensor should not be located directly adjacent to an air conditioning outlet, which may interfere with the detection. www.thelia.org.uk
Sensors (continued)
Ultrasonic This type of movement sensor emits an ultrasonic signal that effectively sets up a standing wave within the space it is monitoring (or covering). The unit then listens to the return signal, or echo, and so long as this remains the same (or constant) the sensor will not change its state. Movement within the monitored space alters this signal, or echo, and the unit notices the change of signal and reacts accordingly. These sensors will react to any solid body movement within the space and they can also be affected by the movement of air from (e.g.) an air conditioning outlet. Typically these units use a frequency of between 30kHz and 50kHz, beyond the range of human hearing and also that of most animals.
Ultrasonic movement detectors give good coverage over areas and higher ceilings.. They are best used in situations where significant, or multiple, movements are occurring. Application can include stock rooms and classrooms. To some degree an ultrasonic detector can see around corners but generally not through walls or partitions.
Microwave The movement sensor for larger spaces, a microwave detector uses similar principles to the ultrasonic approach described above but with a signal emitted in the gigahertz range; frequencies that are more often found in radar systems. These sensors are very sensitive and can require care when commissioning.
Particular attention needs to be paid to potential:
• movement of the surface on which the detector is mounted • Movement of other surfaces that are seen by the detector e.g. signs and other surfaces within the field of view of the detector • Movement of other elements e.g. moving air from draughts or heating and ventilating systems.
• Microwave sensors can potentially detect through thin walls, glass or other surfaces.
Microwave detectors cannot distinguish between a live person and other moving objects and may not, therefore, be appropriate in such applications as automated storage facilities with installed mechanical handling equipment.
The main attractions of microwave sensors are (a) their sensitivity and (b) the fact that some will cover large areas. They are often used in sports halls and similar applications but the perimeter walling needs to be checked for rigidity to avoid false triggering by vibration. Lower range units have been used in classrooms and multi-occupant office and work spaces.
Cameras Lighting systems can be triggered by events detected by cameras using image analytics Cameras in car parking can detect empty spaces – linking to guidance systems and an input to lighting. Standalone cameras can have built-in processors running image analytics.
Thermal imaging Thermal imaging is simply the technique of using the heat given off by an object to produce an image of it or locate it. Thermal imaging can be used to detect people in a building and a combination with other system can feedback information to lighting systems to operate the lights based on human presence. www.thelia.org.uk
Sensors (continued)
Bluetooth (Location Positioning) The Bluetooth technology and the functionality are not new and has been used since the 1990’s. However, these are now being used in a wider range of applications with the advent of the low energy consumption of the BLE (Bluetooth Low Energy) and with other big names such as Apple and Google pushing the market forward.
Bluetooth is a good alternative for indoor positioning and indoor navigation since GPS does not work effectively indoors. Bluetooth beacons can be set up which send signals to a Bluetooth receiving device which can determine the location within an area based on the beacon’s ID. The interface to other technologies and communications such as Bluetooth mesh will need to be considered along with the programming and commissioning of the whole system.
Wi-Fi (Location positioning) This is similar to Bluetooth but Wi-Fi can handle a lot more data and is already available as part of a building’s infrastructure and therefore there are no additional hardware costs associated with using the existing Wi-Fi infrastructure. However, Wi-Fi can be less accurate than using the Bluetooth technology.
Carbon Dioxide (CO2) Carbon dioxide is generated by people as a result of the human metabolism and concentrations within a building can often be used to indicate whether adequate fresh air is being supplied to the space. Moderate to high levels of CO2 concentration in an enclosed area can have adverse health effects and CO2 sensors can monitor the levels to ensure people are receiving fresh air.
On the other hand, CO2 sensors can also detect stationary people in an area when working alone or at odd hours which overcome nuisance triggering of traditional monitoring systems which uses mechanical movement/vibrations to monitor the wellbeing of workers. www.thelia.org.uk
Sensors (continued)
Photocell types Lighting controls employ a wide range of photocells to deliver day light harvesting systems and/or adjustment to ambient lighting conditions. They range in complexity from calibrated photometers used as reference points in road tunnel lighting schemes to low cost devices that operate individual road lighting luminaires from dusk to dawn. The following types are described here:
• Photometers • External photocells • Internal photocells and Light sensors • Cameras
Each of these types of detectors is used in different applications according to their characteristics. Most photocells (except those on (e.g.) lighting columns) should be located to avoid direct sunlight.
Photometers The most accurate type of photocell encountered in lighting control systems, photometers are used in mission critical applications, and in particular they are specified for road tunnel lighting controls. In these applications at least two units are used at each end of a tunnel and their light level readings used to determine the level of threshold lighting appropriate to the current daylight conditions. The photometer is so called because it is a device designed to measure the intensity of light. Its output is a value rather than a decision. These devices are also usually calibrated.
External photocells A photocell is the generic term given to almost any sensor intended to switch or alter the level of artificial lighting.
External photocells are most commonly found in street lights where they are used as dusk to dawn controllers. These devices are usually self-contained units that combine light sensing with a low cost actuator so that it will close at a pre-set lux level and open at another (usually lower) level. The difference between the ON and OFF levels is known as hysteresis and is designed to stop the device from switching ON and OFF too rapidly, when the light is close to the set level. The sensing element within a photocell is either a light dependent resistor (LDR) or a photodiode.
External photocells can also be used as reference input to control larger groups of lights via a system. Applications include both exterior and interior lighting schemes. When used with interior lighting it is often necessary to carry out commissioning in order to relate the light reading to the various levels of daylight penetration within a building. The general principle behind the use of external photocells to manage internal lighting is based on the idea that any daylight penetration into the interior will be directly related to the amount falling on the building.
Internal photocells and light sensors Internal photocells tend to use the same sensing technology as external units, when they are used to look at the incident daylight. They can simplify the system set-up because they can be fitted more locally to the loads they control.
Internal photocells may provide light output value readings to a control system, rather than just ON/ OFF decisions. This type of photocell can be used where lighting is to be dimmed gradually in response to natural light levels.
In industrial buildings (for example) the act of mounting a photocell beneath (say) a rooflight means that it will automatically adjust the system control points when the rooflight deteriorates due to any build-up of dirt. www.thelia.org.uk
Sensors (continued)
An internal light sensor can be used as an integrating device; i.e. the sensor looks down at the task area and receives reflected light containing both natural and artificial components. Also using similar light sensing technology, these devices are best fitted with a filter to ensure they are seeing a light spectrum similar to that seen by the human eye. This type of sensor will be sensitive to the reflecting properties of the surfaces below them. It is generally important to ensure that such sensors see a sample area beneath them and that they do not pick up extraneous light from outside. These photocells provide light output values to the lighting control system, which uses the information to turn lighting ON or OFF and UP or DOWN.
It is also possible to use internal photocells designed to coordinate the use of blinds and electric lights, to avoid situation where a closed blind prompts the lighting control system to turn the lights up, where there is enough natural light available.
Stand-alone lighting controls - Sensors integrated into load controllers Almost all the types of sensors described above are available as either a sensor to be connected to a lighting control system or as a stand-alone device that integrates the sensor with a load controller. Photocells mounted on road lighting columns fit the category with their integrated relay which interrupts the supply to the control gear. The most popular stand-alone devices are PIR movement sensors that either switch, or dim, locally connected luminaires.
Luminaires supplied with integral control sensors can be stand-alone devices. Often called intelligent luminaires, it would be more correct to describe them as self-managed. These are good solutions for some smaller offices and rooms but expert advice should be sought when applying these to wider areas.
In some cases, it is also possible to integrate these self-contained luminaires with the rest of the lighting control system. www.thelia.org.uk
Lighting control modules (load controllers) - covering both switching and dimming
In this guide the term lighting control module (LCM) is a generic description of the unit that actually switches and/or dims the lighting. There are several more specific terms used for these components, either due to its manufacturer’s description or its physical / mechanical application. A LCM may be a single or multi-channel device and can be presented in a range of formats. The following list covers the majority of LCM types that may be encountered within a lighting control system: • Plug-in (or pluggable) LCM • Hard wired LCM • Compact, or luminaire mounted, LCM • DIN rail mounted LCM • Lighting control panel • Dimmer rack
Plug-in (or pluggable) LCM This type of LCM is a popular solution used in many commercial office projects distinguished by the fact that it has multiple socket outlets to supply the luminaires adjacent to it. In effect it is a distribution point for the lighting in its vicinity and integration of controls into installation material. These LCMs have varying degrees of intelligence and addressability. In their simplest form they are little more than marshalling boxes with the focus being on installation cost benefits rather than effective lighting control.
Their complexity then builds in two ways:
1. The number of sockets in the unit controlled by each channel reduces until there is a one-to-one relationship. 2. The degree of addressability within the lighting control system, which ultimately is the ability to identify each individual channel and socket.
The plug-in LCMs vary in their physical configuration and size, which largely depends on their functionality and chosen connector system.
In addition to their outputs being done via socket and plug, some also have their supply and network connections done by connector systems to meet the demands of those installations using modular wiring systems. www.thelia.org.uk
Lighting control modules (continued)
Hard wired LCMs These LCMs are intended for those parts of installations which are fixed and most easily wired using more conventional methods. Generally these units are supplied in adaptable enclosures with mechanical features that facilitate electrical installation. As with plug-in versions, these LCMs have varied levels of intelligence and ability. If they are fully addressable then they will also be connected to the lighting control system network. Typically these units are used in the core areas of office buildings, and usually located in electrical cupboards.
DIN rail mounted LCM Many suppliers offer their LCMs in a DIN standard enclosure to facilitate its installation into electrical distribution equipment. These LCMs clip on to a top hat profile rail and may vary in length; their cross section however must conform to the DIN standard. These LCMs can be combined with other DIN rail devices, like contactors, MCBs etc. to form an integrated lighting supply and control panel, which can benefit installation costs in some applications.
Lighting Control Panel Some projects require LCMs to operate very high current lighting loads that far exceed the capacity of a normal relay. In these situations LCMs may be used to control the coils of heavy duty switching contactors, and it is often convenient to assemble all the necessary components into one large control panel. This type of panel is usually located adjacent to the lighting distribution board and hard wired into the installation. These panels also take care of those instances where the installation requires the lighting wiring to use larger cable sizes due to the distances involved. Most LCMs will only accommodate 4 mm2 cable terminations; some industrial applications require 10 mm2 cables.
Dimmer rack A dimmer rack is usually a multi-channel device that combines an addressable unit with a number of dimmer modules and often includes an isolator and MCBs. In this format it can effectively be used as an intelligent lighting distribution board, effectively reducing installation time and effort. Common sizes offer 4, 8, 12 or more channels and each channel may be rated at 5, 10 or (sometimes) 20 Amps. www.thelia.org.uk
Network components
Lighting control systems vary greatly in size, architecture, complexity and ability; those that have the most features and functions rely on data networks to operate. The network may use cable or be wireless but either way it is likely to require additional equipment - beyond LCMs and sensors - to handle the data traffic and create a reliable lighting control system. In effect network components are used to distribute the systems intelligence, assist in set-up / commissioning processes and to manage the data streams. Suppliers have a number of names for their network components:
• Load Controllers • Processors • Interfaces • Routers • Repeaters • Bridges • Gateways/Application controller
The distinction between the functions of these components is usually indicated by its name; a bridge or repeater is likely to be simply a means to extend a system because of either its length of network or the number of controlled items. Using the word control or controller in the name indicates that the unit may well be more intelligent; it could well be providing the same functions as a bridge or repeater but added to this may be a degree of data gathering, storage and/or self-contained control functions. www.thelia.org.uk
Network components (continued)
Central controller vs Distributed intelligence
A central controller has historically been the brains of the lighting control system or BMS. Advanced in electronics and miniaturisation means that it could be a dedicated device, or it can be software based, which can be hosted locally or remotely. However, distributed intelligence provides improved response and reliability by bringing communication and decision making locally for the users. Also consider the robustness of the system, please refer to the IoT guide LIATS38 – Interim guide to IoT and lighting.
If a lighting control system is required to respond to global commands (i.e. automatic functions that may affect the whole system) then it is likely that some form of central controller will be needed. A central controller can also provide a gateway to other building control / monitoring systems. Arguably the most beneficial role of some central units is their ability to monitor the systems they are attached to; logging the hours run on each output and recording faults. The ability to record hours of use helps the owner to determine how much electricity the lighting is using and the impact any changes in the control programme might have.
Additional beneficial features offered by central controller include emergency lighting testing and monitoring together with fault diagnostics, integration to the BMS of a building or campus, remote access for maintenance, etc.
Lighting management software Virtually all networked lighting control systems rely on some form of software for their set-up, configuration, commissioning and day-to-day operation. The software may be resident on the systems central controller or only provided by the supplier during set-up and any future reconfigurations. There may also be access via the internet that allows the user, the engineer, or any other authorised person, to review and even amend current settings. www.thelia.org.uk
Network components (continued)
Protocols In any lighting control system that links several components on a network the signalling between the units needs to conform to a recognised protocol; i.e. each system component must understand the data language used. The protocol used within any given lighting controls system might be entirely proprietary (i.e. it is specific to that system or supplier) or it might conform to an internationally recognised standard. This section intends only to inform the reader about which protocols / signalling standards are used by lighting controls suppliers and to expand on any abbreviations.
Examples of protocols / standards which may be encountered when discussing a lighting control system:
• Bacnet • RS232 • RS485 • Echelon LonWorks • KNX: previously known as EIB: the European Installation Bus • DMX 512: Digital MultiPlex • RDM: Remote Device Management - an extension of DMX 512 • Zigbee (RF standard) • Bluetooth • DALI: Digital Addressable Lighting Interface (DiiA) • DSI: Digital Serial Interface • Analogue 1-10V dc (also 0-10V dc - occasionally) interface • Internet/ PoE/ Ethernet / Wi-Fi protocols • Mains Borne signalling • Distributed DC • VLC/Li-Fi
Some of the above are known as open protocols, which mean that products from multiple vendors can work on the same network. However, it is important to verify the degree of interoperability between the different systems or components, and check with the manufacturers if necessary.
Multiple protocols might be encountered at different levels within any given lighting control system. Additional expertise may be required when integrating multiple protocols. www.thelia.org.uk
Network components (continued)
Wiring and connectivity The system components need to be linked to form a network. The system network can be implemented over low voltage bus wiring, Ethernet, mains, Wi-Fi, or other wireless means in order for signals to be passed around. This may vary between manufacturers, or even systems from the same manufacturer. Hybrid systems that use multiple connectivity technology are increasingly more common. For example, a central control unit can be connected to the IT infrastructure using Ethernet, a wired connection to the fixtures, and wireless for sensors and controls.
Bus wiring is a particular cabling area where care must be taken during installation to ensure a problem free period after commissioning. Always follow the supplier’s advice concerning the selection of the bus cable, its polarity rules and other installation / topology constraints. Some suppliers may ask for a record of the details of the installed bus cable runs, and installation should always follow the latest regulations and standards for installation.
Busbars Some suppliers offer pre-wired busbar systems to supply lighting with both power and command signals. These are often used to minimise labour costs. Always check with both the busbar and controls supplier regarding compatibility between the signal cable and the chosen protocol. Compatibility with light sources and gear There are two aspects of compatibility that need to be considered when selecting appropriate lighting controls. Firstly, different light sources require different control methods and strategies; while the other aspect relates to the technical compatibility between control gear and functional performance. Reputable suppliers and manufacturers will give good advice on this subject.
Equipment compatibility is largely limited to the ability of a lighting control module to operate the connected control gear. If the control gear requires a DALI command then this protocol must be provided by the lighting management system. www.thelia.org.uk
Network components (continued)
Interfaces to other systems - AV, HVAC, BMS, security The vast majority of lighting controls can interact with other building services and controls. Some examples are briefly described below.
Building management systems (BMS) Most BMS installations were primarily intended to manage the HVAC and rarely include lighting services. However, giving a BMS the ability to intervene and manage the lighting control system is now a very common requirement. For example the BMS might ask the lighting to close down for a holiday period, or some exceptional event, that is not programmed into the lighting controller. The real opportunity lies in the fact that the lighting control system sensors can inform the BMS about occupied zones in great detail. This is an additional value that can be delivered by the lighting control system; potentially enhancing the energy savings in other building services.
Audio Visual Systems (AV) Lecture theatres, meeting and conference rooms often have audio visual systems that can be operated from a control panel on the lectern, or from within a control / projection room. As different use or events require different lighting such controls are often required to operate the lighting as well. The link may require a special interface component to translate the control panel command to a volt free closure into the lighting controls, or it may be that there is specific input that is compatible to both systems.
Security systems The movement sensors within a lighting control system can be used to supplement the coverage of a security system. After hours the operating mode of the sensors can be altered to inform a dedicated LCM output (or volt free contact) that is in turn connected to the security network.
Control of lighting is one of the most visible forms of energy saving. www.thelia.org.uk
STANDARDS AND REGULATIONS This section looks at the relevant building regulations and codes with respect to their influence on the selection and application of lighting control systems. The following documents are specifically considered to be relevant:
Building Regulations: Approved Documents L2A and L2B (England and Wales) • These documents cover the energy usage in new and refurbished non-domestic buildings. There is a strong emphasis on controlling lighting to reduce the energy consumption in use. BS EN 12464-1 Lighting of indoor workplaces • This European application standard provides the lighting design requirements for indoor work places and recommends the use of controls where necessary.
BS EN 12464-2 Lighting of outdoor workplaces • This European application standard provides the lighting design requirements for outdoor work places and recommends the use of controls where necessary.
BS EN 5266 Code of practice for the emergency escape lighting of premises • This British Code of practice provides the requirements for the application of emergency lighting in all work places when the mains supply fails. Activation of the emergency lighting may be by a number of different control mechanisms which are identified in the LIA document: “Considerations for the interface of emergency lighting with normal lighting control systems.”
BS EN50171 Central power supply systems • This European product and application standard covers the central supply of power to the emergency lighting when the main supply fails. Controls are used to facilitate this and advice is given in the LIA document: “Considerations for the interface of emergency lighting with normal lighting control systems.” BS EN 50172 Emergency escape lighting systems • This European standard specifies the provision of illumination of escape routes and safety signs in the event of a failure of the mains supply. This is detected and controlled by controls. See LIA document: “Considerations for the interface of emergency lighting with normal lighting control systems.”
BS EN12193 Sports lighting
• This European standard specifies the provision of lighting for sports events. Control of that lighting and the emergency lighting is made by controls. www.thelia.org.uk
Standards and regulations (continued)
BS EN15193 Energy performance of buildings – requirements for lighting
• This European application standard covers the prediction of lighting energy use in buildings. There is an emphasis on the use of controls for lighting to reduce energy consumption in use.
Building Management Systems (BMS) systems
• This is a computer-based control system installed in buildings that controls and monitors the building’s mechanical and electrical equipment
CIBSE Lighting Design Guide LG7
• This is a lighting design guide based on BS EN 12464-1 (see above)
CIBSE Commissioning Code L
• CIBSE Commissioning Code L presents current standards of good commissioning practice in the form of recommendations and guidance.
BREEAM
• A design and assessment method for sustainable buildings
LEED
• Developed by the U.S. Green Building Council (USGBC), LEED is intended to help building owners and operators be environmentally responsible and use resources efficiently. www.thelia.org.uk
GLOSSARY
Area control unit Communications or signal bus A control unit controlling a significant area of a building into A communications network used to connect field control which one or more local control units may be connected. devices such as outstations and unitary controllers.
Building management system (BMS) Configuration A BMS has at least one permanent operator workstation The process of linking basic pre-defined control (BMS supervisor) connected via a communications functions to provide a control strategy. network to a number of direct digital control (DDC) controllers which are often referred to as outstations. Controlled illuminance Managing the output of luminaires by using an internal Building logbook light sensor to set a target level of illuminance. A document detailing the state of the building services systems within a building as defined by Approved Control strategy Document L2 2002 of the Building Regulations. A list of required control functions for various areas of the building. Commissionable system A system designed, installed and prepared to Correlated colour temperature (CCT) specified requirements in such a manner as to The temperature of a full radiator (black body) which enable commissioning to be carried out. emits radiation having a chromaticity nearest to that of the light source being considered. Commissioning Lighting commissioning is the process of ensuring that a Corridor link lighting scheme performs according to the design intent which Facility that relates office lighting to circulation lighting so should embrace the needs of the owner and occupants. It that exit routes are kept lit while any office lighting is on. includes the setting-to-work of an installation, the regulation of Critical path analysis the system and the fine tuning of the system. A method for defining the time critical processes in a project. Commissioning completion certificate A document signed off by the relevant parties as Design criteria defined by the contract to confirm that commissioning The specified numerical quantity together has been completed to their satisfaction. with allowable tolerances.
Commissioning management Design intent The planning, organisation, co-ordination and A written specification of the whole lighting and control control of commissioning activities. system prepared by the lighting designer giving the design criteria, control strategy and other system Commissioning manager (CM) The firm or person appointed to manage requirements, as appropriate. the commissioning process. Digital multiplex (DMX) system E.g. DMX512 - Asynchronous serial digital data Commissioning method statement (CMS) A document specifying the processes required to transmission standard protocol for controlling lighting achieve commissioning and those responsible for equipment and accessories. Although it was originally completing those processes. defined by the United States Institute of Theater Technology (USITT), its technical definition is always Commissioning plan or timetable being reviewed and updated by ESTA (Entertainment A time schedule for the various works required Service and Technology Association). to complete commissioning. Dimming Commissioning specification varying the light output / intensity of a luminaire. The document that prescribes the requirements with ‘Dimming’ systems are generally those that are used in which the various commissioning services have to conference rooms etc. whereas ‘regulation’ or variable comply. (Note: the specification should refer to drawings, output is used to describe the same control in offices. schedules and relevant parts of the Code, manuals, guides and other standards.) www.thelia.org.uk
External light sensor Lighting connection unit Light sensing device mounted externally to A unit that connects a luminaire to the low measure ambient lighting conditions. voltage power supply.
Field control device Lighting controller A control device such as an outstation or unitary controller. Any control unit for a lighting circuit.
Fit out Lighting designer (LD) The process of altering the internal configuration The person responsible for the detailed design of of a building to suit the user’s needs. the lighting scheme.
Flexibility Local control unit The ability of a lighting installation to adapt to A control circuit for a small area that may be an individual changing needs and/or layouts. (One of the popularly cellular office or part of a larger open plan area. The control promoted benefits of lighting controls.) unit should be in the vicinity of the luminaire(s) it controls.
Gateway Low voltage A device used to link two or more control systems Voltage level up to 1000V. which have different communication protocols. Mains-borne signalling Group dependence Transmission of command or data signals super- Similar to ‘corridor link’ but used where the linked lighting imposed onto the power cabling (also known as power is required for comfort or environmental reasons. line carrier (PLC) signalling)
Handover Maintenance factor The process of handing the building over from the The ratio of the illuminance provided by an installation at contractor to the client following practical completion. some stated time, with respect to the initial illuminance e.g. that after 100 hours of operation. The maintenance factor is Hard and soft points the product of the lamp lumen maintenance factor, the lamp Points in the system where hardware (hard) or software survival factor (where group replacement without spot (soft) can be checked during the commissioning process. replacement is carried out), the luminaire maintenance factor and the room surface maintenance factor. Hard-fired Term used to describe certain solid state dimmer circuits. Marshalling box Plug-in connection unit for luminaires that is similar to HID lamp Abbreviation for high intensity discharge lamp a plug-in lighting control module. It may or may not have intelligence / addressability. Usually contains High frequency control gear between six and ten sockets. Generic term used to describe electronic ballasts Miniature circuit breaker (MCB) for fluorescent lighting. A circuit and cabling protective device used in Intelligent luminaires place of a fuse. Luminaires with in-built sensors and control circuitry. Modular wiring Internal light sensor Pre-fabricated wiring harnesses designed to provide rapid A photo-sensitive device that reads internal lighting levels, installation of lighting circuits and small power in ceiling usually as observed from the ceiling looking down. voids. Basically a ‘plug and socket’ approach to wiring.
IR Occupancy detection Abbreviation for ‘infra red’, which is commonly used as a Sensing the presence of occupants through PIR, means of transmitting coded commands for the purpose microwave, ultrasonic or acoustic technology. of remote control. Usually initiated by hand. Sensing technologies may be combined (c/f security systems) to give greater accuracy / reliability. Leading-edge dimmer Type of dimmer that ‘chops’ the leading (or rising) Operating and maintenance manual (O&M edge of the mains sine wave to reduce power manual) A series of documents detailing the delivered to luminaires. design, mode of operation and maintenance requirements of building services systems. www.thelia.org.uk
Operator workstation RF A device used to provide a central monitoring facility for Abbreviation for ‘radio frequency’, which is used in a a BMS. Also referred to as a central station, head end, similar manner to ‘infra-red’ transmission. This host or BMS supervisor. technology is also used to provide ‘wireless’ communication between system devices. Outstation A device capable of control and monitoring functions to Scene Setting which sensors actuators and other controls are The use of a lighting control system to create a number connected. Outstations are linked together by means of of different lighting effects that can be set (and recalled) a communications bus. using a single command from a show controller or push- button. (The latter can be called a ‘go to’ switch.) Override A system, usually manual in operation, which will Specification override the automatic control strategy. The document that prescribes the system design and requirements for commissioning by reference to Performance testing drawings, information schedules and relevant codes, The testing of a system, or a grouping of systems, to manuals, guides and standards. determine if certain performance criteria are met. Switching Photocell ON-OFF operation. A photo-sensitive device used to provide a reference lighting level. System integration The linking of two or more control systems PIR from different manufacturers. Abbreviation for ‘passive infra-red’, which is a presence / occupancy sensing technology that is based on Testing looking at moving ‘hot bodies’ or infra-red signatures. The measurement and recording of system parameters to assess specification compliance. Point data Data collected at pre-determined points in the Time schedule system during the commissioning process. A programme used to manage lighting according to the time of day. Practical completion A legally defined point in the construction process where a Trailing-edge dimmer designated person, often the architect, agrees that all major Type of dimmer that ‘chops’ the trailing (or falling) construction tasks have been satisfactorily completed. edge of the mains sine wave to reduce power There are still likely to be small defects (snags) that must delivered to luminaires. be rectified later. Unitary control device Pre-commissioning A control device that controls one single unit, which Specified systematic checking of a completed installation will often be an integral part of that un to confirm its state of readiness for commissioning.
Predictive occupancy control The use of a time schedule designed to control lighting use in line with the hours of occupation.
Ramp speed The rate of fading or dimming a light. Used in ‘scene setting’ to add interest to the establishment of different lighting effects.
Regulation Varying the output of fluorescent luminaires by managing the control gear.