In the Q1 issue of Lighting in Design, we ran an article on office lighting best practices courtesy of www.opensourcedworkplace.com. Local senior electrical engineer and lighting designer, Bjorn Smidt-Hart reached out to the magazine after the publication of the article with some concerns.
While overall, the information was pertinent, he was concerned some of the guidelines presented in the article, without the application of the fundamental core principles of lighting in place, might be endangering the public unknowingly and lead to dissatisfied clients.
Smidt-Hart was invited to comment on the article, and offer his advice to those tasked with providing office lighting:
1: Before picking lighting sources and finalising on them, it is necessary for those in charge to study the office layout and plan carefully. Otherwise, it could lead to haphazard placement of lights which would then cause more disruption in office activities – poor positioning of lighting sources is as bad as poor lighting itself.
Smidt-Hart says: To elaborate on the placement of lights, one needs to consider what activities and tasks are being undertaken within the workplace, the office. The activities of an advertising agency vary greatly to that of an accounting office. Thus, these varying activities would require varying lighting conditions in order for the activities to be undertaken safely and preformed efficiently. Table 1 of SANS 10114 Part 1: Artificial lighting of interiors prescribes the minimum maintained illuminance values for various interiors, areas, tasks, or activities.
Additional compliances to national building regulations and emergency conditions must be complied with. Thus, the activities and tasks within a space are to be complemented equally with quality lighting to allow employees to perform these safely and productively.
2: Ceiling lighting is one of the first concerns when it comes to choosing office lights, as these will be fixed in maximum quantity all over the office space. It is important to ensure that the overhead lights don’t have glare to them, that is, they are not overly bright. Furthermore, the positioning of the ceiling light should not be directly over the employee’s desk – that can only be feasible if the lights are smaller.
Smidt-Hart says: The simplest and ‘cost effective’ means of lighting an office building or office floor, especially for open plan space, is through the use of a monotonous ceiling grid lighting layout, using a single type luminaire. This type of lighting may not always be cost effective, depending on the luminaire selected to addressing the tasks and activities in the workplace.
Before selecting this type of lighting, one should consider what would be beneficial to the Employer and the employees throughout the lifecycle of the lighting installation. Is it sustainable for the Employer (cost effective to implement, operate and maintain, dispose of and replace)? Is the environment and task area being illuminated adequately to allow tasks to be performed safely, efficiently and in comfort?
Although glare affects visibility and performance, there are many other factors to consider, some of which are:
- The employees undertaking the tasks.
- How to effectively use natural and artificial light to illuminate a room.
- Contrast in luminance and colour between the detail and its background.
- The colour and reflectance of surfaces within a room.
- Suitability of the light distribution for that application (direct, diffused, semi-direct, indirect lighting).
- Uniformity of illuminating the task and surrounding areas.
- Flicker and stroboscopic effect.
- Ease of maintenance.
- Visual comfort.
3: Add corrective lighting as a complement so that the balance between light and shadow is maintained. Corrective lighting acts as a mediator between the different kinds of lighting and colour temperature in the office – the natural light outside, the main lighting source used at the workplace and computer/mobile screens being used there. Such lighting makes adjustments so that the employees don’t have to strain their vision and can work in better conditions.
Smidt-Hart says: Contrast in luminance and colour between the detail and its background is important to consider to avoid fatigue as a result of the eyes being strained as the eyes constantly adjust to the varying conditions, an extreme example of this is if one were reading between a computer screen in front of a sun filled window and fined texted documents on a glossy reflective desk.
4: It is widely agreed that natural daylight is the best kind of lighting one can use for the most productive work environment. However, these days it is increasingly difficult for companies to find office spaces that are exposed to considerable daylight, so it follows that daylight-like lighting must be mimicked by closest available artificial lighting. Thus, the colour temperature of the lighting used in such offices, especially bigger and wider office spaces, should be between 5000K and 7000K, according to lighting experts.
Smidt-Hart says: The above statement is inaccurate. Implementing natural daylight into interior lighting is beneficial as it promotes synchronisation of circadian rhythm and wellbeing within employees. Artificial lighting design is moving towards simulating the circadian rhythm to assist in promoting wellbeing within employees which further promotes productivity.
5: It has been observed that brighter and warm, but white-based lighting correlates to energy and wakefulness for employees, boosting performance and productivity, while dim lights make one drowsy and lethargic at times. The idea is to find a right balance between yellow and white lights and use lighting that falls somewhere in the middle. Dimmer lighting can always be used in recreational areas to create a more relaxed atmosphere.
Smidt-Hart says: Confusion is created in the above statement whereby “dim” is being associated with low, warmer colour temperature. “Dim” lighting refers to low levels of illumination and not to the colour temperature of lighting.
Warm lighting (2000-3000 K) is viewed as ‘yellow’ light which promotes relaxation, neutral white (4000 K) promote alertness, while cooler to blueish white light (>5000 K) promote peak coordination and concentration. It is beneficial to promote synchronisation of circadian rhythm and wellbeing within employees.
6: Even today, many offices use fluorescent lights overhead to save costs, but that is not a recommended choice. Fluorescent lighting might be a cheaper option for offices looking to cut cost, but using such lighting can come at a cost of employees’ health and well-being. Fluorescent lights are very bright and can seem rather harsh to employees with sensitive eyes and/or migraine tendencies. As such lighting hurts eyes when one is exposed to them for too long, it causes disturbance in sleep patterns and causes tiredness. Thus, such lights should be avoided.
Smidt-Hart says: Lighting products of poor quality and poor performance should be avoided. Whether the lighting products are fluorescent or LED, employees may be exposed to unnecessary hazards if the lighting products do not operate and perform as required for the intended purpose.
7: If the office has a separate sitting area where guests are welcomed, it would be more aesthetically pleasing if the lighting in there is not too bright. Here, dimmer, more yellow-white-toned lights (around 2700 K) can be used to provide a calmer, more relaxed look and pleasant environment. Moreover, one can be creative with the lighting structure in such areas, including any lounges in the entire office, the cafeteria, recreation room, etc.
Smidt-Hart says: Here the use of different colour temperatures of light and intensities of illumination are used to create different sensory environments relating to the intention and purpose of the area to be illuminated.
8: Consider using task lights. In some cases, overhead lighting may not be the best option, but task lighting can salvage the situation. Task lights are small in size, and the advantage is that these can be easily plugged in to outlets as convenient to the employee and their needs. Thus, these can provide concentrated light just where the employee needs some, and using such lights will also allow the employees control over where and how they would prefer lighting for their work.
Smidt-Hart says: One should ensure that correct illumination levels are maintained over the task area, that employees are aware of the consequences of not using task lighting and the hazards of working in a workspace with below minimum prescribed illumination levels.
The workplace should, where possible promote natural light, then substitute with task lighting.
A benefit of task lighting by individual luminaires at the task area is that the general area ceiling lighting does not need to provide the necessary illumination for the task, thus less energy is consumed by the general lighting. Consider an open plan office where only certain employees make use of task lighting while others are supplemented by natural lighting.
9: Remember that some types of lights heat up and cause overheating and stuffiness in the office space. This is true for smaller offices and for low quality lighting. Such lighting will probably not have a long life and may also come with other repercussions because of the poor quality. It is advisable not to use such lighting and instead, pay a little more for better quality and longer, more sustainable use, as employees will spend many hours every week in the office and should be comfortable.
Smidt-Hart says: All lighting generates heat. Cooling systems and building ventilation designs need to take lighting systems into account.
It is important to procure quality lighting products that tend be efficient and generate less heat. Having effective and continuous maintenance programmes in place, cleaning light fittings regularly do wonders in reducing heat and energy consumption while improving illumination levels.
10: In case a combination of natural and artificial lighting is being used in the office, it is important to make sure that the sunlight from outside does not create direct glare. If any of the desk spaces or seating areas is placed in direct sunlight, the glare will distract and hurt the employees’ eyes and if it is in close quarters, it can make them feel uncomfortably warm as well. The workstations in such a case should be placed facing the general direction of natural light, but not directly.
Smidt-Hart says: Although the use of natural lighting to illuminate interiors is promoted; mitigating glare, high contrast zones, thermal and visual discomfort needs to be attended to by implementing natural daylight control measures (such as glazing, blinds, louvres, or office layouts).
11: Different areas of the office need separate kinds of lighting. Areas such as discussion and conference rooms can use ambient lighting, not dim, but less bright than workstation lighting, as the tasks here are not likely to involve much desk work. However, such areas are important zones of the office, where meetings and important conversations may be held. Lighting does need to be paid attention to, but perhaps these zones would do with only a few lights in the form of lamps or standing lamp lights rather than traditional overheads.
Smidt-Hart says: Different task areas, activities would require varying lighting conditions in order for the tasks and activities to be undertaken safely and preformed efficiently. Table 1 of SANS 10114 Part 1: Artificial lighting of interiors prescribes the minimum maintained illuminance values for various interiors, areas, tasks, or activities.
Additional compliances to national building regulations and emergency conditions must be complied with. Thus, the activities and tasks within a space are to be complemented equally with quality lighting to allow employees to perform these safely and productively.
12: Consider keeping table lamps as an option for those employees who would like some more light just at their desk. Many employees may be working late into the night and in that case, most of the overhead lights can be dimmed or switched off, keeping only task lights and the desk lamp on for the working members. This will also save electricity and will give employees more options to choose what kind of light they want to work in.
Smidt-Hart says: One should ensure that correct illumination levels are maintained over the task area, that employees are aware of the consequences of not using task lighting and the hazards of working in a workspace with below minimum prescribed illumination levels.
The workplace should, where possible promote natural light, then substitute with task lighting.
A benefit of task lighting by individual luminaires at the task area is that the general area ceiling lighting does not need to provide the necessary illumination for the task, thus less energy is consumed by the general lighting. Consider an open plan office where only certain employees make use of task lighting while others are supplemented by natural lighting.
13: Always be cognitive of the fact that where there is light, there will be some amount of shadow. It is important to consider where the shadows would fall and accordingly place light fixtures above or close to workstations. This is particularly true for task lights, which are smaller and angled particularly to cast light over certain points and may hence create unwanted shadows. Positioning in this case is of maximum importance and corrective lighting may be used alongside.
Smidt-Hart says: Uniform illumination over a task area is favourable. Working in a task area where there are large variances in illumination, like shadows, may could the operator’s eyes to become easily fatigued as they need to constantly adjust between the varying illumination levels.
14: Consider choosing lighting that can be lowered or increased in intensity as the need arises. As evening sets in and the employees prepare to wind up their day, the lights can be lowered in intensity and set to a warmer tone to calm and relax the mind. For employees working at night, ensure that the lighting remains warm, since the computer screen already has a lot of blue light, which can disrupt the employees’ sleep schedule.
Smidt-Hart says: Again, control of artificial light and use of natural light are important to promote synchronisation of circadian rhythm and wellbeing within employees.
15: It will happen at some point that some of the lights will need to undergo repair. Those lights might either go out suddenly or start flickering symptomatically. But the company must ensure that these lights are repaired as soon as possible, particularly if they are placed over workstations or other places where tasks are performed regularly.
Smidt-Hart says: In addition to attending to failing lamps or luminaires, employers should implement lighting maintenance programmes to ensure continuous and periodic maintenance of the lighting systems to allow tasks and activities to be performed safely and maintain productivity, including emergency lighting systems. It is important that verification and measurement of illumination levels be conducted and form part of the maintenance programme to ensure illumination levels are maintained.
and remain operational prior to failing. Maintenance should identify failing lighting parts before they critically fail and potentially present unsafe working conditions.
16: Office lighting is not just limited to overhead or desk lighting. Lighting is also used for visual appeal, particularly in corporate offices where companies would like people who visit to get a good first impression, much of which can be achieved by good lighting. Nowadays good quality LED lights are available in various shapes and forms. These can be used in visitor’s lounges and over display cases to provide stylish and beautiful lighting.
Smidt-Hart says: Aesthetic lighting within the office space may be used to promote the environmental comfort and atmosphere within the given space.
17: For senior employees who have their own offices, customizable lighting could be an option so that they can decrease the brightness or increase it as and when they need, depending on the task they are busy with. Further, perhaps the department in charge of choosing and installing the lighting could provide a briefing to these employees whenever new types of lights are fixed, which perform new functions. This will ensure that the employees understand how to use the lights and that they are used optimally.
Smidt-Hart says: Although a valid point of discussion relating to senior employees, similar consideration should be attributed to employees who are visually impaired or have other disabilities. As such consideration regarding the type of illumination, lamp, luminaire, mounting height or type of light switches, proposed lighting systems with or without automation or wireless control to be implemented are now of importance.
18: Another important component of lighting in any public place is safety and exit signage. An office is no different, since so many people go in and out all day long. These signs are important in case a perilous situation befalls the office, so the company must ensure that exit and emergency exit signs are always lit up and are repaired immediately in case they break down. LED signs are available in the markets now that one can easily use for this purpose – signs using these kinds of lights can last up to 20-25 years.
Smidt-Hart says: In addition to providing functional and aesthetic lighting within an office space, emergency lighting must be considered and implemented where required in accordance to SANS 10400-T of the building regulations and SANS 10114 Part 2: Emergency lighting.
19: It is necessary to remember that lighting should also correspond to the kind of task it is required for. If paperwork is to be done, or reading, for example, direct and bright light will be required. In dimmer lighting, the employees will have trouble seeing and will require additional sources of light. In case the employee is working on a computer system, the lighting can be ambient because the screen will already cast a lot of light and using brighter light sources will hurt the employee’s eyes as well as cause strain.
Smidt-Hart says: The lighting is to be designed and implemented for the necessary task, which should consider appropriate levels of contrast and uniformity to promote visual comfort.
20: Consider having a lighting control system installed for your office. This will help in utilizing lighting sources more optimally, saving power and thus saving money. Further, with a lighting control system in place, all the lights fixed in your office will be included in that one system and will make the entire process of monitoring and using the lighting, much simpler. The system will also be able to provide comprehensive information and reports on which lighting sources are consuming more electricity, which ones are used most often and so on. Ensure that the control system is also cognizant of current or preferably potential damages to lighting sources, such as blown fuses, etc, so that the safety of the office and employees is better guaranteed.
Smidt-Hart says: When implementing lighting control systems, one should also consider how such controlled systems are to operate under emergency conditions if some of the luminaires are to be used as emergency lighting.
21: Look for the lux value of the lights when you are selecting them for the office. Simply understand, lux value is the amount of intensity with which a light hits a certain surface, varying with distance. Experts say that the more light and brightness a task requires, the higher the lux value of the lights should be. For offices, it is recommended that light sources have at least 500 lux value for the necessary brightness.
Smidt-Hart says: It should be noted that lamps and luminaires are rated in terms of wattage, colour temperature and lumens, not lux. Thus, the higher the lumen value of lamp or luminaire, the illumination intensity shall be greater.
22: If the office space is vast and spread out, including several pathways and corridors, the company can make use of strip lighting on the floor or along the walls to serve as a guide for people passing through the office. Creative lighting forms can be used here, such as lit arrows, string lights and so on. Such lighting also adds a signature style, grace and a certain class to the office space.
Smidt-Hart says: This is acceptable.
23: While every employee may have different lighting requirements for work, companies should consider taking care of such needs for particular employees. Not just employees with sensitive eyes or migraine tendencies, those who are senior in age may also need different kind of lighting to work well. This also makes the need for customizable lighting even more prominent and useful in the long run.
Smidt-Hart says: Although it is important to consider the wellbeing of employees, as this promotes productivity and safer working environments, it can become difficult and costly for employers to address the lighting needs of all employees. Consider the scenario of a centrally ventilated open plan office, at what temperature should the room be at? The use of natural light should be promoted as much as possible.
24: When fixing lighting, specifically lighting systems, remember to check about colour rendering. The higher the Colour Rendering Index of a lighting source, the better it is able to render colours of objects as realistically as they would look in natural light. Good colour rendering will also be soothing and easy on the employees’ eyes and will display colours correctly on nearby screens as well. Preferably, lights with CRI of 85-90 should be used to keep the indoors environment looking as natural as possible.
25: One final thing to remember is that your office lighting, its forms and colours and the way it is all placed, should, like all other décor and components of your office space, represent the company’s brand and image as far as possible. Every company has a theme and based on that, it can have furniture, décor and lighting as well. You can experiment with simple lighting from table lamps to overheads, and with more sophisticated sources as well, such as spotlights and chandelier for the reception area. Lighting is not just about requirement; it is also about aesthetics and pleasing visuals.
Smidt-Hart says: The environment within which one works should be illuminated in such a way as to promote functionality, productivity, safety, comfort and wellbeing.
Smidt-Hart concludes
When tasked to provide best practice office lighting for normal visual conditions, one should consider the following factors:
- Psycho-physiological aspects such as visual comfort and well-being.
- Requirements for visual tasks.
- Conditions about current regulations, directives and standards.
- Visual ergonomics.
- Practical experience.
- Contribution to functional safety and emergency conditions.
- Periodic inspection and maintenance requirements.
- Life cycle and energy efficiency of the lighting systems.
These factors would assist along the detailed lighting design process in specifying and formulating together with the customer the goals and requirements that exist for the lighting system, ensuring that the customers visual needs are sought out.
