Lighting in the workplace
For many facility managers, the main motive to switch to LED lighting will be to lower the operating costs of occupying an office through both reduced energy consumption and less frequent maintenance. But these benefits should not override the need for quality of light.
Simply increasing efficiency at the expense of visual comfort or the appropriate distribution of light would be an unhealthy trade-off. In that spirit the latest European standard on indoor workplace lighting, EN 12464-1, is intended to improve office lighting in a design-led manner.
It emphasises both quantity and quality of light, pushing businesses to provide sufficient lighting while simultaneously economising on energy consumption. For many, that is going to mean adopting LED lighting technology for the first time.
The standard also encourages that all types of light sources are considered, a definition including – for the first time – natural light, as well as the specification of minimum lighting levels for walls and ceilings.
For successful office installations, close and early dialogue between lighting planners and facilities managers in the course of a new build or lighting upgrade is critical. After that, LED luminaires that provide the required glare control and luminous distribution should be shortlisted for each office area, before the most efficient one from those that meet the criteria is selected.
Here are five tips to help create more effective and efficient office lighting:
Reception area: the “front door” of the office, the entry point for all staff and visitors, always says something about the business and its values. Lighting in the reception area should combine comfortable lighting levels with visitors with sufficient task lighting for receptionists and visual cues to locate desks, doors and stairways. For example, PAR 16 spotlights that can be used as adjustable ceiling lights giving directional light to areas you need. LED PAR16s provide similar output and beam profile characteristics of halogen and CFL lamps while using only a fraction of the power.
Indeed, Verbatim has recently introduced PAR16 GU10s and MR16 GU5.3s LED lamps with diamond cut optics to reduce glare, stray light and hotspots associated with many competing products. The LED spotlights particularly mimic the warmth and dimming characteristics of halogen lamps along with exceptional beam management and high brightness.
The UK’s Chartered Institution of Building Services Engineers (CIBSE) recommends a minimum illuminance of 200 lux (lm/m2) for office reception areas. Aside from the general light, use coloured LEDs for accents and cove lighting to guide visitors to the reception desk and make seating areas more inviting – or even use them to reinforce branding by reflecting corporate colour schemes.
The open-plan office: Lighting the open-planned office effectively is not simple, largely because the potentially wide variety of visual tasks performed – CAD work, proof reading, technical drawing – would ideally all receive optimal illumination. And while several studies have shown that productivity increases with overall light levels, it is equally important not to bombard your workers with harsh lighting from fluorescent tube lighting.
Achieving that balance in practice is difficult, but there are some general guidelines. Illuminating ceilings and walls will make any room feel higher and larger, while ensuring uniform brightness helps to control glare – one of the key requirements in all office lighting standards.
The CIBSE’s Office Lighting Guide states that to avoid rooms appearing dark they need to achieve around 30% of the average working plane illuminance on the ceiling, and 50% on the walls. So a typical working plane illuminance of 400 lux should be augmented with an average wall illuminance of 200 lux, and an average ceiling illuminance of 120 lux.
That changes office dimensions, however: if the ceiling height is below 2.4 metres, the 30% level on the ceiling can be reduced – but to no lower than 20%. Any less and the ceiling will look dark, possibly even oppressive.
Workstation areas and controls: the watchwords here are glare and contrast – and minimising both will help to create the best lighting environment for staff working mainly with displays. That means positioning their screens perpendicular to windows, and ensuring that overhead lighting is not positioned directly above desks, but distributed more evenly.
Square-shaped, recessed LED luminaires are good for controlling overhead glare while creating a comfortable and bright office ambience. Many companies provide 600mm x 600mm linear ceiling lighting LED systems for offices. However, even small variations may result in undesirable effects so levels of overhead glare and desirable room surface brightness need to be balanced correctly.
CIBSE and others recommend that general lighting in an open plan office provides an overall background illuminance of 300 lux, but with the option of an additional 200 lux at each workstation to provide a minimum working illuminance of 500 lux.
Task lighting: for spot-like illumination of visual tasks, LightingEurope recommend the use of warmer white light with reduced blue content. For technical drawing, more demanding visual tasks, a minimum illuminance of 750 lux is required.
It is also important to avoid any intense or uneven lighting in a staff member’s field of view, and to use well-distributed, diffuse light to reduce the degree of contrast between ambient light levels and screen brightness. Ensure that task lighting does not reflect off of screens – this kind of glare is expressly outlawed by the latest European workplace lighting standards. Desks and screens should be arranged to avoid glare and bright reflections, by ensuring that they do not directly face windows or bright lights.
Match natural light with LED: the consensus among designers is that natural, wide-spectrum daylight offers the best office light, and architects now strive to design buildings incorporating as much as possible. But the level of daylight varies throughout the day, as well as with site orientation, latitude, the seasons and the local weather.
Unlike conventional sources, intelligent lighting systems based on LEDs are able to augment natural light levels and colours, offering the flexibility to adapt to all conditions. They also take advantage of the broader light spectrum produced by high-quality LED sources, which is closer to that of natural light than fluorescent lamps.
According to CIBSE, a CCT of around 4000K is best for blending daylight and artificial light. So while a lamp with a static CCT would never be perfect because the colour of daylight is constantly changing, the dynamic lighting control possible with LEDs can be used to adjust the output to provide the best match.
Don’t forget, controls are important too. For large open-plan offices, ultrasonic ceiling-mounted occupancy sensors with manual-on automatic switches will help make savings when rooms are empty. Wall-mounted occupancy motion-detection sensors would work in office layouts with closed off areas and corridors yet still provide light where and when it is needed.
In addition, the company is an innovator in fast-growing LED and OLED lighting, developing products that offer low power consumption, long life and a better lighting experience. It is also an emerging supplier of water filtration systems; its Cleansui brand is Japan’s favourite water filter.
Verbatim is a subsidiary of Mitsubishi Kagaku Media owned by Mitsubishi Chemical Corporation, one of the world’s largest chemical companies, which invests heavily in R&D across many diverse sectors. The company’s operating principles are founded on helping people to live in a healthy, comfortable and sustainable way. Verbatim’s regional organisations are EMEA, APAC and Americas, with offices in most countries in the world. The company’s European headquarters are based in the UK. For further information, visit http://www.verbatim.com