The new era of LED lighting has over-turned existing thinking on the lighting of workplaces. Most commercial organisations are keen to benefit from the very real cost savings offered by the new technology and many are planning refurbishment as a priority. These are the key factors that should be kept in mind when considering your next step.
1. Visual comfort high priority – Vertical surfaces to be lit
The key to an effective working environment, from a lighting perspective, is comfort for the eye. Vision has to work hard focussing on a screen so it doesn’t need more visual challenges than necessary in the office environment. Lighting designers talk of uniformity between the vertical and horizontal planes. Simply the reflected light emanating from walls, ceilings and daylight itself as it streams through windows has an effect that can add to optical strain and worker stress. The purpose of a good office lighting scheme is to minimise the perceived contrast between windows and interior surfaces. Reflected light from walls adds to the overall ambient lighting levels too – they must have a reflective colour of at least 80% reflectance to contribute as a light source. Something to consider when planning the interior decor scheme. Remember also to include internal walls and partitions in this consideration, everything in view from waist level and above. Also take into account that a ‘natural’ colour rendering of white will create a space where people and flesh tones appear ‘real’ – creating a more comfortable workspace.
2. Visual comfort high priority – Glare minimised
Indirect and diffused light are the most comfortable types of light to live with in an office. Bouncing light off a ceiling is a popular way of softening light. Suspended ceilings are ideal mediums to reflect light off but they need to be sufficiently high to have an overall effect and there has to be a minimum clearance of 300mm between the fitting and the ceiling, to allow a fixture to bounce the light appropriately.
Glare is an extreme form of visual discomfort and is caused by large variations in perceived light intensities. It is vital to be vigilant about daylight and as important to balance this strong natural light with equally bright artificial interior lights. In your choice of lighting opt for fittings that offer a UGR factor of less than 19.
3. Energy efficient lighting
Before we talk about the efficiencies of new lighting technologies, spare a thought for nature. After all daylight is the cheapest and best form of lighting – be aware of south west facing windowed offices that will need less daytime artificial lighting, when planning your scheme. Later we will talk about light sensing control systems that offer real cost savings and occupancy switches.
If you are currently planning an office refurbishment, no doubt it will be motivated by the benefits of moving from fluorescent lighting to an LED scheme. In most offices the ceiling grid panel light has to be considered as the ‘work-horse’ of the typical office lighting scheme. LED offers an easy fit swap-in and out alternative that provides significant energy savings. As a semi-conductor technology developments in LED lighting move at a rapid pace. Only one year ago we would have been content with a light (lumens) to power (watts) ratio of 70 to 80 lm/w. Integral LED have been first to announce 117 lm/w panel (picture) and they will shortly be followed by other LED lighting manufacturers. It is key to any office lighting project to ensure that the most efficient and therefore the most cost saving panel is specified in order to ‘future-proof’ the scheme.
In many ways control is the future of lighting. A new term, ‘Daylight Harvesting’ is now all the rage. It deploys lux level sensors to dim and turn off the fixtures that are not required. This is especially useful for lighting zones that are around the perimeter, near to windows and skylights. Ultimately you can micro-control a complete scheme using a centralised control system like Dali. All light sources are addressable to a control package and separately managed. If Dali is a little too hi-tech then ask your electrical contractor to zone-up your office with groups of fixtures. In this way you can operate the scheme based upon time scheduling to match usage or by utilising occupancy detection. Ironically night time requires lower levels of light as artificial light sources are not required to balance out the higher levels of daylight. Be open to dim all lights on a timed basis.
5. Task Lighting
If there is a key take-away from this list – it’s to embrace task lighting in your scheme. Office lighting is often two dimensional because it washes strong white light into a space which flattens everything in the environment. Less light allows for contrast and areas of dark and light which shapes interior features. Mostly this happens because of a determination to provide a generalised task light. It is a level of illumination conventionally measured at 500 lux which is harsh and bleaching. So the trick here is to use more localised task lights one per desk and hence freeing up the ceiling fittings and other ambient lights to lower levels. This adds to a more comfortable environment that exhibits a lower ambient lux level which is more restful on the eye and provides enough contrast for focal points to be highlighted – i.e. artwork, a feature wall – break out area etc.
Remember to revise your maintenance costs. How many electricians does it take to change a light bulb – is shortly going to be a thing of the past. Fluorescent tubes on the blink, dodgy starters and halogen lights that go pop in the night. LED replacements have a lifetime of 20 years and they still won’t go pop, they will just fade away. So factor that cost saving into your refurbishment proposal and the numbers will come up looking like a ‘no-brainer’. It will also provide an essential ingredient for a positive BREEAM status. Additionally, consider lighting high bay and other hard to access areas if the opportunity exists. You will not have to replace awkwardly positioned fittings for an age.
7. Circadian Lighting
No fancy office lighting scheme would be complete without an acknowledgement to circadian systems. They may sound fanciful but this is a science used by NASA no less. Changing the hue of light can add to productivity and the alertness of workers. Adding blue into the spectrum keeps your co-workers awake whilst a redder white is appropriate for rest areas. Affordable systems are available and a realistic consideration.
If you have an office interior project – call us to discuss your lighting options – we will be happy to help!