With the manufacture of fluorescents banned last September, there is a huge opportunity for contractors to specify and install new lighting schemes for offices as we move towards winter. Andrew Fairhurst, Sales Director at Collingwood Lighting advises on how to get it right.
Stocks of fluorescents will be dwindling a year on from their manufacturing ban. This means that there will be a huge number of offices looking to upgrade their lighting this winter.
According to a report by Cluttons, there is almost 1.3 billion square feet of office space in the UK and most of this is in smaller or medium sized buildings for which an owner would turn to a contractor for advice.
Financially it makes sense for them to switch to LED luminaires, which will save 60 to 70% of their current lighting energy use. A typical payback for many offices would be two years or less.
Lighting specification
Beyond the energy saving arguments, LED luminaires will also help create a more productive and comfortable working environment.
It’s worth remembering that these buildings will have a number of different areas, and the needs of an open plan office are different to those of a meeting room, break out area or kitchen.
Good lighting design
A good lighting design combines ambient, accent and task lighting. Ambient lighting will come from both natural lighting and ceiling fixtures, with the latter normally spread at even intervals to disperse light over a general area. Wall and spotlights create both accent lighting for features and signage and task related lighting. Remember though that some task lighting will come from portable plug-in lamps.
According to CIBSE guidelines, the recommended illuminance level for general office tasks is between 300 lux for screen-based work and 500 lux for paper-based activities. You can achieve this this by combining natural light, overhead lighting fixtures and task lighting.
But we also need to light a person’s face for business and video meetings, which means that we must consider the vertical element of lighting, particularly at face height. This is between 1.2m for sitting and 1.8m. You need a minimum of 150 lux in this area.
Luminaire selection
Most people working in an office will be working on a PC, so for these areas you need to select luminaires with a unified glare rating (UGR) of less than 19.
Other factors to consider are the colour temperature, which can vary from a warm light of 2,000K to a cool white of 4,000-5,000K. For productivity and concentration, Collingwood Lighting recommends 4,000K for where people work.
Lighting control
While LED lighting will yield significant energy savings, installing lighting control can reduce this further.
Consider daylight linking sensors for the luminaires nearest the windows. These will dim the lights up and down in response to natural light levels to save energy.
You might also install presence detection sensors for each work area to save energy when specific areas of the office are vacant. For cellular offices and meeting rooms, absence detectors are recommended, which will turn the lights off when there is no further movement.
Other rooms
Other areas in a commercial office such as toilets, kitchens, corridors and stairways require different lighting.
A kitchen still needs bright uniform lighting to reduce the chance of accidents. Toilets, though, only need a level of 100 lux at floor level and 200 lux at sink level and surrounding surfaces. It’s worth installing presence detectors in both rooms.
Similarly, for stairs and corridors you need to provide light for safety. CIBSE recommends an illuminance of at least 100 lux at floor level. Again, think about presence detectors to save energy but allow a reasonable amount of time before the lighting switches off, or consider linking a presence detector to multiple fittings to light the entire area simultaneously.
You should aim to create something a bit special for a reception area and a meeting room where there are likely to be visitors. Think about lighting features, pictures or signage for the former and remember to provide lighting at 200 lux for reading in a seated area.
For a meeting room, you need to provide lighting for different tasks, so dimming control would be wise. And a pendant over a table and some wall lights create a positive impression.
Good office lighting will save energy but also create a productive work environment. It pays to spend a bit of time thinking about a design and ensuring you specify the right luminaires and control. Get it right and both the building owner and the people working there will thank you.