The Importance of Good Office Lighting

by on 09/11/2009

 

2x light bulbsIt sounds expensive! That’s usually people’s first reaction when presented with the idea of appointing a professional to provide a lighting design service. That’s definitely not the case. Good lighting design can add value to a project by reducing operational, maintenance and equipment costs, lowering energy consumption and enhancing satisfaction and productivity. The installation of a centralised lighting control system will reduce lighting energy, improve the lighting quality and can have a payback period of as little as two years for some offices. This article offers an insight into some of the technical and practical issues that should be considered in order to achieve a good balanced design. Some suggestions have been made as to a typical design approach however it is important to note that these are strictly generic. Every office requires a specific lighting solution carefully designed to meet the functional requirements and to complement the office design. This is best done in conjunction with an independent lighting designer who can offer a full range of services according to the project requirements.

A source of further information and guidance is The Society of Light and Lighting which acts as the professional body for lighting and is controlled by CIBSE (The Chartered Institution of Building Services Engineers). The Society provides a number of lighting guides, technical statements and fact files.

Introduction

The type of lighting in one’s workplace makes a very important contribution to the overall level of comfort that a building occupier and user will experience. One of the main functions of lighting is to enable work to be done quickly and easily with a high degree of accuracy and to increase productivity. This however must not be the sole aim of office lighting. Good lighting can also be motivational and mood influencing, producing in the end user satisfaction and a sense of wellbeing.

The best highest quality of light to work under is daylight. it varies naturally during the day to provide visual interest and renders colours accurately. It is also the most sustainable way to light a workplace. Unfortunately most of us do not have access to plentiful daylight within our working environment. Where daylight is poor or unavailable the quality of the artificial lighting system becomes a significant factor in defining the overall quality and comfort that an occupier will experience in the space. Therefore it is essential that the artificial lighting is carefully designed to complement the available daylight and ensure that the right quality and quantity of light is provided in the right place and at the right time.

Issues

All too often unacceptable lighting can be found within an office environment. Illumination levels tend to be too high, the quality and colour of light harsh and uncomfortable and there tends to be a lack of flexibility and control. There are several reasons for this. In new office developments and refurbishments the lighting is usually designed and provided by the developer before the end user is known. Therefore this will support generic requirements without meeting any specific needs. Sometimes this base provision of lighting is stripped out and replaced when a tenant moves in. This is neither responsible nor sustainable. In some offices the artificial lighting tends to be forgotten once installed and not adapted to keep up with a change in office use or layout, the type of task being carried out, or to take into account developments in technology. More often than not neither daylight nor artificial lighting are properly considered. This can be due to a failure by the project team to identify the benefits of good lighting design, the failure to think about the lighting design early enough within a project or due to a lack of budget. This will usually result in an inefficient unsustainable lighting scheme that does not fulfil the varied requirements for performance, comfort and ambience. If the decision is based on the grounds of budgetary constraints it almost certainly is a false economy. Good lighting design can add value to a project by reducing operational, maintenance and equipment costs, lowering energy consumption and enhancing satisfaction and productivity. The installation of a centralised lighting control system will reduce lighting energy, improve the lighting quality and can have a payback period of as little as two years for some offices.

General considerations

Good lighting is dependent on a balance between the following visual factors:

  • Performance. Ensuring that there is enough light to carry out a task, delivered to the right place in way that is not uncomfortable for the occupant.
  • Ambience. The creative use of light to attractively reveal the space, interior design and architecture.
  • Comfort. Ensuring that the light provided enables a task to be carried out comfortably and without strain.

Performance

The main issues are what lighting level needs to be provided, how even the lighting is and the avoidance of glare.

Often in offices high levels of very uniform illumination are provided across the entire floor. This includes circulation spaces, lobbies and break out areas. This is not necessary as it is expensive, wastes energy and visually is dull. A far better approach is to provide a lower level of light in the overall office area with the ability to increase lighting where required. The increase in light levels can be achieved by:

  • raising light levels using a lighting control system
  • the addition of task lighting i.e. lights on the desks

It is good to add areas of contrast to break up the uniformity and add some visual interest. It is interesting to discover that during the day lighting levels should be higher to help balance with higher levels of daylight outside. After dark, lighting levels can be reduced to balance lower levels of light outside. This will also reduce energy consumption.

Glare from direct sunlight and bright daylight must be avoided at all cost. This is best done through the use of external or internal shading devices, i.e. blinds. Light fittings can also be a source of veiling reflections in computer screens. British Standards set very onerous brightness limits based on old CRT screen technology. This can result in a very gloomy office environment. However, the limits can usually be relaxed as most computers employ positive polarity flat screens with anti-reflective coatings. It is worth mentioning that there appears to be a trend towards shiny, reflective computer screens. If this continues, veiling reflections may once again become a problem and there could be a return to onerous brightness limits resulting in a rather depressing workplace.

Ambience

Ambient lighting is feature lighting that is provided to add visual interest, texture and to reveal the internal architecture. The best quality of ambient lighting is daylight. Natural variations in colour and intensity provide a comfortable environment to work within. Office areas that do not enjoy daylight and even areas that do during dark winter afternoons will benefit from feature lighting to enhance the ambience.

Feature lighting should be provided to assist with the overall orientation of the office space. Lobbies, break out areas and meeting rooms etc. should be lit differently to the main office spaces. Providing specific lighting to columns and walls within a space is one example of how the monotony of a uniform lighting scheme can be relieved.

Another thing to consider is the use of the colour of light within a space. White light sources are available in a variety of whites from warm (yellowish) to cool (blueish) white. Contrasting areas of warm and cool light can make a space more interesting. It is generally recommended that warm colour temperature lamps are used where lower lighting levels are employed and cooler light sources for areas that are lit to higher levels.

Comfort

Visual comfort in a space is dependent upon the brightness of surfaces including light sources within the field of view. If areas are too bright or the contrast between lit surfaces is too high this will create glare. If areas are too dim or the contrast between lit surfaces is too low then this may result in a dull and non-stimulating working environment. In order to provide visual comfort within a space it is important that there are sensible contrast ratios between lighting to the task, the immediate surroundings, the near field and the far field. It is important that walls, ceilings, floors and furniture are as light coloured as possible. This will also greatly improve the efficiency of every lighting system.

Good practice is to provide some brightness to walls and the ceiling. A good way to achieve brightness to the ceiling is to use a suspended lighting system. A system that provides a combination of uplighting and downlighting provides the best balance between diffuse and directional light and therefore the best lighting quality. However this is not always possible due to limited office ceiling heights. If this is the case the next best thing is to use a light fitting that has an element of self brightness in order to break up what is otherwise a dark ceiling.

Recent studies have shown that personal control over a person’s working has a positive effect on their comfort and motivation. Individual control can be over blinds, the level of light on the desk and the heating and cooling of that space.

 

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