Environmental factors and layout
There are various types of environmental factors that may present in offices. They include: lighting, noise, thermal comfort and general office layout.
Good lighting in workplaces is essential to enable people to see clearly and perform their work safely. The key factors to consider when determining the adequacy of lighting are the:
- amount of light in an area;
- number, type and position of the light sources; and
- tasks or activities performed, how often and for how long these are performed.
In general, good lighting should enable people to easily view their work and environment without the need to strain their eyes. However, different activities require different levels and qualities of light. Activities that do not require a high level of visual acuity – for example, walking through a corridor does not require high levels or an optimum quality of light. On the other hand, tasks such as drawing or checking a document for errors involve fine and detailed work requiring a moderate to high level of visual control, and so greater levels and a higher quality of light are required.
How much light is needed?
We are able to see quite well in a wide range of lighting levels due to the ability of the eye to adapt to different lighting conditions. For example, when you move from a bright room into a relatively dark area, or vice versa, your eyes adapt and over time (some seconds) you are able to see more clearly. To reduce the demands on your eyes and the need to adapt when changing tasks or viewing fields, or when moving from one work area to another, specific levels of lighting for particular types of tasks are recommended.
How is light measured?
The amount of light in an area can be measured using a light meter (or lux meter), which measures the amount of light falling onto a surface known as the luminance of that surface. Recommended luminance levels for different types of work areas are approximate and are shown in the accompanying table.
|Class of task||Recommended Illuminance (Lux)||Characteristics of the Activity and Interior||Activities & Interiors|
|Intermittent use||80||Interiors requiring intermittent use with visual tasks limited to movement and orientation||Staff change rooms|
|Simple||160||Occasional reading of clearly printed documents for short periods||Waiting rooms|
|Ordinary or moderately easy||240||Continuously occupied interiors where moderately easy visual tasks with high contrasts or large detail are required||Computer usage|
|Moderately difficult||400||Areas where visual tasks are moderately difficult with low contrasts||Routine office work|
|Difficult||600||Areas where visual tasks are difficult with low contrasts||Drawing offices, proof reading|
Recommended illuminance levels for various types of office tasks, activities and interiors. Adapted from AS 1680 : Interior lighting
Quality of light
This refers not only to the level of lighting, but also to other factors which have a significant impact on how well we are able to perform a task. The following factors need to be taken into account when designing lighting for office environments. A lighting designer should be consulted for designing lighting in a new office area.
- the number of lights in use – having the correct number of lights will provide evenness of lighting over the area;
- the type of lights, e.g. fluorescent tubes, tungsten and halogen lights – the most common type of office lighting is fluorescent, most resembling natural light and long-lasting. Fluorescent lights can provide different qualities of light, such as white, warm, natural, daylight or colours;
- the type of light fittings used – the design of light fittings can influence the direction of lighting;
- the position of the lights – lights should be positioned to illuminate the workstations;
- how colours appear under them; and
- maintenance of the lighting system.
When identifying, assessing or controlling lighting issues in offices, you need to take into account the time of day and year, as this will affect the quantity and quality of natural light in a work area. This is particularly important when designing lighting systems. Natural light is important as helps maintain a normal circadian rhythm and therefore is useful in reducing fatigue.
Some of the office lighting issues may be caused by natural light entering a work area. Getting the balance between natural and artificial light can be difficult therefore providing staff with control and adjustment of natural light, for example, venetian or vertical blinds, many of these issues can be addressed.
Glare occurs when one part of an area is much brighter than the background or vice versa. For example, if a bright window is positioned behind a computer screen, the contrast (difference between dark and light) can be so great that the eyes have to constantly adapt to the change.
There are several ways to reduce glare in the office environment:
- control natural light from windows, e.g. venetian blinds enable people to adjust the light in their work areas;
- reduce the contrast between the foreground and background, e.g. the use of a slightly darker partition with a matte surface reduces the contrast between a computer screen and the surrounding area;
- reposition the workstation to reduce the light falling on the work surface; and
- reduce the general lighting to suit the task being performed.
Light reflected from a surface can make it difficult to see what is on it. For example, it can be difficult to read a screen when light from artificial lighting or windows is reflected from it. To identify reflections, observe a work surface or screen and ask the operator if they have difficulty seeing their work due to reflections. Don’t forget, light from windows changes during the day and with the seasons.
To assess reflections, hold a sheet of paper above a screen or place a mirror over the work surface to reveal the source of the reflections visible from the usual working position. Check whether the mirror indicates overhead lighting or other sources of light as a problem for that work surface.
Reflections from screens have been reduced by the development of colour monitors, Windows-based systems, LCD screens and non-reflective screen surfaces. Additional controls for reflections include positioning the screen side-on to the main light source. A light screen background also reduces difficulties caused by reflections. If these options do not resolve the problem, then consider moving the workstation to another position. This is particularly relevant where the screen is used for prolonged periods of time. These controls should be used in preference to the use of screen filters, which can reduce the quality of the screen display and require regular cleaning.
Annoying reflections can also occur in workplaces where there are highly polished floors or glass covered wall paintings. These issues should be addressed when planning and setting up an office. Even glossy paper documents can reflect light and become unreadable.
Shadows can reduce the visibility of work, contribute to glare problems and cause the adoption of poor posture in order to view work. A simple observation and test by holding a piece of paper above the viewing surface can indicate whether shadows fall over that work surface. Assessing the effect of shadows may be achieved by observing a person’s posture. If a person is adopting a poor posture to read or see their work, then shadows may be a significant problem (also consider glare and reflections).
To reduce shadows, increase the number and spread of overhead lighting, repositioning work or redirecting lighting. Barriers to light falling on the work surface, for example, an overhead shelf should be removed or relocated to reduce shadows. An adjustable task lamp may provide specific lighting where shadows are a problem, where light from a particular direction is required or when an increase in general lighting is not practicable. A task lamp can, however, create pools of light, causing the eyes to have to adapt rapidly when looking at the whole work surface, so the removal of barriers to light falling on the work surface is the preferred control measure.
Posture and the visual environment
When people find it difficult to see what they are working with, it is common for them to lean closer to the object or to bring it (e.g. a document) closer to their eyes. In both cases, this may lead to an awkward posture. People who report discomfort at work should be observed performing their usual duties. A well supported, neutral posture is less likely to result in discomfort. Where the person is not well supported by their chair, leans towards their work or adopts a posture as shown in Figure 10, there may be a problem caused by poor lighting, poor screen design or position, or uncorrected visual problems.
If lighting is contributing to poor posture, the location and all aspects of the lighting relative to the task need to be considered, for example:
- Is a shadow being cast over the work surface?
- Is there enough light for the task being performed?
- Are reflections or glare causing the person to adopt an unsatisfactory posture?
- Where visual problems are thought to exist, advice should be sought from a medical specialist or optometrist.
Eye muscles can become tired when constantly focused on close work. To identify if this is an issue in your office, ask people if they get tired eyes or other eye strain symptoms such as headaches, sore eyes, feeling of grit in the eyes.
To control visual fatigue, a change of focus, such as a view out of a window or to a picture along a hallway at a distance from the operator, can provide exercise to other muscles of the eyes while resting the tired muscles. Moving the eyes and blinking helps keep the eyes moist and from drying out and help prevent any eye discomfort.
Choice of colours can determine the mood of an environment and the level of reflection from a surface.
It is recommended that ceilings have high reflectance, (reflecting around 80% of the light) and are usually white or off white. Walls should have 50 – 75% reflectance (subdued cool colours) and a gloss or semi gloss finish. Floors should have low (less than 20%) reflectance and therefore should be darker and not glossy. The use of colourful posters or non-reflective paintings can relieve monotony and provide visual relief.
Some lights can be a source of annoyance, particularly older fluorescent tubes which may flicker when malfunctioning. Regular maintenance will help control the effects of light flicker.
Further information about lighting in office environments, and workplace facilities are available in the both the WA Code of practice: Workplace facilities and in the national code of practice Managing the Work Environment and Facilities and in Australian/New Zealand Standard AS/NZS1680 - Workplace and Interior lighting.
What is noise?
Noise is usually defined as any disturbing sound. In practice it is referred to as ‘sound’ when pleasant, and ‘noise’ when annoying.
Sources of noise
Noise within the office can originate from internal and external sources. Internal noise sources include office equipment (e.g. telephones, printers and photocopiers), people (e.g. conversations) and background noise generated by the building (e.g. from lifts and air conditioning). Background noise generally goes unnoticed unless there is a malfunction of equipment. In fact, some background noise is desirable as an absolutely quiet environment can be uncomfortable.
External noise sources can include road traffic and general industrial noise. Where noise is of a higher level, regulations in WA pertain and the Code of practice: Managing noise at workplaces can be used to provide practical guidelines to assess the risk of industrial noise exposure. Guidelines on appropriate noise levels for particular work environments may be found in AS 2107: Acoustics: Recommended Design Sound Levels and Reverberation Times for Building Interiors . The National model Code of Practice - Managing Noise and Preventing Hearing Loss at Work has a small section on noise in an office environment and its effects on concentration.
Why is the control of noise in the office important?
Generally, the levels of noise in office areas are below those levels known to pose a risk to hearing. In offices, ‘annoyance’ noise is likely which may interfere with communication, annoy or distract people and affect a person’s performance of tasks like reading and writing.
This can be costly for an organisation. Noise that prevents a person from understanding an instruction or warning signal may also be a risk to safety. For these reasons, it is important to consider what can be done to control unwanted noise in the office.
Identifying disturbing noise in the office
To identify disturbing noise sources in an office it is best to ask the people working in the area a series of questions, for example:
- What noise is most disturbing (if any)?
- When does it occur?
- What effect does it have?
- How do you deal with disturbing noise?
This may be done using a general walk-through survey that includes interviewing people.
Where noise issues have been identified as a problem in an office environment, assessment and development of noise control measures should be undertaken.
A qualified person should be consulted where specialist assessment or advice is required.
Some privacy during conversations is required, particularly in open-plan offices. This requirement should be built in at the design stage of the office layout, when the distance between people and orientation of workstations is determined.
People should be able to have telephone conversations and perform work without the person next to them listening to every word.
Partitions are frequently installed to provide privacy between workstations. This involves considering the design of the whole environment including the size, construction and continuity of partitioning and all other surfaces in the office.
Expert advice should be sought when designing partitioning to provide speech privacy. For further information refer to AS 2822 : Acoustics: Methods of assessing and predicting speech privacy and speech intelligibility .
If you need to control noise in an office environment, there are several things you can do:
- use a layout which separates noise generating activities or equipment from tasks requiring concentration;
- isolate noisy equipment such as printers or photocopiers by placing them in separate rooms;
- use sound-absorbent materials, including suitable floor coverings, wall panels, ceiling panels and dividing screens. Installation of barriers should also take into account the effect this may have on ventilation and any sense of isolation it may cause with staff;
- provide acoustic-grade dividing screens to reduce conversation noise. Studies have found that partitions with sound absorbing panels of at least 1,600mm height are required to have any effect on the transfer of sound between workstations. These panels need to be used in conjunction with other sound absorbing surfaces – floors, walls and ceilings – to be effective. In an open-plan office compromises may be made to allow communication between workstations by using 1,200mm height partitions between employees and 1,600mm between work sections;
- select equipment with the lowest noise specifications practicable;
- install noise barriers – including double-glazed windows, solid walls and fences to reduce external noise sources;
- lower the volume setting on a disruptive telephone. This is a simple way to reduce existing noise levels;
- adopt administrative controls such as encouraging employees to use meeting areas away from work areas for conversations;
- use masking sound, i.e. electronically generated background noise that is deliberately introduced to mask or cover up intrusive noises. It is best to control unwanted noise rather than try to mask it. Masking has generally been found to be an unsatisfactory way of dealing with unwanted noise (consult an expert on this issue); and
- orient workstations so that one person does not use the phone in a direct line to the ear of the person in the next workstation.
Comfort is influenced by clothing, the job being undertaken, temperature, humidity and air flow. People may feel uncomfortable if the temperature within an office is either too low or too high. High humidity can create a stuffy, sticky atmosphere and contribute to feelings of tiredness. There are considerable individual differences between people regarding what is comfortable and it is unlikely that a single temperature or level of humidity will suit everybody.
To identify thermal comfort issues in office environments, ask the people working in the area a series of questions like:
- Do you find the atmosphere hot, cold, stuffy or draughty?
- When do you notice these conditions?
- What effect do these conditions have on your work?
- How do you deal with them?
- Where do you notice these conditions?
Where thermal comfort is an issue, there will usually be a history of complaints from staff.
Where problems are identified by many staff, thermal comfort issues should be assessed by an appropriately qualified person and control measures developed in consultation with employees.
Some general suggestions for improving thermal comfort include:
- regulate air conditioning for temperature and humidity;
- consider the outside climate conditions and how people are dressed (in Winter people wear warmer clothes therefore the inside temperature can be cooler, in summer people wear lighter cloths therefore the office can be warmer). This has added benefits of also being more environmentally efficient.
- avoid locating workstations directly in front of or below air conditioning outlets;
- install deflectors on air vents to direct airflow away from people. These measures will help prevent staff being annoyed by draughts;
- control direct sunlight (radiant heat) with blinds, louvres and window treatments;
- minimise draughts and thermal differences between the head and the feet (thermal gradients); and
- ensure adequate air flow. Feelings of stuffiness can result when air flow is low, and draughts occur when air flow is high. An air flow rate of between 0.1 and 0.2 metres per second is desirable.
Air in offices may be contaminated by several different sources, including odours and micro-biological and chemical contaminants. In an office environment, the quality of the air is often controlled through an air conditioning system.
A building’s air conditioning system can be considered its lungs. The function of such a system is to draw in outside air, filter, heat, cool or humidify it and circulate it around the building. The system expels a portion of the air to the outside environment and replaces this expelled portion with fresh or outside air.
Refer to guidelines on appropriate air quality standards for the office environment are contained in the relevant Australian Standards, particularly AS 1668.2: The Use of Ventilation and Air Conditioning in Buildings: Mechanical Ventilation in Buildings . There are several air contaminants which can lead to health problems for workers in offices.
Legionnaire’s disease is an infection caused by exposure to legionella bacteria. Infection can often be traced to exposure to mists of airborne droplets carrying the bacteria. These may be related to contaminated air conditioning cooling towers and warm water systems. Other sources may include aerosols from spa baths or potting mix.
Effective prevention of exposure to legionella is achieved through appropriate design and maintenance of air conditioning systems. In law requires:
- a risk management plan to be in place; and
- regular testing and maintenance of systems.
The WA Code of practice: Prevention and control of legionnaires’ disease can provide more information. The WA Department of Health also provides information on the prevention of Legionnaires’ Disease.
Sick Building Syndrome
Sick Building Syndrome (SBS) refers to a situation where a proportion of people complain of symptoms of discomfort such as a headache, eye, nose or throat irritation, fatigue, dizziness or nausea while inside a building and the symptoms go away upon leaving the building. Instances of SBS are rare and may be related to psychosocial factors in the workplace as well as poor air quality.
Where air quality problems exist or SBS is thought to be a problem, specialist advice should be sought.
General office layout
Provision of adequate space in an office to enable a person to operate effectively is essential. There are three types of space that need to be considered:
- primary space – amenities, meeting rooms, lift lobbies and similar areas;
- secondary space – corridors and storage; and
- tertiary space – space required in a workstation to accommodate a desk, chair, drawers, filing cabinet and other necessary equipment.
The building block approach is one method used to determine the amount of space required by personnel. This is based upon a functional analysis of their needs that is the tasks they perform in their jobs. This method recommends a minimum of 6 square metres per person for tertiary space and additional space for secondary and primary space requirements. It enables planners to provide enough space for all the requirements of technical people working in offices including clerical and administrative staff. AS 1668.2 recommends an overall 10 square metres per person for offices, including primary, secondary and tertiary spaces. This standard relates to the ventilation of the building. The important thing to design for in all circumstances is the functional needs of the employee.
Generally carpet is preferred in office areas to provide a comfortable walking surface and to reduce noise, reflected light from polished floor surfaces and the risk of slips and falls. Selection of wool mix carpets reduces the build-up of static electricity which can give a mild electric shock. Carpets should be properly laid without loose edges or ripples and should be well maintained. Where there are tasks requiring pushing and pulling wheeled equipment, carpet should be low profile to prevent high force manual handling.
Walkways should provide safe access and egress at all times. The use of walkways for temporary storage can introduce tripping or falling hazards and block emergency exits. The through traffic using walkways can be a source of noise and distraction for staff positioned near them. Walkways near office workstations should be bordered by sound absorbing panelling to help reduce noise.
Partitions are used to divide workstations and provide visual and auditory privacy. They can also reduce unwanted distractions, provide a background visual surface for computer screens, reduce contrasting light intensities, help direct a person’s line of sight towards an external window for relief of visual fatigue, and control external and reflected light. Partitioning can cast shadows and reduce levels of light if not appropriately designed or installed.
Storage facilities such as filing cabinets, lockers and shelves often sit on the border of a walkway. When choosing the location of this equipment it is important to consider what other activities occur in the area. For example, a filing cabinet requires approximately 1.2 metres of space in front of it to enable someone to access a fully opened bottom drawer. If this projects into a frequently used walkway it becomes an obstruction and a hazard will be created.
Function of the space
The size and layout of a work area should accommodate the equipment and the needs of the users. Where equipment such as photocopiers, faxes and printers are used, there is a need to accommodate the equipment and allow for additional traffic and general activity.
Eating and relaxation facilities
A separate space, with access to hot water and a sink, should be provided for meal and tea breaks and to allow employees to take rest breaks away from their work desks.
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