In my previous post, I highlighted some of the areas that could be investigated to ensure that your built environment stays healthy, ensuring a healthy working population. The image below shows a summary of the cause and effect of sick building syndrome.

Summary of Effects of SBS

This follow up will show how to create a conducive working environment in buildings from a service engineer’s perspective. This post provides more detailed advice on how to minimize risk in the main problem areas associated with Sick Building Syndrome and to help establish a reasonable working environment. I will highlight 10 areas to consider when tackling this problem:

Air quality, including ventilation, outdoor air supply and air movement

The ventilation system should deliver air of suitable quality and in sufficient quantity to:

  • create and maintain a healthy and comfortable environment, ie provide fresh air;
  • dilute and remove airborne impurities and pollutants, e.g. odours, tobacco smoke, fumes and dusts;
  • create and maintain a comfortable temperature and humidity;
  • prevent stagnation and draughts.

In offices where natural ventilation is not an option, a mechanical ventilation system will normally be adequate if it conforms with the following standards:

  • There should be a minimum fresh-air flow of 8 litres per second per person in no smoking areas and a flow rate of up to 32 litres per second per person where heavy tobacco smoking may occur.
  • An area with an air flow velocity in excess of 0.25 to 0.35 metres per second should be considered as draughty and of less than 0.1 metres per second as stagnant.
  • Rooms housing office machinery such as photocopiers, and rest rooms where tobacco smoking is allowed, should have separate extract ventilation systems.
  • Air inlets for the ventilation system should be sited to avoid introducing pollution from outside the building.

If you need to check that standards are being achieved, you should arrange to measure:

  • fresh air supply rates;
  • air velocities in the workplace.

But remember, turning up the ventilation rate is not the only way to deal with a problem with air quality.  A more effective response will be to identify what is polluting the air, whether it be odours, tobacco smoke, fumes or dusts, and tackle.

Home Air Quality


Failure to control the workplace temperature is unlikely by itself to cause Sick Building Syndrome. But excessive temperatures and wide variations in temperature can influence other factors by, for instance, increasing the possibility of exposure to airborne pollutants.

The recommended minimum for workrooms in general is 16°C but actual need will vary according to circumstances and the particular types of work involved. In the normal office environment, it would be reasonable to maintain a temperature of around 19°C.

To check that this standard is being achieved, you should measure the air temperature with an ordinary dry bulb thermometer, close to workstations, at working height and away from windows. In considering systems for maintaining the overall heating standards, you will need to take full account of any localized effects of sunlight and radiant heat from office machinery.

Remember, the heating or cooling system used should not allow dangerous or offensive fumes to escape into the workplace e.g. cooling refrigerant fumes.


As with temperature, humidity on its own is unlikely to be a cause of Sick Building Syndrome. Unreasonable humidity levels in combination with other factors can, however, exacerbate problems. For example, high humidity encourages the growth of harmful bacteria; low humidity contributes to a dusty atmosphere and to dry eyes, nose, throat and skin.

In offices, it is generally considered in the interests of worker efficiency that humidity be maintained in the range of 40% to 70%. In warm offices, the relative humidity should be at the lower end of this range.

Controls should be checked frequently. The checks should also cover the operation and cleanliness of the humidifying equipment.


The lighting should:

  • where possible, be designed to give individual control;
  • utilise natural light;
  • avoid glare, flicker, and noise;
  • be kept clean and defective units replaced promptly;
  • be appropriate for the work, in particular for work with display screen equipment.


The intensity of noise is unlikely to cause Sick Building Syndrome symptoms on its own. More probably it will be the disruptive effect on the workforce who may perceive the noise as an imposed, unnecessary nuisance.

Office equipment which has low noise emission characteristics will help reduce the noise burden in the office. However, there are other sources of unpredictable and intrusive noise which may need careful consideration, e.g. air at outlet vents and in ductwork, water in pipes, and vibration from air conditioning plant.

Because of the way noise is absorbed or reflected by surrounding surfaces, it is particularly important that any renovations which involve the removal of carpets, soft furnishings or false ceilings take full account of the effect on overall noise levels.

Office equipment and furnishings

Office equipment and new furnishings can release chemicals, known as volatile organic compounds (VOC in short), into the workplace, and these have been associated with Sick Building Syndrome. Most problems should be solved during commissioning or the first months of occupation but you may find that symptoms are associated with the introduction of new equipment and furnishings. If this is the case you may need to consult the experts to determine the best course of action.

Maintenance of the building and the building services systems

Good maintenance procedures are often the best way to prevent or reduce Sick Building Syndrome symptoms, and careful planning will help produce the best results. Make sure your maintenance scheme covers:

  • the fabric of the building;
  • building services (eg heating, ventilation, air-conditioning and lighting systems);
  • building furnishings;
  • office equipment.
Effect of maintenance on ventilation duct work
Effect of Maintenance in ventilation duct work

An effective scheme will include drawing up schedules to record the type and frequency of:

  • system performance testing;
  • visual inspections of physical condition;
  • examination of system components;
  • replacement of items with fixed life spans, such as filters;
  • cleaning operations.

In addition, a record of your cleaning, inspection, testing and maintenance operations will help to sustain efficient operating systems. Laying down procedures for bringing abnormal conditions to the attention of the building management will help you spot and tackle problems promptly.

Cleaning operations, including furnishings

Cleaning can be a major factor in preventing Sick Building Syndrome.  Cleaning patterns for particular areas should be set according to individual circumstances but the following frequencies of cleaning operations are suggested as a guide:

  • wet areas of plant including cooling coils and humidifiers (annually);
  • ventilation systems including grills and vents (annually);
  • windows and light fittings (monthly/3 monthly);
  • internal surfaces, office carpeting, furnishings and furniture including desks and chairs (daily),
  • deep cleaning of soft furnishings (annually).

Management systems

Although there is little direct evidence that management and work organization systems can cause Sick Building Syndrome, it is very likely that dissatisfaction with the job and working conditions can exacerbate symptoms and lead to more complaints. Symptoms are more likely to be reported among those who have least control over their working environment. Typical problem areas are:

  • large, open plan offices where staff have little privacy,
  • limited opportunity to alter heating, ventilation or lighting, and
  • little say in how their sometimes monotonous work is organised.

Well motivated staff, confident that their concerns are taken seriously, will be more likely to give early warning of developing problems and more appreciative of efforts to improve the situation, particularly where scope for altering the physical characteristics of office areas may be limited.

demotivated work force
Poorly motivated workforce

Good communications and good relationships between management and staff will be important ingredients in helping to keep management in touch with staff concerns and staff informed about management’s efforts to deal with problems.  Involving workers representatives or the safety committee, where one has been established, can be a useful way to help achieve this.

Work organization, including display screen equipment work

Dissatisfaction can result from bad job and workstation design. Proper job design is probably the most important aspect of work for most people. If you can, involve individual members of staff in designing their own jobs and setting their own targets. Take full advantage of opportunities to break up routine procedures by, for example, introducing some variety in the tasks set, well timed rest breaks and regular job rotation.

Open plan access to external windows where possible, the provision of plants, and careful choice of colour scheme can all help towards greater satisfaction.

The National Environmental Management Authority, NEMA area office will be able to give you general advice on Sick Building Syndrome and how to deal with it. They may also be able to put you in touch with local specialist and organizations who can offer you professional advice for example Visionary Engineering Ltd and unlike doctors, we never go on strike. With this expert advice on the condition of your building, you can always ensure a healthy built environment is maintained for the well being and productivity of occupants.

Specilist treating SBS
Specialist service engineers “diagnosing and treating” sick building syndrome

Today in Engineering History: Born in 5th May 1861, Peter Cooper Hewitt, an American electrical engineer invented the mercury-vapour lamp and was an important forerunner of fluorescent lamps. He studied the production of light using electrical discharges (while Thomas Edison was still developing incandescent filaments). The mercury-filled tubes he developed from the late 1890s, gave off an unattractive blue-green light. Although unsuitable in homes, its brilliance won wide adoption by photo studios because the black and white film of the time needed just bright light, despite its colour. There were many other industrial uses for the lamp. His manufacturing company (est. 1902) was bought by General Electric in 1919 which produced a new design in 1933. He took out his first eight mercury vapour lamp patents on 17 Sep 1901.


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