Health & Safety

Office Air Conditioning Energy

Introducing engineering measures to control the thermal effects in a workplace environment, for example heat effects, may involve insulating any plant which acts as a radiant heat source, thereby improving air movement, increasing ventilation rates and maintaining the appropriate level of humidity. The radiant heat effects of the sun on indoor environments can be addressed either by orientating the building so that it doesn’t suffer from the effects of solar loading, or where this is not possible, by the use of blinds or shutters on windows. Where workers are exposed to cold and it is not reasonably practicable to avoid exposure you should consider, for example, using cab heaters in fork-lift trucks in cold stores;

Restriction of exposure by, for example, re-organising tasks to build in rest periods or other breaks from work. This will allow workers to rest in an area where the environment is comfortable and, if necessary, to replace bodily fluids to combat dehydration or cold. If work rates cause excessive sweating, workers may need more frequent rest breaks and a facility for changing into dry clothing;

Medical pre-selection of employees to ensure that they are fit to work in these environments;

Use of suitable personal protective clothing (which may need to be heat resistant or insulating, depending on whether the risk is from heat or cold);

Acclimatisation of workers to the environment in which they work, particularly for hot environments;

Training in the precautions to be taken; and Supervision, to ensure that the precautions identified by the assessment are taken.

Below is an excerpt from the Health and Safety Executive

Your Health

The measures outlined in this section contribute to the general working environment of people in the workplace.

Ventilation Measures

Workplaces need to be adequately ventilated. Fresh, clean air should be drawn from a source outside the workplace, uncontaminated by discharges from flues, chimneys or other process outlets, and be circulated through the workrooms.

Ventilation should also remove and dilute warm, humid air and provide air movement which gives a sense of freshness without causing a draught. If the workplace contains process or heating equipment or other sources of dust, fumes or vapours, more fresh air will be needed to provide adequate ventilation.

Windows or other openings may provide sufficient ventilation but, where necessary, mechanical ventilation systems should be provided and regularly maintained.

Temperatures in Indoor Workplaces

Environmental factors (such as humidity and sources of heat in the workplace) combine with personal factors (such as the clothing a worker is wearing and how physically demanding their work is) to influence what is called someone´s ´thermal comfort´.

Individual personal preference makes it difficult to specify a thermal environment which satisfies everyone. For workplaces where the activity is mainly sedentary, for example offices, the temperature should normally be at least 16 °C. If work involves physical effort it should be at least 13 °C (unless other laws require lower temperatures).

Work in Hot or Cold Environments

The risk to the health of workers increases as conditions move further away from those generally accepted as comfortable. Risk of heat stress arises, for example, from working in high air temperatures, exposure to high thermal radiation or high levels of humidity, such as those found in foundries, glass works and laundries. Cold stress may arise, for example, from working in cold stores, food preparation areas and in the open air during winter.

Assessment of the risk to workers´ health from working in either a hot or cold environment needs to consider both personal and environmental factors. Personal factors include body activity, the amount and type of clothing, and duration of exposure.

Environmental factors include ambient temperature and radiant heat; and if the work is outside, sunlight, wind velocity and the presence of rain or snow.

Energy Consumption

As 30% of the UK energy consumption comes from commercial property, the Government revised the Building Regulations to reduce energy consumption and hence minimise CO2 emissions.

Building Regulations Part L sets minimum legal standards for each energy consuming component within a building and provides an overall building efficiency rating.This will lead to energy labelling for buildings in the near future.

Part F sets out minimum legal requirements for ventilation, recognising the importance of fresh air to a healthy and productive working environment.

The introduction of the 10% renewable energy target will enforce the use of renewable energy sources within local council boundaries. Briefly stated, building projects must account for at least 10% of carbon emissions with some form of on-site renewable energy.

The true cost of an air conditioning system is the full life cycle cost. This is best expressed in the 1:5:200 ratio, where for every £1 spent on capital expenditure, £5 will be spent on maintenance and £200 will be spent on the energy costs over the life cycle of the system.

Investing in energy efficient systems has a significant effect on reducing this ratio.


Further advice on thermal comfort in the workplace can be found on HSE´s website