Hot summers bring regular queries about the maximum temperatures under which staff and pupils should be expected to work in schools.

What does the law say?

Although it is generally accepted that people work best at a temperature between 16°C and 24°C, there are no specific legal maximum working temperatures for schools or for offices or other workplaces. However, there are some sources of legal protection for school staff and pupils:

  • The Health and Safety at Work etc Act 1974 requires employers to ensure the health, safety and welfare of their staff and others present in the workplace (eg pupils), thereby providing a need to seek to protect against excessive working temperatures.
  • Regulation 7 of the Workplace (Health, Safety and Welfare) Regulations 1992 requires employers to ensure that temperatures in workplaces should be 'reasonable' although it does not specify a maximum reasonable temperature.

These legal requirements can be enforced by Health and Safety Executive (HSE) inspectors who may issue legally binding notices to employers obliging them to comply with the requirements.

What is ‘reasonable’?

Clearly, very high temperatures can affect the ability staff and pupils to concentrate and to work effectively, and can cause physical discomfort and illness. If people get too hot, they risk dizziness, fainting, or even epileptic fits or heat cramps. In very hot conditions the body’s blood temperature rises. If the blood temperature rises above 39°C, there is a risk of heat stroke or collapse. Delirium or confusion can occur above 41°C. Blood temperatures at this level can prove fatal and, even if people recover, they may suffer irreparable organ damage.

Even at the lower temperatures likely to be experienced in classrooms, heat still leads to a loss of concentration and increased tiredness, which means that teachers are more likely to put themselves or others at risk. Children, particularly very young ones, are likely to suffer most in extreme heat and may not know how to protect themselves. Although there is no legal maximum temperature in UK law, the World Health Organisation recommends 24°C (75°F) as a maximum for comfortable indoor working, with anything above 26°C as definitely unacceptable.

The TUC has called for a maximum temperature of 30°C, 27°C for those doing strenuous work, although employers should still attempt to reduce temperatures if they exceed 24°C and workers feel uncomfortable.

The NEU believes that because of the nature of the way in which teachers work, and the presence of children, a maximum indoor working temperature of 26°C - lower than the TUC recommendation - is appropriate.

It is important that all schools have in place contingency plans to help staff and pupils cope with the heat. There is little that can be done to alleviate particular problems if schools do not plan in advance and also take note of the weather forecast for the week ahead.

The Workplace Regulations require that a sufficient number of thermometers should be available, at a convenient distance from any part of the workplace, to enable temperatures to be measured in any part of the workplace. They do not require a thermometer to be provided in every room. Alcohol, liquid crystal strips and digital thermometers can lose accuracy over time and should be used as a general guide. The NEU recommends taking several classroom readings with thermometers, including the official school one, before initiating any action.

What precautions must be taken by the school?

The HSE’s Approved Code of Practice (ACoP) on the 1992 Workplace Regulations requires employers to take all reasonable steps to achieve a reasonably comfortable temperature.

The ACoP requires workplaces to be ventilated by a sufficient quantity of fresh or purified air. Windows which are intended to be opened to allow natural ventilation should therefore be able to be opened. Where windows are not intended to be opened, there should be an alternative means of artificial ventilation.

The ACoP also states that shade should, where necessary, be provided by window blinds and that special measures such as electric fans or portable air cooling equipment should be provided where necessary.

Schools should implement planned measures to reduce temperatures as soon as staff complain that working conditions are beginning to become uncomfortable or as soon as it is known that temperatures are going to become uncomfortable, according to the weather forecast. If in doubt, 26°C should be used as the trigger for these measures.

Measures that could be considered include the following:

  • Introducing a properly designed air conditioning system into the building: in some buildings this is not possible, either because of the age or type of the building, or because of planning restrictions. A properly maintained air conditioning system is a very effective way of reducing temperatures. However, air conditioning systems are expensive and use a very high level of power; other more environmentally friendly solutions can also be considered.
  • Redesigning the work area: often simply moving people away from windows, or reducing heat gain by installing reflective film or blinds to windows, can be a very effective way of keeping a workplace cooler.
  • The installation of fans or natural ventilation: providing fans or windows that open can also help staff and pupils to cool down, although both these become less effective at higher tempertures. Portable air-cooling cabinets are also available, which are much more effective.
  • Development of shady areas over time, either through planting of trees or the construction of shelters in playgrounds.
  • Curtailing of certain heat-generating activities, for example, use of computers, Bunsen burners, ovens, design and technology equipment, strenuous physical activity in PE lessons etc, unless effective heat extraction measures can be put in place.
  • Provision of water coolers.
  • Permission to be given for pupils to drink water in classrooms. (The NEU is in favour of this at all times of the year.)
  • Reallocation of classes to cooler rooms whenever possible.
  • Relaxation of dress codes for staff and pupils.
  • Appropriate changes to the school lunch menu.
  • Ensuring that windows can be safely opened.
  • Installation of white blinds and/or reflective film on windows.
  • Use of portable air conditioning units in the worst affected classrooms/staff room (although these can be noisy).
  • Provision of suitably sized fans for those rooms which are not so badly affected.
  • Timetabling sports days for earlier in the summer term.
  • Consideration of the needs of pregnant teachers who will feel the effects of the heat more acutely than anyone else and may, eg the need to be excused playground duty.
  • Starting and finishing school early, if staff are happy with such an arrangement, provided that adequate notice has been given to parents.

The requirement to take ‘all reasonable steps’ means that employers cannot use cost as an excuse, other than where the measures would be disproportionately expensive.

Again, these legal requirements can be enforced by HSE inspectors who may issue notices to employers obliging them to comply with these requirements.

Other steps may also need to considered such as closing classrooms which are unacceptably hot and teaching classes elsewhere, or even sending pupils home, provided reasonable notice has been given to parents.

It is important not to neglect security issues that will arise when windows and doors are left open, and to consider the risks posed by intruders.

Ventilation requirements

Regulation 6 of the Workplace (Health, Safety and Welfare) Regulations 1992 require that ‘effective and suitable’ provision must be made to ensure that every enclosed workplace is ventilated by a sufficient quantity of fresh or purified air. In Wales, teaching accommodation must be capable of being ventilated at a maximum rate of eight litres of fresh air per second for each of the usual number of people in these areas when they are occupied.

The Government has consistently refused to introduce a maximum working temperature into regulations, in line with the minimum temperature protection. Building Bulletin 101 – Ventilation of School Buildings gives guidance on providing ventilation and avoiding overheating in school buildings.

Taking action on high temperatures

Where any problems are encountered in schools as a result of high temperature, NEU safety representatives should take these up as a matter of urgency with the head teacher. They should seek to resolve the situation to protect both the health and welfare of staff and pupils and the educational progress of pupils who find it difficult to concentrate in sustained high temperatures.

If any problems arise, such as the head teacher refusing to take the actions outlined in this briefing note, or if adjustments made do not have any significant effect, NEU safety representatives are advised to contact the NEU Adviceline for further advice and assistance.

For more information, please download the full ‘Hot weather and classroom temperature’ guidance.

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