An apology to begin: if you came here seeking legal precedent to close down your classroom when the mercury hits 30 degrees, you are about to be disappointed.

Under UK law, there is no temperature at which it becomes legally too hot to work. That’s because of workplaces like factories and forges, where high temperatures are commonplace (much like those classrooms stuffed with 32 Year 9s in mid-July, you might say).

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There’s also no legal requirement at the lower end of the scale, either, although government guidance suggests that workplaces should be no lower than 16 degrees, or 13 degrees if the work is physical. The guidance goes on to highlight employers’ need to “keep the temperature at a comfortable level”.

Well, boo to that. 

What is the maximum temperature?

But there are also health and safety laws to comply with. The Health and Safety at Work Act 1974 says that employers have a duty to protect those in their workplaces (including against excessive working temperatures), while Regulation 7 of the Workplace (Health, Safety and Welfare) Regulations 1992 says employers must ensure that temperatures are “reasonable” (although, again, no temperature is specified).

So the law is no help when you are sweating it out on a Friday afternoon and the pupils are all in desperate need of a siesta. But you might get some luck if you argue from a health and safety perspective. 

Teaching unions

What about the unions, can they help?

The NEU teaching union does recommend a maximum of 26 degrees in classrooms, stating that anything above this limit is “too hot for effective teaching and learning”.

Its guidance also takes on the definition of “reasonable”, stating that: “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 degrees, there is a risk of heat stroke or collapse. Delirium or confusion can occur above 41 degrees. Blood temperatures at this level can prove fatal and, even if people recover, they may suffer irreparable organ damage.”

Reasonable adjustments

But, ultimately, it’s down to your headteacher to decide when the heat is too much. If you’re making a case for closure, however, there are precedents to point to.

Back in July 2006, when temperatures across the country reached a record high of 36 degrees, dozens of schools sent pupils home early to avoid the worst of the heat, or stayed closed altogether.

A BBC news story at the time reported that Northern Parade Junior School in Portsmouth had closed as “pupils were close to collapsing” and a teacher had been sent home with exhaustion.

And Shenley Brook End School in Milton Keynes was hampered by its modern, glass-filled design and closed early for “the protection of pupils”, because, according to the headteacher: “It’s like sitting in your car with the windows up and the sun beating down on the windscreen.”

The NEU’s page on high classroom temperatures also offers advice on precautions that can be taken during especially hot times, such as installing reflective film or blinds to windows, curtailing of certain heat-generating activities (such as use of computers, Bunsen burners, ovens, design and technology equipment), and adjusting the school timetable to avoid the hottest part of the day.

Will any of this actually happen in your school? Start lobbying now.

Zofia Niemtus is deputy commissioning editor at Tes