The UK is braced for some of the hottest temperatures on record.

Many of us will be dreading days in the office, or working from home, in sweltering heat.

The Met Office has even issued a 'severe heat' warning for much of the country.

But are there rules about how hot our workplace is allowed to get?

Are employers obligated to keep the temperature in the workplace below a certain level? And what are their obligations to employees who are particularly vulnerable to extreme heat?

Lewys Traylor, a legal advisor at DAS Law, gives the lowdown on what employers and employees need to know:

Does an employer have to keep the office cool?

There is no law that sets a maximum temperature in a workplace.

The Workplace (Health, Safety and Welfare) Regulations 1992 simply say that the temperature should be ‘reasonable’.

What is ‘reasonable’ will vary according to the type of workplace, although there have been attempts to put pressure on the government to set a maximum working temperature.

On July 11 2022, the TUC called for the introduction of an upper limit of 27C, at which point an employer would be required to take action, with an absolute maximum of 30C, (or 27C for those doing strenuous jobs), above which workers would not have to continue working and an employer would be liable for prosecution.

However, that pressure has not resulted in any regulatory change, so employees who feel that their workplace is too warm should bring it to the attention of their employers, who should then consider what steps can and should be taken to address the issue.

What about those who work outdoors?

There is no maximum temperature for those doing outside work, but the Health and Safety at Work Act 1974 states employers should do everything ‘reasonably practicable’ to ensure a safe and healthy workplace, and this may include providing water or sunscreen as appropriate.

Do I have to continue to wear my usual work attire during a heatwave?

There is no general rule to say whether you must continue to wear a suit, or office wear, if temperatures spike.

This comes down to reasonable behaviour on the part of both the employer and the employee.

Most workplaces will have a dress code and guidelines on what they consider to be acceptable standards of dress in the workplace, but employers should consider what is reasonable, and excessive heat is a health and safety issue so should be considered when making any decisions.

So what should employers do?

The Health and Safety Executive (HSE) suggests that an employer should monitor the ‘thermal comfort’ levels of employees, which describes their state of mind as to whether they feel too hot or cold.

If there is an issue in relation to the thermal comfort of staff, an employer should consider carrying out a risk assessment of the workplace. The HSE gives a ‘thermal comfort checklist’ to refer to.

Additional steps should be taken for employees who are:
• Pregnant;
• Suffering from conditions; or
• Taking medication particularly affected by temperature fluctuations.

For these categories of employee, care should be taken in the form of specific risk assessments or health surveillance, with adjustments to working conditions or practices made where appropriate.

The TUC have also offered advice on what employers can do to limit the negative effects of the heatwave on their staff.

They suggest a variety of extra measures to keep workers cool and hydrated, from temporarily relaxing the dress code to making fans and a steady supply of cold drinks available.

Where possible, they also recommend allowing flexible working, helping staff avoid the discomfort of a crowded and oppressively warm train or bus by arriving early or working late and avoiding peak commuting times.

No specific maximum temperature applies on public transport.

Good practice is to plan journeys accordingly, take adequate refreshments and take appropriate steps to stay cool.

Disclaimer: This information is for general guidance regarding rights and responsibilities and is not formal legal advice as no lawyer-client relationship has been created. Note that the information was accurate at the time of publication, but laws may have since changed.