Recent news headlines have reignited a longstanding debate about whether there should be a legal maximum working temperature in the UK, particularly for those in physically demanding jobs such as construction. London mayor Sadiq Khan is reported to be exploring flexible working hours during heatwaves to protect workers from extreme heat and unions such as GMB and Unite are calling for a 27oC limit for manual work. The recent heatwave has resulted in the conversation gaining traction once again and there is increasing pressure for action. What are the risks for working in high temperatures? Working in high temperatures presents challenges for construction workers, both physically and mentally. Extreme heat can lead to dehydration, heat exhaustion and heat stroke, which can become medical emergencies if not addressed quickly. The physical nature of construction work, combined with exposure to the sun and the need for heavy gear, makes workers susceptible to overheating. These conditions not only affect health but also reduce concentration and increase the likelihood of accidents. Is a legal maximum working temperature in the UK really necessary? One of the central questions raised by the current discussion is whether the new legislation is necessary. It is likely that many contractors would take the view that health and safety on site is already governed by legal obligations, codes of practice and risk assessments and therefore their workers are already adequately protected. Under the Construction (Design and Management) Regulations, employers are required to provide “reasonable” workplace temperatures for indoor areas of construction sites. Where the site is outdoors, employers must provide protection from adverse weather. The Health & Safety Executive currently advises that employers should conduct risk assessments and implement appropriate control measures during periods of excessive heat. Therefore, providing the risk of high temperatures is assessed and operations adjusted accordingly, perhaps by pausing work during the midday sun and encouraging regular breaks, it appears the new legislation is unnecessary. However, at Bolt Burdon Kemp, so many of our workplace injury cases are a direct result of an employer breaching the duty of care owed to their employees by permitting unsafe working conditions or failing to provide the right training and/or equipment. A subjective interpretation of ‘reasonable temperature” leaves too much room for inconsistency and could be used to advantage contractors with little regard for safety or those operating under pressure to meet deadlines. How do other countries handle the heat? In 2023, Spain introduced a ban on outdoor work during extreme heat, particularly for construction and agriculture. This was introduced following an incident during a 44oC heatwave in 2022 where a street cleaner sadly died. Employers must now adjust working conditions or suspend work entirely when red or orange weather warnings are issued. The United Arab Emirates imposes a legally mandated “midday break” from 12:30 to 15:00 during the summer for workers in exposed open areas such as construction sites. Employers who do not comply are subject to fines and suspension of operations. In 2024, just 51 violations were recorded across 134,000 inspections, yielding a 99.9% compliance rate, suggesting that this approach has been effective in the UAE. These two approaches favour flexibility over a fixed temperature limit. However, Slovenia has recently put in place new rules under which employers must give outdoor workers mandatory rest periods to prevent heat related health problems. This rule applies when temperatures exceed 30oC. Together, these policies reflect a growing international recognition of the risks that high temperatures pose to outdoor workers. While Spain and the UAE focus on adapting their schedules based on weather alerts or fixed hours, Slovenia’s approach introduces a temperature-based threshold like the 27oC limit proposed by unions such as GMB and Unite. How would a legal maximum working temperature work in practice? The practicality of enforcing a universal maximum working temperature in the UK construction sector is debatable. Unlike office environments, where air conditioning and controlled settings make enforcement relatively simple, outdoor construction sites vary widely in conditions depending on location, time of day and the task at hand. A fixed temperature may seem straightforward but could lead to impractical outcomes, such as frequent shutdowns that delay projects and impact livelihoods. Furthermore, an individual’s tolerance to heat can vary widely depending on age, health and workload intensity. A younger, physically fit worker may tolerate 27oC better than an older worker with underlying health conditions. Effective protection of construction workers in extreme heat may not lie in an absolute temperature limit, but in the creation of robust industry frameworks. These should be developed in partnership with the government, regulators, unions and industry specialists. This will help to ensure practical, consistent and enforceable measures across the sector with the ultimate goal of ensuring safety for construction workers. Conclusion Whether or not the UK government chooses to legislate a maximum working temperature, the reality of climate change means that construction firms must adapt to more extreme summer conditions. While many businesses already implement sensible protective procedures, the absence of clear, enforceable standards creates a fragmented safety landscape. This patchwork system leaves too much room for interpretation, putting lives at risk and placing the burden on individual workers and employers. A clear legal framework, whether based on a temperature threshold, mandated rest breaks or flexible scheduling could help ensure that all workers, regardless of employer or location, are adequately protected from the dangers of extreme heat. About the author: Olivia Ward is a solicitor at London law firm Bolt Burdon Kemp Got a story? Email news@theconstructionindex.co.uk Read More