Heatwaves and the school environment

The UK’s record-breaking heatwave in July has intensified the focus on how temperature, humidity, and air quality is controlled in buildings, according to the Building Engineering Services Association (BESA)

The UK has no legal limit on extreme temperatures at which workers can refuse to work, but the increasing frequency of heatwaves has prompted trade unions to call for a 27°C limit on outside working and 30°C inside.
They have also been pushing for a greater commitment from employers to make workplaces safer and healthier as part of the Government’s ‘Living with Covid’ strategy. Several unions formed a coalition with scientists and groups representing Covid sufferers and bereaved families to launch a ‘Covid-19 Safety Pledge’ with the support of the Cabinet Office.
The Pledge is designed to ensure that workplaces – including those that are also public spaces such as schools and hospitality venues – adopt measures designed to minimise the spread of Covid infections and make public what they have done to safeguard health and well-being.
A key element is the measuring, monitoring, and mitigation of indoor air quality (IAQ) and draws on guidance produced and provided for free by BESA. This follows a presentation by the Association’s head of technical Graeme Fox to the Trade Union Congress (TUC) explaining the three pieces of guidance* produced by the Association since the start of the pandemic.


He also pointed out that numerous studies have shown how elevated temperatures – well below what the UK experienced in July – negatively affect the human body. For example, research by the US space agency NASA shows that productivity falls by 3.6% for every 1deg C the indoor temperature rises above 22°C.
The British Council for Offices (BCO) says temperatures in commercial buildings should be maintained at between 20 and 24°C. It also recommends ventilation rates of 12 litres per second per person (l/s pp) of filtered air with an additional 10% in high density occupied spaces to protect the health and well-being of occupants.
The BCO also says that controlling humidity is crucial, but its most recent studies showed the average relative humidity (RH) in offices was 38% whereas for good health it should be between 40 and 60%. At 35% people will experience eye irritation, nasal dryness, and sore throats. This also has important implications for making our buildings more infection resilient to reduce the impact of viruses, flu, and colds – a particular issue for schools where infections move quickly around tightly packed classrooms.
“The poor performance of our building stock tends to hit the national headlines during periods of extreme heat or cold, but then to drop into the background again,” said Fox. “However, this time feels a bit different. I think the pandemic and the current energy crisis have concentrated minds – so the heatwave has created further momentum for addressing this in a more strategic way.”
Fox also believes the publicity surrounding heat pumps and growth in that market will also have an impact with more end users able to take advantage of a technology that heats in winter and cools in summer. “Some of those early heat pump adopters were probably feeling a bit smug this month,” he said.
“There is a lot going on with our climate and plenty of theories flying around about the likely impact on health, well-being and productivity, but one thing we can all be sure of is that higher summer temperatures are here to stay,” said Fox. “This has important implications for the building engineering sector and means our efforts to adapt existing buildings to the effects of climate change are increasingly important.”
He stressed, however, that this was not an attempt by BESA to promote air conditioning; rather it wanted to encourage a “nuanced approach to indoor climate control”.
“Air conditioning is a key technology, but so are some of the other tools we have at our disposal such as mechanical ventilation with heat recovery (MVHR), air filtration, and humidity control. We also need to improve our approach to the fabric of buildings so we can build in more passive mitigation measures – and planned maintenance will be key to ensuring equipment can continue to function properly whatever the weather conditions.
“All of these require some level of financial investment, but not all are expensive – and with the barrage of different factors now facing our building stock, any investment in building performance is guaranteed to pay back handsomely.”


The Public & Commercial Services (PCS) union worked with Independent SAGE – the group of scientists working together to advise the government and the public about dealing with and recovering from the Covid-19 pandemic – to develop the Pledge.
It is “a simple commitment to adhere to health and safety law and best practice”, according to the coalition, and includes particular provision for measuring and assessing IAQ. The PCS called for employers to follow the BESA guidance to improve ventilation, filtration and air cleaning in offices, schools, and other workplaces – along with other aspects of building safety.
Independent SAGE believes all indoor areas should be assessed by a specialist for air quality, design, and ventilation. All building users should be provided with accurate and accessible information on ventilation in each space and what constitutes safe occupancy and unsafe air quality levels.
They are also calling for continuous real time CO2 monitoring with a notification when levels go above 800 parts per million (ppm) – as a proxy for measuring IAQ. All building users would be provided with information on what to do when conditions are unsafe and will have the right to remove themselves without threat of repercussions.
Employers should assess their physical environment and working practices according to health and safety law including risk assessments, to ensure that they are designed to safeguard against the spread of infection, the SAGE scientists added.
“The involvement of trade unions and this extremely influential group of scientists at the highest level of government brings the prospect of ‘safe havens’ that protect people from poor air quality much closer,” said Fox.
“I found union officials very receptive to our guidance and the principle of protecting workers from sources of outdoor pollution and the cocktail of indoor contaminants that can be found in many workplaces.
“They recognise that improving building ventilation can play a huge part in helping the country recover from the pandemic and make buildings more infection resilient in preparation for future health emergencies,” he added.
“They also noted the importance of using properly trained and accredited ventilation and IAQ specialists to carry out remedial work on buildings and on avoiding ‘silver bullet’ solutions.”

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