Mineral Products Association                            HRSC0018

Written evidence submitted by the Mineral Products Association

About MPA

1. The Mineral Products Association (MPA) is the trade association for the aggregates, asphalt, cement, concrete, dimension stone, lime, mortar and industrial sand industries. With the merger of British Precast, and affiliation of the British Association of Reinforcement (BAR), Eurobitume, MPA Northern Ireland, MPA Scotland and the British Calcium Carbonate Federation, it has a growing membership of 520 companies and is the sectoral voice for mineral products. MPA membership is made up of the vast majority of independent SME quarrying companies throughout the UK, as well as the 9 major international and global companies. It covers 100% of UK cement and lime production, 90% of GB aggregates production, 95% of asphalt and over 70% of ready-mixed concrete and precast concrete production. In 2018, the industry supplied £16 billion worth of materials and services to the Economy. It is also the largest supplier to the construction industry, which had annual output valued at £172 billion in 2018. Industry production represents the largest materials flow in the UK economy and is also one of the country’s largest manufacturing sectors.

Q2. How can sustainable cooling solutions and adaptation strategies be implemented in such a way as to minimise overheating, reduce energy consumption and prevent overloading of the electricity grid during peak demand?

2. The starting point needs to be a greater incentive to apply passive design techniques to tackle overheating, which should be prioritised over technological solutions such as reversable heat pumps. The use of passive measures, including the use of thermal mass with ventilation[1],[2], should be more overtly driven by the building regulations, helping to reduce both overheating and year-round energy consumption.

3. Thermal mass is a property of medium and heavyweight construction materials that can help keep buildings warmer in winter but also, critically, cooler in summer. For concrete and masonry, the combination of being able to absorb heat during the hottest time of the day and release it slowly over the cooler hours means that it can be very effective in regulating temperatures, to the extent that it can mitigate the need for air conditioning.[3] Other materials such as timber and steel do not generally provide this effect to anywhere near the same extent.

4. Using this approach is already very common in non-residential buildings such as offices and schools, where thermal mass combined with passive ventilation at night can achieve a comfortable temperature when a building is in use. Research has estimated that using this combination can reduce the energy needed for cooling by around 50%.[4]

5. Residential buildings are used differently and need careful design to enable night-time ventilation without noise or security concerns, but the principle is the same and has been used in hotter climates for millennia. The recent launch of Part O of the Building Regulations now addresses these considerations more fully but stops short of recognising thermal mass with ventilation in its ‘Simplified Method’ of compliance. The outgoing overheating compliance measures this replaces did account for thermal mass, so this omission can be viewed as a backwards step in the drive to tackle overheating, especially with regards to solutions requiring less energy use.

6. There is plenty of published evidence showing the performance merits of thermal mass with ventilation, for example a recent study of an apartment block in London shows the beneficial effect on both the peak domestic heating load and the frequency and extent of overheating in the building compared to an equivalent lighter weight apartment block.[5] 

Q3. What actions can be taken to protect those most vulnerable to the impacts of extreme heat?

7. For buildings such as residential care homes, hospitals, or schools it is well worth prioritising thermal mass with ventilation even more to protect older, younger or less healthy people, leading to use of heavy materials such as concrete and masonry over lighter weight materials such as timber. There is a useful side benefit of improving fire and flood resilience as well, which given the change in the climate and, in the case of schools, their greater likelihood of arson attacks, is of significant value. It should be recognised that any adaptation measures for reducing overheating risk should also consider the full range of health and well-being impacts related to climate change.

Q6. What can be done to protect the UK’s existing public and private sector housing stock from the impacts of extreme heat while ensuring that homes are sufficiently warm in the winter months?

8. Even where buildings are not specifically designed to take advantage of their thermal mass, its presence in concrete and masonry construction is nevertheless beneficial. Where such buildings require their insulation to be upgraded, it should be located externally to ensure the thermal mass benefits are not lost[6]. The use of internal insulation should only be considered where it is not practical to locate it externally. A significant amount of the UK’s existing housing stock has thermal mass, so its summertime benefits must be actively retained to avoid downgrading their ability to cope with extreme heat. In addition to masonry cavity wall construction, this housing stock also includes solid-walled construction, which accounts for around 31% of the 27.7 million dwellings in Great Britian[7].

Q7. What role might reversible heat pumps (which can act as both heating and cooling systems) and other emerging technological solutions, such as the development of smart materials, play in meeting future cooling demands?

9. There is a risk that the drive for technological solutions to meet the climate challenge will undermine the current 'fabric first' approach to building design. Standard (non-reversible) heat pumps will undoubtedly help towards the goal of new-build becoming carbon neutral, but this must be underpinned by a high standard of year-round fabric performance in both winter and summer. The introduction of reversible heat pumps however, should be avoided as far as possible as it could disincentivise a more energy-efficient passive approach and so increase energy demand in the domestic sector. It should be noted that conventional (mechanical) cooling is responsible for over 7% of global greenhouse gas emissions[8]. Alongside the additional energy costs this will incur, there will be further costs associated with plant maintenance and the need for periodic replacement, all of which is undesirable from an economic and domestic poverty perspective.

Q9. Does the Government’s Future Homes Standard adequately consider overheating in homes? If not, what additional elements should it include?

10. The Future Homes Standard should put much more emphasis on passive design and the use of thermal mass with ventilation for comfort and energy efficiency, especially as the climate continues to change and extremes of heat become more likely and more frequent. With this in mind, the current edition of Part O (which will be linked to the Future Homes Standard) should be updated so the ‘Simplified Method’ it employs is technically more sophisticated and takes account of thermal mass alongside shading, ventilation and other measures to limit overheating.

Q11. Does the UK need a dedicated Heat Resilience Strategy? What lessons can be learned from other nations when it comes to national strategies for heat resilience?

11. Heat resilience should be considered alongside other key issues of adaptation to climate change, including flood and fire resilience and energy efficiency, and of course mitigation of climate change. This should focus on buildings but also how the economy, public services and other elements of modern life adapt to a changing climate. This includes social adaptation, and education of people around how to live in a hotter climate.

August 2023