Air pipes

What 40C temperatures could do to UK infrastructure

The hot weather is straining the pipes that pump water, the power lines that supply power, and the roads and railroads that bring people home at night. As global temperatures continue to rise, national infrastructure will be tested like never before.

Climate change is intensification of heat waves in the UK, a wealthy country with the capacity and resources to adapt to warmer temperatures. Still, very little has been done over the past ten years to combat overheating in buildings and the growing risk to critical infrastructure. The country is not prepared to withstand temperatures above 38°C consistently for long periods of time, which is more common in Mediterranean countries.

UK infrastructure has generally been designed to retain heat in the winter, but needs to become efficient in keeping the heat out in the summer. As is, around 20 % existing UK infrastructure is at risk of overheating – and this threat is expected to increase as average temperatures rise.

Rail

Railways across the UK contain thousands of kilometers of steel tracks. Steel has a high thermal conductivity, which means it can absorb and transfer a lot of heat faster than other building materials, and reach up to 20°C higher than the ambient air temperature. Steel rails elongate in the heat, pushing against the base and sides of the track. When there is no room to expand, the rail can warp, which takes a few days to repair and requires significant delays.

In warmer European countries, including Spain and France, the steel used in railway tracks is usually treated differently before and during manufacture. For example, different fabricated alloys can be used, or the steel can be fabricated differently so that it can more effectively evacuate thermal stress when deployed.

About 40% of the UK rail network is electrified, using both catenaries and conductor rails. Power lines can sag in hot weather, so trains must run at much slower speeds to avoid electrical fires. Slow rides also exert less force, reducing the risk of track warping.

Fortunately, modern overhead lines are less affected by hot weather as they contain automatic tensioning systems with springs or balancing weights that adjust to temperature variations. Older overhead power lines still contain fixed voltage connectors to trains and are far more vulnerable to failure during heatwaves – these need to be replaced to prepare the UK rail network for hotter summers in the future .

Water

Water pipes don’t just burst or fracture during the coldest months of the year. As households consume more water in hot weather, water pressure in underground pipes increases. During this time, parched soil can become loose and dry, leaving room for water pipes to move, especially elbows, joints and connectors. When combined with high temperatures and UV rays on exposed parts of the network, pipes can burst.

Poorly maintained water pipes struggle to withstand long periods of high temperatures, fluctuating pressure loads, and erratic rainfall. Weak spots in pipelines are typically capped and insulated with polyethylene, a flexible plastic foam insulation.

This ensures that damage from overheating is limited, but more research is needed to make water utilities more resilient. In the meantime, the UK could extend the life of its pipes by wrapping weak spots more frequently and widening the layer of protective material elsewhere.

Electricity

Hot weather can cause major problems for networks that generate and distribute electricity. Power transmission cables in the UK are often coated with aluminum or rubber, which are liable to expand when heated.

The pylons are usually covered with glass and ceramics – better insulators that prevent the structures from conducting electricity. These are, however, too expensive to cover long lengths of transmission cables. Electric utilities will need to research alternative materials to help electrical wires and cables withstand higher temperature swings.

The UK could also install conductors able to work in hotter conditions and build taller utility poles.

Similar to train transmission cables, power lines expand and relax at extreme temperatures, increasing resistance and reducing the efficiency of the entire system at distributing power. A sharp drop in efficiency can shut down power plants and plunge people trying to cool off into blackouts.

Building a net zero country requires not only a transition to carbon-free technologies, but also the adaptation of existing infrastructure to meet the challenges of climate change. An economy capable of slowing and possibly reversing global warming can only emerge if we adapt what already exists to the inevitable impacts to come.

This article first appeared on The conversation.