Urban Heat Island: What It Is and Why It Matters to Construction
If you ever feel like the temperature drops ten degrees when you leave a city for its rural surroundings, you’re more in touch with your surroundings than you’d think. On average, cities can be anywhere between 2 – 6 degrees Fahrenheit warmer than their surrounding rural areas. As cities get bigger and encompass more and more concrete this number could continue to go up. The impact of this heat-retention within cities could contribute to higher global temperatures, increased danger of heat-related illness and death and even quicker crumbling infrastructure and buildings.
The phenomenon is called Urban Heat Island effect – UHI.
The Growth of Cities on Earth
It’s estimated that 3% of the earth is covered by Urban areas. This may seem like a very small percent of the world but it’s much higher than you think. 71% of the planet is water. Of the 29% that’s made up of land, one-third of it is dessert and a second third of forest. That only leaves about 10% of habitable land for 7.8 billion people.
3% is actually quite a bit.
As the world’s population grows, it’s expected that cities will as well. The UN predicts that 68% of people will live in cities by 2050. It’s more vital than ever that cities are made to be sustainable without negatively impacting our planet or compromising the future of earth. The UN refers to this as “Sustainable Urbanization”.
Urban Heat Island is an indication that we have not been successful so far. As awareness grows about this phenomenon and other by-products of past construction practices, more rehabilitation and eco-friendly construction trends will arise. The Comprehensive Everglades Restoration Plan in Florida is another example of current efforts to reverse past construction projects that have negatively impacted the environment.
Why and How Does Urban Heat Island Happen?
Grass, trees and other vegetation have a natural ability to cool the air through moisture evaporation. This process is a byproduct of photosynthesis. Vegetation also provides shade to the ground, helps to reflect UV rays back at the sky and simply doesn’t retain heat. When building a city, trees, grass, plants and shrubs are naturally cleared away to build roads, buildings, parking lots and stores.
The new materials that take the place of the plants retain heat instead of reflecting or dispersing it. Concrete alone can be up to 50 degrees warmer than the air temperature through this heat absorption. The more areas that are absorbing heat, the more heat that will be let off over time. Think about how rocks around a campfire continue to let off heat long into the night. Or how a stove element takes time to cool, even after you’ve cut off the heat source. Temperatures rise in those areas until you have the Urban Heat Island effect.
Why Does the Urban Heat Island Effect Matter?
With any kind of increase in temperature that has been trending over time, there’s always the environmental concern associated with it. If cities see higher and higher temperatures it can result in summer heat closures, worsening air quality, heat warnings and heat-related illnesses and death. But the impact of UHI could mean a lot of big changes and opportunities for the construction industry, both with the health and safety of employees but also in upcoming construction trends.
Health and Safety In an Urban Heat Island
Construction workers who primarily work in cities need to be aware of the impact that heat absorption is having on year-over-year temperatures – from a safety perspective. Construction workers makeup 73% of yearly heat-related illness cases and are 13-times more likely to die from a heat-related illness compared to other industries. If cities are only getting hotter, then these numbers will continue to increase.
How To Combat Rising Temperatures & Heat Danger in Construction
Working during off-peak temperature times has been more difficult in the past because construction equipment is noisy. Working through the night or early in the morning isn’t always possible because of city bylaws. With electric equipment providing a new quiet alternative to traditional equipment, the trend of working through the night or early in the morning could be on the rise. This is just one way that urban construction projects could battle these rising temperatures.
New technologies that monitor heart rate and body temperature could become more commonplace in urban construction projects. Rentals of cooling systems and air-conditioned break rooms will rise. Companies will start investing in cooling and light-weight safety clothing.
The true key to battling these changes, however, is to get to the source of the problem. This is where the real opportunities for the industry can be found.
How Cities Are Battling Urban Heat Island
As the impact of Urban Heat Island is studied, city planners and building designers are provided with more information about what causes it and how to fight it. Between 2009 and 201, New York City painted 9.2 million square feet of rooftops white. Since white is a light reflector the idea is that it would help the city buildings to reflect heat instead of absorbing it. The problem with this particular ‘solution” is that it is much more of a band-aid fix that could require maintenance, upkeep and could be difficult to maintain. Instead, cities and building designers are looking at more long-term solutions that could help battle Urban Heat Island.
Changes to Buildings to Battle Urban Heat Island
Some of these long-term solutions include reducing concrete use in buildings and replacing them with reflecting materials. All-glass buildings are one example of this. The UV rays bounce off the glass instead of absorbing into the building to then act as a radiator of heat. But paint and glass are man-made products to help solve a man-made solution. One of the best ways to combat Urban Heat Island is to fall back to nature.
Green roofs and integrating more park spaces within city limits are perhaps one of the best long-term changes that could help cities battle the Urban Heat Island phenomenon. Vegetation provides the best and most natural way to help combat intense UV rays. Besides helping to reduce the Urban Heat Island effect, green roofs can reduce air conditioning costs, improve insulation and even reduce noise transfer both within and around the building.
Lighter colored asphalt that will reflect more and absorb less are becoming more popular for large paving projects as well. More companies are also looking at paving alternatives. Interlock brick and “cool pavement” options are also options to help reduce heat absorption.
How Efforts to Combat Urban Heat Island Will Impact Construction
It’s clear that smart cities and technological construction builds aren’t the only trends that will impact bids in the future. In the same way that being knowledgeable in technology with construction practices can help you win bids, being knowledgeable in green construction trends will too.
Building with sustainable materials, working with green roofs and recognizing LEED certification opportunities for buildings will help to set yourself apart from other contractors. The number of projects that will incorporate these new trends will grow. Being able to confidently rise to these projects and have the skills to complete them while meeting customer expectations will help secure your future as a construction worker in the age of eco-building.
Not only will it help to keep our planet healthy for the future but these changes will ultimately keep the construction industry safe for future generations of contractors.
