Delhi’s Extreme Heat: Do FRP Covers Warp on Roads?

Extreme weather is nothing new to Delhi, the capital of India, particularly during the sweltering summer months when temperatures on the roads may reach over 60°C (140°F). Urban infrastructure, including concrete and asphalt as well as utility installations like manhole covers, is severely strained by the unrelenting heat. With the rising use of Fiber Reinforced Polymer FRP manhole cover in the city, a common question arises: Can FRP covers withstand Delhi’s extreme heat, or do they warp, deform, or fail under thermal stress?

Delhi’s Urban Heat Island Problem

 As a densely built urban zone, Delhi faces the classic urban heat island effect.Temperature extremes are exacerbated by the absorption and radiation of heat from concrete structures and asphalt roadways, which produce microclimates.  Traditional infrastructure materials are known to suffer under these conditions. Concrete can crack due to expansion and contraction, while metal covers become dangerously hot, posing burn risks and expanding enough to jam in place.

In this context, municipal authorities have sought alternative materials that can handle thermal fluctuations without losing structural integrity. Enter FRP—a material increasingly used for its strength, durability, and thermal resistance.

Can FRP Manhole Covers Handle the Heat?

 The short answer is yes. High-quality FRP manhole covers are specifically designed to withstand extreme temperatures—both high and low—without warping or deteriorating. These covers are made from thermoset polymer resins reinforced with fiberglass, which gives them dimensional stability under thermal stress.

Key properties that make FRP ideal for Delhi’s heat:

• Low Thermal Expansion: FRP has a much lower thermal expansion coefficient compared to metals, meaning it doesn’t expand significantly with heat. This eliminates the problem of jammed or lifted covers.

• Heat Resistance: Most FRP covers are tested for thermal tolerance up to 150°C. Even road surface temperatures in Delhi’s summers remain well below this limit, ensuring safety and performance.

• UV Stability: UV-resistant additives are used in the resin matrix to prevent surface degradation, color fading, and brittleness due to long-term sun exposure.

• No Surface Heat Conductivity: Unlike metal, FRP does not conduct and retain heat. This keeps the surface relatively cooler and safer for pedestrians, even during midday in peak summer.

Field Performance in Delhi

FRP coverings have been successfully used in pilot projects and installations in New Delhi Municipal Council (NDMC) zones, especially in major places like Connaught Place, Lodhi Road, and Karol Bagh. These areas, with high foot traffic and vehicular load, are now using FRP covers with anti-slip surfaces and color-coded tops.

Feedback from field workers confirms that FRP covers are easier to lift and replace without using tools that get stuck due to thermal expansion—unlike cast iron covers, which swell and jam in place under the sun. Additionally, FRP’s consistent performance during both extreme heat and winter fog conditions makes it a viable all-season solution for Delhi’s diverse climate.

Maintenance and Durability Advantages

 FRP covers do not crack or crumble due to heat-induced stress, reducing the frequency of replacement. Their surface does not degrade or chalk under UV rays, which prolongs their lifespan and keeps them aesthetically clean in urban landscapes.

Conclusion

FRP manhole covers do not decay or distort in Delhi's scorching summers, despite what many people think.  In fact, they outperform traditional materials by offering thermal stability, safety, and longevity. As Delhi continues to push for climate-resilient infrastructure, especially under Smart City initiatives, FRP covers are proving to be a practical and future-proof choice for the capital’s demanding climate.