Facing A Humid Coastal Environment, How Do Local Governments Select Manhole Covers?

For cities located along the coast, the air contains a higher amount of moisture and has greater humidity, with multiple rainy seasons throughout the year. Public infrastructure such as manhole covers are exposed to damp air for extended periods and are also prone to being soaked by rainwater. This situation accelerates the rate of corrosion of manhole covers and increases the risk of injury to people.

Traditional materials manhole covers:

• Iron elements in cast iron are prone to react with oxygen in humid environments to form rust. In particular, in coastal areas where the air contains salt, the rate of corrosion is further accelerated.

• The cement component in concrete is susceptible to carbonation reactions in humid environments, leading to a decrease in strength. Moreover, the steel bars in the concrete are prone to rust in a wet environment, further weakening the structural strength of the manhole covers.

In contrast, SMC, as a new type of composite material, can effectively cope with humid environments:

• Corrosion Resistance

SMC possesses corrosion-resistant properties that effectively resist the erosion of various chemical substances, including but not limited to water, gasoline, alcohol, electrolytic salts, acetic acid, sodium-potassium compounds, asphalt, and various acidic and alkaline soils and acid rain. This excellent chemical stability ensures that the material maintains its physical characteristics and appearance quality over long-term use, performing well even when exposed to outdoor environments for extended periods.

• Weather Resistance

In addition to resisting chemical erosion, SMC exhibits good weather resistance. It can maintain performance stability under different climatic conditions, from -50°C to 200°C, and is resistant to aging.

• Electrical Insulation

SMC materials also have outstanding electrical insulation properties, meaning they almost do not conduct electricity under the influence of an electric field. This feature makes it an ideal choice for use in high-humidity environments, especially in densely populated or space-limited areas, where SMC can effectively prevent accidental electrical conduction caused by excessive humidity, enhancing safety.

Governments need to choose products suitable for local conditions to reduce the risks of corrosion, damage, and electrical conductivity of manhole covers, ensuring their long-term usability and safety. On the roads of coastal cities, particularly on seaside roads, JQ's SMC manhole covers are often seen.