Manholes in plumbing systems must have what type of covers?

Manholes in plumbing systems require gas-tight covers to ensure safety and prevent the escape of harmful gases. A gas-tight cover is designed to prevent gases such as methane or sewer gas from leaking into the surrounding environment, which is crucial for protecting public health and maintaining air quality. These gases can be hazardous, and their containment is essential, particularly in systems that handle wastewater or sewage.

In addition to safety concerns, gas-tight covers can help reduce the risk of unpleasant odors and maintain the integrity of the plumbing system. This feature is especially important in urban settings where multiple infrastructures may be present.

In contrast, options like standard plastic or open covers do not provide the necessary sealing needed to contain gases, while aluminum covers, although durable, may not offer the gas-tight properties required for such environments. Therefore, gas-tight covers are the appropriate choice for manholes in plumbing systems due to their effective containment of potentially harmful gases.