The weight of these circular metal coverings found in streets and sidewalks varies considerably depending on their composition, size, and intended use. Typical examples range from lightweight covers for pedestrian areas weighing under 50 pounds to heavy-duty versions for high-traffic roads exceeding 250 pounds. Material choices like cast iron, ductile iron, or composite materials influence the final weight.
A standardized weight ensures the cover remains securely in place, preventing displacement by traffic or accidental removal. This safeguards pedestrians and vehicles from hazardous open manholes. Historically, heavier covers were primarily cast iron, but modern materials like ductile iron offer increased strength and durability at potentially lighter weights, improving safety and handling. The precise weight specifications are crucial for urban planning, infrastructure maintenance, and worker safety.